Search

Abstract Background The current understanding of climate anxiety among adolescents is sparse. This study identifies the characteristics of adolescents living in Quebec (Canada) who experience impairments induced by climate anxiety, who have feelings of self-efficacy and who adopt pro-environment behaviors. It also characterizes the association between climate anxiety, feelings of self-efficacy, and environmental actions. Methods We used a cross-sectional design to analyze data from the COMPASS study on adolescent health. Participants (n = 45 362) from 113 schools in Quebec (Canada) answered questions about climate anxiety, self-efficacy, behavioral engagement, and several indicators of well-being. Data were analyzed using ordered logistic regressions adjusted for potential confounders (age, gender, school type, material deprivation, etc.). Results 9% of adolescents reported that thinking about climate change made it difficult to sleep at least sometimes. 6% of adolescents reported that thinking about climate change interfered with their ability to get work or assignments done at least sometimes. Only 34% believed they could do something to address the problem, and 43% tried to reduce their behaviors that contribute to climate change at least sometimes. Adolescents who were boys or who were less anxious experienced less impairment and were less involved in the fight against climate change. Adolescents from less affluent families experienced more difficulty sleeping and interference with work but were not more engaged. Those with stronger school connectedness experienced less impairment and were more often involved in the fight against climate change. Adolescents who felt they could do something about climate change were more likely to try to reduce behaviors that contribute to climate change. Conclusion The findings are useful to identify and support vulnerable groups that are more likely to experience impairment due to climate anxiety. The feeling of climate self-efficacy was not well developed among some groups of adolescents. Improving adolescents’ beliefs in their capacity to help address climate change may be a key strategy to promote pro-environmental actions. As the threat of climate change increases, it will be important to follow the evolution of climate anxiety and engagement among adolescents.

Abstract Background Several recent global events may have impacted adolescent sleep and exacerbated pre-existing disparities by social positions (i.e., social roles, identity or sociodemographic factors, and/or group memberships that are associated with power and oppression due to the structures and processes in a given society at given time). Current understanding of sleep among adolescents is critical to inform interventions for a more equitable future, given the short and long-term consequences of inadequate sleep on health and well-being. This study aimed to provide contemporary evidence on sleep disparities by key social positions among adolescents in Canada. Methods Cross-sectional analyses were conducted using self-reported data collected during 2020–2021 (the first full school year after the COVID-19 pandemic onset) from 52,138 students (mean [SD] age = 14.9 [1.5]) attending 133 Canadian secondary schools. Multiple regression models were used to test whether sleep quality (how well students slept during past week), duration (weekday, weekend, weighted daily average), and guideline adherence (8–10 h/day) differed by sex and gender, race and ethnicity, and socioeconomic status (SES). Results Females reported a mean [95% CI] difference of -1.7 [-3.7, 0.4] min/day less sleep on weekdays than males, but 7.1 [4.5, 9.6] min/day more sleep on weekends, resulting in no difference in average daily sleep between males and females. Females were less likely to report good quality sleep compared to males (AOR = 0.57 [0.54, 0.60]). SES followed a generally monotonic trend where higher scores were associated with more sleep on weekdays (Δhighest: lowest = -28.6 [-39.5, -17.6]) and weekends (Δhighest: lowest = -17.5 [-3.8, -31.2]) and greater likelihood of higher sleep quality (AORhighest: lowest = 3.04 [2.35, 3.92]). Relative to White adolescents, weekday and average daily sleep duration were lower among all other racial identities; mean differences ranged from ∼ 5–15 min/day, with Black students reporting the least sleep. Conclusions Differences in sleep duration and quality were most profound among adolescents from the lowest and highest SES. Racial disparities were more evident on weekdays. Compensatory weekend sleep appears more pronounced in females than males. Addressing sleep inequities is critical, as a robust predictor of multiple health outcomes.

IntroductionResearch characterizing substance use disparities between gender minority youth (GMY) and non-GMY (i.e. girls and boys) is limited. The aim of this study was to examine the differences in substance use behaviours among gender identity (GI) groups and identify associated risk and protective factors. MethodsCross-sectional data from Canadian secondary school students (n = 42 107) that participated in Year 8 (2019/20) or Year 9 (2020/21) of the COMPASS study were used. Hierarchal logistic regression models estimated current substance use (cigarettes, e-cigarettes, binge drinking, cannabis and nonmedical prescription opioids [NMPOs]). Predictor variables included sociodemographics, other substances, mental health outcomes, school connectedness, bullying and happy home life. Interaction terms were used to test mental health measures as moderators in the association between GI and substance use. ResultsCompared to non-GMY, GMY reported a higher prevalence for all substance use outcomes. In the adjusted analyses, GMY had higher odds of cigarette, cannabis and NMPO use and lower odds for e-cigarette use relative to non-GMY. The likelihood of using any given substance was higher among individuals who were involved with other substances. School connectedness and happy home life had a protective effect for all substances except binge drinking. Bullying victimization was associated with greater odds of cigarette, e-cigarette use and NMPOs. Significant interactions between GI and all mental health measures were detected. ConclusionFindings highlight the importance of collecting a GI measure in youth population surveys and prioritizing GMY in substance use–related prevention, treatment and harm reduction programs. Future studies should investigate the effects of GI status on substance use onset and progression among Canadian adolescents over time.

IntroductionLes travaux de recherche caractérisant les disparités en matière de consommation de substances entre les jeunes faisant partie de minorités de genre et les jeunes ne faisant pas partie de minorités de genre, c’est-à-dire les filles et les garçons, sont limités. L’objectif de cette étude était d’explorer les différences dans les comportements liés à la consommation de substances entre groupes d’identité de genre et de déterminer les facteurs de risque et les facteurs de protection correspondants. MéthodologieNous avons utilisé les données transversales associées aux élèves canadiens du secondaire (n = 42 107) qui avaient participé à l’année 8 (2019-2020) ou à l’année 9 (2020-2021) de l’étude COMPASS. Des modèles de régression logistique hiérarchiques nous ont permis d’estimer la consommation de substances (cigarettes, cigarettes électroniques, consommation excessive d’alcool, cannabis et opioïdes à des fins non médicales). Les variables prédictives comprenaient les caractéristiques sociodémographiques, la consommation d’autres substances, les résultats en matière de santé mentale, les liens avec l’école, l’intimidation et une vie familiale heureuse. Nous avons utilisé des termes d’interaction pour tester les mesures de la santé mentale en tant que modérateurs de l’association entre l’identité de genre et la consommation de substances. RésultatsComparativement aux jeunes ne faisant pas partie de minorités de genre, les jeunes faisant partie de minorités de genre avaient une prévalence plus élevée pour tous les résultats liés à la consommation de substances. Dans les analyses ajustées, les jeunes faisant partie de minorités de genre avaient une probabilité plus élevée de fumer des cigarettes, de consommer du cannabis et d’utiliser des opioïdes à des fins non médicales et une probabilité plus faible d’utiliser des cigarettes électroniques par rapport aux autres jeunes. La probabilité de consommer une substance donnée était plus élevée chez ceux qui consommaient d’autres substances. La connexion à l’école et une vie familiale heureuse avaient un effet protecteur contre toutes les substances, sauf la consommation excessive d’alcool. La victimisation par intimidation était associée à une plus grande probabilité d’usage de cigarettes, de cigarettes électroniques et d’opioïdes à des fins non médicales. Nous avons observé des interactions statistiquement significatives entre l’identité de genre et l’ensemble des mesures de la santé mentale. ConclusionNos constatations soulignent l’importance de recueillir une mesure de l’identité de genre dans les enquêtes sur les jeunes et de prioriser les jeunes faisant partie de minorités de genre dans les programmes de prévention, de traitement et de réduction des méfaits liés à la consommation de substances. Les études ultérieures devraient porter sur les effets de l’identité de genre sur le début et l’évolution de la consommation de substances chez les adolescents canadiens au fil du temps.

Abstract Background Physical activity behaviours are known to be highly correlated. Adolescents who participate in one type of physical activity (e.g., physical education) have a greater likelihood of participating in other physical activities (e.g., organized sports); however, little research has examined participation rates in various physical activity behaviours concurrently. This study identified longitudinal physical activity profiles among secondary school aged youth in Ontario, Canada. Methods We used data from the COMPASS Study, a school-based prospective cohort study of adolescents in Canada. Using a repeated measures latent class analysis, Ontario students who participated in grade 9 PE in 2015-16 were analysed through to 2018-19 (n = 1,917). Latent classes were defined by: PE participation, guideline adherence (≥ 60 min/day of moderate to vigorous activity over the last 7 days), and sport participation (varsity, community, and/or intramural). Multinomial logistic regression models were used to examine associations between latent class membership and student characteristics. Results Three distinct latent classes were identified for females and four were identified for males. These classes were: (1) Guidelines (high probability of guideline adherence; females: 44%; males: 16%), (2) PE & Sports (high probability of PE and sport participation; females: 33%; males: 43%), (3) Guidelines & Sports (high probability of guideline adherence and sport participation; females: 23%; males: 23%;), and (4) Inactive (low probability of all physical activity indicators; males: 18%). Strength training, sleep, and English grade were associated with class membership among females. Ethno-racial identity, weekly spending money, strength training, and English and math grades were associated with class membership among males. Conclusions Findings suggest that latent physical activity profiles differ by sex. Guideline adherence was the most common class among females, indicating high levels of independent physical activity, whereas PE & Sport participation was the most common class among males, indicating greater tendency towards organized activities. Additionally, a substantial number of male students were not engaging in any physical activity. Participation in both PE and sports did not necessarily lead to meeting physical activity guidelines, highlighting that these activities alone may not be providing sufficient levels of physical activity that align with current recommendations for Canadian youth.

IntroductionThe COVID-19 pandemic intensified the impact of risk factors for adolescent mental health, including financial worry. Social support has shown to protect from negative mental health during times of stress. We examined the effect of financial worry on changes in anxiety and depression symptoms among Canadian adolescents prior to and during the pandemic, and assessed whether social support from family and friends moderated any changes. MethodsWe analyzed 2-year linked data from the 2018/19 (pre-pandemic) and 2020/21 (during-pandemic) waves of the COMPASS study, with reports from 12 995 Canadian secondary school students. A series of multilevel linear regressions were conducted to examine the main hypotheses under study. ResultsStudents scored an average (SD) of 7.2 (5.8) on the anxiety (GAD-7) and 10.0 (6.5) on the depression (CESD-10) scales; 16.1% reported they experienced financial worry during the pandemic. Financial worry was a strong and significant predictor of increased anxiety scores (+1.7 score between those reporting “true/mostly true” versus “false/mostly false”) during the pandemic, but not for depression scores. Low family and friend support were associated with anxiety, and low family support was associated with depression. No significant interactions were detected between social support and financial worry. ConclusionPandemic-related financial worry was significantly associated with anxiety in our large sample of Canadian adolescents. Clinical and public health initiatives should be aware of adolescents’ financial worry and its associations with anxiety during times of crisis.

IntroductionLa pandémie de COVID-19 a intensifié les effets des facteurs de risque associés à la santé mentale des adolescents, en particulier les préoccupations financières. Par ailleurs, on sait que le soutien social offre une protection contre les problèmes de santé mentale pendant les périodes de stress. C’est dans ce cadre que nous avons exploré l’effet des préoccupations financières sur les variations des symptômes d’anxiété et de dépression chez les adolescents canadiens avant et pendant la pandémie, pour déterminer si le soutien social apporté par la famille et les amis modérait ces variations. MéthodologieNous avons analysé des données couplées sur deux ans provenant des vagues 2018-2019 (avant la pandémie) et 2020-2021 (pendant la pandémie) de l’étude COMPASS pour 12 995 élèves canadiens du secondaire. Nous avons réalisé une série de régressions linéaires multiniveaux pour explorer les principales hypothèses à l’étude. RésultatsLes élèves ont obtenu un score moyen de 7,2 (écart-type : 5,8) pour l’anxiété (échelle GAD-7) et de 10,0 (6,5) pour la dépression (échelle CESD-10), et 16,1 % des élèves ont déclaré avoir eu des préoccupations financières pendant la pandémie. Les préoccupations financières ont constitué un facteur de prédiction important et statistiquement significatif de scores d’anxiété plus élevés (+1,7 entre ceux qui ont répondu « vrai/le plus souvent vrai » et ceux qui ont répondu « faux/le plus souvent faux ») pendant la pandémie, mais non en ce qui concerne les scores de dépression. Il existe un lien entre un faible soutien de la part de la famille et des amis et l’anxiété ainsi qu’entre un faible soutien de la part de la famille et la dépression. Aucune interaction importante n’a été observée entre le soutien social et les préoccupations financières. ConclusionLes préoccupations financières liées à la pandémie ont été fortement associées à l’anxiété dans notre large échantillon d’adolescents canadiens. Les initiatives cliniques et sanitaires doivent tenir compte des préoccupations financières des adolescents et de leurs liens avec l’anxiété en période de crise.

Abstract Background To assess whether changes in breakfast and water consumption during the first full school year after the emergence of the COVID-19 pandemic varied based on sex/gender, race/ethnicity, and socioeconomic status among Canadian adolescents. Methods Prospective annual survey data collected pre- (October 2019-March 2020) and post-COVID-19 onset (November 2020-June 2021) the Cannabis, Obesity, Mental health, Physical activity, Alcohol, Smoking, and Sedentary behaviour (COMPASS) study. The sample consisted of 8,128 students; mean (SD) age = 14.2 (1.3) years from a convenience sample of 41 Canadian secondary schools. At both timepoints self-reported breakfast and water consumption were dichotomized as daily or not. Multivariable logistic generalized estimating equations with school clustering were used to estimate differences in maintenance/adoption of daily consumption post-COVID-19 based on demographic factors, while controlling for pre-COVID-19 behaviour. Results Adjusted odds ratios (AOR) with 95% confidence intervals are reported. Females (AOR = 0.71 [0.63, 0.79]) and lower socioeconomic status individuals (AORLowest:Highest=0.41 [0.16, 1.00]) were less likely to maintain/adopt daily breakfast consumption than male and higher socioeconomic status peers in the 2020–2021 school year. Black identifying individuals were less likely than all other racial/ethnic identities to maintain/adopt plain water consumption every day of the week (AOR = 0.33 [0.15, 0.75], p

IntroductionLes produits de tabac chauffé sont de nouveaux produits du tabac susceptibles d’attirer les jeunes. Cette étude visait à explorer, dans quatre provinces canadiennes, si la proximité et la densité des détaillants de produits de tabac chauffé autour des écoles secondaires étaient associées à une utilisation de ces produits chez les adolescents. MéthodologieUne recherche menée en ligne entre novembre 2020 et mars 2021 a permis de repérer les détaillants qui vendaient des dispositifs IQOS et des bâtonnets HEETS (conçus pour les dispositifs IQOS) dans des zones tampons circulaires de 500 m, 1 000 m et 1 500 m autour de 120 écoles secondaires ayant participé à l’étude COMPASS 2020-2021. Les données sur la proximité et la densité des détaillants ont été liées à des données transversales sur les élèves (N = 40 636), et des modèles de régression multiniveaux ont été utilisés pour explorer l’association entre, d’une part, la proximité et la densité des détaillants de produits de tabac chauffé et, d’autre part, l’utilisation de produits de tabac chauffé, après ajustement pour les covariables pertinentes. RésultatsSi seulement 10,0 % des écoles étaient situées à moins de 1 000 m d’au moins un détaillant vendant des dispositifs IQOS, 65,0 % d’entre elles étaient situées à proximité d’au moins un détaillant vendant des bâtonnets HEETS. L’école fréquentée par l’élève était responsable de 23,7 % de la variabilité de la probabilité d’utilisation de produits de tabac chauffé. Toutefois, la proximité et la densité des détaillants de produits de tabac chauffé autour des écoles n’ont présenté aucune association significative avec la probabilité d’utilisation de ces produits chez les élèves. ConclusionBien que l’école fréquentée par l’élève soit responsable d’une part importante de la variabilité de l’utilisation de produits de tabac chauffé, ces résultats laissent penser que les élèves pourraient obtenir des produits de tabac chauffé par des sources autres que les commerces de détail. Il faut continuer de surveiller la situation, car l’utilisation des produits de tabac chauffé chez les adolescents est susceptible d’évoluer.

IntroductionHeated tobacco products (HTPs) are novel tobacco products that may appeal to youth. This study explored whether HTP retailer proximity and density to secondary schools were associated with youth use of HTPs in four Canadian provinces. MethodsAn online search between November 2020 and March 2021 identified retailers selling IQOS devices and HEETS (tobacco sticks used in IQOS) within 500 m, 1000 m and 1500 m radius circular buffer zones around high schools (N = 120) participating in the COMPASS study in 2020–2021. Retailer proximity/density data were linked to crosssectional student-level data (N = 40 636 students), and multilevel regression models examined the association between HTP retailer proximity and density and current HTP use, controlling for relevant covariates. ResultsWhile only 10.0% of schools had at least one retailer selling IQOS devices within 1000 m of the school, 65.0% of schools had at least one retailer selling HEETS. The school a student attended accounted for 23.7% of the variability in the likelihood of currently using an HTP. However, HTP retailer proximity to and density around schools were not significantly associated with the likelihood of students currently using HTPs. ConclusionWhile the school a student attended accounted for a significant amount of variability in HTP use, these findings suggest that students may be obtaining HTPs through other, non-retail sources. Continued monitoring is warranted as HTP use among youth may change.

Abstract Background Very little research has examined how perceptions of cannabis access among underage youth in Canada have changed since cannabis was legalized and since the onset of the COVID-19 pandemic. As such, this paper examines the effect of the early and ongoing stages of the COVID-19 pandemic period on youth perceptions of cannabis access over time since the onset of the Cannabis Act in 2018 in a large sample of Canadian youth. Methods Using data from the COMPASS study (T1:2018/19, T2:2019/20, T3:2020/21), we used both repeat cross-sectional data [T1 (n = 38,890), T2 (n = 24,109), and T3 (n = 22,795)] to examine overall trends in perceptions of cannabis access, and sequential cohort longitudinal data [n = 4,677 students linked from T1 to T3] to examine the differential changes in perceptions of cannabis access among students over time. Results In the cross-sectional sample, the frequency of students reporting that cannabis was easy to access decreased by 26.7% from T1 (51.0%) to T3 (37.4%), although respondents who have used cannabis were more likely to report access was easy. In the longitudinal sample, perceptions of cannabis access being easy increased over time, especially among cannabis users. Perceived ease of access appears to have been slightly impeded during the initial pandemic period but rebounded during the ongoing pandemic period. Conclusions While the prevalence of youth reporting that cannabis is easy to access has declined since legalization and throughout the early and ongoing pandemic periods, a substantial number of underage youth continue to report that cannabis is easy to access. This suggest that there is an ongoing need for continued cannabis control efforts to address this issue.

IntroductionSelon la théorie de l’élargissement et de la construction des émotions positives, les émotions positives contribuent à élargir les pensées et les comportements des individus, ce qui se traduit par une accumulation de ressources (comme la résilience) qui catalysent des spirales ascendantes de bien-être. Or il y a pénurie relative de travaux portant sur cette hypothèse de spirales ascendantes dans le contexte de l’adolescence. MéthodologieDes adolescents (n = 4 064) d’écoles secondaires canadiennes ont été interrogés chaque année pendant trois ans dans le cadre de l’étude COMPASS. Les associations réciproques entre émotions positives et résilience ont été analysées comme prédicteurs de l’épanouissement. RésultatsLes adolescents qui ont connu des émotions positives plus fréquemment que d’habitude ont déclaré avoir des niveaux plus élevés de résilience un an plus tard. De même, les adolescents avec des niveaux plus élevés de résilience ont déclaré avoir davantage d’émotions positives l’année suivante. Les niveaux élevés de résilience et d’émotions positives ont prédit positivement l’épanouissement. ConclusionLes émotions positives entraînent une cascade de résultats bénéfiques, notamment une résilience et un bien-être accrus, ce qui catalyse une spirale ascendante vers l’épanouissement. Les opportunités d’accroître ces émotions positives au début de l’adolescence pourraient contribuer à la construction de ressources susceptibles de placer les élèves sur la voie d’un bien-être accru.

IntroductionThe broaden and build theory of positive emotions maintains that positive emotions serve to broaden individuals’ thoughts and behaviours, resulting in the accrual of resources (e.g. resilience) that catalyze upward spirals of well-being. However, there is a relative dearth of research examining the upward spiral hypothesis in the context of adolescence. MethodsAdolescents (n = 4064) in participating Canadian high schools were surveyed annually for three years as part of the COMPASS study. Reciprocal associations between positive emotions and resilience were examined as predictors of flourishing. ResultsAdolescents who experienced positive emotions more frequently than usual reported higher levels of resilience one year later. Similarly, adolescents who had higher levels of resilience than usual reported more positive emotions the following year. Higher than usual levels of resilience and positive emotions positively predicted flourishing. ConclusionPositive emotions result in a cascade of beneficial outcomes including increased resilience and enhanced well-being, catalyzing an upward spiral towards flourishing. Opportunities to enhance positive emotions early on in adolescence may help build resources that can set students on the path towards increased well-being.

Background: Income inequality is a structural determinant of health linked to increased risk of overweight and obesity, although its links to the health of adolescent populations are not well understood. This study investigated the longitudinal associations between census-division-level (CD) income inequality and BMI trajectories among Canadian adolescents, and determine if these associations vary by gender. Methods: Study data are from the Cannabis use, Obesity, Mental health, Physical Activity, Alcohol use, Smoking, and Sedentary behaviour (COMPASS) cohort of adolescents attending secondary schools in Canada. Our sample included 14,675 adolescents who were followed up across three waves of the COMPASS study (2016–2017, 2017–2018, and 2018–2019) and linked to 30 CDs. Measures of income inequality and other area-level covariates were derived and linked to COMPASS participants using data from the 2016 Canadian Census. We utilized multilevel mixed-effects linear regression modelling to quantify the associations between income inequality and BMI and test for effect modification by gender. Sensitivity analyses were run excluding those with BMI scores in the range considered overweight or obesity at baseline. Results: Higher CD income inequality was significantly associated with higher z-transformed BMI scores (β = 0.11, 95% CI = 0.034 to 0.19). The interaction term between income inequality and time was not statistically significant, indicating that this association remained constant over time. Once stratified by gender, the association between inequality and BMI became stronger for males (β = 0.14, 95% CI = 0.060 to 0.022) and attenuated for females (β = 0.063, 95% CI = −0.047 to 0.17). Conclusion: Attending schools in CDs with higher income inequality was associated with higher BMI scores among male but not female adolescents. Further work is needed to investigate this discrepancy and identify the structural mechanisms that mediate the relationship between inequality and adolescent health.

Introduction Research suggests that there is often a high degree of missingness in youth body mass index (BMI) data derived from self-reported measures, which may have a large effect on research findings. The first step in handling missing data is to examine the levels and patterns of missingness. However, previous studies examiningyouth BMI missingness used logistic regression, which is limited in its ability to discern subgroups or identify a hierarchy of importance for variables, aspects that may go a long way in helping understand missing data patterns. Methods This study used sex-stratified classification and regression tree (CART) models to examine missingness in height, body mass and BMI data among 74 501 youth participating in the 2018/19 COMPASS study (a prospective cohort study examining health behaviours among Canadian youth), where 31% of BMI data were missing. Diet, movement, academic, mental health and substance use variables were examined for associations with missingness in height, body mass and BMI. Results CART models indicated that the combination of being younger, having a selfperception of being overweight, being less physically active and having poorer mental health yielded female and male subgroups highly likely to be missing BMI values. Survey respondents who did not perceive themselves as overweight and who were older were unlikely to be missing BMI values. ConclusionThe subgroups identified by the CART models indicate that a sample that deletes cases with missing BMI would be biased towards physically, emotionally and mentally healthier youth. Given the ability of CART models to identify these subgroups and a hierarchy of variable importance, they are an invaluable tool for examining missing data patterns and appropriate handling of missing data.

IntroductionLes données issues de mesures de l’indice de masse corporelle (IMC) autodéclarées par les jeunes comportent souvent de graves lacunes, ce qui peut avoir un effet important sur les résultats des recherches les utilisant. La première étape du traitementdes données manquantes consiste à étudier leur niveau et leur structuration. Or les études antérieures qui ont analysé les données manquantes sur l’IMC chez les jeunes ont utilisé une régression logistique, une approche limitée dans sa capacité à discerner des sous-groupes ou à obtenir une hiérarchie dans l’importance des variables, des dimensions pourtant susceptibles de contribuer grandement à la compréhension de la structuration des données manquantes. MethodsCette étude a utilisé des modèles d’arbre de classification et de régression (CART, pour classification and regression tree) stratifiés selon le sexe pour analyser les données manquantes sur la taille, la masse corporelle et l’IMC chez 74 501 jeunes participant à l’étude COMPASS 2018-2019 (une étude de cohorte prospective qui a porté sur les comportements de santé des jeunes canadiens), dans laquelle 31 % des données sur l’IMC étaient manquantes. Des variables telles que le régime alimentaire, le mouvement, les résultats scolaires, la santé mentale et l’utilisation de substances ont été étudiées afin de vérifier leurs associations avec les données manquantes sur la taille, la masse corporelle et l’IMC. ResultsD’après les modèles CART, le fait d’être à la fois plus jeune, de se sentir en surpoids, d’être moins actif physiquement et d’avoir une santé mentale moins bonne a produit des sous-groupes de filles et de garçons où il était très probable que des valeurs d’IMC soient manquantes. Les données manquantes sur l’IMC étaient moins probables chez les répondants de l’enquête plus âgés et ne se sentant pas en surpoids. ConclusionSi l’on se fie aux sous-groupes produits par les modèles CART, utiliser un échantillon au sein duquel les cas dont la valeur de l’IMC est manquante ont été supprimés conduirait à tenir davantage compte des jeunes en meilleure santé sur les plans physique, émotionnel et mental. Étant donné que les modèles CART sont aptes à discerner ces sous-groupes ainsi qu’à établir une hiérarchie dans l’importance des variables, ils constituent un outil précieux pour étudier la structuration des données manquantes et la manière appropriée de gérer ces dernières.

Abstract Background Unhealthy lifestyle behaviours are becoming increasingly common and might contribute to the growing burden of mental disorders in adolescence. We examined the associations between a comprehensive set of lifestyle behaviours and depression and anxiety in middle adolescents. Methods School-based survey responses were collected from 24,274 Canadian high school students at baseline and 1-year follow-up (average age 14.8 and 15.8 years, respectively). Using linear mixed-effects models, we examined prospective associations of adherence to recommendations for vegetables and fruit, grains, milk and alternatives, meat and alternatives, sugar-sweetened beverages [SSB], physical activity, screen time, sleep, and no use of tobacco, e-cigarettes, cannabis, and binge drinking at baseline with the depressive and anxiety symptoms (measured by CESD-R-10 and GAD-7 scales, respectively) at follow-up. Results Adherence to recommendations was low overall, particularly for vegetables and fruit (3.9%), grains (4.5%), and screen time (4.9%). Students adhering to individual recommendations, particularly for meat and alternatives, SSB, screen time, sleep, and no cannabis use, at baseline had lower CESD-R-10 and GAD-7 scores at follow-up. Adhering to every additional recommendation was associated with lower CESD-R-10 (β=-0.15, 95% CI -0.18, -0.11) and GAD-7 scores (β=-0.10, 95% CI -0.14, -0.07) at follow-up. Assuming cumulative impact, this might translate into 7.2- and 4.8-point lower CESD-R-10 and GAD-7 scores, respectively, among students adhering to 12 vs. 0 recommendations over four years of high school. Conclusions The results highlight the preventive potential of population-based approaches promoting healthy lifestyle behaviours, particularly those with the lowest prevalence, as a strategy to improve mental health in adolescence.

Loneliness, a feeling of distress, has aggravated due to the COVID-19 pandemic lockdowns and reduced social interactions. The objective of this study was to explore whether increased loneliness due to the COVID-19 pandemic was associated with various health behaviours in adolescence, a critical period for the development of lasting lifestyle habits. We used self-reported data from 40,521 Canadian adolescents aged 12–19 years (collected between November 2020 and June 2021) for this cross-sectional study. Logistic regression was used to predict the odds of skipping breakfast and not meeting movement behaviour guidelines [moderate-to-vigorous physical activity (≥60 min/day), recreational screen time (≤2 h/day), sleep duration (≥8 h/day)] among adolescents with increased loneliness due to the COVID-19 pandemic. We found higher odds of skipping breakfast [boys: OR 1.40 (95% CI: 1.32, 1.49), girls: OR 1.62 (95% CI: 1.53, 1.71)], exceeding screen time guidelines [boys: OR 1.43 (95% CI: 1.24, 1.66), girls: OR 1.72 (95% CI: 1.54, 1.92)], and insufficient sleep duration [boys: OR 1.38 (95% CI: 1.28, 1.48), girls: OR 1.36 (95% CI: 1.27, 1.45)] in adolescents with increased loneliness (versus decreased/stayed the same loneliness group). However, we found clinically insignificant results with moderate-to-vigorous physical activity. Future longitudinal studies in adolescents are needed to confirm the directionality of these associations. Recovery efforts are needed to support adolescent social health and establish healthy behavioural habits across the lifespan.

Purpose: The purpose of this study was to assess if adolescent sub-populations in Canada (i.e., based on race/ethnicity, sex/gender, socioeconomic status, and urbanicity groups) experienced a larger change in sleep duration and guideline adherence between 2019 and 2020 (pre-pandemic) and the 2020–2021 (mid-pandemic) school years. Methods: Longitudinally linked data from 2019 to 2020 (pre-pandemic) and 2020–2021 (mid-pandemic) of a prospective cohort study of secondary school students (M = 14.2, SD = 1.3 years, N = 8209) in Canada were used for analyses. Regression modelling tested the main effects of race/ethnicity, sex/gender, socioeconomic status, and urbanicity on changes in sleep duration as well as adherence to Canada's 24-h Movement Guidelines for sleep (8–10 h/night). Interactions between identity variables (race/ethnicity or sex/gender) and other main effect variables were subsequently tested. Results: Females gained more sleep (4.5 [1.5, 7.5] min/day more) and increased guideline adherence (AOR = 1.16 [1.04, 1.30] than males on average. Asian race/ethnic identity was associated with less sleep gain than White identity −10.1 [-19.4, −0.8], but not guideline adherence. Individuals in large urban areas gained less sleep and adhered less to guidelines than individuals from any other level of urbanicity (−21.4 [-38.5, −4.2] to −15.5 [-30.7, −0.2] min/day). Higher individual SES scores were associated with greater sleep gain (linear trend: 11.16 [1.2–21.1]). The discrepancies in sleep gain and guideline adherence between males and females were significantly modified by race/ethnicity and urbanicity. Discussion: Increases in sleep duration may be one of the few benefits to adolescents during the COVID-19 pandemic but were not equally distributed across sub-populations. Efforts to promote better sleep adherence may need to account for sex/gender differences, especially in less urbanized areas and certain racial/ethnic groups.

IntroductionIn population health surveillance research, survey data are commonly analyzed using regression methods; however, these methods have limited ability to examine complex relationships. In contrast, decision tree models are ideally suited for segmenting populations and examining complex interactions among factors, and their use within health research is growing. This article provides a methodological overview of decision trees and their application to youth mental health survey data. MethodsThe performance of two popular decision tree techniques, the classification and regression tree (CART) and conditional inference tree (CTREE) techniques, is compared to traditional linear and logistic regression models through an application to youth mental health outcomes in the COMPASS study. Data were collected from 74 501 students across 136 schools in Canada. Anxiety, depression and psychosocial well-being outcomes were measured along with 23 sociodemographic and health behaviour predictors. Model performance was assessed using measures of prediction accuracy, parsimony and relative variable importance. ResultsDecision tree and regression models consistently identified the same sets of most important predictors for each outcome, indicating a general level of agreement between methods. Tree models had lower prediction accuracy but were more parsimonious and placed greater relative importance on key differentiating factors. ConclusionDecision trees provide a means of identifying high-risk subgroups to whom prevention and intervention efforts can be targeted, making them a useful tool to address research questions that cannot be answered by traditional regression methods.

IntroductionDans la recherche en surveillance de la santé de la population, les données d’enquête sont couramment analysées à l’aide de méthodes de régression. Or ces méthodes disposent d’une capacité limitée à analyser les relations complexes. À l’opposé, les modèles d’arbres décisionnels sont parfaitement adaptés pour segmenter les populations et étudier les interactions complexes entre facteurs, et leur utilisation dans la recherche en santé est en pleine croissance. Cet article fournit un aperçu de la méthodologie des arbres décisionnels et de leur application aux données d’enquête sur la santé mentale des jeunes. MethodsLa performance de deux techniques courantes de construction d’arbres décisionnels, soit l’arbre de classification et de régression (CART) et l’arbre d’inférence conditionnelle (CTREE), est comparée aux modèles classiques de régression linéaire et logistique par le biais d’une application aux résultats en santé mentale des jeunes de l’étude COMPASS. Les données ont été recueillies auprès de 74 501 élèves de 136 écoles au Canada. L’anxiété, la dépression et le bien‑être psychologique ont été mesurés, de même que 23 variables sociodémographiques et facteurs de prédiction des comportements liés à la santé. La performance du modèle a été évaluée au moyen de mesures de prédiction de l’exactitude, de la parcimonie et de l’importance relative des variables. ResultsLes modèles d’arbres décisionnels et les modèles de régression ont systématiquement mis en évidence les mêmes ensembles de facteurs de prédiction les plus importants pour chaque résultat, ce qui indique un niveau général de concordance entre méthodes. Trois modèles ont présenté une exactitude prédictive plus faible, mais se caractérisent par une plus grande parcimonie et accordent une importance relative plus élevée aux principaux facteurs de différenciation. ConclusionLes arbres décisionnels permettent de cerner les sous-groupes à risque élevé qu’il convient de cibler dans le cadre des efforts de prévention et d’intervention. Ils constituent donc un outil utile pour répondre aux questions de recherche auxquelles les méthodes de régression classiques ne peuvent pas répondre.

Abstract Background The impact of the COVID-19 pandemic and consequent public health restrictions on the mental health of adolescents is of global concern. The purpose of this study was to examine how Canadian adolescents coped during the early pandemic and whether different coping methods were associated with changes in mental health from before the pandemic to the early lockdown response. Methods Using two-year linked survey data (2018–2020) from a prospective cohort of secondary school students (n = 3,577), linear regression models were used to examine whether changes in mental health (anxiety [Generalized Anxiety Disorder-7 scale], depression [Center for Epidemiologic Studies Depression 10-item scale Revised], emotion regulation [Difficulties in Emotion Regulation Scale], psychosocial well-being [Flourishing scale]) were related to each coping behaviour. Results The most common reported coping behaviours included staying connected with friends online (78.8%), playing video games, watching TV/movies, and/or surfing the internet/social media (76.2%), studying or working on schoolwork (71.0%), and getting exercise (65.2%). The use of positive coping mechanisms during the early pandemic period (e.g., keeping a regular schedule, time with family, time with friends online) was associated with less adverse mental health changes from before to during the early lockdown; whereas, negative coping mechanisms (e.g., spending time alone, eating junk food) were consistently associated with more adverse mental health changes. Conclusion This study demonstrates the importance of social support and connections with both friends and family, as well as keeping and maintaining a routine, over the pandemic. Interventions supporting positive relationships and engagement in these coping behaviours may be protective for adolescent mental health during disruptive events.

IntroductionAs a largely social behaviour, substance use may have decreased for some youth overall in Canada during the COVID-19 pandemic; however, continued use may indicate nonadherence to pandemic-related restrictions and social distancing measures. In a sample of Canadian adolescents (aged 12–19 years), our objective was to examine how substance use (cannabis, binge drinking, cigarettes, vaping) is associated with perceptions of, and adherence to, early COVID-19-related public health measures, taking into consideration sociodemographic factors. MethodsCross-sectional data were retrieved from online data collected during Year 8 of the COMPASS school-based study, during the early months of the COVID-19 pandemic (May–July 2020) in British Columbia, Ontario and Quebec. We fitted two models using generalized estimating equations to examine how substance use was associated with separate measures of (1) perceptions of, and (2) adherence to early COVID-19 restrictions. ResultsIn our sample, 10% of adolescents perceived COVID-19 restrictions as too weak and 14% perceived them as too strict. Nearly half (46%) reported taking restrictions very seriously, and 5% did not take them seriously at all. Binge drinking, cigarette use and vaping were associated with perceptions that restrictions were too strict and with nonadherence. However, adolescents who used cannabis were less likely to perceive COVID-19-related restrictions as too strict. ConclusionThis study highlights the association of adolescent substance use with perceptions of, and adherence to, COVID-19-related public health restrictions in Canada. Our findings emphasize a need for continual monitoring of substance use behaviours during the COVID-19 pandemic to better characterize adolescent risk and further inform targeted public health strategies accordingly.

IntroductionDans la mesure où la consommation de substances est un comportement principalement social, elle est susceptible d’avoir diminué chez certains jeunes partout au Canada pendant la pandémie de COVID-19, et le maintien d’une consommation est susceptible d’indiquer un non-respect des restrictions liées à la pandémie et des mesures de distanciation physique. Notre objectif était d’analyser, dans un échantillon composé d’adolescents canadiens (de 12 à 19 ans), la manière dont la consommation de substances (cannabis, consommation excessive d’alcool, cigarettes, produits de vapotage) est associée aux perceptions et au respect des premières mesures de santé publique liées à la COVID-19, en tenant compte de facteurs sociodémographiques. MéthodologieDes données transversales ont été extraites des données en ligne recueillies au cours de la huitième année de l’étude réalisée en milieu scolaire COMPASS, pendant les premiers mois de la pandémie de COVID-19 (mai à juillet 2020) en Colombie-Britannique, en Ontario et au Québec. Nous avons ajusté deux modèles à l’aide d’équations d’estimation généralisées afin d’analyser la manière dont la consommation de substances était associée à deux mesures : celle des perceptions à l’égard des premières restrictions liées à la COVID-19 et celle du respect de ces restrictions. RésultatsDans notre échantillon, 10 % des adolescents ont perçu les restrictions liées à la COVID-19 comme étant trop faibles et 14 % les ont perçues comme étant trop strictes. Près de la moitié (46 %) des répondants ont déclaré avoir pris les restrictions très au sérieux, et 5 % ne les ont aucunement prises au sérieux. La consommation excessive d’alcool (« binge drinking »), l’usage de la cigarette et le vapotage ont été associés à des perceptions selon lesquelles les restrictions étaient trop strictes et au non-respect de ces restrictions. Toutefois, les adolescents consommant du cannabis étaient moins susceptibles de percevoir les restrictions liées à la COVID-19 comme trop strictes. ConclusionCette étude fait ressortir le lien entre la consommation de substances chez les adolescents et leurs perceptions et leur respect à l’égard des restrictions de santé publique liées à la COVID-19 au Canada. Nos constatations mettent en évidence la nécessité d’assurer une surveillance continue des comportements de consommation de substances pendant la pandémie de COVID-19 afin de mieux caractériser les risques à l’adolescence et de guider en conséquence les stratégies de santé publique ciblées.

IntroductionCanadian youth are insufficiently active, and schools may play a role in promoting student physical activity (PA). Based on the Comprehensive School Health (CSH) framework, this study examined whether school characteristics are associated with secondary school students meeting national PA recommendations over time. MethodsWe used COMPASS survey data from 78 schools in Ontario and Alberta and 9870 Grade 9 and 10 students attending those schools. Students who provided two years of linked PA data (2013/14 and 2015/16) and gender were included. Multilevel analysis was conducted by gender, evaluating the relationship of school-level characteristics (guided by CSH) with students achieving all three PA recommendations after two years (≥ 60 min/day of moderate-to-vigorous PA, vigorous PA ≥ 3 days/week, strengthening activities ≥ 3 days/week). ResultsMore than half (56.9%) of students achieving the PA recommendations at baseline were no longer achieving them after two years, and just a quarter (25.6%) of students not achieving the recommendations at baseline achieved them after two years. School-level factors were significantly associated with students achieving the recommendations, but these factors differed by student strata (i.e. by gender and baseline PA status). Generally, student access to equipment, public health partnerships and staff time for health were associated with increased odds of achieving the PA recommendations for certain students. ConclusionModifications to school characteristics within CSH may play a role in supporting students in achieving or continuing to achieve the PA recommendations after two years. Further research is needed to better understand the underlying dynamics of the observed relationships.

IntroductionLes adolescents canadiens ne sont pas suffisamment actifs, mais les écoles peuvent participer à la promotion de l'activité physique auprès des élèves. Cette étude, qui s'appuie sur l'Approche globale de la santé en milieu scolaire (AGSMS), visait à vérifier si certaines caractéristiques des écoles étaient associées à la mise en pratique des recommandations nationales en matière d'activité physique par les élèves de niveau secondaire au fil du temps. MéthodologieNous avons utilisé les données de l'étude COMPASS visant 78 écoles de l'Ontario et de l'Alberta et 9 870 élèves de 9e et de 10e année fréquentant ces écoles. Les élèves ayant fourni des données couplées sur leur activité physique durant deux années scolaires (2013‑2014 et 2015‑2016) et sur leur genre ont été retenus. Une analyse multiniveaux a été réalisée par genre dans le but d'évaluer la relation entre les caractéristiques des écoles (classées selon l'AGSMS) et la mise en pratique des trois recommandations en matière d'activité physique (60 min/jour ou plus d'activité physique d'intensité moyenne à élevée, activité physique d'intensité élevée 3 jours/semaine ou plus, activité de renforcement 3 jours/semaine ou plus) deux ans plus tard. RésultatsPlus de la moitié (56,9 %) des élèves respectant les recommandations en matière d'activité au départ ne les respectaient plus deux ans plus tard, et seulement le quart (25,6 %) des élèves ne les respectant pas au départ les avaient mises en pratique deux ans plus tard. Plusieurs facteurs liés à l'école ont été fortement associés à la mise en pratique des recommandations chez les élèves, mais ils étaient variables d'un groupe à l'autre (selon le genre et le niveau initial d'activité physique). De façon générale, l'accès à de l'équipement, les partenariats de santé publique et l'allocation de temps au personnel pour la santé étaient associés à une probabilité accrue de mettre en pratique les recommandations en matière d'activité physique chez certains élèves. ConclusionLa modification des caractéristiques des écoles dans le cadre de l'AGSMS peut aider les élèves à mettre en pratique les recommandations en matière d'activité physique ou à ce qu'ils maintiennent ces recommandations deux ans plus tard. D'autres recherches sont nécessaires pour éclaircir la dynamique à l'origine des relations observées.

Chronic stress has become an epidemic with negative health risks including cardiovascular disease, hypertension, and diabetes. Traditional methods of stress measurement and monitoring typically relies on self-reporting. However, wearable smart technologies offer a novel strategy to continuously and non-invasively collect objective health data in the real-world. A novel electrocardiogram (ECG) feature has recently been introduced to the Apple Watch device. Interestingly, ECG data can be used to derive Heart Rate Variability (HRV) features commonly used in the identification of stress, suggesting that the Apple Watch ECG app could potentially be utilized as a simple, cost-effective, and minimally invasive tool to monitor individual stress levels. Here we collected ECG data using the Apple Watch from 36 health participants during their daily routines. Heart rate variability (HRV) features from the ECG were extracted and analyzed against self-reported stress questionnaires based on the DASS-21 questionnaire and a single-item LIKERT-type scale. Repeated measures ANOVA tests did not find any statistical significance. Spearman correlation found very weak correlations (p

BackgroundDespite increasing evidence that social media use is associated with adolescents’ mental well-being, little is known about the role of various factors in modifying the effect of this association during adolescence. This study examined the association between social media use and psychological distress among adolescents and explored whether sex, age, and parental support moderate this association.MethodsData came from a representative sample of middle and high school students in Ontario, Canada. Cross-sectional analyses included 6,822 students derived from the 2019 Ontario Student Drug Use and Health Survey.ResultsOur results showed that 48% of adolescents used social media for 3 h or more per day, and 43.7% had moderate to severe psychological distress, with a higher prevalence among females (54%) than males (31%). After adjustment for relevant covariates, heavy social media use (≥3 h/day) was associated with increased odds of severe psychological distress [odds ratio (OR): 2.01; 95% confidence interval (CI):1.59–2.55]. The association of social media use with psychological distress was modified by age (p

Abstract Background Youth voice has been largely absent from deliberations regarding public health measures intended to prevent SARS-CoV-2 transmission, despite being one of the populations most impacted by school-based policies. To inform public health strategies and messages, we examined the level of student support of mask use in public spaces and school mask requirements, as well as factors associated with students’ perspectives. Methods We used cross-sectional survey data from 42,767 adolescents attending 133 Canadian secondary schools that participated in the COMPASS study during the 2020/2021 school year. Multinomial regression models assessed support for i) wearing a mask in indoor public spaces and ii) schools requiring students to wear masks, in association with COVID-19 knowledge, concerns, and perceived risk. Results Wearing masks in indoor public spaces was supported by 81.9% of students; 8.7% were unsupportive and 9.4% were neutral/undecided. School mask requirements were supported by 67.8%, with 23.1% neutral and 9.1% unsupportive. More females supported mask wearing in public spaces (83.9% vs. 79.1%) and school mask requirements (70.8% vs. 63.5%) than males. Students had increased odds of supporting mask use in public spaces and school mask requirements if they reported concerns about their own or their family’s health, had discussions regarding ways to prevent infection, perceived COVID-19 to be a risk to young people, and knew that signs are not always present in COVID-19 cases and that masks prevent SARS-CoV-2 transmission if someone coughs. Conclusions During the year following the beginning of the pandemic, most students supported the required use of masks in schools and wearing masks in indoor public spaces. Improving knowledge around the effectiveness of masks appears likely to have the largest impact on mask support in adolescent populations among the factors studied.

BackgroundEvidence examining the longitudinal associations between different types of screen behaviours and mental health among adolescents is limited. The present study examined the association between five types of screen behaviours and symptoms of anxiety and depression one year later. This study also assessed how changes in screen time were associated with changes in anxiety and depressive symptoms and whether the observed relationships were moderated by sex.MethodsLongitudinal data of 17,174 students in grades 9–12 (53.5% females; mean age: 15.1 ± 0.9 years) attending high schools in Canada from two waves (year 6: 2017/18, year 7: 2018/19) of the COMPASS study were analyzed. Leisure screen time and mental health measures were self-reported. To test if the associations between screen time and anxiety, and depression vary by sex, two-way interactions were examined for sex. Analyses accounted for school clustering, race/ethnicity, sex, age, income, body mass index z-score, and previous year anxiety and depression symptoms.ResultsThere were significant longitudinal associations between time spent on each type of screen and subsequent anxiety and depression symptoms. The strength of the associations varied by type of screen behaviour. Interaction analysis indicated a sex difference for television viewing and anxiety and depression symptoms, and internet surfing and anxiety symptoms. A dose-response relationship was observed between phone talking and anxiety symptoms. Beta estimates indicated that an increase in screen duration was associated with a further increase in anxiety and depression symptoms.ConclusionHigher screen time was longitudinally associated with higher anxiety and depression symptoms at one-year follow-up in adolescents. Time-change associations between screen usage and depressive and anxiety symptoms were observed. Also, associations differed based on sex and screen type, whereby greater increases in screen use predicted greater emotional distress. Findings from this prospective analysis suggest that screen time is an important determinant of anxiety and depressive symptoms among adolescents. Future studies are recommended to help inform programs promoting screen time reduction with a goal to enhance adolescents’ mental health.

IntroductionLa présente étude avait pour objectifs d’explorer dans quelle mesure les adolescents ont adopté des mesures préventives contre la COVID-19 au cours des premiers mois de la pandémie et de comprendre leur adoption par l’examen de facteurs indépendants liés à l’adoption et par la détermination de la puissance de ces facteurs, en particulier parmi les sous-groupes qui ne sont pas censés être les premiers à adopter de telles mesures. MéthodesLes analyses portent sur des données recueillies au printemps 2020 auprès de 29 écoles secondaires de l’est du Québec qui ont participé à l’étude COMPASS. Les participants (n = 6 052) ont déclaré eux-mêmes leurs connaissances, leur perception du risque et les pratiques de prévention à adopter dans le contexte de la pandémie de COVID-19. Les données ont été analysées à l’aide de modèles d’équation structurelle fondés sur le sexe et le niveau d’anxiété. RésultatsLa majorité des répondants ont déclaré avoir adopté les mesures préventives recommandées contre la COVID-19. Les résultats ont montré trois voies menant à l’adoption de ces mesures par les adolescents : les connaissances sur la pandémie, la perception du risque lié à la COVID-19 et, en particulier, les discussions avec les proches au sujet des mesures préventives et de ce qu’il faut faire en cas d’infection. ConclusionMême si la plupart des participants adolescents à cette étude ont semblé se conformer aux mesures préventives contre la COVID-19, des facteurs comme les discussions avec les proches émergent en tant qu’éléments à favoriser pour améliorer l’adoption des mesures préventives par les adolescents.

Objectives: To examine associations between e-cigarette use, cigarette smoking, physical activity, and sedentary behaviour among a large sample of Canadian adolescents (Grades 9–12) by sex. Methods: Cross-sectional data from 55,629 students who participated in COMPASS Year 6 (2017–2018) were used. Exposures included e-cigarette use and cigarette smoking. Outcomes included meeting recommendations for moderate- to vigorous- physical activity (MVPA;≥60 min/d), muscular strengthening exercises (MSE;≥3 time/wk), and recreational screen time (ST;≤2 h/day) and participating in intramurals or competitive team sports. Logistic regressions were performed after adjusting for relevant covariates. Results: Male adolescents showed higher prevalence of e-cigarette use (40.0% vs 31.3%) and cigarette smoking (4.4% vs 2.9%) than females. Both males and females who used e-cigarettes were more likely to meet MVPA and MSE recommendations, but less likely to meet the ST recommendation than those who did not use e-cigarettes. E-cigarette use was also consistently associated with more sport participation in males, however, among females the results were mixed. Current cigarette use was associated with meeting the MVPA recommendation and less participation in intramurals in males; however, in females, current cigarette smoking was consistently associated with less participation in any sports. Former cigarette use was associated with participation in competitive team sport within school and meeting the MSE recommendation in females only. Conclusions: This study found that associations between e-cigarette use and cigarette smoking with physical activity, sedentary behaviour, and sport participation are largely gendered. Identifying differential co-occurrence of risk behaviours by gender is important for future health promotion efforts targeting physical activity among adolescents.

Stress is an increasingly prevalent mental health condition that can have serious effects on human health. The development of stress prediction tools would greatly benefit public health by allowing policy initiatives and early stress-reducing interventions. The advent of mobile health technologies including smartphones and smartwatches has made it possible to collect objective, real-time, and continuous health data. We sought to pilot the collection of heart rate variability data from the Apple Watch electrocardiograph (ECG) sensor and apply machine learning techniques to develop a stress prediction tool. Random Forest (RF) and Support Vector Machines (SVM) were used to model stress based on ECG measurements and stress questionnaire data collected from 33 study participants. Data were stratified into socio-demographic classes to further explore our prediction model. Overall, the RF model performed slightly better than SVM, with results having an accuracy within the low end of state-of-the-art. Our models showed specificity in their capacity to assess “no stress” states but were less successful at capturing “stress” states. Overall, the results presented here suggest that, with further development and refinement, Apple Watch ECG sensor data could be used to develop a stress prediction tool. A wearable device capable of continuous, real-time stress monitoring would enable individuals to respond early to changes in their mental health. Furthermore, large-scale data collection from such devices would inform public health initiatives and policies.

Summary: Background: Understanding what factors lead to youth polysubstance use (PSU) patterns and how the transitions between use patterns can inform the design and implementation of PSU prevention programs. We explore the dynamics of PSU patterns from a large cohort of Canadian secondary school students using machine learning techniques. Methods: We employed a multivariate latent Markov model (LMM) on COMPASS data, with a linked sample (N = 8824) of three-annual waves, Wave I (WI, 2016–17, as baseline), Wave II (WII, 2017–18), and Wave III (WIII, 2018–19). Substance use indicators, i.e., cigarette, e-cigarette, alcohol and marijuana, were self-reported and were categorized into never/occasional/current use. Outcomes: Four distinct use patterns were identified: no-use (S1), single-use of alcohol (S2), dual-use of e-cigarettes and alcohol (S3), and multi-use (S4). S1 had the highest prevalence (60.5%) at WI, however, S3 became the prominent use pattern (32.5%) by WIII. Most students remained in the same subgroup over time, particularly S4 had the highest transition probability (0.87) across the three-wave. With time, those who transitioned typically moved towards a higher use pattern, with the most and least likely transition occurring S2→S3 (0.45) and S3→S2 (

Background: Our objective was to explore associations between indicators of more risky cannabis use (i.e., solitary use, frequent use, and younger age of initiation) and different modes of cannabis use (i.e., smoking, vaping and/or edibles). Methods: Data were gathered from a large sample of Canadian youth in Alberta, British Columbia, Ontario, and Quebec who participated in Year 8 (2019–20) of the COMPASS study, and who reported using cannabis in the past year (n = 4,763). Generalized estimating equations were used to examine associations between risky cannabis use and modes of cannabis use, stratified by gender. Results: Overall, 38% of students reported using multiple modes of cannabis use. Consistent among both males and females, students who used cannabis alone (35%) and at a higher frequency (55%) were more likely to use multiple modes than smoking only. Among females, those who used cannabis alone were more likely to report using edibles only compared to smoking only (aOR=2.27, 95%CI=1.29–3.98). Earlier cannabis use initiation was associated with lower likelihood of vaping cannabis only among males (aOR=0.25; 95%CI = 0.12–0.51), and lower likelihood of using edibles only among females (aOR=0.35; 95%CI = 0.13–0.95), than by smoking only. Conclusions: Our findings suggest that multiple modes of use may be an important indicator or risky cannabis use among youth, given associations with frequency, solitary use, and age of onset.

Objectives: There are few studies describing longitudinal changes in vaping patterns among current youth e-cigarette users. The objective of this study was to identify-one-year changes in e-cigarette use patterns among a longitudinal sample of Canadian youth e-cigarette users between 2017/18 and 2018/19. Methods: The longitudinal sample included n = 4,071 current (past 30-day) e-cigarette users in grades 9–11 attending schools in four Canadian provinces. Students reported the number of days they used e-cigarettes in the past 30 days in 2017/18 and 2018/19. Based on responses, students could have escalated, reduced, stopped, or maintained their level of vaping. The prevalence of each e-cigarette use pattern was identified across demographic characteristics and regression models identified significant predictors of each use pattern. Results: Over one year, 49.2% of current youth e-cigarette users escalated, 12.8% reduced, 20.2% stopped, and 17.8% maintained their frequency of e-cigarette use. Baseline e-cigarette use frequencies varied according to use pattern. Current youth e-cigarette users with higher baseline vaping frequencies had lower odds of escalating and stopping e-cigarette use and higher odds of reducing e-cigarette use relative to maintaining the same frequency of use. Conclusions: While about half of current youth e-cigarette users increased their frequency of e-cigarette use over a 1-year period, a significant number also decreased or stopped vaping at a time when the prevalence of youth e-cigarette use increased rapidly in Canada. There is a need for longitudinal data to monitor and evaluate changes to e-cigarette use patterns that may be in response to changing public health policies.

Abstract Background Despite the benefits of physical activity (PA), the majority of Canadian youth are falling short of the recommended 60 min of moderate-to-vigorous physical activity (MVPA) per day. School-based physical activity programs such as intramurals, are important opportunities for youth to be physically active. There is limited evidence available on the impact of gender-specific (e.g., female-only, male-only) and co-ed intramurals on youth PA over time, however, evidence suggests female-only intramurals may be important for female MVPA. This research aims to capitalize on a natural experiment to generate practice-based evidence on the impact of changes in gender-specific and co-ed intramurals on youth MVPA over time. Methods This study used linked longitudinal school- and student-level data from Ontario secondary schools in year 5 (Y5:2016–2017), year 6 (Y6: 2017–2018) and year 7 (Y7: 2018–2019) of the COMPASS study. Data on intramurals from 55 schools were used to determine the changes to gender-specific and co-ed intramurals that occurred from Y5 to Y6. Baseline demographic characteristics were measured and data on PA and sport participation were collected in Y5, Y6 and Y7 on a sample of 4417 students. Hierarchical linear mixed regression models were used to estimate how changes in gender-specific and co-ed intramurals were associated with youth MVPA over time. Results Participation in intramural, varsity and community sport were all positively and significantly associated with youth MVPA. Changes in gender-specific and co-ed intramurals were not significantly associated with youth MVPA in Y6 or Y7. However, the positive association between maintaining the addition of gender-specific intramurals on female MVPA in Y7 was on par with the significance level of α = 0.05, suggesting that adding gender-specific intramurals may be important for female MVPA. Conclusions Adding gender-specific and co-ed intramurals may not be sufficient strategies to increase PA among youth. Further research should explore the effect of gender-specific intramurals on youth PA, as this study may have been underpowered at the school-level. Gender-specific intramurals may promote a supportive PA environment that promotes MVPA, especially among females. These intramurals may be an important component of more comprehensive strategies to increase youth MVPA.

Abstract Objective The aim of this research was to examine the bidirectional association between self-reported symptoms of mental disorder and physical activity among a large sample of Canadian secondary school students over time. Methods Linked survey data were obtained from 28,567 grade 9 to 12 students across Canada participating in two waves of the COMPASS Study (2017–18; 2018–19). Autoregressive cross-lagged models were run to examine the reciprocal relationships between self-reported moderate-to-vigorous physical activity (MVPA) and symptoms of depression (CESD-10) and anxiety (GAD-7). Models were stratified by gender, and accounted for grade, ethno-racial identity, and school-level clustering. Results Autoregressive associations show that neither symptoms of anxiety nor depression, at baseline, were predictive of mean MVPA at follow-up – consistent for the full sample and among both males and females. Higher MVPA among males at baseline was associated with lower symptoms of both anxiety (β = − 0.03, p = 0.002) and depression (β = − 0.05, p

IntroductionHaving a better understanding of individual factors associated with e-cigarette initiation can help improve prevention efforts. Therefore, this study aimed to (1) identify baseline characteristics associated with e-cigarette initiation, and (2) determine whether changes in these baseline characteristics were associated with e-cigarette initiation. MethodsThis study used data from Year 6 (2017/18, baseline) and Year 7 (2018/19, follow-up) of the COMPASS study. The final sample included 12 315 students in Grades 9 to 11 who reported never having tried e-cigarettes at baseline. Students reported demographic information, other substance use, school behaviours, physical activity, sedentary behaviour, sleep, symptoms of anxiety and depression, and emotional regulation and flourishing scores. Hierarchical GEE models, stratified by gender, examined the association between (1) baseline characteristics and e-cigarette initiation at follow-up and (2) changes in baseline characteristics and e-cigarette initiation at follow-up. ResultsIn total, 29% of students who had not yet initiated e-cigarette use reported initiating e-cigarette use at follow-up. Students in Grades 10 and 11 were less likely to initiate e-cigarette use. Other substance use, skipping school and meeting the physical activity guidelines at baseline and one-year changes to these behaviours were associated with e-cigarette initiation among both male and female students. Additionally, some differences were noted between females and males. ConclusionGiven that other health behaviours were associated with e-cigarette initiation, prevention approaches should target multiple health-risk behaviours to help prevent youth e-cigarette use. Additionally, school-based approaches may benefit by being implemented at the beginning of high school or in junior high school.

IntroductionUne meilleure compréhension des facteurs individuels associés à l’initiation à la cigarette électronique contribuerait à l’amélioration des mesures de prévention. Ainsi, cette étude vise à 1) relever les caractéristiques de départ associées à l’initiation à la cigarette électronique et 2) déterminer si des changements dans ces caractéristiques sont associés à l’initiation à la cigarette électronique chez les adolescents canadiens. MéthodologieCette étude a utilisé les données de l’année 6 (2017-2018, année de référence) et de l’année 7 (2018-2019, année de suivi) de l’étude COMPASS. L’échantillon final comprenait 12 315 élèves de la 9e à la 11e année qui avaient déclaré ne jamais avoir essayé la cigarette électronique au cours de l’année de référence. Les renseignements fournis par les élèves portaient sur leurs caratéristiques individuelles, la consommation d’autres substances, les comportements scolaires, l’activité physique, les comportements sédentaires, les troubles du sommeil, les symptômes d’anxiété et de dépression, la régulation émotionnelle et l’épanouissement. Des modèles hiérarchiques faisant appel aux équations d’estimation généralisées (EEG), stratifiés selon le sexe, ont permis d’analyser l’association entre 1) les caractéristiques de départ et l’initiation à la cigarette électronique lors de l’année de suivi et 2) des changements dans les caractéristiques de départ et l’initiation à la cigarette électronique lors de l’année de suivi. RésultatsAu total, 29 % des élèves qui n’avaient encore jamais essayé la cigarette électronique ont déclaré en avoir fait l’usage au moment du suivi. Les élèves de 10e et 11e année étaient proportionnellement moins nombreux à avoir essayé la cigarette électronique. La consommation d’autres substances, l’école buissonnière et le respect des directives en matière d’activité physique pendant l’année de référence ainsi que des changements vers ces comportements mesurés au moment du suivi ont été associés à l’initiation à la cigarette électronique à la fois chez les garçons et chez les filles. Certaines différences ont été observées entre les filles et les garçons. ConclusionÉtant donné que d’autres comportements liés à la santé ont été associés à l’initiation à la cigarette électronique, les stratégies de prévention devraient cibler les combinaisons de comportements à risque pour la santé afin de prévenir l’usage de la cigarette électronique chez les jeunes. De plus, mettre en œuvre des approches en milieu scolaire au début ou pendant le premier cycle du secondaire serait certainement bénéfique.

Physical activity may play a role in promoting or preventing substance use among youth. The purpose of this study was to examine the association between different types of physical activity [i.e., non-competitive school sport, competitive school sport, outside of school sport and minutes of moderate to vigorous physical activity (MVPA) per day] and substance use (i.e., current smoking, e-cigarette, cannabis, binge drinking) among Canadian youth. Interaction effects between physical activity and school connectedness were also examined. Using data from the COMPASS study (2018–19; n = 73,672), four multi-level logistic regression models were developed to investigate whether physical activity lessened or worsened the odds of (1) smoking; (2) e-cigarette use; (3) cannabis use; and (4) binge drinking. Models were stratified by gender to reflect the inherent differences between genders. Models were adjusted for demographic factors and other covariates. Sport participation was consistently associated with substance use, whereas less evidence was found for meeting MVPA guidelines. Non-competitive school sport lessened the odds of cannabis use for males and females. However, non-competitive school sport only lessened the odds of e-cigarette use for females but increased the odds of binge drinking for males. Participation in competitive school sport lessened the odds of cigarette smoking but increased the odds of e-cigarette use and binge drinking for males and females. Outside of school sport lessened the odds of cigarette smoking and cannabis use but increased the odds of e-cigarette use and binge drinking for males and females. A significant moderation effect was found for males participating in sport outside of school and meeting MVPA guidelines who were at a lower risk of e-cigarette use in the presence of high levels of school connectedness. Our study provides evidence for further consideration and provision of extracurricular activities, specifically non-competitive sport, in protecting against substance use. Caution is required in claiming that sport participation or physical activity, in general, is negatively associated with substance use among youth.

Abstract Background The purpose of this study was to explore whether the way youth perceive their weight and their experiences of bullying victimization account for the increased risk of depression and anxiety symptoms, and poor psychosocial well-being, associated with overweight/obesity in a large sample of Canadian secondary school students. We also explored if associations differed by gender. Methods We used cross-sectional survey data from year 7 (2018–19) of the COMPASS study. The sample included 57,059 students in grades 9–12 (Secondary III-V in Quebec) at 134 Canadian secondary schools (Alberta, British Columbia, Ontario, Quebec). First, multiple regression models tested associations between body mass index (BMI) classification and mental health outcomes (anxiety [GAD-7] and depression [CESD-10] symptoms, and psychosocial well-being [Diener’s Flourishing Scale]). Second, weight perception and bullying victimization were added to the models. Models were stratified by gender and controlled for sociodemographic covariates and school clustering. Results When weight perception and bullying victimization were added to the models, obesity BMI status no longer predicted internalizing symptoms and flourishing scores relative to normal-weight BMIs. Students with ‘overweight’ or ‘underweight’ perceptions, and experiences of bullying victimization in the past month, reported higher anxiety and depressive symptomatology, and lower flourishing levels, in comparison to students with ‘about right’ weight perceptions and without experiences of bullying victimization, respectively, controlling for BMI status. Results were largely consistent across boys and girls. Conclusions Results suggest perceptions of weight and experiences of bullying independently contribute to differences in mental health outcomes by weight status among youth. Continued efforts targeting weight-based bullying and weight bias, and the promotion of body size acceptance and positive body image, may help reduce the risk of mental illness and poor mental health among adolescents.

Abstract Background Given the high rates of cannabis use among Canadian youth and that adolescence is a critical period for cannabis use trajectories, the purpose of this paper was to examine the effect of the early stages of the COVID-19 pandemic period on youth cannabis use in the context of a natural experiment. We used 3-year linked data from the COMPASS study, including 7653 Canadian (Quebec, Ontario) adolescents from which 1937 completed all 3 survey waves (pre-COVID-19 [2018, 2019] and online [2020] during the early pandemic period [May–July 2020]). Structural equation modeling (SEM) and double difference (DD) models were used to estimate pre-COVID-19 to initial COVID-19 pandemic period change (2019–2020) in cannabis use (monthly, weekly, daily) compared to 2018 to 2019 change to adjust for age-related effects. Models were adjusted for age of entry into the cohort and sociodemographic characteristics. Results In the SEM and DD models, monthly, weekly, and daily cannabis use increased across all waves; however, the expected increases from the pre-COVID-19 wave (2019) to the initial COVID-19 period wave (2020) were lesser relative to the changes seen across the 2018 to 2019 waves. The cross-sectional data from May to July 2020 identified that the majority of youth who use cannabis did not report increased cannabis use due to COVID-19 or using cannabis to cope with COVID-19. Conclusion During the early stages of the COVID-19 pandemic period, there does not appear to be a detrimental effect on youth cannabis use, when adjusted for age-related changes. Further prospective research is needed to explore the impact of the ongoing pandemic response on youth cannabis use onset and progression.

Abstract Background Youth who go hungry have poorer mental health than their counterparts – there are gender differences in this relationship. This study investigated the role of social support in the association between hunger and mental health among a nationally representative sample of youth in Canada in gender-specific analyses. Methods We used a probability-based sample of 21,750 youth in grades 6–10 who participated in the 2017–2018 Canadian Health Behaviour in School-aged Children. Self-report data were gathered on hunger, mental health (measured via the World Health Organization-5 well-being index) and five sources of support – peer, family and teacher support as well as the school climate and neighborhood support. We conducted adjusted, gender-specific, multilevel regression analyses assessing the association between mental health, social support and hunger. Results We found that youth who reported lower support were more likely to experience going to bed hungry (relative to never hungry) across all support factors. As for the social support factors, all the social support factors were associated with a higher mental health score, even after controlling for hunger. Despite these results our final set of models showed that our measures of social support did not alleviate the negative association between hunger and mental health. As for gender-specific findings, the negative association between hunger and a mental health was more pronounced among females relative to their male counterparts. We also found that certain social support factors (i.e., family, teacher and neighborhood support) were associated with a higher mental health score among females relative to males while controlling for hunger status. Conclusions We find that five social support factors are associated with a higher mental health score among ever hungry youth; however, social support did not overpower the negative association between hunger and mental health. Food insecurity is a challenge to address holistically; however, hungry youth who have high social support have higher odds of better mental health.

Background: Nearly one-third of secondary school students report experiencing depressive symptoms in the past year. Existing research suggests that increasing rates of depression are due in part to increasing income inequality. The aim of this study is to identify mechanisms by which income inequality contributes to depression among Canadian secondary school students. Methods: We used data from a large sample of Canadian secondary school students that participated in the 2017/18 wave of the Cannabis, Obesity, Mental health, Physical activity, Alcohol, Smoking, and Sedentary behaviour (COMPASS) study. The sample included 61,642 students across 43 Census divisions (CDs) in Quebec, Ontario, Alberta, and British Columbia. We used multilevel path analysis to determine if the relationship between CD-level income inequality and depression was mediated by student's psychosocial well-being and/or social cohesion. Results: Attending schools in CDs with higher income inequality was related to higher depression scores among Canadian secondary students [unstandardized ß (ß) = 5.36; 95% CI = 0.74, 9.99] and lower psychosocial well-being (ß = −14.83, 95% CI = −25.05, −4.60). Income inequality was not significantly associated with social cohesion, although social cohesion was associated with depression scores among students (ß = −0.31; 95% CI = −0.34, −0.28). Discussion: Findings from this study indicate that income inequality is associated with adolescent depression and that this relationship is mediated by psychosocial well-being. This study is the first of its kind in Canada to assess the mechanisms by which income inequality contributes to adolescent depression. These findings are applicable to school-level programs addressing mental health.

Abstract Background Emerging evidence suggests perceptions of being overweight account for many of the psychosocial consequences commonly associated with obesity. Previous research suggests an obesity achievement gap, yet limited research has explored weight perception in association with academic performance. Moreover, underweight perceptions have typically been excluded from research. The current study examined how BMI classification and weight perception relate to academic performance in a large cohort of youth. Methods We used cross-sectional survey data from 61,866 grade 9–12 students attending the 122 Canadian schools that participated in Year 6 (2017/2018) of the COMPASS study. Mixed effect regression models were used to examine associations between students’ BMI classification and weight perceptions and their math and English/French course grades. All models were stratified by sex and adjusted for sociodemographic covariates and school clustering. Results For English/French grades, males and females with overweight or underweight perceptions were less likely to achieve higher grades than their peers with perceptions of being at “about the right weight”, controlling for BMI and covariates. For math grades, females with overweight perceptions, and all students with underweight perceptions, were less likely to achieve higher grades than their peers with “about the right weight” perceptions. All students with BMIs in the obesity range were less likely to report grades of 60% or higher than their peers with “normal-weight” BMIs, controlling for weight perception and covariates. Overweight BMIs were predictive of lower achievement in females for English/French grades, and in males for math grades, relative to “normal-weight” BMIs. Results for students that did not respond to the weight and weight perception items resembled those for obesity BMI and overweight/underweight perceptions, respectively. Conclusions Overall, this study demonstrates that an obesity achievement gap remains when controlling for students’ perceptions of their weight, and that both underweight and overweight perceptions predict lower academic performance, regardless of BMI classification. Results suggest barriers to academic success exist among youth with larger body sizes, and those with perceptions of deviating from “about the right weight”.

Introduction: Few studies have assessed the relationship between chronic disease risk behaviours and body mass index (BMI) in a longitudinal, sex/gender-specific context. This study used gender-specific analyses to assess the extent to which chronic disease risk behaviour latent classes are associated with BMI and weight status at follow-up. Methods: Longitudinal data from 4510 students in Grades 9 to 12, tracked from 2013– 2015, who participated in the COMPASS study were used to assess gender differences in the lagged association between previously determined latent classes (of physical activity and substance use) with BMI using multilevel mixed-effects models. Our multilevel regression models assessed the association between two latent classes, active experimenters and inactive non-using youth, with BMI when stratified by gender. Results: Male inactive non-substance-using youth were associated with a 0.29 higher continuous BMI (95% CI: 0.057, 0.53) and odds of overweight/obesity increased by 72% (OR = 1.72, 95% CI: 1.2, 2.4) for binary BMI at follow-up relative to active youth who experiment with substance use. No significant associations were detected in females. Conclusion: Over time, physical activity has a protective role on BMI in male youth. Both substance use and physical inactivity should be addressed in obesity prevention efforts. Gender stratification in analyses is also important since females and males have different contributing factors to increases in BMI.

Abstract Background There remains a need for prospective research examining movement behaviours in the prevention and management of mental illness. This study examined whether changes in adherence to the 24-h Movement Guidelines (moderate-to-vigorous physical activity [MVPA], sleep duration, screen time) were associated with depression symptoms among youth. Methods Conditional change models were used to analyze two waves of longitudinal questionnaire data (2016/17, 2017/18) from students in grades 9–12 (N = 2292) attending 12 schools in Ontario and British Columbia, Canada, as part of the COMPASS study. One-year change in adherence to the MVPA, screen time, and sleep duration guidelines were modeled as predictors of depressive symptoms, adjusting for covariates and prior year depressive symptoms. Models were stratified by sex. Results Continued adherence to sleep guidelines and transitioning from inadequate to sufficient sleep were associated with lower depressive symptoms than continued nonadherence, and continued adherence was associated with lower depression than transitioning from sufficient to short sleep. For screen time, transitioning from exceeding guidelines to guideline adherence was associated with lower depressive symptoms than continued nonadherence. MVPA guideline adherence was not associated with depression scores, when controlling for sleep and screen time guideline adherence change and covariates. When combined, meeting additional guidelines than the year prior was associated with lower depressive symptoms among females only. Conclusions Adherence to the sleep guidelines emerged as the most consistent predictor of depression symptoms. Promoting adherence to the Movement Guidelines, particularly sleep, should be considered priorities for youth mental health at a population level.

Introduction: Following cannabis legalization in Canada, a better understanding of the prevalence of unprompted cannabis use reduction and subsequent effects on youth academic outcomes is needed to inform harm reduction and health promotion approaches. Methods: We analyzed a longitudinally linked sample (n = 91774) from the COMPASS prospective cohort study of Canadian high school students attending Grades 9–12 in Ontario and Alberta between 2013–2014 and 2016–2017. We investigated the prevalence of spontaneous cannabis use reduction and cessation between grade transitions (Grades 9–10, 10–11, 11–12) and the effect of cessation on academic achievement (current or recent math and English course marks) and rigour (usual homework completion and past-month truancy). Results: Only 14.8% of cannabis users decreased their use between grades. Of these, two-thirds made only incremental downward changes, a pattern which held true for all three transitions. Cessation rates from daily and weekly use decreased every year. After cessation, students had better odds than continuing users (OR = 1.23, 95% CI: 1.03– 1.48) and worse odds than never-users (OR = 0.55, 95% CI: 0.31–0.97) for some subcategories of math performance. Students who quit cannabis universally improved class attendance (OR = 2.48, 95% CI: 1.93–3.19) and homework completion (OR = 2.32, 95% CI: 1.85–2.92) compared to continuing users. Conclusion: Increased academic rigour may underlie any improvements seen in academic performance after cannabis cessation. High school students who use cannabis likely need targeted support to facilitate reduction or cessation and subsequent academic recovery. This indicates that a school-based focus on cannabis harm reduction is justified.

Introduction: This study examined the associations of micro-level factors with current alcohol use and binge drinking among a large sample of Canadian youth. Methods: This descriptive-analytical study was conducted among high school students enrolled in the COMPASS study between 2012/13 and 2017/18. We used generalized estimating equations modelling to determine associations between micro-level factors and likelihood of current versus non-current alcohol use and binge drinking among respondents. Results: Students reporting current cannabis use were more likely to report current alcohol use over never use (odds ratio [OR] = 4.46, 95% confidence interval [CI]: 4.33–4.60) compared to students reporting non-current cannabis use. Students reporting current smoking of tobacco products were more likely to report current binge drinking over never binge drinking (OR = 2.52, 95% CI: 2.45–2.58), compared to non-smoking students. Students reporting weekly disposable incomes of more than $100 were more likely to report current over never binge drinking (OR = 2.14, 95% CI: 2.09–2.19), compared to students reporting no weekly disposable income. Conclusion: Higher disposable incomes, smoking of tobacco products and use of cannabis were associated with current alcohol use and binge drinking among youth. Findings may inform design of polysubstance use prevention efforts in high schools.