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Simple Summary: Infection with human papillomaviruses (HPV) increases the risk of developing head and neck cancer (HNC). There are over 200 known genotypes of HPV, but only a minority are carcinogenic. Cutaneous genotypes, which are traditionally isolated from the skin, were thought to be benign. However, recent evidence shows that they could be related to some cancers including HNC. Our goal in this study has been to investigate if there is an interaction between HPV16, a high-risk genotype from the alpha genus, with cutaneous HPV (beta and gamma genera) in HNC. We found preliminary evidence that among those infected with HPV16, co-infection with beta HPV could weaken the carcinogenic effect whereas coinfection with gamma HPV could strengthen the carcinogenic effect. While our findings show there might be an interaction between HPV16 and cutaneous HPV, these results are not conclusive and warrant further investigation. Future studies with larger sample sizes are needed. Objectives: Human papillomavirus 16 (HPV16) is an established risk factor for Head and Neck Cancer (HNC). Recent reports have shown that genotypes from the beta (β) and gamma (γ) genera, also known as cutaneous HPV, can be found in the oral cavity, but their role is largely unidentified. We investigated the interaction between oral HPV16 and cutaneous HPV in HNC. Methods: We use data on incident HNC cases (n = 384) and frequency-matched hospital-based controls (n = 423) from the HeNCe Life study in Montreal, Canada. Participants were tested for alpha HPV and cutaneous genera using oral mouth rinse and brush samples. We used unconditional logistic regression to obtain adjusted odds ratios (aOR) and 95% confidence interval (CI) as a measure of the effect between HPV and HNC and assessed the interaction between HPV genotypes on the multiplicative and additive scales. Results: Prevalence of HPV infection was higher among cases (73%) than controls (63.4%), with cases more likely to be coinfected with more than a single genotype, 52.9% vs. 43.5%, respectively. Infection with HPV16 alone had a strong effect on HNC risk aOR = 18.2 [6.2, 53.2], while infection with any cutaneous HPV, but not HPV16, appeared to have the opposite effect aOR = 0.8 [0.6, 1.1]. The observed effect of joint exposure to HPV16 and any cutaneous HPV (aOR = 20.4 [8.3, 50.1]) was stronger than the expected effect based on an assumption of independent exposures but was measured with considerable imprecision. While the point estimate suggests a positive interaction between HPV16 and cutaneous HPV, results were imprecise with relative excess risk due to interaction (RERI) = 2.4 [−23.3, 28.2]. Conclusion: There could be biologic interaction between HPV16 and genotypes from cutaneous genera, which warrants further investigation. Although cutaneous HPVs are not usually found in tumor tissues, they are cofactors that could interact with HPV16 in the oral cavity and thus strengthen the latter's carcinogenic effect. [ABSTRACT FROM AUTHOR]

Objectives: To identify associations of Andersen and Newman's (A&N) predisposing, enabling, and need factors with self-reported oral health status and self-reported unmet dental treatment needs in a sample of people living with HIV (PLHIV) in British Columbia (BC), Canada.Methods: Participants responded anonymously to a 41-item online questionnaire with the following inclusion criteria: a) be at least 19 years old; b) self-identify as HIV-positive; c) be able to provide consent and be willing to voluntarily participate in the study; d) be residing in British Columbia; and e) be able to proficiently respond to the questions in English. Following the descriptive statistics, associations between A&N model factors and the main outcome variables (self-reported oral health status and self-reported dental treatment needs) were evaluated using bivariate inferential analyses.Results: A total of 186 participants met the inclusion criteria. Approximately 40% (n = 74) of participants rated the health of their mouth as fair/poor and more than half (n = 112; 60.2%) reported having bleeding gums, tooth decay or tooth sensitivity. The bivariate analysis for the self-reported oral status as the outcome variable showed "having fair/poor general health" (P = 0.001), "unemployment" (P = 0.019), "avoiding dental treatment due to cost" (P = 0.005), and "not visiting a dental professional within the last year" (P < 0.001) as the strongest predictors. For the second outcome variable unmet dental treatment needs, the strongest predictors were "experience of being discriminated by dental professionals" (P = 0.001), "having fair/poor general health" (P = 0.006), and "suffering from past and current medical conditions due to HIV" (P < 0.001).Conclusions: Several predisposing, enabling and need factors from the A&N model were associated with self-reported oral health status and unmet dental treatment needs of PLHIV. Results from this study highlight the needs of improving access to affordable dental care to address the unmet oral health needs of PLHIV. [ABSTRACT FROM AUTHOR]

Objectives: To identify the predisposing, enabling, and need factors of the Andersen and Newman (A&N) model and their associations with the pattern of dental service utilization in a sample of people living with HIV (PLHIV) in British Columbia.Methods: Participants responded anonymously to a 40-item online questionnaire to explore the patterns of dental service utilization. Following the descriptive statistics, the associations between A&N model factors and main outcome variables (having a dental visit in the last year and reasons for the dental visit) were evaluated using simple and multiple logistic regression analyses.Results: Out of 600 potential PLHIV participants, 210 responded to the survey and 186 met the inclusion criteria. The experience of being discriminated against by dental professionals (P = 0.005), having dental anxiety (P < 0.001), not having dental insurance (P = 0.001), and having living condition difficulties (P = 0.004) were significantly associated with nonemergency dental visits. In multiple logistic regression analysis, dental anxiety (OR = 0.1; 95 percent CI 0.0; 0.4), having a regular dentist (OR = 3.7; 95 percent CI 1.1; 12.6), and visiting a dental office in the last year (OR = 21.6; 95 percent CI 6.1; 76.5) were the strongest predictors of dental service utilization in this study.Conclusions: Several predisposing, enabling, and need factors from the A&N model were associated with dental service utilization by PLHIV. In addition to various psychosocial barriers, a significant number of respondents reported experiencing stigma and discrimination from their oral care providers. [ABSTRACT FROM AUTHOR]

Background: This study aimed to estimate the extent to which oral sex behavior is associated with an increased risk of oropharyngeal cancers (OPCs), and how much of the association is mediated by oral human papillomavirus (HPV) infection. Methods: We used data from a hospital‐based case‐control study conducted in Montreal, Canada. Information on oral sex behaviors was collected. Oral rinse and oral brush specimens were analyzed for HPV positivity and genotyping. Logistic regression estimated the odds ratios (OR) and 95% confidence intervals (CI) for the association between oral sex behaviors and OPC. Results: Onset of oral sex practice at age 16 years or younger had an increased risk of OPCs relative to those with onset after age 30 years (OR = 2.98; 95% CI 1.37‐6.47). This association decreased (OR = 1.09; 95% CI 0.25‐4.71) when restricted to those positive for HPV. Conclusions: Our results suggest that the association between oral sex and OPC seems mediated by oral HPV infection. [ABSTRACT FROM AUTHOR]

Objectives. We investigated the perspectives of people using a wheelchair and their difficulties in accessing dental services. Methods. Our participatory research was on the basis of a partnership between people using a wheelchair, dental professionals, and academic researchers. Partners were involved in a committee that provided advice at all stages of the project. Our team adopted a qualitative descriptive design. Between October 2011 and October 2012 we conducted semistructured individual interviews with 13 adults who lived in Montreal, Québec, Canada, and used a wheelchair full time. We audio-recorded and transcribed verbatim interviews, and we interpreted data using an inductive thematic analysis. Results. Oral health is of heightened importance to this group of people, who tend to use their mouth as a "third hand." We identified successive challenges in accessing dental services: finding a dentist and being accepted, organizing transportation, entering the building and circulating inside, interacting with the dental staff, transferring and overcoming discomfort on the dental chair, and paying for the treatments. Conclusions. Governments, dental professional bodies, dental schools, and researchers should work with groups representing wheelchair users to improve access to dental services. [ABSTRACT FROM AUTHOR]

Objective: Human papillomaviruses (HPV) are changing dramatically the epidemiologic landscape of head and neck cancers (HNCs). Their role in the aetiology of these cancers varies widely among HNCs subsites, sex and geographical regions worldwide. We describe HPV prevalence and its association with HNCs risk overall and by anatomical subsite in a sample of Canadians.Materials and Methods: The HeNCe Life study recruited 460 incident HNCs cases and 458 controls frequency-matched by age and sex from four Montreal hospitals in 2005-2013. We tested oral rinse and oral brush specimens for mucosal HPV genotypes. HPV positivity was categorized hierarchically as either negative, exclusively non-α-9 species types, α-9 types other than HPV16, and HPV16. We estimated odds ratios (OR) and 95% confidence intervals (CI) for the associations between HPV and HNCs using unconditional logistic regression, controlling for confounders.Results: The prevalence of HPV infection among controls and cases was 14.5% and 41.2% in oral rinse and 3.1% and 24.4% in oral brush samples, respectively. HPV16 was the predominant genotype with an oral rinse and oral brush prevalence of 26.3% and 16.2% among cases and 2.4% and 0.2% among controls, respectively. HPV infection was associated with an increased risk of HNCs overall (OR=4.18; 95% CI, 2.94-5.95) and oropharyngeal cancer only (OR=10.3; 95% CI, 6.8-15.7). HNCs and oropharyngeal cancer were strongly associated with HPV16 (OR=18.1; 95% CI, 9.1-35.8, and OR=47.2; 95% CI, 23.1-96.6, respectively).Conclusion: HPV infection, particularly HPV16, was associated with an increased HNCs risk, most strongly for oropharyngeal cancers. [ABSTRACT FROM AUTHOR]

Excess body fatness in late adulthood has been observed to increase ovarian cancer risk, but the association is relatively weak. Body fatness can change over time, and timing may differently influence risk. We used a life course epidemiology approach to identify whether the relation between body fatness and ovarian cancer risk is best described by a critical period, accumulation or sensitive period hypothesis. In a population-based case-control study of ovarian cancer in Montreal, Canada (2011-16), data on body mass index (BMI) at each decade starting at age 20 was available. Among 363 cases and 707 controls aged ≥ 50 years, we used a Bayesian relevant life course exposure model to estimate the relative importance of BMI for three pre-specified periods across the adult life course, i.e., early childbearing years, late childbearing years, and peri/postmenopause, on ovarian cancer risk. The accumulation hypothesis best described BMI in relation to ovarian cancer overall, with an odds ratio (OR) for the lifetime effect of BMI (per 5 kg/m 2 increase) of 1.10 (95% credible interval [CrI]: 0.90-1.35). For invasive ovarian cancer, the OR (95% CrI) for the lifetime effect was 1.16 (0.92-1.48), with BMI during early childbearing years showing the highest relative importance, suggesting this may be a sensitive period. For borderline cancer, the lifetime effect OR was not strongly supportive of an association (OR: 0.90, 95% CrI: 0.53-1.32). The results suggest that a sensitive period of early childbearing years is a candidate hypothesis for further investigation., Competing Interests: Declarations. Ethics approval: This study was performed in line with the principles of the Declaration of Helsinki. The PROVAQ study was approved by the Research Ethics Committee of the Centre de recherche du CHUM as well as the participating hospitals. Consent to participate: All participants provided written informed consent. Competing interests: The authors have no relevant financial or non-financial interests to disclose., (© 2024. Springer Nature B.V.)

Background: The second-to-fourth digit ratio (2D:4D) is thought to reflect prenatal exposure to sex steroids. We investigated the relationship between 2D:4D and odds of prostate cancer., Method: Data were collected in PROtEuS, a population-based case-control study conducted in Montréal, Canada (2005-2012), including 1931 incident prostate cancer cases aged < 76 years and 1994 population controls. In-person interviews elicited information on potential risk factors. Digit lengths were measured by interviewers applying a standard protocol. Odds ratios (OR) and 95 % confidence intervals (CI) were estimated using unconditional logistic regression adjusting for potential confounders., Results: The OR of prostate cancer for a standard deviation increase in 2D:4D was 0.91 (95 % CI: 0.85-0.98). For less and more aggressive cancers, ORs were 0.93 (95 % CI: 0.87-1.00) and 0.85 (95 % CI: 0.77-0.93), respectively. There was an interaction with ancestry (p=0.04), whereas the OR among men of African descent was 1.23 (95 % CI: 0.96-1.57, based on 128 cases)., Conclusion: Findings suggest an inverse association between 2D:4D and odds of overall prostate cancer, more pronounced for aggressive cancers. This supports the notion that high levels of testosterone in utero, estimated by a low 2D:4D ratio, are associated with a higher risk of prostate cancer. Contrastingly, a high digit ratio was associated with greater cancer odds among participants of African descent. Upon replication, 2D:4D could prove to be an easily measured marker of prostate cancer risk., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: Striking geographic variations in prostate cancer incidence suggest an aetiological role for spatially-distributed factors. We assessed whether neighbourhood social deprivation, which can reflect limited social contacts, unfavourable lifestyle and environmental exposures, is associated with prostate cancer risk., Methods: In 2005-2012, we recruited 1931 incident prostate cancer cases and 1994 controls in a case-control study in Montreal, Canada. Lifetime residential addresses were linked to an area-based social deprivation index around recruitment (2006) and about 10 years earlier (1996). Logistic regression estimated adjusted odds ratios (ORs) and 95% confidence intervals (CIs)., Results: Men residing in areas characterised by greater social deprivation had elevated prostate cancer risks (ORs of 1.54 and 1.60 for recent and past exposures, respectively; highest vs lowest quintiles), independently from area- and individual-level confounders and screening patterns. The increase in risk with recent high social deprivation was particularly elevated for high-grade prostate cancer at diagnosis (OR 1.87, 95% CI 1.32-2.64). Associations were more pronounced for neighbourhoods with higher proportions of separated/divorced or widowed individuals in the past, and with higher percentages of residents living alone recently., Conclusions: These novel findings, suggesting that neighbourhood-level social deprivation increases the risk of prostate cancer, point out to potential targeted public health interventions., (© 2023. The Author(s), under exclusive licence to Springer Nature Limited.)

Human papillomavirus (HPV) infection and tobacco smoking are well-known risk factors for head and neck cancers (HNC). Although an effect modification between oral HPV infection and tobacco smoking may exist, evidence is lacking on how they interact temporally. We investigated the latency and life course effects of tobacco smoking on risk of HNC among HPV-positive (HPV +ve ) and negative (HPV -ve ) individuals. We used data from 631 ever-smoker participants of a hospital-based case-control study conducted in four major hospitals in Montréal, Canada. Cases (n = 320), incident, histologically confirmed, primary squamous cell carcinomas, were frequency-matched to controls (n = 311) by age and sex. Sociodemographic and behavioral factors (e.g., tobacco and alcohol use and sexual history) were collected using a structured interview applying a life grid technique. Oral exfoliated cells were used for HPV DNA detection and genotyping. Latency effects were estimated flexibly using a Bayesian relevant exposure model and further extended with a life course approach. Retrospective smoking trajectories for HPV +ve cases and controls had similar shapes. Exposure to tobacco smoking even 40 years before diagnosis was associated with an increased HNC risk among both HPV +ve and HPV -ve participants. The effect of smoking before the start of sexual activity compared to afterwards was higher among HPV +ve individuals. This pattern of association was less profound among HPV -ve participants. Temporal interactions may exists between oral HPV infection and life course smoking trajectories in relation to HNC risk., (© 2019 UICC.)

Objective: To understand the oral healthcare experiences of humanitarian migrants in Montreal and their perceptions of ways to improve access to oral healthcare., Methods: We used focused ethnography informed by a public health model of the dental care process. The adapted McGill Illness Narrative Interview (MINI) guided interviews of a purposeful sample of humanitarian migrants who received or needed dental care in Montreal. Each interview (50-60 min) was audio-recorded for verbatim transcription. Observation of dental care episodes occurred during mobile dental clinics in underserved communities over the same period (2015-2016). Data analysis combined deductive codes from the theoretical frameworks and inductive codes from interview transcripts and field notes to inform themes., Results: We interviewed 25 participants (13 refugees and 12 asylum seekers) from 10 countries, who had been in Canada for a range of 1 month to 5 years. The dental care experiences of participants included delayed consultation, proximity to dental clinics, quality care, limited treatment choices, high cost, and long waiting times. A more inclusive healthcare policy, lower fees, integration of dental care into public insurance, and creation of community dental clinics were proposed strategies to improve access to dental care., Conclusion: Humanitarian migrants in this study experienced inadequate oral healthcare. Their lived experiences help us to identify gaps in the provision of oral healthcare services, and suggestions of participants have great potential to improve access to oral healthcare.

Canada received over 140,000 refugees and asylum seekers between 2015 and 2017. This paper presents a protocol with the purpose of generating robust baseline data on the oral health of this population and build a long-term program of research to improve their access to dental care in Canada. The three-phase project uses a sequential mixed methods design, with the Behavioral Model for Vulnerable Populations as the conceptual framework. In Phase 1a, we will conduct five focus groups (six to eight participants per group) in community organizations in Ontario, Canada, to collect additional sociocultural data for the research program. In Phase 1b, we will use respondent-driven sampling to recruit 420 humanitarian migrants in Ontario and Quebec. Participants will complete a questionnaire capturing socio-demographic information, perceived general health, diet, smoking, oral care habits, oral symptoms, and satisfaction with oral health. They will then undergo dental examination for caries experience, periodontal health, oral pain, and traumatic dental injuries. In Phase 2, we will bring together all qualitative and quantitative results by means of a mixed methods matrix. Finally, in Phase 3, we will hold a one-day meeting with policy makers, dentists, and community leaders to refine interpretations and begin designing future oral health interventions for this population.

Identifying life periods during which social conditions have the highest impact on risk of common cancers in a population may help to reveal their underlying shared social mechanisms. We used the life course framework to estimate the extent to which life course SEP is associated with risk of nine cancers. In addition, we tested whether these associations conform to a critical period or cumulative life course model. Data were from a population-based case-control study of occupational exposures and cancer conducted in Montreal, Canada. Participants were males aged 35-70 years (n = 2,547) residing in the Montreal metropolitan area with primary, histologically confirmed cancers diagnosed between 1979 and 1985. Population controls (n = 512) were sampled from electoral lists. SEP was measured at three different periods of life based on respondent's report: during childhood, young adulthood and mid-life. We used a structured modeling approach using a series of unconditional logistic regressions to test which models best fit the data. Life course SEP increased the risk of all cancers. SEP in childhood was identified as a critical period for prostate and all gastrointestinal tract cancers except for esophagus cancer. In addition, the accumulation model best explained the data for melanoma and lung squamous cell carcinoma. Our findings suggest that childhood social circumstances are a common risk factor for several cancers among men; our results provide insights into the mechanisms involved in the etiology of nine cancers., (© 2018 UICC.)