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Introduction: Web-based epidemiologic surveys are being widely used, but still present lower response rates compared to traditional methods. Their design can influence survey response rates. Objective: Analyse the influence of questionnaire length, frequency of reminders, and the interaction between them, on the response rates of five web-based questionnaires. Methods: This is a 2×2 factorial study. Participants registered into the "coortesnaweb" platform (n=1,277) were randomly assigned to respond to short or long questionnaires, and to receive high or low frequency of reminders. We analysed the influence of these factors on the response rates of five web-based questionnaires applied in a longitudinal manner. The relative risk of responding to an additional questionnaire was also analysed. Results: The mean response rate was 54.3%. Sending reminders more frequently was positively associated with the response rates for the first questionnaires. Questionnaire length did not influence response rates. We found no interaction between questionnaire length and frequency of reminders. Women and highly educated participants had, respectively, 13.0% and 28.0% increased probability of responding an additional questionnaire. Conclusions: We obtained high response rates for the first questionnaires. Sending reminders more frequently and providing conditional incentives should be employed. Long questionnaires did not jeopardize response rates of web-based questionnaires.

Background: Many low- and middle-income countries have high levels of violence. Research in high-income countries shows that risk factors in the perinatal period are significant precursors of conduct problems which can develop into violence. It is not known whether the same early influences are important in lower income settings with higher rates of violence. This study compared perinatal and sociodemographic risk factors between Brazil and Britain, and their role in explaining higher rates of conduct problems and violence in Brazil. Methods: Prospective population-based birth cohort studies were conducted in Pelotas, Brazil (N = 3,618) and Avon, Britain (N = 4,103). Eleven perinatal and sociodemographic risk factors were measured in questionnaires completed by mothers during the perinatal period. Conduct problems were measured in questionnaires completed by mothers at age 11, and violence in self-report questionnaires completed by adolescents at age 18. Results: Conduct problems were predicted by similar risk factors in Brazil and Britain. Female violence was predicted by several of the same risk factors in both countries. However, male violence in Brazil was associated with only one risk factor, and several risk factor associations were weaker in Brazil than in Britain for both females and males. Almost 20% of the higher risk for conduct problems in Brazil compared to Britain was explained by differential exposure to risk factors. The percentage of the cross-national difference in violence explained by early risk factors was 15% for females and 8% for males. Conclusions: A nontrivial proportion of cross-national differences in antisocial behaviour are related to perinatal and sociodemographic conditions at the start of life. However, risk factor associations are weaker in Brazil than in Britain, and influences in other developmental periods are probably of particular importance for understanding male youth violence in Brazil.

The objective of this study is to examine the association between preterm infants' size at 1 year and attention-deficit/hyperactivity disorder (ADHD) assessed categorically and dimensionally in childhood and adolescence. We studied infants born < 37 weeks' gestation from two Brazilian birth cohorts (n = 653). ADHD was evaluated using the Development and Well-Being Assessment (DAWBA) interview at the age of 6 years in one cohort and by a structured interview according to DSM-5 criteria at 18 years in the other one. The presence of child attention difficulties was measured by the Strengths and Difficulties Questionnaire (SDQ) at 6 and 11 years in the 2004 and 1993 cohorts, respectively. We estimated associations of weight, length, head circumference, and BMI z-scores at 1-year chronological age with ADHD using Poisson Regression Model; and with attention difficulties using Linear Regression, adjusting for covariates. Mean birth weight was 2500 g and gestational age was 34.5 weeks. The aggregated ADHD prevalence in the two cohorts was 2.7%, and the median score for attention difficulties was 3.0. We found that increased head circumference at 1 year was associated with a lower risk of ADHD diagnosis (RR = 0.7, 95% CI 0.4, 0.9; p = 0.04 per standard deviation difference) and with fewer dimensional attention symptoms. In sensitivity analysis with other mental disorders, head circumference was associated with depression, but not with anxiety. Our findings emphasize poor head growth in the first year of life as a potential determinant of attentional difficulties in the preterm infant population. [ABSTRACT FROM AUTHOR]

Background: The study of gene-environment interactions (G by E) is one of the most promising strategies to uncover the origins of mental disorders. Replication of initial findings, however, is essential because there is a strong possibility of publication bias in the literature. In addition, there is a scarcity of research on the topic originated from low- and middle-income countries (LMIC). The aim of this study was to replicate G by E hypotheses for externalizing problems among adolescents in a middle-income country. Methods: As part of the Pelotas 1993 Birth Cohort Study, 5,249 children were enrolled at birth and followed up to the age of 15 years, with an 85.7% retention rate. We sought an interaction between the homozygosity of the 10-repeat allele at the dopamine transporter ("DAT1") gene and prenatal maternal smoking in the development of hyperactivity problems during adolescence assessed by the Strengths and Difficulties Questionnaire. We also tested for an interaction between the uVNTR polymorphism at the monoamine oxidase A ("MAOA") and the experience of childhood maltreatment in the occurrence of conduct problems among adolescent boys. Results: Although there was a clear association between prenatal maternal smoking and hyperactivity scores in adolescence ("p" less than 0.001), no main genetic or interaction effects for the "DAT1" gene were detected. Similarly, childhood maltreatment showed to be associated with conduct problems among boys ("p" less than 0.001), with no observable main genetic or interaction effects for the "MAOA" gene. Conclusions: In the largest mental health G by E study performed in a LMIC to date, we did not replicate previous positive findings from the literature. Despite the presence of main environmental effects, there was no evidence of effect modification by genotype status. Additional replication efforts to measure G by E are needed to better understand the origins of mental health and illness, especially in LMIC. (Contains 1 table and 2 figures.)

A prior study conducted in high-income countries demonstrated that specific sedentary behavior, such as TV viewing, is prospectively associated with adiposity in both active and inactive adolescents. The aim of this study was to examine the joint associations of sedentary behaviors and moderate- and vigorous-intensity physical activity (MVPA) with adiposity among Brazilian adolescents. This prospective cohort study included 377 participants of the 1993 Pelotas (Brazil) Study who completed an accelerometry assessment at age 13 years and a dual-energy X-ray absorptiometry (DXA) assessment at age 18 years. Accelerometer-measured MVPA was dichotomized into high (≥60 min/day) and low (<60 min/day). Accelerometer-measured sedentary time (SED) was dichotomized into low (<49 min/h) and high (≥49 min/h) based on the median. Self-reported TV viewing time was also dichotomized into low (<3 h/day) and high (≥3 h/day) based on the median. We combined the two MVPA groups (high and low) and two SED groups (low and high) to form the four MVPA&SED groups: high&low, high&high, low&low, and low&high. We also created four MVPA&TV groups in the same manner. Fat mass index (FMI; kg/m2) was calculated using DXA-derived fat mass. Multivariable linear regression analyses compared FMI at 18 years among the four MVPA&SED groups and among the four MVPA&TV groups, adjusting for socioeconomic status, energy intake, and baseline adiposity. The analysis results showed that SED or TV viewing time was not prospectively associated with adiposity in both active and inactive Brazilian adolescents. This study suggests that the association between specific sedentary behaviors, such as TV viewing, and adiposity may differ across societal settings—in this case, high-income vs. middle-income countries. [ABSTRACT FROM AUTHOR]

Estudo transversal de base populacional na Cidade de Pelotas, Sul do Brasil, entre 1999 e 2000, para descrever a distribuição de adiposidade abdominal na população de acordo com os níveis de interven��ão e identificar fatores de risco. O estudo incluiu uma amostra de 1.935 adultos (20-69 anos) residentes na zona urbana do município. Obesidade abdominal foi classificada como nível I para circunferência da cintura (CCnI) de 80-88cm em mulheres e de 94-102cm em homens; e nível II (CCnII) > 88cm para mulheres e > 102cm para homens. Apresentavam obesidade abdominal 62% das mulheres e 37% dos homens. Os valores de CCnI foram 23% e 19% e de CCnII 39% e 19%, para mulheres e homens, respectivamente. Após ajuste para fatores de confusão, o aumento da idade e estar casado ou vivendo em união, em homens e mulheres, mantiveram-se fortemente associadas com CCnII. Escolaridade manteve-se como fator de risco apenas para homens e renda familiar apenas para mulheres, nas quais, o efeito da renda manteve-se inversamente associado com a obesidade abdominal. A utilização da medida da CC deveria ser incorporada às ações de promoção à saúde, principalmente, no acompanhamento e monitoramento da população.

OBJETIVO: O melanoma tem incidência crescente, sendo que a prevalência dos tumores malignos epiteliais é alta, e o diagnóstico precoce contribui significativamente para a redução da morbimortalidade dessas doenças. O objetivo da pesquisa é medir a prevalência das lesões cutâneas pré-malignas e malignas e determinar a sensibilidade e a especificidade de um rastreamento para essas lesões. MÉTODOS: Foi realizado um estudo transversal de base populacional com escolha aleatória de 48 setores censitários da zona urbana de Pelotas, RS, Brasil. Um total de 2.112 domicílios foram visitados, sendo entrevistadas 1.292 pessoas de 50 anos de idade ou mais. O rastreamento possuía questões específicas sobre o surgimento de lesões de pele nos últimos seis meses e/ou a presença de lesões em áreas expostas. Os que responderam afirmativamente foram encaminhados ao exame médico. Também foi examinada uma subamostra daqueles que haviam respondido negativamente às questões do rastreamento. RESULTADOS: A prevalência corrigida das lesões cutâneas pré-malignas e malignas foi de 20,7%. A sensibilidade do rastreamento foi de 20,1%, a especificidade, de 86,9%, o valor preditivo positivo, de 29%, o valor preditivo negativo, de 80,4%, e acurácia, de 72,9%. Com diferentes pontos de corte, o valor máximo da sensibilidade atingiu 38,8%, e a especificidade não se alterou significativamente. CONCLUSÕES: O estudo demonstrou alta prevalência de lesões cutâneas pré-malignas e malignas em adultos. O rastreamento para essas lesões mostrou baixa sensibilidade e especificidade inferior ao desejado, independentemente dos pontos de corte.

INTRODUCTION: Although there was a considerable reduction in infant mortality in Pelotas, Rio Grande do Sul in the last decade, its perinatal causes were reduced only by 28%. The associated factors of these causes were analised. MATERIAL AND METHOD: All hospital births and perinatal deaths were assessed by daily visits to all the maternity hospitals in the city, throughout 1993 and including the first week of 1994. RESULTS: The perinatal mortality rate was 22.1 per thousand births. The multivariate analysis showed the following risk factors: low socioeconomic level, male sex and maternal age above 35 years . Among multigravidae women, the fetal mortality rate was significantly increased for mothers with a previously low birthweight and a previous stillbirth. For early neonatal mortality the risk was significantly increased by a smaller number of antenatal visits than 5 and low birthweight. CONCLUSIONS: Main risk factors for perinatal mortality: low socioeconomic level, maternal age above 35 years and male sex. For early neonatal mortality the risk was significantly increased by a smaller number of antenatal visits than 5 and low birthweight.

OBJETIVO: Avaliar as mudanças na prevalência de tabagismo durante a gravidez na cidade de Pelotas, RS, Brasil, com base nos estudos da população materno-infantil realizados nos anos de 1982 e 1993. METODOLOGIA: Estudo transversal, tendo sido identificados 6.011 e 5.304 recém-nascidos, cujas famílias residiam na área urbana da cidade de Pelotas, respectivamente em 1982 e 1993. RESULTADOS: O tabagismo materno durante a gestação apresentou uma discreta redução de 35,7%, em 1982, para 33,5% em 1993 (p < 0,05). O hábito de fumar esteve inversamente relacionado com a renda e o número de consultas no pré-natal.

A evolução da mortalidade perinatal foi estudada em Pelotas, Rio Grande do Sul, através de dois estudos de coorte realizados em 1982 e 1993. Todos os nascimentos hospitalares e os óbitos foram monitorizados com visitas diárias aos hospitais. A causa da morte foi determinada através de informações do prontuário, entrevista com o pediatra e de necrópsias. O coeficiente de mortalidade perinatal sofreu uma redução de 31% na década. O sub-registro que era de 42,1% em 1982, foi de apenas 6,8% em 1993. Dentre as causas de mortalidade perinatal, houve uma redução em 1993 de 58% para óbitos fetais antepartum, 47% para imaturidade e 62% para outras causas. Os coeficientes para asfixia sofreram um aumento de 4,5/1.000 para 8,3/1.000. As meninas apresentaram um coeficiente de mortalidade perinatal menor do que os meninos. Os coeficientes de mortalidade perinatal conforme peso ao nascer e renda familiar sofreram importantes reduções, sendo que a mais notável foi para crianças de baixo peso e de famílias de renda alta, com uma queda de 68%. Assim como em 1982, os recém-nascidos pré-termo tiveram coeficientes três vezes mais elevados do que crianças pequenas para a idade gestacional. Apesar da queda dos índices de mortalidade na década, as diferenças entre os grupos sociais mantiveram-se grandes.

Estudou-se a tendência temporal da mortalidade infantil através de dois estudos de coorte realizados em Pelotas, Rio Grande do Sul, em 1982 e 1993. Ambas coortes incluíram todos os nascimentos hospitalares e óbitos verificados através de visitas regulares aos hospitais, cartórios e cemitérios. As informações sobre a causa de morte foram obtidas através de entrevistas com pediatras, revisão do prontuário, necrópsias e entrevista com os pais das crianças. O coeficiente de mortalidade infantil caiu de 36,4 por mil nascidos vivos para 21,1 na década. As principais causas de mortalidade infantil em 1993 foram as perinatais, malformações congênitas, diarréia e infecções respiratórias. Crianças com baixo peso ao nascer apresentaram mortalidade 12 vezes maior do que crianças com peso adequado, e crianças pré-termo, duas vezes mais do que crianças com retardo de crescimento intra-uterino. Crianças de famílias com renda baixa (um salário mínimo) apresentaram mortalidade sete vezes superior àquelas com renda alta (10 salários mínimos). A mortalidade de crianças de baixo peso ao nascer e alta renda familiar decresceu em 67%, contra apenas 36% para as de baixa renda. Conclui-se que, mesmo com uma queda expressiva da mortalidade infantil na década, persistem importantes desigualdades sociais.

Em 1982, todos os nascimentos ocorridos na cidade de Pelotas, RS - Brasil, foram estudados e essas crianças foram acompanhadas prospectivamente durante os primeiros anos de vida. Em 1993, repetiu-se o estudo com metodologia similar, com a finalidade de avaliar as eventuais mudanças no nível de saúde materno-infantil, ocorridas durante esses onze anos. Todas as cinco maternidades da cidade foram visitadas diariamente e os 5.304 nascimentos ocorridos foram incluídos no estudo. As crianças foram pesadas e medidas, sendo sua idade gestacional avaliada através do método de Dubowitz. As mães foram examinadas e entrevistadas sobre um grande número de fatores de risco. A mortalidade dessas crianças foi monitorizada por visitas regulares a hospitais, cemitérios e registros de óbito, e todas as internações hospitalares foram acompanhadas. Dois estudos aninhados de casos e controles foram realizados para investigar fatores de risco para mortalidade e hospitalizações. Uma amostra sistemática de 655 crianças foram examinadas em casa com um e três meses de idade, e essas mesmas crianças, acrescidas de outras 805 (que incluíram todos os recém-nascidos de baixo peso) foram também acompanhadas aos seis e doze meses de idade. O desenvolvimento psicomotor dessas amostras foi também avaliado. As perdas de acompanhamento aos doze meses foram de apenas 6,6%. Em relação aos dados de 1982, a pesquisa de 1993 mostrou redução de cerca de 30% na mortalidade perinatal e de quase 50% na mortalidade infantil, assim como aumento de um mês na duração mediana da amamentação. Por outro lado, não houve qualquer alteração nas prevalências de baixo peso ao nascer e de déficit de comprimento/idade aos doze meses. O artigo a que se refere este resumo descreve a metodologia do estudo, ao qual se segue uma série de outras publicações.

Background: Trajectories of attention-deficit hyperactivity disorder (ADHD) traits spanning early childhood to mid-life have not been described in general populations across different geographical contexts. Population trajectories are crucial to better understanding typical developmental patterns.Methods: We combined repeated assessments of ADHD traits from five population-based cohorts, spanning ages 3 to 45 years. We used two measures: (i) the Strengths and Difficulties Questionnaire (SDQ) hyperactive-inattentive subscale (175 831 observations, 29 519 individuals); and (ii) scores from DSM-referenced scales (118 144 observations, 28 685 individuals). Multilevel linear spline models allowed for non-linear change over time and differences between cohorts and raters (parent/teacher/self).Results: Patterns of age-related change differed by measure, cohort and country: overall, SDQ scores decreased with age, most rapidly declining before age 8 years (-0.157, 95% CI: -0.170, -0.144 per year). The pattern was generally consistent using DSM scores, although with greater between-cohort variation. DSM scores decreased most rapidly between ages 14 and 17 years (-1.32%, 95% CI: -1.471, -1.170 per year). Average scores were consistently lower for females than males (SDQ: -0.818, 95% CI: -0.856, -0.780; DSM: -4.934%, 95% CI: -5.378, -4.489). This sex difference decreased over age for both measures, due to an overall steeper decrease for males.Conclusions: ADHD trait scores declined from childhood to mid-life, with marked variation between cohorts. Our results highlight the importance of taking a developmental perspective when considering typical population traits. When interpreting changes in clinical cohorts, it is important to consider the pattern of expected change within the general population, which is influenced by cultural context and measurement. [ABSTRACT FROM AUTHOR]

Background: Physical inactivity is responsible for 7% of diabetes deaths worldwide, but little is known whether low levels of physical activity (PA) during adolescence increase the risk of diabetes in early adulthood. We evaluated the cross-sectional and longitudinal associations between PA throughout adolescence and HbA1c concentration in early adulthood. Methods: HbA1c was measured by high performance liquid chromatography. PA was assessed by self-report at the ages of 11, 15, and 18 years and by accelerometry at the ages of 13 (subsample) and 18 years. The loss percentages of follow up were 12.5% at 11 years, 14.4% at 15 years, and 18.7% at 18 years. Results: At 18 years, boys showed higher HbA1c than girls. At age 18 years, accelerometrybased PA at 18 years was inversely related to HbA1c levels in boys. Self-reported leisure-time PA at ages 11, 15, and 18 were unrelated to HbA1c in both genders. PA at 13 years of age was unrelated to HbA1c among both genders. In trajectory analysis, PA and accelerometer PA trajectories were not associated with later HbA1c. Conclusion: Objectively measured PA at 18 years was cross-sectionally inversely associated with HbA1c in boys only. No prospective associations were identified. [ABSTRACT FROM AUTHOR]

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Objective: Shared genetic mechanisms have been hypothesized to explain the comorbidity between ADHD and asthma. To evaluate their genetic overlap, we relied on data from the 1982 Pelotas birth cohort to test the association between polygenic risk scores (PRSs) for ADHD (ADHD-PRSs) and asthma, and PRSs for asthma (asthma-PRSs) and ADHD. Method: We analyzed data collected at birth, 2, 22, and 30 years from 3,574 individuals. Results: Subjects with ADHD had increased risk of having asthma (OR 1.92, 95% CI 1.01–3.66). The association was stronger for females. Our results showed no evidence of association between ADHD-PRSs and asthma or asthma-PRSs and ADHD. However, an exploratory analysis suggested that adult ADHD might be genetically associated with asthma. Conclusion: Our results do not support a shared genetic background between both conditions. Findings should be viewed in light of important limitations, particularly the sample size and the self-reported asthma diagnosis. Studies in larger datasets are required to better explore the genetic overlap between adult ADHD and asthma. [ABSTRACT FROM AUTHOR]

Purposes: The aims of this study were to investigate the cross-sectional and prospective associations between accelerometer-measured physical activity and cardiometabolic health in the transition to adulthood. Methods: Data from the 1993 Pelotas (Brazil) Birth Cohort were analyzed (n = 2280). Moderate-to-vigorous intensity physical activity (MVPA) (measured using a triaxial accelerometer) and cardiometabolic health (total fat mass, blood glucose, non-high-density lipoprotein cholesterol, triglycerides, and mean resting blood pressure) were examined at age 18 and 22 yr. Results: Overall, inverse dose-response associations between MVPA and cardiometabolic health at age 18 and 22 yr were observed in cross-sectional analyses of data from men and women. Prospective analyses showed that, in general, MVPA declined, and cardiometabolic health worsened in this 4-yr period in both men and women. Cardiometabolic health at age 22 yr reflected both MVPA at age 18 yr (β, -0.007; 95% confidence interval [CI], -0.014 to 0.000) and changes in MVPA from 18 to 22 yr (β, -0.030; 95% CI, -0.043 to -0.016) in men, but only changes in MVPA in women (β, -0.035; 95% CI, -0.058 to -0.011). In analyses of change overtime, men who improved MVPA by 20 to 30 min-d-1 showed significant improvements in cardiometabolic health over 4 yr. The magnitude of association was slightly stronger for MVPA in 10-min bouts than for MVPA accumulated in bouts of 1 min, especially in women. Conclusions: Moderate-to-vigorous intensity physical activity is an important predictor of cardiometabolic health in early adulthood. Strategies to prevent declines in MVPA at this life stage are required to prevent deteriorating cardiometabolic health profiles. [ABSTRACT FROM AUTHOR]

Aim: To evaluate the longitudinal association between physical activity behavior at 11 years of age and the incidence of mental health problems from 11 to 15 years of age. Methods: Individuals born in the city of Pelotas, Brazil, in 1993 have been followed up since birth. At 11 and 15 years of age, mental health was assessed using the Strengths and Difficulties Questionnaire (SDQ). At 11 years of age, physical activity was assessed through a validated questionnaire. The continuous SDQ score at 15 years was used as the outcome variable. The main exposure was physical activity behavior at 11 years of age divided into 3 categories (0, 1-299, ≥300 min/wk). Results: The incidence of mental health problems from 11 to 15 years was 13.6% (95% CI, 12.4-14.9). At 11 years, 35.2% of the adolescents achieved 300 min/wk of physical activity. In the unadjusted analysis, physical activity was inversely related to mental health problems (P = .04). After adjustment for confounders, the association was no longer significant in the whole sample but was still significant among boys. Conclusion: Physical activity appears to be inversely related to mental health problems in adolescence, but the magnitude of the association is weak to moderate. [ABSTRACT FROM AUTHOR]

Reduced physical activity (PA) is an independent risk factor for lung function decline, hospitalization and mortality in chronic obstructive pulmonary disease (COPD) and affects a large proportion of patients from Europe and the United States. However, little is known of the level of PA of COPD patients in Latin America. The aim of this study was to provide information of the level of PA and its determinants in COPD patients in Latin America. This is an observational, cross-sectional study on patients with COPD in seven Latin American countries. PA level was evaluated with the short version of the International Physical Activity Questionnaire (IPAQ) and the association between PA and other variables was investigated. Complete information of PA level was obtained in 734 COPD patients consecutively recruited from specialized outpatient clinics; 448 (61%) were men, with a mean age of 69.6 years (standard deviation [SD] = 8.7) and a mean FEV1 (% predicted) = 49.1% (17.5%). In 37.9% the level of PA was low, and the average sitting time was 36.1 h per week. Patients with low levels of PA were older, with higher levels of dyspnea and higher CAT scores. Additionally, we found that patients with low level of PA presented more symptoms during the day. Low levels of PA have been observed in a large proportion of COPD patients of Latin America, which is higher in women and older patients and it is related with worse functional and clinical characteristics. [ABSTRACT FROM AUTHOR]

Background: Growth faltering has been associated with poor intellectual performance. The relative strengths of associations between growth in early and in later childhood remain underexplored.Objectives: We examined the association between growth in childhood and adult human capital in 5 low- and middle-income countries (LMICs).Methods: We analyzed data from 9503 participants in 6 prospective birth cohorts from 5 LMICs (Brazil, Guatemala, India, the Philippines, and South Africa). We used linear and quasi-Poisson regression models to assess the associations between measures of height and relative weight at 4 age intervals [birth, age ∼2 y, midchildhood (MC), adulthood] and 2 dimensions of adult human capital [schooling attainment and Intelligence Quotient (IQ)].Results: Meta-analysis of site- and sex-specific estimates showed statistically significant associations between size at birth and height at ∼2 y and the 2 outcomes (P < 0.001). Weight and length at birth and linear growth from birth to ∼2 y of age (1 z-score difference) were positively associated with schooling attainment (β: 0.13; 95% CI: 0.08, 0.19, β: 0.17; 95% CI: 0.07, 0.32, and β: 0.25, 95% CI: 0.10, 0.40, respectively) and adult IQ (β: 0.74, 95% CI: 0.35, 1.14, β: 0.73, 95% CI: 0.35, 1.10, and β: 1.52, 95% CI: 0.96, 2.08, respectively). Linear growth from age 2 y to MC and from MC to adulthood was not associated with higher school attainment or IQ. Change in relative weight in early childhood, MC, and adulthood was not associated with either outcome.Conclusions: Linear growth in the first 1000 d is a predictor of schooling attainment and IQ in adulthood in LMICs. Linear growth in later periods was not associated with either of these outcomes. Changes in relative weight across the life course were not associated with schooling and IQ in adulthood. [ABSTRACT FROM AUTHOR]

Objectives. To evaluate the spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) over 6 months in the Brazilian State of Rio Grande do Sul (population 11.3 million), based on 8 serological surveys. Methods. In each survey, 4151 participants in round 1 and 4460 participants in round 2 were randomly sampled from all state regions. We assessed presence of antibodies against SARS-CoV-2 using a validated lateral flow point-of-care test; we adjusted figures for the time-dependent decay of antibodies. Results. The SARS-CoV-2 antibody prevalence increased from 0.03% (95% confidence interval [CI] = 0.00%, 0.34%; 1 in every 3333 individuals) in mid-April to 1.89% (95% CI = 1.36%, 2.54%; 1 in every 53 individuals) in early September. Prevalence was similar across gender and skin color categories. Older adults were less likely to be infected than younger participants. The proportion of the population who reported leaving home daily increased from 21.4% (95% CI = 20.2%, 22.7%) to 33.2% (95% CI = 31.8%, 34.5%). Conclusions. SARS-CoV-2 infection increased slowly during the first 6 months in the state, differently from what was observed in other Brazilian regions. Future survey rounds will continue to document the spread of the pandemic. [ABSTRACT FROM AUTHOR]

Summary: Background: Gestational weight gain (GWG) has been associated with the accumulation of body fat in offspring, but little is known about the intergenerational relationship. Objective: To assess the effect of GWG in grandmothers and mothers on the child's body mass index (BMI). Methods: This is a sub‐study nested in the 1993 Pelotas (Brazil) Birth Cohort at 22 years follow‐up visit. We calculated the BMI‐for‐age z‐score (BAZ) and evaluated overweight (>2 SD in ≤5 years of age and >1 SD for >5 years of age for BAZ). Grandmothers' and mothers' GWG were calculated as the difference between weight in the beginning of pregnancy and the last recorded weight before delivery. We standardized the GWG by adjusting for pre‐gestational BMI. We also categorized GWG as adequate, excessive, or insufficient, in accordance with the Institute of Medicine (2009). Linear and logistic regressions stratified by child's age (≤2 years; 2.01‐5 years; >5 years) were used. Structural equations were modelled to calculate the total, indirect, and direct effects of grandmothers' and mothers' GWG on children's BAZ. Results: Nine hundred and forty‐six out of 1113 children evaluated were 5 years of age or under. There was an indirect effect (through maternal birthweight, maternal pre‐gestational BMI, maternal GWG, and child birthweight) of grandmother GWG on grandchild BAZ, from 2.01 to 5 years of age [β = 0.12 95%CI: 0.04‐0.20 (P < 0.01)]. Maternal GWG directly increased the child's BAZ at >5 years of age [β = 0.34 95%CI: 0.15‐0.53 (P < 0.001)]. Conclusions: GWG's effect on BMI does seem to be transmitted across three generations. Managing this will require health education during the gestational period for women and their families. [ABSTRACT FROM AUTHOR]

Abstract Background Socioeconomic inequalities in child nutrition may change rapidly over time, particularly in populations undergoing the nutrition transition. Yet, the few available studies are repeated cross-sectional surveys. By studying three prospective birth cohorts in the same city over a period of more than two decades, we describe secular trends in overweight and stunting at different ages, according to socioeconomic position. Methods Population-based birth cohort studies were launched in the city of Pelotas (Brazil) in 1982, 1993 and 2004, with follow-up visits at twelve, 24 and 48 months. Children were weighed and measured at every visit. Z-scores of length/height-for-age and body mass index-for-age were calculated using the WHO Child Growth Standards. The slope and relative indices of inequality, based on family income quintiles, were estimated for each follow-up visit. Results Between the 1982 and 2004 cohorts, stunting among four-year-olds declined (from 10.9% to 3.6%), while overweight increased (from 7.6% to 12.3%). In every visit, stunting prevalence was inversely related to income. Both absolute and relative inequalities declined over time; among four-year-olds stunting dropped from 26.0% in the 1982 cohort to 6.7% in the 2004 cohort in the poorest group, while in the richest group stunting prevalence dropped from 2.7% in 1982 to 1.1% in the 2004 cohort study. The secular trend towards increased overweight was evident for four-year-olds, in almost all socioeconomic groups, but not among one and two-year-olds. Among four-year old children, overweight prevalence increased in all income quintiles, by 130% in the middle-income group, 64% in the poorest and 41% in the richest group. Conclusions The decline in stunting is remarkable, but the increase in overweight among four-year olds – particularly among the poorest and the middle-income groups– requires concerted efforts to prevent the long term consequences of child overweight.

Abstract Background The Developmental Origins of Health and Disease hypothesis suggests that intrauterine, infancy and early childhood variables play a key role at programming later health. However, little is known on the programming of behavioral variables, because most studies so far focused on chronic disease-related and human capital outcomes. The aim of the present study was to evaluate the effects of prenatal, infancy and childhood weight and length/height gains on objectively-measured physical activity (PA) in adolescence. Methods This is a prospective birth cohort study in Pelotas, Brazil, including 457 adolescents (mean age: 13.3 years) with weight and length/height data at birth, one, three and six months, one and four years of age. PA was measured using a GT1M Actigraph accelerometer, and expressed as (a) minutes per day spent on sedentary, light, moderate, vigorous and very-vigorous activities; (b) total counts per day. Results 61.3% of the adolescents accumulated 60+ minutes of moderate-to-vigorous PA per day. Weight and length/height trajectories in infancy and childhood were similar between those classified as active or inactive at 13.3 years. However, those classified as inactive were heavier and taller at all ages; differences were statistically significant only in terms of length at three, six and 12 months. Conclusions Weight gain in infancy and childhood did not predict variability in adolescent PA, but those active in adolescence showed somewhat smaller average gains in length in infancy. These findings suggest that PA may partially be sensitive to early hormonal programming, or that genetic factors may affect both early growth and later metabolism or predisposition for PA.

Abstract Background Large epidemiological studies in DNA biobanks have increasingly used less invasive methods for obtaining DNA samples, such as saliva collection. Although lower amounts of DNA are obtained as compared with blood collection, this method has been widely used because of its more simple logistics and increased response rate. The present study aimed to verify whether a storage time of 8 months decreases the quality of DNA from collected samples. Methods Saliva samples were collected with an OrageneTM DNA Self-Collection Kit from 4,110 subjects aged 14–15 years. The samples were processed in two aliquots with an 8-month interval between them. Quantitative and qualitative evaluations were carried out in 20% of the samples by spectrophotometry and genotyping. Descriptive analyses and paired t-tests were performed. Results The mean volume of saliva collected was 2.2 mL per subject, yielding on average 184.8 μg DNA per kit. Most samples showed a Ratio of OD differences (RAT) between 1.6 and 1.8 in the qualitative evaluation. The evaluation of DNA quality by TaqMan®, High Resolution Melting (HRM), and restriction fragment length polymorphism-PCR (RFLP-PCR) showed a rate of success of up to 98% of the samples. The sample store time did not reduce either the quantity or quality of DNA extracted with the Oragene kit. Conclusion The study results showed that a storage period of 8 months at room temperature did not reduce the quality of the DNA obtained. In addition, the use of the Oragene kit during fieldwork in large population-based studies allows for DNA of high quantity and high quality.

OBJECTIVE: To describe the evolution of seropositivity in the State of Rio Grande do Sul, Brazil, through 10 consecutive surveys conducted between April 2020 and April 2021. METHODS: Nine cities covering all regions of the State were studied, 500 households in each city. One resident in each household was randomly selected for testing. In survey rounds 1–8 we used the rapid WONDFO SARS-CoV-2 Antibody Test (Wondfo Biotech Co., Guangzhou, China). In rounds 9–10, we used a direct ELISA test that identifies IgG to the viral S protein (S-UFRJ). In terms of social distancing, individuals were asked three questions, from which we generated an exposure score using principal components analysis. RESULTS: Antibody prevalence in early April 2020 was 0.07%, increasing to 10.0% in February 2021, and to 18.2% in April 2021. In round 10, self-reported whites showed the lowest seroprevalence (17.3%), while indigenous individuals presented the highest (44.4%). Seropositivity increased by 40% when comparing the most with the least exposed. CONCLUSIONS: The proportion of the population already infected by SARS-Cov-2 in the state is still far from any perspective of herd immunity and the infection affects population groups in very different levels. [ABSTRACT FROM AUTHOR]

OBJECTIVE: To estimate the prevalence of SARS-CoV-2 antibodies and the adherence to measures of social distancing in children and adolescents studied in three national surveys conducted in Brazil between May–June 2020. METHODS: Three national serological surveys were conducted in 133 sentinel cities located in all 27 Federative Units. Multistage probability sampling was used to select 250 individuals per city. The total sample size in age ranges 0–9 and 10–19 years old are of 4,263 and 8,024 individuals, respectively. Information on children or adolescents was gathered with a data collection app, and a rapid point-of-case test for SARS-CoV-2 was conducted on a finger prick blood sample. RESULTS: The adjusted prevalence of antibodies was 2.9% (2.2–3.6) among children 0–9 years, 2.2% (1.8–2.6) among adolescents 10-19 years, and 3.0% (2.7–3.3) among adults 20+years. Prevalence of antibodies was higher among poor children and adolescents compared to those of rich families. Adherence to social distancing measures was seen in 72.4% (71.9–73.8) of families with children, 60.8% (59.6–61.9) for adolescents, and 57.4% (56.9–57.8) for adults. For not leaving the house except for essential matters the proportions were 81.7% (80.5–82.9), 70.6% (69.6–61.9), and 65.1% (64.7–65.5), respectively. Among children and adolescents, social distancing was strongly associated with socioeconomic status, being much higher in the better-off families. CONCLUSIONS: The prevalence of antibodies against SARS-CoV-2 showed comparable levels among children, adolescents, and adults. Adherence to social distancing measures was more prevalent in children, followed by adolescents. There were important socioeconomic differences in the adherence to social distancing among children and adolescents. [ABSTRACT FROM AUTHOR]