Secular trends and social inequalities in child behavioural problems across three Brazilian cohort studies (1993, 2004 and 2015).

AIMS: Previous epidemiological evidence identified a concerning increase in behavioural problems among young children from 1997 to 2008 in Brazil. However, it is unclear whether behavioural problems have continued to increase, if secular changes vary between sociodemographic groups and what might explain changes over time. We aimed to monitor changes in child behavioural problems over a 22-year period from 1997 to 2019, examine changing social inequalities and explore potential explanations for recent changes in behavioural problems between 2008 and 2019. METHODS: The Child Behaviour Checklist was used to compare parent-reported behavioural problems in 4-year-old children across three Brazilian birth cohorts assessed in 1997 (1993 cohort, n = 633), 2008 (2004 cohort, n = 3750) and 2019 (2015 cohort, n = 577). Response rates across all three population-based cohorts were over 90%. Moderation analyses tested if cross-cohort changes differed by social inequalities (demographic and socioeconomic position), while explanatory models explored whether changes in hypothesized risk and protective factors in prenatal development (e.g., smoking during pregnancy) and family life (e.g., maternal depression and harsh parenting) accounted for changes in child behavioural problems from 2008 to 2019. RESULTS: Initial increases in child behavioural problems from 1997 to 2008 were followed by declines in conduct problems (mean change = -2.75; 95% confidence interval [CI]: -3.56, -1.94; P < 0.001), aggression (mean change = -1.84; 95% CI: -2.51, -1.17; P < 0.001) and rule-breaking behaviour (mean change = -0.91; 95% CI: -1.13, -0.69 P < 0.001) from 2008 to 2019. Sex differences in rule-breaking behaviour diminished during this 22-year period, whereas socioeconomic inequalities in behavioural problems emerged in 2008 and then remained relatively stable. Consequently, children from poorer and less educated families had higher behavioural problems, compared to more socially advantaged children, in the two more recent cohorts. Changes in measured risk and protective factors partly explained the reduction in behavioural problems from 2008 to 2019. CONCLUSIONS: Following a rise in child behavioural problems, there was a subsequent reduction in behavioural problems from 2008 to 2019. However, social inequalities increased and remained high. Continued monitoring of behavioural problems by subgroups is critical for closing the gap between socially advantaged and disadvantaged children and achieving health equity for the next generation.

Wheezing trajectories from childhood to adulthood in a population-based cohort.

BACKGROUND: Wheezing may lead to asthma and reduced pulmonary function in later life. The study aims to identify wheezing trajectories and investigate their relation with pulmonary function and asthma-related outcomes at 22 years of age. METHODS: Individuals from a population-based cohort in Brazil (1993 Pelotas Birth Cohort) with post-bronchodilator pulmonary function data at 22 years (3350) were included in the study. From parentally reported (4 and 11 years) and self-reported (15, 18 and 22 years) history of wheezing in the last 12 months, we used a group-based trajectory modelling approach to derive wheezing trajectories. RESULTS: Four trajectories were identified: never/infrequent, transient-early, late-onset and persistent wheeze. After adjustments, wheezing trajectories remained associated with lower post-bronchodilator values of pulmonary function. Individuals in the persistent wheeze trajectory had a markedly poorer pulmonary function and also showed greater odds of asthma-related outcomes compared to other trajectories groups. Those following this trajectory had on average -109 ml (95% CI: -188; -35), -1.80 percentage points (95% CI: -2.73; -0.87) and -316 ml/s (95% CI: -482; -150) lower FEV1, FEV1/FVC ratio and FEF25-75% respectively; higher odds of self-reported medical diagnosis of allergy (OR 6.18; 95% CI: 3.59; 10.61) and asthma (OR 12.88; 95% CI: 8.91; 18.61) and asthma medication use (OR 9.42; 95% CI: 5.27; 16.87) compared to the never/infrequent group. CONCLUSIONS: Wheezing trajectories, especially the persistent wheeze trajectory, were related to lower pulmonary function values and increased risk of asthma and allergy diagnosis in early adulthood.

Innovative methods to analyse the impact of gender norms on adolescent health using global health survey data.

BACKGROUND: Understanding how gender norms affect health is an important entry point into designing programs and policies to change norms and improve gender equality and health. However, it is rare for global health datasets to include questions on gender norms, especially questions that go beyond measuring gender-related attitudes, thus limiting gender analysis. METHODS: We developed five case studies using health survey data from six countries to demonstrate approaches to defining and operationalising proxy measures and analytic approaches to investigating how gender norms can affect health. Key findings, strengths and limitations of our norms proxies and methodological choices are summarised. FINDINGS: Case studies revealed links between gender norms and multiple adolescent health outcomes. Proxys for norms were derived from data on attitudes, beliefs, and behaviours, as well as differences between attitudes and behaviours. Data were cross-sectional, longitudinal, census- and social network-based. Analytic methods were diverse. We found that gender norms affect: 1) Intimate partner violence in Nigeria; 2) Unhealthy weight control behaviours in Brazil and South Africa; 3) HIV status in Zambia; 4) Health and social mobility in the US; and 5) Childbirth in Honduras. INTERPRETATION: Researchers can use existing global health survey data to examine pathways through which gender norms affect health by generating proxies for gender norms. While direct measures of gender norms can greatly improve the understanding of how gender affects health, proxy measures for norms can be designed for the specific health-related outcome and normative context, for instance by either aggregating behaviours or attitudes or quantifying the difference (dissonance) between them. These norm proxies enable evaluations of the influence of gender norms on health and insights into possible reference groups and sanctions for non-compliers, thus informing programmes and policies to shape norms and improve health.

Associations between sleep duration trajectories from adolescence to early adulthood and working memory, schooling and income: a prospective birth cohort study from Brazil.

OBJECTIVE: This study aimed to evaluate the relationship between sleep duration trajectories from adolescence to early adulthood and working memory, schooling and income at 22 years in the Pelotas 1993 Birth Cohort. METHODS: Sleep duration was self-reported at ages 11, 18 and 22. Sleep trajectories were identified using finite mixture models. Schooling was recorded as the number of completed years of education. Working memory was evaluated using The Digit Span test and income was recorded for who reported have a job and received a payment for this in the previous month. All analyses were stratified by sex. RESULTS: We used crude and adjusted (for demographic, health and behavior characteristics measured at perinatal and 11-years) linear or quantile regression analyses. A total of 2915 individuals were included. Three trajectories for males were used: "increase and maintenance" (3.4%), "fast reduction and maintenance" (45.0%) and "constant reduction" (51.6%). For females, we used the trajectories: "increase and decrease" (2.4%), "fast reduction and maintenance" (25.6%) and "constant reduction" (72.0%). Males from "increase and maintenance" and females from "increase and decrease" trajectories scored, on average, 1.6 and 1.8 points lower, respectively, in working memory test. They presented a median of 1.4 and 2.6 fewer schooling years, respectively, compared to individuals from the "fast reduction and maintenance" trajectory. Regarding income, no significant association was observed. CONCLUSION: Sleep duration during adolescence could affect cognitive and educational outcomes in early adulthood. Individuals who presented the expected sleep trajectory (decrease of sleep duration across adolescence) presented better outcomes.

Sleep duration trajectories from adolescence to emerging adulthood: Findings from a population-based birth cohort.

This study aimed to describe longitudinal trajectories of sleep duration, among adolescents and adults from the Pelotas (Brazil) 1993 Birth Cohort, as well as characterize different trajectories groups according to socioeconomic, demographic and behavior characteristics. Sleep duration, hours per day (from Monday to Friday), bedtime and wake-up time were self-reported by participants at ages 11, 18 and 22 years. Covariables included socioeconomic, demographic, health and behavior characteristics. Trajectory analysis was performed using a semi-parametric, group-based modelling approach. Prevalence and 95% confidence interval were obtained to describe covariables and sleep trajectory groups. Chi-square test was employed in statistical analysis and all analyses were stratified by sex. A total of 3.395 individuals were included in the analysis. In both sexes, bedtime became later across years, while wake-up time presented little variation. Differences according sex were more pronounced from 18 years onwards. Three trajectories of sleep duration from 11 to 22 years were identified for males: "increase and maintenance" (3.4%), "fast reduction and maintenance" (45.0%) and "constant reduction" (51.6%). While in females the trajectories identified were: "increase and decrease" (2.4%), "fast reduction and maintenance" (25.6%) and "constant reduction" (72.0%). Men and women who belong to trajectories with longer sleep durations were more likely to present higher percentages of some risk behaviors and poor socioeconomic condition. Our results have provided longitudinal information regarding sleep duration trajectories in a medium-sized city in Brazil, aiming at filling an existing gap in literature from low- and middle-income countries.

Associations between growth from birth to 18 years, intelligence, and schooling in a Brazilian cohort.

BACKGROUND: Growth faltering in the first 1000 d is associated with lower human capital among adults. The existence of a second window of opportunity for nutritional interventions during adolescence has been postulated. OBJECTIVES: We aimed to verify the associations between growth from birth to 18 y and intelligence and schooling in a cohort. METHODS: A total of 5249 hospital-born infants in Pelotas, Brazil, were enrolled during 1993. Follow-up visits to random subsamples took place at 6, 12, and 48 mo and to the full cohort at 11, 15, and 18 y. Weight and length/height were collected in all visits. The Wechsler Adult Intelligence Scale was applied at age 18 y, and primary school completion was recorded. Conditional length/height and conditional BMI were calculated and expressed as z scores according to the WHO Growth Standards. These express the difference between observed and expected size at a given age based on a regression that includes earlier anthropometric measures. Analyses were adjusted for income, parental education, maternal skin color and smoking, and breastfeeding duration. RESULTS: In the adjusted analyses, participants with conditional length ≥1 z score at 1 y had mean intelligence quotient (IQ) scores at 18 y 4.50 points (95% CI: 1.08, 7.92) higher than those with conditional length ≤-1 at 1 y. For height-for-age at 4 y, this difference was equal to 3.70 (95% CI: 0.49, 6.90) IQ points. There were no associations between conditional height at 11, 15, or 18 y and IQ. For the same previously mentioned comparison, the prevalence ratio for less than primary schooling was 1.42 (95% CI: 1.12, 1.80) for conditional height at 1 y. There were no consistent associations with conditional BMI. CONCLUSIONS: Our findings show that adolescent growth is not associated with intelligence and schooling, and are consistent with the literature on the associations between intelligence and schooling and early linear growth.

Maternal smoking during pregnancy and offspring body composition in adulthood: Results from two birth cohort studies.

OBJECTIVE: To evaluate the association of maternal smoking during pregnancy with offspring body composition in adulthood and explore the causality of this association. DESIGN: Birth cohort. SETTING: Population-based study in Pelotas, Brazil. PARTICIPANTS: All newborn infants in the city's hospitals were enrolled in 1982 and 1993. At a mean age of 30.2 and 22.6 years, the 1982 and 1993 cohorts, respectively, followed the subjects and 7222 subjects were evaluated. PRIMARY OUTCOME MEASURES: Body mass index (BMI), fat mass index, android to gynoid fat ratio, waist circumference, waist to height ratio, lean mass index and height. RESULTS: Prevalence of maternal smoking during pregnancy was 35.1% and 32.6%, in 1982 and 1993 cohorts, respectively. Offspring of smoking mothers showed higher mean BMI (ß: 0.84; 95% CI: 0.55 to 1.12 kg/m2), fat mass index (ß: 0.44; 95% CI: 0.23 to 0.64 kg/m2), android to gynoid fat ratio (ß: 0.016; 95% CI: 0.010 to 0.023), waist circumference (ß: 1.74; 95% CI: 1.15 to 2.33 cm), waist to height ratio (ß: 0.013; 95% CI: 0.010 to 0.017) and lean mass index (ß: 0.33; 95% CI: 0.24 to 0.42 kg/m2), whereas height was lower (ß: -0.95; -1.26 to -0.65). Weight gain in the first 2 years captured most of the association of maternal smoking with BMI (96.2%), waist circumference (86.1%) and fat mass index (71.7%). CONCLUSIONS: Maternal smoking in pregnancy was associated with offspring body composition measures in adulthood.

Estudio de cohorte de base poblacional sobre la enfermedad pulmonar obstructiva crónica en Latinoamérica: métodos y resultados preliminares. Fase II del estudio PLATINO / A Population-Based Cohort Study on Chronic Obstructive Pulmonary Disease in Latin America: Methods and Preliminary Results. The PLATINO Study Phase II

ANTECEDENTES: El estudio basal del PLATINO, llevado a cabo entre 2003 y 2005 en 5 ciudades latinoamericanas (São Paulo, Ciudad de México, Montevideo, Santiago, Caracas), mostró una prevalencia elevada de la enfermedad pulmonar obstructiva crónica (EPOC). Métodos/diseño: Se llevó a cabo un estudio de seguimiento en 3 de los 5 centros (Montevideo, Santiago y São Paulo) después de un periodo de 5, 6 y 9 años, respectivamente, con el objetivo de verificar la estabilidad del diagnóstico de EPOC a lo largo del tiempo, la evolución de la enfermedad en cuanto a supervivencia, morbilidad y función respiratoria, y análisis de los biomarcadores genéticos e inflamatorios en sangre. Se añadieron algunas preguntas adicionales al cuestionario original y se obtuvieron los certificados de defunción a partir de los registros oficiales nacionales. RESULTADOS: El trabajo de campo se ha completado en los 3 centros. De las muestras originales de la fase I del PLATINO pudimos localizar y entrevistar al 85,6% en Montevideo, al 84,7% en Santiago y al 77,7% en São Paulo. Los individuos no localizados se caracterizaban por un mayor nivel de estudios en Brasil y era más probable que fueran fumadores actuales en Santiago y São Paulo que en Montevideo. La calidad global de las espirometrías fue ≥ 80% según los criterios de la American Thoracic Society. El número de muertes fue de 71 (Montevideo), 95 (Santiago) y 135 (São Paulo), y se obtuvieron los certificados de defunción a partir de los registros de mortalidad nacionales del 76,1, del 88,3 y del 91,8% de los casos en Montevideo, Santiago y São Paulo, respectivamente. CONCLUSIONES: Este estudio muestra que es posible realizar estudios longitudinales de base poblacional en Latinoamérica, con tasas de seguimiento elevadas y una alta calidad de los datos de espirometría. La idoneidad de los registros de mortalidad nacionales varía en los distintos centros de Latinoamérica

BACKGROUND: The PLATINO baseline study, conducted from 2003-2005 in five Latin American cities (São Paulo, Mexico City, Montevideo, Santiago, Caracas), showed a high prevalence of chronic obstructive pulmonary disease (COPD).Methods/design: A follow-up study was conducted in three out of the five centers (Montevideo, Santiago, and São Paulo) after a period of 5, 6 and 9 years, respectively, aimed at verifying the stability of the COPD diagnosis over time, the evolution of the disease in terms of survival, morbidity and respiratory function, and the analyses of inflammatory and genetic biomarkers in the blood. Some questions were added to the original questionnaire and death certificates were obtained from the national official registries. RESULTS: The fieldwork has been concluded in the three centers. From the original samples in the PLATINO study phase i, we were able to locate and interview 85.6% of patients in Montevideo, 84.7% in Santiago and 77.7% in São Paulo. Individuals who could not be located had higher education levels in Brazil, and were more likely to be current smokers in Santiago and São Paulo than in Montevideo. The overall quality of spirometries was ≥80% according to American Thoracic Society criteria. The number of deaths was 71 (Montevideo), 95 (Santiago) and 135 (São Paulo), with death certificates obtained from the national mortality registries for 76.1%, 88.3% and 91.8% of cases in Montevideo, Santiago and São Paulo, respectively. CONCLUSIONS: This study shows that is possible to perform population-based longitudinal studies in Latin American with high follow-up rates and high-quality spirometry data. The adequacy of national mortality registries varies among centers in Latin America

Airflow obstruction in never smokers in five Latin American cities: the PLATINO study.

BACKGROUND: Although chronic obstructive pulmonary disease (COPD) is mostly related to tobacco smoking, a variable proportion of COPD occurs in never smokers. We investigated differences between COPD in never smokers compared with smokers and subjects without COPD. METHODS: PLATINO is a cross-sectional population-based study of five Latin American cities. COPD was defined as postbronchodilator FEV(1)/FVC <0.70 and FEV(1) <80% of predicted values. RESULTS: Among 5,315 subjects studied, 2278 were never smokers and 3036 were ever smokers. COPD was observed in 3.5% of never smokers and in 7.5% of ever smokers. Never smokers with COPD were most likely older and reported a medical diagnosis of asthma or previous tuberculosis. Underdiagnosis was as common in obstructed patients who never smoked as in ever smokers. CONCLUSIONS: Never smokers comprised 26% of all individuals with airflow obstruction. Obstruction was associated with female gender, older age and a diagnosis of asthma or tuberculosis.

Physical activity as a predictor of adolescent body fatness: a systematic review.

Adolescent obesity has increased dramatically in several countries in recent decades; however, the contribution of physical activity level to adolescent adiposity requires clarification. This article investigates the effect of physical activity on subsequent levels of adiposity in adolescence. The methodological aspects of the studies included in this article, particularly in terms of measurement accuracy for both exposure (physical activity) and outcome (adiposity) variables, are also evaluated. Systematic searches of the literature were undertaken using online databases, including PubMed/MEDLINE, examination of citations and contacting of authors. The online databases were searched from their earliest records until 2007. Only longitudinal studies with 50 or more adolescents were included. Two independent reviewers assessed the quality of the studies using the Downs and Black checklist. Thirteen observational, five experimental and six quasi-experimental studies (without a control group) were identified. Almost all studies were carried out in high-income settings and showed protective effects of physical activity for both prevention and treatment of adolescent obesity. However, experimental studies undertaken with obese adolescents at baseline usually combined physical activity with dietary changes, making it difficult to assess the effect of physical activity itself on the treatment of obesity. Physical activity estimated from questionnaires and body mass index (BMI) were the most frequently used measures. Despite the feasibility of using these approaches in epidemiological studies, significant limitations are evident. Questionnaires are subjective and adolescents may not report physical activity level accurately. Furthermore, BMI is not an accurate measure of fatness for adolescents, as it is also associated with lean mass, hence bias may arise from its longitudinal association with physical activity level. Despite the majority of studies reviewed showing protective effects of physical activity on adiposity, particularly in individuals who are obese at baseline, the current literature on this issue is sparse and several methodological drawbacks are evident. The main limitations relate to a lack of validity in the measurements of both physical activity and body composition. Further studies are needed in order to generate evidence-based recommendations for the quantity and quality of adolescent physical activity required to prevent or treat adolescent obesity.

Prevalence and associated factors with sunscreen use in Southern Brazil: A population-based study.

BACKGROUND: Sunscreen use is important for the prevention of skin cancer, but population-based information about its prevalence and associated factors are scarce in Brazil. OBJECTIVE: We sought to evaluate the prevalence and associated factors with sunscreen use among Brazilian adults. METHODS: We conducted a cross-sectional population-based study with a representative sample of adults aged 20 years or older living in the urban area of the city of Pelotas, Southern Brazil. We evaluated sunscreen use at the beach, at work, and during outdoor sports, for at least 20 minutes between 10 am and 4 Pm, from December 2004 to March 2005. The outcome measure was dichotomized in individuals who never used sunscreen, and those who used sunscreen, regardless of frequency. RESULTS: Prevalence of sunscreen use at the beach, work, and outdoor sports was 60.8% (95% confidence interval 55.6-66.0), 13.7% (95% confidence interval 10.7-16.6%), and 30.2% (95% confidence interval 24.1-36.3), respectively. At work, the median number of days of exposure was 70 days, whereas at the beach it was 10, and for sports it was 16. Women, whites, those with higher educational achievement, and those with higher income were more likely to use sunscreen. LIMITATIONS: No data on adequacy of sunscreen use were gathered. CONCLUSION: Our data show that the individuals most exposed to sunlight are those who use sunscreen the least. Interventions targeting this group are required, because this is also the population with the lowest socioeconomic level.