Early exposure to cannabis and bipolar disorder incidence: Findings from a 22-year birth cohort study in Brazil.

BACKGROUND AND OBJECTIVES: Bipolar disorder is a chronic condition affecting millions of people worldwide. Currently, there is some evidence to suggest that cannabis use during adolescence may be an environmental risk factor for its onset, however inconsistencies have been observed across the literature. Considering this, we aimed to assess whether early lifetime cannabis is associated with subsequent bipolar disorder in young adults between 18 and 22 years of age. METHODS: Using data from the 1993 Pelotas (Brazil) birth cohort (n = 5249), cannabis exposure was examined at age 18 by self-report, and bipolar disorder diagnosis was measured at age 22 using the Mini International Neuropsychiatric Interview (MINI). In order to control the analysis, we considered socioeconomic status index, sex, skin color, physical abuse by parents and lifetime cocaine use. RESULTS: A total of 3781 individuals were evaluated in 2015 aged 22 years, of whom 87 were diagnosed with the bipolar disorder onset after the age of 18. Lifetime cannabis use predicted bipolar disorder onset at 22 years old (OR 1.82, 95% CI [1.10, 2.93]), and the effect remained after adjusting for socioeconomic status, sex, skin color, and physical abuse by parents (OR 2.00, 95% CI [1.20, 3.25]). However, this association was attenuated to statistically non-significant after further adjustment for all available covariates, including lifetime cocaine use (OR 1.79, 95% CI [0.95, 3.19]). We also found similar results for early cocaine use, where the association with bipolar disorder onset did not maintain significance in the multivariate model (OR 1.35, 95% CI [0.62, 2.86]). Otherwise, when we considered cannabis or cocaine lifetime use as a unique feature, our findings showed that the adolescent exposure to cannabis or cocaine increased the odds by 1.95 times of developing bipolar disorder at 22 years age, even when controlling for all other study variables (OR 2.14, 95% CI [1.30, 3.47]). Finally, our models suggest that cocaine use may potentially exert a major influence on the effect of lifetime cannabis use on bipolar disorder onset, and that physical abuse by parents and sex may modify the effect of cannabis use for later bipolar disorder onset. CONCLUSION: Based on our findings, early cannabis exposure predicted bipolar disorder onset in young adults, but this association was confounded by cocaine use. Contrary to schizophrenia, cannabis as a sole exposure was not associated with bipolar disorder onset after adjusting for control variables.

Maternal smoking during pregnancy and birthweight on the third generation: results from two birth cohort studies.

The purpose of this research is to investigate whether grandmother's smoking during pregnancy reduces the grandchildren's birthweight and whether maternal smoking during pregnancy modified this association. We also evaluated the effect of duration and intensity of smoking. This study included data from three generations from two birth cohorts carried out in Pelotas, a southern Brazilian city: women enrolled in the perinatal study in the 1982 and 1993 cohorts (G1); daughters (G2) of those G1 mothers who were followed to adulthood; and first children (G3) born from G2 women. Information on maternal smoking during pregnancy was obtained from women (G1) shortly after delivery of the two cohorts and from G2 in the follow-up in adulthood of the 1993 cohort. Mothers (G2) reported G3 birthweight during the follow-up visit at adulthood. Multiple linear regression was used to obtain effect measures adjusted for confounders. The study included 1602 grandmothers (G1), mothers (G2), and grandchildren (G3). Prevalence of maternal (G1) smoking during pregnancy was 43% and mean G3 birthweight was 3118.9 g (SD: 608.8). Grandmother's smoking in the pregnancy was not associated with grandchild's birthweight. However, offspring of both G1 and G2 smokers had lower mean birthweight than those whose mother and grandmother did not smoke (adjusted ß: - 223.05; 95% CI: - 415.16, - 32.76). CONCLUSION: No significant association was observed between grandmother's smoking in the pregnancy and grandchild's birthweight. But it seems that grandmother's smoking in pregnancy has an effect on grandchild's birthweight when the mother also smoked in the pregnancy. . WHAT IS KNOWN: • Most studies on the association of maternal tobacco smoking in pregnancy with offspring birthweight have been restricted to two generations, and an inverse association is well known. WHAT IS NEW: • Besides to investigate whether grandmother's smoking during pregnancy reduces the grandchildren's birthweight, we examined whether this association varied according to maternal smoking during pregnancy.

Child maltreatment associates with violent victimization in young adulthood: a Brazilian birth cohort study.

BACKGROUND: Maltreatment in childhood may leave people vulnerable to further experiences of violence and more severe effects of stress later in life. Longitudinal studies of risk for violent victimisation after maltreatment are lacking in low- and middle-income countries. The objective of this study was to quantify the risk for violent victimization in the family and community in young adulthood following experiences of childhood maltreatment (experiences of physical, emotional and sexual abuse and neglect) up to age 15 years in an urban Brazilian population. METHODS: 3246 participants in a prospective, population-based birth cohort study in Pelotas, Rio Grande do Sul, Brazil, were assessed at birth, 15 and 22 years. Sociodemographic factors were reported by mothers at birth and adolescents at age 15 years. Maltreatment and violent victimisation were self-reported in confidential questionnaires at 15 and 22, respectively. Multinomial logistic regression analyses estimated the association between having experienced any maltreatment and later experiences of family and community violence in young adulthood (no adult violence, violence only in the family context, only in the community, or both violence in the family and community), adjusting for sociodemographic factors. RESULTS: 39% of females and 27% of males reported any maltreatment up to age 15 years. At 22 years, rates of past year violence in the family or community were 17.6% for females and 20.2% for males. Maltreatment was strongly associated with community violence (Females: OR = 2.96, CI = 1.83-4.80; Males: OR = 2.01, 95%CI = 1.01-4.00) and its co-occurrence with family violence (Females: OR = 2.33, 95%CI = 1.34-4.04; Males: OR = 3.20, 95%CI = 1.82-5.65) in young adulthood, after adjustment for background sociodemographic factors. CONCLUSION: Childhood maltreatment is an important risk factor for later violent victimisation in both the family and community context. The effects of repeated trauma through the life-course needs research and clinical attention.

ADHD in childhood predicts BMI and body composition measurements over time in a population-based birth cohort.

BACKGROUND/OBJECTIVES: Obesity has been reported as an attention-deficit hyperactivity disorder (ADHD) comorbidity. So far, few studies have aimed to explore the potential causal relationship between ADHD and obesity, as well as used other measures of body composition like fat-free mass (FFM) and fat mass (FM) as measures of obesity. This study aimed to test the association between ADHD and body composition (body mass index [BMI] and others) and to evaluate the potential causal relationship with obesity. SUBJECTS/METHODS: Data from the 1993 Pelotas (Brazil) birth cohort at age 11-, 15-, 18-, and 22-year follow-up was used. We performed a cross-lagged panel model (CLPM) analysis between ADHD symptoms and BMI to explore the causal relationship between both traits. Finally, we tested whether ADHD, inattention, and hyperactivity symptom scales were associated with BMI, FM, and FFM at 22 years. RESULTS: In the CLPM, higher ADHD scores at age 11 predicted higher BMI at age 15 (ß = 0.055, 95% CI [0.037; 0.073]). ADHD symptoms at age 11 was also associated with a decrease in the FFM (ß = -0.16, 95% CI [-0.28; -0.05]), and an increase in the BMI (ß = 0.17, 95% CI [0.10; 0.23]) and FM (ß = 0.17, 95% CI [0.06; 0.29]) at 22 years. At 22 years of age, ADHD was associated with FFM and FM. Moreover, an increase in BMI was observed with an increase in several symptoms of ADHD in general (ß = 0.06, 95% CI [0.004; 0.12]), and hyperactivity symptoms (ß = 0.15, 95% CI [0.05; 0.25]). CONCLUSION: ADHD at 11 years predicted a higher BMI at 15 years, and body fat composition in adulthood, suggesting higher scores on ADHD symptoms in early life may be a critical point for body composition in early adulthood. The hyperactivity symptoms may play an important role in the BMI increase.

Maternal smoking during pregnancy and intelligence quotient of offspring aged 18 and 30 years: Evidence from two birth cohorts in southern Brazil.

Maternal smoking during pregnancy causes several harmful effects, including deficits in the intelligence quotient (IQ), a measure associated with academic achievements and higher socioeconomic position. We aimed to measure the association between maternal smoking during pregnancy and offspring's IQ in two birth cohorts from Pelotas, Brazil. Data from the 1982 and 1993 birth cohorts were analyzed. Smoking during pregnancy was ascertained at the perinatal follow-up, and IQ was measured at 30 years (1982) and 18 years (1993). Simple and multiple linear regressions were used for crude and adjusted analysis. Mediation analysis was performed using birth weight and breastfeeding as possible mediators. Data analysis was conducted in 2020. There were 3611 and 4050 participants from the 1982 and 1993 cohorts, respectively. After adjustment for potential confounders, the inverse association between smoking during pregnancy and children's IQ remained significant in both cohorts. Offspring of mothers who smoked during pregnancy had an average of 1.32 less IQ points (95%CI: -2.23, -0.242) in the 1982 cohort, and an average of 1.66 less IQ points (95%CI: -2.42, -0.90) in the 1993 cohort. Neither cohort showed association with paternal smoking (negative controls) after adjustment. Breastfeeding's mediated effects accounted for 26.2% and 23.9% of the association in the 1982 and 1993 cohorts, respectively, while birth weight's accounted for 6.8% and 30.1%, respectively; indirect effects were not significant. The inverse association between maternal smoking and IQ and the lack of association with paternal smoking reinforces our findings of a negative association between exposure and outcome.

Prevalence of ideal cardiovascular health in young adults: A birth cohort from southern Brazil.

BACKGROUND: Ideal cardiovascular health (ICH) aims at primordial prevention of cardiovascular diseases in the population. However, there is a lack of research describing ICH in youth from middle-income countries. The aims of this study were to describe the prevalence of ICH at 18- and 22-year-old and to investigate the influence of socioeconomic status. METHODS: The sample consisted of participants from the Pelotas 1993 birth-cohort followed-up at 18- (n = 4,106) and 22-year-old (n = 3,810). Ideal metrics were created for diet, smoking, body mass index, physical activity, blood pressure, total cholesterol, and blood glucose. The presence of 4 or more ideal metrics was defined as ICH. Socioeconomic status was obtained using wealth quintiles calculated with factor analysis based on analysis based on the ownership of household and education. The impact of socioeconomic status on ICH metrics was statistically measured using the slope index of inequality. RESULTS: The prevalence of ICH was 84.5% (95% confidence interval [CI] = 82.7-86.2%) and 84.1% (82.3-85.8%) at 18-year-old and decreased to 61.1% (58.4-63.7%) and 68.7% (66.2-71.2%) at 22-years old, for male and female, respectively. Socioeconomic status influenced ICH and its components differently in males and females. Wealthiest females had ICH prevalence 19 percentage points (pp) (11-27 pp) higher compared to the poorest, whereas poorest males had ICH prevalence 12 pp (1-21 pp) higher compared to the wealthiest. Longitudinal decreases in ICH components were mostly present in the poorest females. CONCLUSIONS: In middle-income countries, the prevalence of ICH is high at 18-year-old and decreases in a 4-year follow-up. Socioeconomic status influences differently individuals' ICH between sexes. Efforts are needed to maintain ICH in youth and different strategies may be required between the social status.

The neurodevelopmental nature of attention-deficit hyperactivity disorder in adults.

BACKGROUND: Population studies have suggested that most adults with attention-deficit hyperactivity disorder (ADHD) did not have the disorder in childhood, challenging the neurodevelopmental conceptualisation of ADHD. Arbitrary definitions of age at onset and lack of defined trajectories were accounted for the findings. AIMS: The objective of this study was to assess the proportion of individuals presenting with either a neurodevelopmental trajectory or late-onset disorder, and to assess risk factors associated with them. METHOD: Data of 4676 individuals from the 1993 Pelotas birth cohort at 11, 15, 18 and 22 years of age were used. Polythetic and latent class mixed model analyses were performed to define ADHD trajectories from childhood to adulthood, and characterise the neurodevelopmental or late-onset courses. Regression models were applied to assess factors associated with different trajectories. RESULTS: Classical polythetic analyses showed that 67% of those with ADHD at 22 years of age had a neurodevelopmental course of the disorder. Latent class mixed model analysis indicated that 78% of adults with ADHD had a trajectory of persistent symptoms, more common in males. The remaining adults with ADHD had an ascending symptom trajectory that occurred after puberty, with late-onset ADHD associated with female gender and higher IQ. CONCLUSIONS: Both polythetic and latent trajectories analyses provided empirical evidence supporting that the large majority of adults with ADHD had a neurodevelopmental disorder.

How different online recruitment methods impact on recruitment rates for the web-based coortesnaweb project: a randomised trial.

BACKGROUND: The number of web-based E-epidemiologic studies using online recruitment methods is increasing. However, the optimal online recruitment method in terms of maximizing recruitment rates is still unknown. Our aim was to compare the recruitment rates of three online recruitment methods and to describe how these rates differ according to individual's socioeconomic and demographic factors. METHODS: A total of 2394 members of the 1993 Pelotas birth cohort that provided an e-mail address, a Facebook name, and a WhatsApp number during a face-to-face follow-up were randomly allocated to be recruited by e-mail, Facebook or WhatsApp (798 individuals per method). This was a parallel randomised trial applying a block randomisation (block size = 3). Between January and February 2018, we sent messages inviting them to register into the web-based coortesnaweb platform. Recruitment rates were calculated for each method, and stratified according to the individual's socioeconomic and demographic characteristics. We also analysed absolute and relative inequalities on recruitment according to schooling and socioeconomic position. RESULTS: Out of the 2394 individuals analysed, 642 registered into the platform. The overall recruitment rate was 26.8%. Recruitment rates for women were almost 10 percentage points higher compared to men. Facebook was the most effective recruitment method, as 30.6% of those invited through the social network were recruited. Recruitment rates of e-mail and WhatsApp were similar (recruitment rate = 24.9%). E-mail and Facebook were the most effective recruitment methods to invite highly educated and wealthier individuals. However, sending e-mails to recruit individuals also reflected in the highest inequalities according to schooling and socioeconomic position. In contrast, the lowest inequalities according to socioeconomic position were observed using Facebook. CONCLUSIONS: Facebook was the most effective online recruitment method, also achieving the most equitable sample in terms of schooling and socioeconomic position. The effectiveness of online recruitment methods depends on the characteristics of the sample. It is important to know the profile of the target sample in order to decide which online recruitment method to use. TRIAL REGISTRATION: Brazilian Registry of Clinical Trials, identifier: RBR-3dv7gc , retrospectively registered in 10 April 2018.

Association of risk behaviours, socio-economic characteristics and academic progress in adolescents: an analysis of the 1993 birth cohort in Pelotas, Brazil.

To analyze how socio-economic factors and behavioural characteristics are related to the failure of academic progress. Data of the 1993 Birth Cohort of the city of Pelotas, Brazil, were analyzed using four follow-up waves. As a measure of the failure of academic progress, we used indicators of the age-grade gap. We analyzed the association of demographic, socio-economic, and behavioural characteristics. Factors associated with failure of academic progress were assessed through logistic regression. There are a higher odds of the age-grade gap when the adolescent is not white, man, of low socio-economic status, whose parents have low schooling and living in large families. In relation to risk behaviours, alcohol and tobacco consumption represent higher odds of the age-grade gap at age 18. The results show that socio-economic factors and behavioural characteristics are important predictors of academic progress. Public policies that seek to promote education should be targeted at the most vulnerable groups, decreasing the observed inequalities.

Association between interleukin-6, C-reactive protein and adiponectin with adiposity: Findings from the 1993 pelotas (Brazil) birth cohort at 18 and 22 years.

BACKGROUND: Most of the literature has shown a direct association between adiposity, interleukin-6 (IL-6) and C-reactive protein (CRP), and an inverse association with adiponectin. The aim of this paper was to assess the association of obesity measurements and IL-6, CRP and adiponectin. METHODS: We performed cross-sectional/longitudinal analysis in the 1993 Birth Cohort in Brazil. Associations between IL-6 (pg/mL), CRP (mg/L) and adiponectin (µg/Ml) with body mass index (BMI), waist circumference (WC), percentage total fat mass (FM) (BODPOD) and trunk FM (DXA) were verified. Four trajectory variables were generated: (a) highest tertile/obesity according to BMI in both follow-ups; (b) highest tertile/obesity only at 18 years; (c) highest tertile/obesity only at 22 years; (d) not in the highest tertile/not obese at both ages. RESULTS: We found a direct association for IL-6 and CRP and an inverse association for adiponectin with measures of adiposity. For instance, for females, the highest mean IL-6 and CRP, respectively, was for those who had been in the obese category at 18-22 years (2.49; 3.75), in the highest tertile of WC (2.11; 3.08), in the highest % of FM (1.56; 3.30 l), and in the highest tertile of trunk FM (2.07; 3.26) (p < 0.001 for all these results in the adjusted analysis). Adiponectin showed an inverse association for the above variables, with lower mean values for males than females. CONCLUSION: There was a longitudinal and direct association between adiposity and IL-6 and CRP, and an inverse association with adiponectin at 22 years.

Lifelong robbery victimisation and mental disorders at age 18 years: Brazilian population-based study.

PURPOSE: Urban violence is a major problem in Brazil and may contribute to mental disorders among victims. The aim of this study was to assess the association between robbery victimisation and mental health disorders in late adolescence. METHODS: At age 18 years, 4106 participants in the 1993 Pelotas Birth Cohort Study were assessed. A questionnaire about history of robbery victimisation was administered, the Self-Report Questionnaire was used to screen for common mental disorders, and the Mini International Neuropsychiatric Interview was used to assess major depressive disorder and generalised anxiety disorder. Cross-sectional prevalence ratios between lifetime robbery victimisation and mental disorders were estimated using Poisson regression with robust standard errors, adjusting for socioeconomic variables measured at birth and violence in the home and maltreatment measured at age 15. RESULTS: There was a dose-response relationship between frequency of lifetime robberies and risk of mental disorders. Adolescents who had been robbed three or more times had twice the risk (PR 2.04; 95% CI 1.64-2.56) for common mental disorders, over four times the risk for depression (PR 4.59; 95% CI 2.60-8.12), and twice the risk for anxiety (PR 1.93; 95% CI 1.06-3.50), compared with non-victims, adjusting for covariates. Experiencing frequent robberies had greater impact on common mental disorders than experiencing an armed robbery. Population attributable fractions with regard to robbery were 9% for common mental disorders, 13% for depression, and 8% for anxiety. CONCLUSIONS: Robberies are associated with common mental disorders in late adolescence, independently of violence between family members. Reducing urban violence could significantly help in preventing common mental illnesses.

Are cytokines (IL-6, CRP and adiponectin) associated with bone mineral density in a young adult birth cohort?

BACKGROUND: Studies have shown that cytokines play a role in bone remodeling. METHODS: In 1993, all hospital births occurred in Pelotas (Brazil) were identified and a total of 5249 newborns were included in the present cohort. Sub-samples of this cohort were visited during childhood and all members were traced at 11, 15, 18 and 22 years old. At 18 and 22 years the following biomarkers were measured: IL-6, CRP and adiponectin (the last one in a sub-sample) and bone mineral density (BMD-mg/cm2) was evaluated at 22 years. Crude regression analysis as well as adjusted for confounders (birth weight, pregnancy maternal smoking, gestational age, skin color, schooling, income, smoking, alcohol, physical activity, medical diagnosis of asthma, diabetes and hypertension, BMI, height, calcium intake, corticosteroid use, age at menarche, insulin and testosterone) were performed between the three biomarkers and the whole-body, lumbar spine and femoral BMD. RESULTS: No statistical significant association was found between IL-6 and CRP with BMD, in males. Significant inverse association in the adjusted analysis, among females, was found for the highest tertiles of CRP at 22 y (beta - 15.2 mg/cm2; 95% CI: -25.4; - 4.9; p = 004), of CRP and IL-6 at 22 years (beta - 20.0 mg/cm2; 95% CI: -31.7; - 8.3; p = 0.003), and of IL-6 and CRP at both ages (beta - 20.3 mg/cm2; 95% CI: -38.0; - 2.5; p = 0.001) with total body BMD. Significant association, among males, was also found between the highest tertile of adiponectin at 22 y (beta - 23.3 mg/cm2; 95% CI: -35.5; - 11.1; p = < 001; beta - 22.5 mg/cm2; 95% CI: -42.9; - 2.2; p = 0.03; and beta - 31.8 mg/cm2; 95% CI: -55.5; - 9.1; p = 0.006) and total body, lumbar spine and femur neck BMD, respectively; and, among females, - 17.8 mg/cm2; 95% CI: -34.9; - 0.9; p = 0.033, with lumbar spine BMD. CONCLUSION: CRP at 22 years, in females, seems to be a marker for total body BMD; adiponectin at 22 years is also a marker for BMD at the three sites, in males, and for lumbar spine BMD, in females.

[Breastfeeding and externalizing behaviors in childhood and adolescence in a birth cohort]. / Amamentação e comportamentos externalizantes na infância e adolescência em uma coorte de nascimentos.

OBJECTIVE: To assess the association between breastfeeding duration and externalizing behaviors in childhood and adolescence. METHODS: Data from the 1993 Pelotas Birth Cohort was used. Information on breastfeeding was assessed at 12 months of age. Behavior was assessed at 4 years of age using the Child Behavior Checklist (CBCL), and at ages 11 and 15 years using the Strengths and Difficulties Questionnaire (SDQ), both administered to the mother or caretaker. Of 5 249 cohort participants, those with complete data on breastfeeding and externalizing behaviors were included: 630 children at 4 years of age, 1 277 adolescents at 11 years, and 1 199 at 15 years. Poisson regression with robust variance was used to assess the association between breastfeeding duration and externalizing behaviors. RESULTS: After adjustment for confounders, children who were breastfed for least 6 months had lower risk of hyperactivity (RR = 0.54; 95%CI: 0.32-0.91) at age 11 compared to those breastfed for less than 1 month. However, no association was observed between breastfeeding duration and externalizing behaviors at ages 4 and 15. CONCLUSIONS: Although breastfeeding for at least 6 months was inversely associated with hyperactivity at 11 years of age no association was observed at 4 and 15 years of age. Further longitudinal studies should focus on other aspects influencing externalizing behaviors, such as presence of the father in the family, domestic violence and abuse, and the quality of mother-child relationship.

Visceral and subcutaneous abdominal adiposity and pulmonary function in 30-year-old adults: a cross-sectional analysis nested in a birth cohort.

BACKGROUND: Several studies have verified body fat distribution in association with pulmonary function (PF), mainly waist circumference, but few have used measures able to distinguish abdominal fat compartments. The present study aims to verify the association of visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) with PF measures. METHODS: In 1982, all hospital births occurring in Pelotas, Brazil, were identified and those livebirths have been followed. In 2012-13, the cohort participants were evaluated and VAT and SAT measured using ultrasound; forced expiratory volume in the first second (FEV1) or forced vital capacity (FVC) were patronized in z-scores stratified by sex. The associations were verified using crude and adjusted linear regressions. RESULTS: The present analyses comprised 3438 individuals (1721 women). VAT was inversely associated with spirometric parameters, in both crude and adjusted models. SAT showed inverse associations in the crude analyzes in males and a positive trend after adjustment, except for SAT and FVC in males. To each centimeter of VAT, mean adjusted FEV1 z-scores decreased 0.072 (95% CI -0.107; -0.036) in men and 0.127 (95% CI -0.164; -0.090) in women, and FVC z-scores decreased -0.075 (95% CI -0.111; -0.039) and 0.121 (95% CI -0.158; -0.083), in men and women, respectively. CONCLUSIONS: VAT has a consistent inverse association with FEV1 and FVC in both sexes. On the other hand, SAT showed inconsistent results with PF parameters.

Physical activity throughout adolescence and body composition at 18 years: 1993 Pelotas (Brazil) birth cohort study.

BACKGROUND: Adolescence is a period of accelerated development and increases in body composition. Physical activity (PA) practice has been associated with the development of major components of body composition (bone, muscle and fat). However, the longitudinal effects of PA of different intensities during adolescence are still not well understood. Thus, the main goal this study has investigate the association between practice of moderate- and vigorous-intensity physical activity throughout adolescence and body composition, specifically lean mass (LM) and fat mass (FM), at age 18. METHODS: In this cohort study, physical activity was measured at 11, 15 and 18 years, using questionnaires. Thresholds of 300, 150 and 75 min per week, were used for MVPA, moderate- and vigorous-intensity physical activity, respectively. Consistent physical activity was defined as reaching the thresholds at the three follow-ups. FM and LM at age 18 were assessed by DXA and expressed as fat mass (FMI) and lean mass (LMI) indexes. To verify the association between the trajectories of MVPA, moderate- and vigorous-intensity physical activity in adolescence and FM and LM at 18, multivariate analyses were performed through multiple linear regressions adjusted for co-variables. RESULTS: A total of 3,176 adolescents were evaluated. The consistent practice of moderate- and vigorous-intensity physical activity according to thresholds during adolescence were directly related to the LMI in boys (moderate-intensity - ß = 0.40 and CI95 % 0.13; 0.68 and vigorous-intensity - ß = 0.95 and CI95 % 0.69; 1.21) and girls (Moderate-intensity - ß = 0.23 and CI95 % 0.02; 0.45 and vigorous-intensity - ß = 0.80 and CI95 % 0.29; 1.32). Practice of vigorous-intensity physical activity alone showed to be inversely associated with the FMI in boys (ß = -0.53 and CI95 % -0.96;-0.10). CONCLUSION: Consistent physical activity practice during adolescence was associated with greater lean mass in both sexes. In boys, vigorous-intensity physical activity was associated with less fat mass.

Impact of the age at menarche on body composition in adulthood: results from two birth cohort studies.

BACKGROUND: Evidence suggests that early menarche is positively associated with adiposity in adulthood. However, it is important to assess whether this association is due to early menarche or to the association of adiposity in late childhood with age at menarche. We evaluated the association between age at menarche and body composition in adolescence and adulthood, among subjects who have been prospectively followed in two Brazilian birth cohort studies. METHODS: In 1982 and 1993, the hospitals births in Pelotas were identified, and these subjects have been followed for several times. Information on age at menarche was obtained from the women (1982 cohort) and their mothers (1993 cohort). At 30 and 18 years, the following body composition measures were evaluated: body mass index, waist circumference, fat-free mass index and fat mass index measured by dual-energy x-ray absorptiometry, and thickness of the abdominal visceral fat layer measured by ultrasound. The analyses were adjusted for: birth weight, maternal pregestational weight, gestational age, family income, household score index, maternal schooling, weight-for-height z-score at 4 years (1982), and body mass index at 11 years (1993). RESULTS: At 30 and 18 years, 2045 and 2092 women were evaluated, respectively. The prevalence of early menarche (≤11 years of age) was 24.7 % in the 1982 and 27.6 % in the 1993 cohort. In the 1982 cohort, early menarche was positively associated with all body composition variables compared to those with late menarche (≥14 years of age) even after adjusting for confounders (fat mass index: 2.33 kg/m2, 95 % Confidence interval: 1.64; 3.02). However, in the 1993 cohort, after adjusting for body mass index at 11 years, the regression coefficient for the association with fat mass index decreased from 2.2 kg/m2 (95 % Confidence interval: 1.7; 2.6) to 0.26 (95 % Confidence interval: -0.08; 0.60). CONCLUSIONS: The association between age at menarche and body composition in adulthood is strongly explained by pre-pubertal adiposity.

Body mass index at 11 years and bone mass at age 18: path analysis within the 1993 Pelotas (Brazil) birth cohort study.

BACKGROUND: We investigated whether Body Mass Index (BMI) at 11 years old has a direct effect on bone mass at age 18 operating through alterations to bone growth and development, or whether the association is mediated by concurrent BMI, fat mass (FM), and fat free mass (FFM). METHODS: Path analysis was used to explore the association between BMI at age 11 and whole-body bone mineral content (BMC) and bone mineral density (BMD) assessed by dual-energy x-ray absorptiometry (DXA) at age 18 in a prospective birth cohort study comprising 3,307 adolescents; we also evaluated the degree to which this association was mediated by BMI, FM (kg) and FFM (kg) assessed by plethysmography (BOD POD) at age 18. RESULTS: We found a positive association between BMI at age 11 and BMC (males [ß = 179.7 g, 95% CI 161.4; 198.0]; females [ß = 179.9 g, 95% CI 165.3; 194.6]) and BMD (males [ß = 0.030 g/cm2, 95% CI 0.024; 0.035]; females [ß = 0.029 g/cm2, 95% CI 0.025; 0.033]) at age 18. This association was largely mediated by BMI and FFM at age 18 in both female and male adolescents. FM at age 18 was not an important mediator. CONCLUSIONS: Concurrent BMI and FFM were the main mediators of the association between BMC/BMD in late adolescence and BMI in early adolescence.

Cadherin-13 gene is associated with hyperactive/impulsive symptoms in attention/deficit hyperactivity disorder.

Several efforts have been made to find new genetic risk variants which explain the high heritability of ADHD. At the genome level, genes involved in neurodevelopmental pathways were pointed as candidates. CDH13 and CTNNA2 genes are within GWAS top hits in ADHD and there are emerging notions about their contribution to ADHD pathophysiology. The main goal of this study is to test the association between SNPs in CDH13 and CTNNA2 genes and ADHD across the life cycle in subjects with ADHD. This study included 1,136 unrelated ADHD cases and 946 individuals without ADHD. No significant association between CDH13 and CTNNA2 was observed between cases and controls across different samples (P ≥ 0.096 for all comparisons). No allele was significantly more transmitted than expected from parents to ADHD probands. The CDH13 rs11150556 CC genotype was associated with more hyperactive/impulsive symptoms in youths with ADHD (children/adolescents clinical sample: F = 7.666, P = 0.006, FDR P-value = 0.032; Pelotas Birth Cohort sample: F = 6.711, P = 0.011, FDR P-value = 0.032). Although there are many open questions regarding the role of neurodevelopmental genes in ADHD symptoms, the present study suggests that CDH13 is associated with hyperactive/impulsive symptoms in youths with ADHD.

[Association between birth conditions and bone mineral density in adults from the 1982 and 1993 birth cohorts in Pelotas, Rio Grande do Sul State, Brazil]. / Associação entre as condições de nascimento e a densidade mineral óssea de adultos das coortes de nascimentos de 1982 e 1993 de Pelotas, Rio Grande do Sul, Brasil.

This study assessed the association of birth weight, gestational age, and intrauterine growth with bone mineral density (BMD) at 22 and 30 years of age in the 1982 and 1993 birth cohorts in Pelotas, Rio Grande do Sul State, Brazil. BMD was measured by dual-energy X-ray absorptiometry (DXA) and the association was assessed using analysis of variance. Multiple linear regression was used to control for confounding factors: sex; household income at birth; maternal smoking during pregnancy; maternal schooling; maternal ethnicity/skin color; and pre-pregnancy body mass index. The study tested whether body fat in adulthood was a mediator of the association analyzed, using the G-computation Formula. A total of 6,803 participants from the 1982 and 1993 cohorts were evaluated at 30 and 22 years of age, respectively. Birth weight was associated with BMD at all sites, with a greater difference at the femoral neck. Individuals born weighing less than 2,000g had on average -0.036g/cm2 (95%CI: -0.064; -0.008) of BMD in the femoral neck than individuals weighing more than 3,500g. Individuals with an intrauterine growth z-score at least 1.28 standard deviation below the mean had an average of -0.013g/cm2 (95%CI: -0.024; -0.002) of BMD in the lumbar spine compared with individuals with an above-average z-score. The mediation analysis showed that body fat in adulthood did not mediate the association. Birth conditions have been associated with BMD in adulthood and the identification of early factors related to bone loss is essential due to the demographic inversion that has been taking place in low- and middle-income countries.

Este estudo avaliou a associação do peso ao nascer, idade gestacional e crescimento intrauterino com a densidade mineral óssea (DMO) aos 22 e 30 anos, nas coortes de nascimentos de 1982 e 1993 de Pelotas, Rio Grande do Sul, Brasil. A DMO foi medida por absorciometria por raios X com dupla energia (DXA), a associação foi avaliada usando análise de variância e a regressão linear múltipla para o controle de confundimento por: sexo, renda familiar ao nascer, tabagismo materno na gestação, escolaridade materna, cor da pele materna e índice de massa corporal pré-gestacional. Foi testado se a gordura corporal na vida adulta era mediadora da associação analisada, por meio da G-computation Formula. Foram avaliados 6.803 participantes das coortes de 1982 e 1993, aos 30 e 22 anos, respectivamente. O peso ao nascer teve associação com a DMO em todos os sítios, com maior diferença no colo femoral. Os nascidos com menos de 2.000g apresentaram, em média, -0,036g/cm2 (IC95%: -0,064; -0,008) de DMO no colo femoral em comparação àqueles com mais de 3.500g. Aqueles com escore-z de crescimento intrauterino com pelo menos 1,28 desvio padrão abaixo da média apresentaram, em média, -0,013g/cm2 (IC95%: -0,024; -0,002) de DMO na coluna lombar, em relação aos com escore-z acima da média. A análise de mediação mostrou que gordura corporal na idade adulta não mediou a associação. As condições de nascimento foram associadas com a densidade mineral óssea na vida adulta, e a identificação dos fatores precoces relacionados à perda de DMO é essencial devido à inversão demográfica em progresso em países de média e baixa renda.

Este estudio evaluó la asociación del peso al nacer, la edad gestacional y el crecimiento intrauterino con la densidad mineral ósea (DMO) a los 22 y 30 años de edad, en las Cohortes de Nacimiento de 1982 y 1993 de Pelotas, Rio Grande do Sul, Brasil. La DMO se midió mediante absorciometría de rayos X de doble emisión (DXA), y la asociación se evaluó mediante ANOVA y regresión lineal múltiple para controlar la confusión por sexo, ingresos familiares al nacer, tabaquismo materno durante el embarazo, escolaridad materna, color de piel materno e índice de masa corporal antes del embarazo. Se comprobó si la grasa corporal en la edad adulta era un mediador de la asociación analizada, utilizando G-computation Formula. Se evaluaron 6.803 participantes de las cohortes 82 y 93, de 30 y 22 años, respectivamente. El peso al nacer se asoció con la DMO en todos los sitios, con la mayor diferencia en el cuello femoral. Los nacidos con un peso inferior a 2.000g tuvieron una media de -0,036g/cm2 (IC95%: -0,064; -0,008) de DMO en el cuello femoral, que aquellos con más de 3.500g. Aquellos con una puntuación z de crecimiento intrauterino de al menos 1,28 desviaciones estándar por debajo de la media presentaron un promedio de -0,013g/cm2 (IC95%: -0,024; -0,002) de DMO en la columna lumbar, con relación a aquellos con un puntaje z superior a la media. El análisis de mediación mostró que la grasa corporal en la edad adulta no medió la asociación. Las condiciones de nacimiento se asociaron con la DMO en la edad adulta, y la identificación temprana de factores relacionados con la pérdida de DMO es esencial debido a la inversión demográfica que ha estado ocurriendo en los países de ingresos medios y bajos.

Maternal mental health and offspring's IQ: Evidence from two Brazilian birth cohorts.

Maternal mental health during different stages of life can have a significant impact on a child's cognitive development. This study aimed to investigate the association between maternal CMD at two distinct stages of the offspring's life (at 3 months and 11 years) and their IQ scores at 6 and 18 years across two birth cohorts. The study utilized data from two Brazilian birth cohorts: the 1993 cohort (full sample: N = 3719, subsample: N = 436), and the 2004 Pelotas Birth Cohort (N = 3440). IQ assessments were conducted at ages 18 and 6, employing the Wechsler Adult Intelligence Scale, third version (WAIS-III), and Wechsler Intelligence Scale for Children, third version (WISC-III), respectively. The presence of maternal CMD at 3 months and 11 years of age was evaluated using the Brazilian version of the Self-Reporting Questionnaire (SRQ-20). After adjustment, participants whose mothers experienced CMD at 3 months had average IQ scores 1.74 (95 % CI: -2.83 to -0.67) and 2.79 (95 % CI: -5.54 to -0.04) points lower at ages 6 (2004 cohort) and 18 (1993 cohort subsample), respectively. Furthermore, in the 1993 cohort (both full and subsample), maternal CMD at 11 years was associated with lower IQ scores at age 18. Understanding the mechanisms underlying this association, emphasized by these findings, is crucial for promoting children's cognitive development, educational achievement, and overall well-being.