The satisfactory growth and development at 2 years of age of the INTERGROWTH-21st Fetal Growth Standards cohort support its appropriateness for constructing international standards

Background

The World Health Organization recommends that human growth should be monitored with the use of international standards. However, in obstetric practice, we continue to monitor fetal growth using numerous local charts or equations that are based on different populations for each body structure. Consistent with World Health Organization recommendations, the INTERGROWTH-21^st Project has produced the first set of international standards to date pregnancies; to monitor fetal growth, estimated fetal weight, Doppler measures, and brain structures; to measure uterine growth, maternal nutrition, newborn infant size, and body composition; and to assess the postnatal growth of preterm babies. All these standards are based on the same healthy pregnancy cohort. Recognizing the importance of demonstrating that, postnatally, this cohort still adhered to the World Health Organization prescriptive approach, we followed their growth and development to the key milestone of 2 years of age.

Objective

The purpose of this study was to determine whether the babies in the INTERGROWTH-21^st Project maintained optimal growth and development in childhood.

Study Design

In the Infant Follow-up Study of the INTERGROWTH-21^st Project, we evaluated postnatal growth, nutrition, morbidity, and motor development up to 2 years of age in the children who contributed data to the construction of the international fetal growth, newborn infant size and body composition at birth, and preterm postnatal growth standards. Clinical care, feeding practices, anthropometric measures, and assessment of morbidity were standardized across study sites and documented at 1 and 2 years of age. Weight, length, and head circumference age- and sex-specific z-scores and percentiles and motor development milestones were estimated with the use of the World Health Organization Child Growth Standards and World Health Organization milestone distributions, respectively. For the preterm infants, corrected age was used. Variance components analysis was used to estimate the percentage variability among individuals within a study site compared with that among study sites.

Results

There were 3711 eligible singleton live births; 3042 children (82%) were evaluated at 2 years of age. There were no substantive differences between the included group and the lost-to-follow up group. Infant mortality rate was 3 per 1000; neonatal mortality rate was 1.6 per 1000. At the 2-year visit, the children included in the INTERGROWTH-21^st Fetal Growth Standards were at the 49th percentile for length, 50th percentile for head circumference, and 58th percentile for weight of the World Health Organization Child Growth Standards. Similar results were seen for the preterm subgroup that was included in the INTERGROWTH-21^st Preterm Postnatal Growth Standards. The cohort overlapped between the 3rd and 97th percentiles of the World Health Organization motor development milestones. We estimated that the variance among study sites explains only 5.5% of the total variability in the length of the children between birth and 2 years of age, although the variance among individuals within a study site explains 42.9% (ie, 8 times the amount explained by the variation among sites). An increase of 8.9 cm in adult height over mean parental height is estimated to occur in the cohort from low-middle income countries, provided that children continue to have adequate health, environmental, and nutritional conditions.

Conclusion

The cohort enrolled in the INTERGROWTH-21^st standards remained healthy with adequate growth and motor development up to 2 years of age, which supports its appropriateness for the construction of international fetal and preterm postnatal growth standards.

Prevalence and risk factors of psychiatric disorders in early adolescence: 2004 Pelotas (Brazil) birth cohort

PURPOSE

The present study aimed to evaluate the prevalence of psychiatric disorders in early adolescence, to examine the distribution of psychiatric disorders by maternal and child characteristics and to evaluate the occurrence of psychiatric comorbidities.

METHODS

This was a prospective cohort study of all live births in the city of Pelotas, Brazil, in 2004 (n = 4231). A total of 3562 subjects were evaluated at 11 years of age. Psychiatric disorders were assessed using the Development and Well-Being Assessment. Crude and adjusted logistic regression was used to investigate risk factors for any psychiatric disorder.

RESULTS

According to DSM-5 criteria, the overall prevalence of psychiatric disorders was 13.2% (n = 471), 15.6% among the boys and 10.7% among the girls. The most common disorders were anxiety disorders (4.3%), any attention deficit/hyperactivity disorder (4.0%) and any conduct/oppositional disorder (2.8%). Low maternal education, smoking during pregnancy, the presence of moods symptoms during pregnancy or maternal chronic and severe depressive symptoms in the first years of the adolescent´s life, male gender, 5-min Apgar score < 7 at birth and preterm birth were associated with higher odds of any psychiatric disorder at age 11. Psychiatric comorbidities were observed in 107 subjects (22.7%), of whom 73, 24, and 10 had two, three, and four psychiatric diagnoses, respectively.

CONCLUSIONS

Our results underscore the importance of psychiatric disorders as a prevalent condition in early adolescence, which has a direct impact on the planning of public policies and specific mental health care services in this age group.

Socioeconomic inequality in preterm birth in four Brazilian birth cohort studies

OBJECTIVE

To analyze economic inequality (absolute and relative) due to family income in relation to the occurrence of preterm births in Southern Brazil.

METHODS

Four birth cohort studies were conducted in the years 1982, 1993, 2004, and 2011. The main exposure was monthly family income and the primary outcome was preterm birth. The inequalities were calculated using the slope index of inequality and the relative index of inequality, adjusted for maternal skin color, education, age, and marital status.

RESULTS

The prevalence of preterm births increased from 5.8% to approximately 14% (p-trend<0.001). Late preterm births comprised the highest proportion among the preterm births in all studies, although their rates decreased over the years. The analysis on the slope index of inequality demonstrated that income inequality arose in the 1993, 2004, and 2011 studies. After adjustment, only the 2004 study maintained the difference between the poorest and the richest subjects, which was 6.3 percentage points. The relative index of inequality showed that, in all studies, the poorest mothers were more likely to have preterm newborns than the richest. After adjustment for confounding factors, it was observed that the poorest mothers only had a greater chance of this outcome in 2004.

CONCLUSION

In a final model, economic inequalities resulting from income were found in relation to preterm births only in 2004, although a higher prevalence of prematurity continued to be observed in the poorest population, in all the studies.

Social inequalities in mental disorders and substance misuse in young adults : A birth cohort study in Southern Brazil

PURPOSE

To investigate the association between mental disorders and substance misuse at 30 years of age with gender, socioeconomic position at birth, and family income trajectories.

METHODS

The 1982 Pelotas Birth Cohort was used; all 5914 children born alive at hospital were originally enrolled (99.2% of all city births). In 2012, 3701 subjects were located and interviewed (68% retention rate). Mental disorders and substance misuse were assessed, and their prevalence analysed according to gender, socioeconomic status at birth, and four different income trajectories: always poor, never poor, poor at birth/non-poor at age 30, and non-poor at birth/poor at age 30.

RESULTS

While women presented higher prevalence of mental disorders, substance misuse was much more frequent among men. Individuals in the lowest income quintile at birth presented 2-5 times more mental disorders and substance misuse than those in the highest quintile. Young adults who were always poor or were not poor at birth but were poor at 30 years of age had a higher prevalence of mental disorders than the other groups.

CONCLUSIONS

The high rates of mental disorders and lifetime suicide attempts in young adults, especially those who were always poor or became poor after childhood, suggest that recent socioeconomic-related stressful situations may have a higher impact on the current mental health than events earlier in life. However, we could not identify at what specific ages socioeconomic changes were more important.

Breastfeeding and complementary feeding associated with body composition in 18-19 years old adolescents in the 1993 Pelotas Birth Cohort

Background

The first years of life are critical for human development, therefore it is important to investigate early factors that may influence the development of body composition later in life. In this study, we aimed to evaluate the association between breastfeeding duration and age of introduction of complementary feeding with body composition at 18–19 years.

Methods

This is a prospective study conducted with adolescents belonging to the 1993 Pelotas Birth Cohort. Duration of breastfeeding, age of introduction of other types of milk and complementary feeding were obtained from a subsample of this cohort periodically monitored during the first year of life. The fat mass (FM) and fat-free mass (FFM) indices were estimated using plethysmography (BOD POD ™). Crude and adjusted analyses were stratified by sex using a linear regression model.

Results

1438 adolescents (694 boys and 744 girls) had complete information on exposures and outcomes.. Among men, the mean FMI and FFMI were 4.0 ± 3.1 kg / m² and 19.0 ± 1.9 kg / m²; and among women, 8.0 ± 3.2 kg / m² and 15.5 ± 1.7 kg / m², respectively. Neither breastfeeding duration nor age of introduction of complementary foods was associated with mean FMI in both sexes. Mean FFMI was higher among women who were breastfed for three months or more and among men who were breastfed for six months or more. Women who started the complementary feeding after five months of age had lower mean FFMI in adolescence.

Conclusion

The data suggest that only mean FFM in adolescence is associated with early feeding behaviors.

Electronic supplementary material

The online version of this article (10.1186/s40795-017-0201-z) contains supplementary material, which is available to authorized users.

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.

Does objectively measured physical activity modify the association between early weight gain and fat mass in young adulthood?

Background

Substantial evidence suggests that weight gain in early life is associated with increased adiposity and other metabolic disorders later in life. It is, however, unknown whether physical activity (PA) may modify these associations. We aimed to examine whether objectively measured PA at 30 years modified the associations between conditional weight gain in infancy (0–2 y) and childhood (2–4 y) with fat mass index (FMI) and visceral abdominal fat measured at age 30 years.

Methods

Prospective birth cohort study in Pelotas, Brazil, including 1874 participants with weight data at birth, two and four years of age, and measures of FMI, visceral abdominal fat and PA at a mean age of 30.2 years. At age 30, time spent (min/day) in moderate-to-vigorous physical activity (MVPA) was measured objectively using a wrist-worn accelerometer worn for four to seven consecutive days.. Multiple linear regression analyses was performed to assess the associations between conditional weight gain and outcome variables at 30 years, adjusting for covariates. We examined whether PA modified the association between conditional weight gain and the outcomes of interest by introducing an interaction term (conditional weight gain × PA) in the models.

Results

Conditional weight gain in infancy and childhood were both positively associated with later FMI (infancy weight gain: β = 0.68, 95% CI: 0.48, 0.88; P < 0.001; childhood weight gain: β = 0.91, 95% CI: 0.70, 1.11; P < 0.001). A formal test for interaction suggested that MVPA at 30 years of age modified the association between childhood relative weight gain and later FMI (β = −0.006, 95% CI: -0.011, −0.001; P = 0.029), suggesting stronger associations between weight gain and FMI in those with lower levels of MVPA. Conditional weight gain in childhood was also positively associated with visceral abdominal fat (β = 0.24, 95% CI: 0.15, 0424, P < 0.001). There was no evidence for a modification of the latter association after adjustment for physical activity.

Conclusion

Conditional weight gain between 2 and 4 years of age is associated with increased FMI at age 30 years. However, higher levels of MVPA appear to attenuate this detrimental association.

Characteristics and factors associated with hospitalization in early childhood: 2004 Pelotas (Brazil) birth cohort

Hospitalization is a frequent event in early childhood. In Brazil, the National Household Sample Survey of 2008 showed a 9% hospitalization rate among children in the first four years of life. The study aimed to describe the characteristics of hospitalization in the first six years of life and analyze the early factors associated with hospitalization in a birth cohort in southern Brazil. A zero-inflated Poisson model was used to simultaneously examine the effects of co-variables for the occurrence of a given event and to count events. The frequency of at least one episode of hospitalization during the study period was 33.4% (95%CI: 31.8-34.9), and was highest in the first year (19.1%; 95%CI: 17.9-20.4), remaining stable at approximately 10% between the first and fourth years, decreasing to 8.4% (95%CI: 7.6-9.4) between the fourth and sixth years. diseases of the respiratory system were among the leading causes of hospitalization, followed by infectious and parasitic diseases. History of prior hospitalization was one of the most important predictors of odds of hospitalization and risk of multiple hospitalizations. In early childhood, birth weight, gestational age, Apgar score, sex, and type of pregnancy were inversely associated with hospitalization, and environmental characteristics such as maternal smoking in pregnancy, mother's skin color, and low family income were associated statistically with number of hospitalizations. The results point to the importance of focusing efforts on reducing hospitalizations from diseases of the respiratory system, especially in children under one year.

Prolonged breastfeeding for 24 months or more and mental health at 6 years of age: evidence from the 2004 Pelotas Birth Cohort Study, Brazil

BACKGROUND

There is scarce and conflicting evidence on medium- to long-term effects of prolonged breastfeeding on child behavior.

METHOD

A population-based birth cohort study started in 2004 in the city of Pelotas, Southern Brazil. Children were followed up at 3, 12, 24, and 48 months and 6 years of age. Breastfeeding duration was determined based on information collected around the time of weaning. Psychiatric disorders were assessed using the Development and Well-Being Assessment (DAWBA). Children who were never breastfed were excluded from the analysis. Crude and adjusted analyses were performed using Poisson regression with robust variance.

RESULTS

Data on breastfeeding and mental health at the age of 6 years were available for 3377 children. Prevalence of breastfeeding for 24-35 months and ≥36 months was 16.1% (95% CI: 14.8-17.3) and 8.1% (95% CI: 7.2-9.1), respectively. Prevalence of psychiatric disorders among those who were breastfed for <24 months, 24-35 months and ≥36 months was 12.4% (95% CI: 11.1-13.7), 13.1% (95% CI: 10.4-16.2) and 12.3% (95% CI: 8.7-16.8), respectively. No association was found between breastfeeding for 24 months or more and psychiatric disorders among children aged 6 years both in the crude and adjusted analyses.

CONCLUSIONS

In this cohort there was no association between breastfeeding for 24 months or more and an increased prevalence of psychiatric disorders at the age of 6 years. Studies analyzing the medium- and long-term effects of prolonged breastfeeding for 2 years or more are scarce and further research is needed regarding this practice.

Maternal depression and bullying victimization among adolescents: Results from the 2004 Pelotas cohort study

BACKGROUND

Maternal depression impacts on several detrimental outcomes during a child's life course, and could increase their risk of victimization. This longitudinal study examined the association between antenatal maternal depression, postnatal trajectories, and current maternal depression and offspring bullying victimization at 11 years.

METHODS

We included 3,441 11-year-old adolescents from the 2004 Pelotas Cohort Study. Antenatal maternal depression, postnatal trajectories, and current maternal depression data were assessed during the follow-up waves. Bullying victimization was self-reported by the adolescents. We used ordinal logistic regression to estimate the odds ratio (OR) and 95% confidence intervals (CIs), for the association between maternal depression and offspring bullying victimization.

RESULTS

The most prevalent type of bullying was verbal victimization (37.9%). We observed a positive association between antenatal maternal depression, postnatal trajectories, and current maternal depression and physical bullying victimization. Maternal mood symptoms during pregnancy were associated with physical (OR = 1.30, 95%CI = 1.11-1.53), verbal (OR = 1.29, 95%CI = 1.12-1.49), and any victimization (OR = 1.22, 95%CI = 1.05-1.41). Severe current maternal depression was associated with physical (OR = 1.34, 95%CI = 1.10-1.62), social manipulation (OR = 1.29, 95%CI = 1.08-1.53), attacks on property (OR = 1.30, 95%CI = 1.08-1.57) and any victimization (OR = 1.32, 95%CI = 1.12-1.56). Regarding maternal depression trajectories, the "chronic-high" group was associated with higher risk of social manipulation, attacks on property and any victimization, than the "low" group.

CONCLUSIONS

Our results strengthen the evidence of association between maternal depression and offspring bullying victimization, and physical victimization appears to be the main component. Further studies are warranted to confirm our findings and to elucidate the theoretical pathways for this longitudinal association.

Gestational age at birth and behavioral problems from four to 11 years of age: birth cohort study

BACKGROUND

Studies conducted mainly in high-income countries have shown that preterm births are associated with increased risk of behavioral problems and psychiatric disorders. The aim of this study was to assess the prevalence of behavioral problems from middle-childhood to early-adolescence according to gestational age at birth in a middle-income setting.

METHODS

A population-based birth cohort (n = 4231) in Pelotas, Brazil, was followed-up in several occasions from birth to 11 years. Estimated GA was based on last menstrual period or, when unknown or inconsistent, on the Dubowitz method. Behavioral problems were assessed at 4 (Child Behavior Checklist - CBCL), and at 6 and 11 years (Development and Well-Being Assessment - DAWBA) tool. Maternal socio-economic characteristics and depression at 2, 4 and 6 years post-partum, child perinatal characteristics and breastfeeding duration were used as confounders. Analyses were run by linear and logistic regression.

RESULTS

Three thousand two hundred four children had full information on gestational age, CBCL and DAWBA. At 4 years, mean total (42.9 ± 24.0) and mean externalizing (18.8 ± 9.1) CBCL scores were higher among preterm girls born at <34 weeks than among full term girls (33.2 ± 15.1 and 15.0 ± 6.6, respectively). After controlling for confounders the association was no longer significant. At the age of 6 years there was no association between gestational age and behavior, neither in crude nor in adjusted analyses. Odds ratio for any psychiatric disorders at 11 years was 60% (1.6; 1.1-2.1) higher among those born at 34-36 weeks than in full-term children, but the association disappeared in adjusted analyses.

CONCLUSION

At this large cohort, behavioral problems from middle-childhood to early-adolescence are more related to family socio-economic characteristics and to other child perinatal conditions than to gestational age at birth.

Estimates of burden and consequences of infants born small for gestational age in low and middle income countries with INTERGROWTH-21st standard: analysis of CHERG datasets

Objectives To estimate small for gestational age birth prevalence and attributable neonatal mortality in low and middle income countries with the INTERGROWTH-21^st birth weight standard.Design Secondary analysis of data from the Child Health Epidemiology Reference Group (CHERG), including 14 birth cohorts with gestational age, birth weight, and neonatal follow-up. Small for gestational age was defined as infants weighing less than the 10th centile birth weight for gestational age and sex with the multiethnic, INTERGROWTH-21^st birth weight standard. Prevalence of small for gestational age and neonatal mortality risk ratios were calculated and pooled among these datasets at the regional level. With available national level data, prevalence of small for gestational age and population attributable fractions of neonatal mortality attributable to small for gestational age were estimated.Setting CHERG birth cohorts from 14 population based sites in low and middle income countries.Main outcome measures In low and middle income countries in the year 2012, the number and proportion of infants born small for gestational age; number and proportion of neonatal deaths attributable to small for gestational age; the number and proportion of neonatal deaths that could be prevented by reducing the prevalence of small for gestational age to 10%.Results In 2012, an estimated 23.3 million infants (uncertainty range 17.6 to 31.9; 19.3% of live births) were born small for gestational age in low and middle income countries. Among these, 11.2 million (0.8 to 15.8) were term and not low birth weight (≥2500 g), 10.7 million (7.6 to 15.0) were term and low birth weight (<2500 g) and 1.5 million (0.9 to 2.6) were preterm. In low and middle income countries, an estimated 606 500 (495 000 to 773 000) neonatal deaths were attributable to infants born small for gestational age, 21.9% of all neonatal deaths. The largest burden was in South Asia, where the prevalence was the highest (34%); about 26% of neonatal deaths were attributable to infants born small for gestational age. Reduction of the prevalence of small for gestational age from 19.3% to 10.0% in these countries could reduce neonatal deaths by 9.2% (254 600 neonatal deaths; 164 800 to 449 700).Conclusions In low and middle income countries, about one in five infants are born small for gestational age, and one in four neonatal deaths are among such infants. Increased efforts are required to improve the quality of care for and survival of these high risk infants in low and middle income countries.

Screen-based sedentary behavior during adolescence and pulmonary function in a birth cohort

Background

Adolescents spend many hours in sitting activities as television viewing, video game playing and computer use. The relationship between sedentary behavior and respiratory health remains poorly elucidated. To date there have been no studies evaluating the relationship between sedentary behavior and pulmonary function in young populations. The purpose of this study is to examine the association between the trajectory of screen-based sedentary behavior from 11 to 18 years and pulmonary function at 18 years in a Brazilian birth cohort.

Methods

Data from a longitudinal prospective study conducted among the participants of the 1993 Pelotas (Brazil) Birth Cohort. Time spent on television, video games, and computers during a weekday was self-reported at ages 11, 15 and 18 years. For each age, sedentary behavior was defined as the sum of time spent on these screen-based activities. To evaluate the sedentary behavior trajectory during adolescence group-based trajectory modeling was used. Outcome variables were three pulmonary function parameters: forced expiratory volume in one second (FEV₁), forced vital capacity (FVC), and peak expiratory flow (PEF), evaluated by spirometry, at 18 years expressed as z-scores. Crude and adjusted linear regressions, stratified by sex, were performed.

Results

The three-group trajectory of sedentary behavior was the best fitting model. The trajectory groups were: always high (representing 38.8% of the individuals), always moderate (54.1%), and always low (7.1%). In the adjusted analyses, boys in the always-low group for sedentary behavior had higher FVC at 18 years (β = 0.177; 95% CI:0.027;0.327; p = 0.021) than boys in the always-high group. There were no differences for other pulmonary function parameters in boys. No significant association was found for girls.

Conclusion

The trajectory of screen-based sedentary behavior throughout adolescence was not consistent associated with pulmonary function at 18 years.

Electronic supplementary material

The online version of this article (doi:10.1186/s12966-017-0536-5) contains supplementary material, which is available to authorized users.

A different rhythm of life: sleep patterns in the first 4 years of life and associated sociodemographic characteristics in a large Brazilian birth cohort

Objective

Sleep is an important marker of healthy development and has been associated with emotional, behavioral, and cognitive development. There is limited longitudinal data on children's sleep with only a few reports from low- and middle-income countries (LMICs). We investigate sleep parameters and associated sociodemographic characteristics in a population-based longitudinal study in Pelotas, Brazil.

Methods

Data from the Pelotas 2004 Birth Cohort were used (N = 3842). Infant sleep was collected through maternal report at 3, 12, 24, and 48 months: sleep duration, bed and wake time, nighttime awakenings, co-sleeping and sleep disturbances (24 and 48 months).

Results

Compared to children in high-income countries (HICs), children in Brazil showed a substantial shift in rhythms with later bed and wake times by approximately 2 hours. These remain stable throughout the first 4 years of life. This population also shows high levels of co-sleeping which remain stable throughout (49.0–52.2%). Later bedtime was associated with higher maternal education and family income. Higher rates of co-sleeping were seen in families with lower income and maternal education and for children who were breastfed. All other sleep parameters were broadly similar to data previously reported from HICs.

Conclusion

The shift in biological rhythms in this representative community sample of children in Brazil challenges our understanding of optimal sleep routine and recommendations.

•

Biological rhythms are shifted with later bedtime by approximately 2 h (22.18 hours).

•

Later bedtime is associated with higher maternal education and family income.

•

High levels of co-sleeping are prevalent until 4 years of age (49% at 3 months to 52% at 4 years).

•

Co-sleeping was more prevalent in families with lower income and maternal education.

Perinatal and postnatal risk factors for disruptive mood dysregulation disorder at age 11: 2004 Pelotas Birth Cohort Study

BACKGROUND

To date, there have been few studies of DMDD examining the risk factors during gestation and during the first years of life. We assessed the perinatal and postnatal risk factors associated with the occurrence of disruptive mood dysregulation disorder (DMDD) by 11 years of age.

METHODS

Prospective longitudinal study. Mothers completed a standardized questionnaire shortly after childbirth. We used the Development and Well-Being Assessment, administered to the mothers or legal guardians, to identify DMDD among the 11-year-old subjects. We also employed logistic regression to perform bivariate and multivariate analyses, using a theoretical model of conceptual analysis.

RESULTS

We evaluated data related to 3563 subjects at 11 years of age. The prevalence of DMDD was 2.5% (95% CI=2.0-3.0). After adjusting for potential confounders, we found that the early risk factors for the development of DMDD by 11 years of age were maternal mood symptoms during pregnancy, maternal depression during the first years after childbirth, and low maternal level of education.

LIMITATIONS

We were unable to evaluate the genetic characteristics of the family at the birth of each subject, and there were no data available regarding the prenatal or postnatal mental health of the fathers.

CONCLUSIONS

The prevalence of DMDD in early adolescence is low and its risk factors are related to potentially modifiable maternal characteristics. Scientific evidence indicates that DMDD is a major predictor of other psychiatric disorders, especially depression and anxiety. Effective prenatal and postnatal mental health care could prevent mental disorders in offspring.

Focus and coverage of Bolsa Família Program in the Pelotas 2004 birth cohort

OBJECTIVE

To describe the focalization and coverage of Bolsa Família Program among the families of children who are part of the 2004 Pelotas birth cohort (2004 cohort).

METHODS

The data used derives from the integration of information from the 2004 cohort and the Cadastro Único para Programas Sociais do Governo Federal (CadÚnico – Register for Social Programs of the Federal Government), in the 2004-2010 period. We estimated the program coverage (percentage of eligible people who receive the benefit) and its focus (proportion of eligible people among the beneficiaries). We used two criteria to define eligibility: the per capita household income reported in the cohort follow-ups and belonging to the 20% poorest families according to the National Economic Indicator (IEN), an asset index.

RESULTS

Between 2004 and 2010, the proportion of families in the cohort that received the benefit increased from 11% to 34%. We observed an increase in all wealth quintiles. In 2010, by income and wealth quintiles (IEN), 62%-72% of the families were beneficiaries among the 20% poorest people, 2%-5% among the 20% richest people, and about 30% of families of the intermediate quintile. According to household income (minus the benefit) 29% of families were eligible in 2004 and 16% in 2010. By the same criteria, the coverage of the program increased from 43% in 2004 to 71% in 2010. In the same period, by the wealth criterion (IEN), coverage increased from 29% to 63%. The focalization of the program decreased from 78% in 2004 to 32% in 2010 according to income, and remained constant (37%) according to the IEN.

CONCLUSIONS

Among the families of the 2004 cohort, there was a significant increase in the program coverage, from its inception until 2010, when it was near 70%. The focus of the program was below 40% in 2010, indicating that more than half of the beneficiaries did not belong to the target population.

Caesarean section and adiposity at 6, 18 and 30 years of age: results from three Pelotas (Brazil) birth cohorts

Background

Association between caesarian section (C-section) and obesity is controversial and mostly based on body mass index (BMI), which has inherent limitations. Using direct estimates of body fat mass, we aimed to assess the association between C-section and adiposity using fat mass index and BMI z-score in three birth cohort studies from Pelotas, Brazil.

Methods

We measured weight, height and fat mass (using dual X-ray absorptiometry (DXA)) at ages 6, 18 and 30 years among participants in the 2004, 1993 and 1982 population-based Pelotas Birth Cohort Studies, respectively. We used multiple linear regression analysis to examine the crude and adjusted association between C-section and the body composition indicators. We also modelled height as an outcome to explore the presence of residual confounding.

Results

We observed that fat mass index and BMI z-score were strongly and positively associated with C-section in the crude analysis. However, when we adjusted for socioeconomic characteristics, maternal BMI, parity, age and smoking during pregnancy, effect estimates were attenuated towards the null, except for 30-year-old women. In those women from the 1982 cohort, C-section remained associated with fat mass index (β = 0.82; CI95% 0.32;1.32) and BMI z-score (β = 0.15; CI95% 0.03;0.28), even after adjusting for all potential confounders, suggesting an increase in fat mass index and BMI at 30 years among those born by C-section.

Conclusion

We found no consistent association of C-section with fat mass index measured by DXA and BMI z-score in individuals aged 6, 18 and 30 years, except for women in the latter group, which might be explained by residual confounding. Confounding by socioeconomic and maternal characteristics accounted for all the other associations.

Associations of Linear Growth and Relative Weight Gain in Early Life with Human Capital at 30 Years of Age

OBJECTIVE

To assess the associations of birthweight, nutritional status and growth in childhood with IQ, years of schooling, and monthly income at 30 years of age.

STUDY DESIGN

In 1982, the 5 maternity hospitals in Pelotas, Brazil, were visited daily and 5914 live births were identified. At 30 years of age, 3701 subjects were interviewed. IQ, years of schooling, and income were measured.

RESULTS

On average, their IQ was 98 points, they had 11.4 years of schooling, and the mean income was 1593 reais. After controlling for several confounders, birthweight and attained weight and length/height for age at 2 and 4 years of age were associated positively with IQ, years of years of schooling, and income, except for the association between length at 2 years of age and income. Conditional growth analyses were used to disentangle linear growth from relative weight gain. Conditional length at 2 years of age ≥1 SD score above the expected value, compared with ≥1 SD below the expected, was associated with an increase in IQ (4.28 points; 95% CI, 2.66-5.90), years of schooling (1.58 years; 95% CI, 1.08-2.08), and monthly income (303 Brazilian reais; 95% CI, 44-563). Relative weight gain, above what would be expected from linear growth, was not associated with the outcomes.

CONCLUSION

In a middle-income setting, promotion of linear growth in the first 1000 days of life is likely to increase adult IQ, years of schooling, and income. Weight gain in excess of what is expected from linear growth does not seem to improve human capital.

Exploring DSM-5 ADHD criteria beyond young adulthood: phenomenology, psychometric properties and prevalence in a large three-decade birth cohort

BACKGROUND

There are still uncertainties on the psychometric validity of the DSM-5 attention deficit hyperactivity disorder (ADHD) criteria for its use in the adult population. We aim to describe the adult ADHD phenotype, to test the psychometric properties of the DSM-5 ADHD criteria, and to calculate the resulting prevalence in a population-based sample in their thirties.

METHOD

A cross-sectional evaluation using the DSM-5 ADHD criteria was carried out in 3574 individuals from the 1982 Pelotas Birth Cohort. Through receiver operator curve, latent and regression analyses, we obtained parameters on construct and discriminant validity. Still, prevalence rates were calculated for different sets of criteria.

RESULTS

The latent analysis suggested that the adult ADHD phenotype is constituted mainly by inattentive symptoms. Also, inattention symptoms were the symptoms most associated with impairment. The best cut-off for diagnosis was four symptoms, but sensitivity and specificity for this cut-off was low. ADHD prevalence rates were 2.1% for DSM-5 ADHD criteria and 5.8% for ADHD disregarding age-of-onset criterion.

CONCLUSIONS

The bi-dimensional ADHD structure proposed by the DSM demonstrated both construct and discriminant validity problems when used in the adult population, since inattention is a much more relevant feature in the adult phenotype. The use of the DSM-5 criteria results in a higher prevalence of ADHD when compared to those obtained by DSM-IV, and prevalence would increase almost threefold when considering current ADHD syndrome. These findings suggest a need for further refinement of the criteria for its use in the adult population.

Acidentes por quedas, cortes e queimaduras em crianças de 0-4 anos: coorte de nascimentos de Pelotas, Rio Grande do Sul, Brasil, 2004

Resumo: O conhecimento da incidência de acidentes na infância, de acordo com o estágio de desenvolvimento da criança, é importante para a formulação de programas de prevenção dirigidos para cada faixa etária. O objetivo deste estudo foi descrever a incidência de quedas, cortes e queimaduras, até os quatro anos de idade, conforme nível econômico da família e idade e escolaridade maternas, entre as crianças da coorte de nascimentos de Pelotas, Rio Grande do Sul, Brasil, 2004. Foram calculadas as taxas de incidências e razões de taxas de incidências entre 0-12, 12-24 e 24-48 meses. As quedas foram os acidentes mais relatados em todos os períodos, seguidas dos cortes e queimaduras. Os meninos sofreram mais quedas e cortes do que as meninas nos dois primeiros anos de vida. No segundo ano de vida, a incidência de quedas e queimaduras praticamente triplicou e a de cortes dobrou, em comparação ao primeiro ano, dentre ambos os sexos. As queimaduras ocorreram com igual frequência entre meninas e meninos nos três períodos de idade analisados. Em suma, a incidência de quedas e cortes foi maior entre os meninos. Em ambos os sexos, ter mãe adolescente foi associado a quedas e cortes nos três períodos analisados; ter mãe com baixa escolaridade esteve associado a queimaduras e cortes aos 48 meses; e ser de família de baixo nível socioeconômico, a quedas e cortes aos 48 meses.

The antepartum stillbirth syndrome: risk factors and pregnancy conditions identified from the INTERGROWTH-21st Project

OBJECTIVES

To identify risk factors for antepartum stillbirth, including fetal growth restriction, among women with well-dated pregnancies and access to antenatal care.

DESIGN

Population-based, prospective, observational study.

SETTING

Eight international urban populations.

POPULATION

Pregnant women and their babies enrolled in the Newborn Cross-Sectional Study of the INTERGROWTH-21^st Project.

METHODS

Cox proportional hazard models were used to compare risks among antepartum stillborn and liveborn babies.

MAIN OUTCOME MEASURES

Antepartum stillbirth was defined as any fetal death after 16 weeks' gestation before the onset of labour.

RESULTS

Of 60 121 babies, 553 were stillborn (9.2 per 1000 births), of which 445 were antepartum deaths (7.4 per 1000 births). After adjustment for site, risk factors were low socio-economic status, hazard ratio (HR): 1.6 (95% CI, 1.2-2.1); single marital status, HR 2.0 (95% CI, 1.4-2.8); age ≥40 years, HR 2.2 (95% CI, 1.4-3.7); essential hypertension, HR 4.0 (95% CI, 2.7-5.9); HIV/AIDS, HR 4.3 (95% CI, 2.0-9.1); pre-eclampsia, HR 1.6 (95% CI, 1.1-3.8); multiple pregnancy, HR 3.3 (95% CI, 2.0-5.6); and antepartum haemorrhage, HR 3.3 (95% CI, 2.5-4.5). Birth weight <3rd centile was associated with antepartum stillbirth [HR, 4.6 (95% CI, 3.4-6.2)]. The greatest risk was seen in babies not suspected to have been growth restricted antenatally, with an HR of 5.0 (95% CI, 3.6-7.0). The population-attributable risk of antepartum death associated with small-for-gestational-age neonates diagnosed at birth was 11%.

CONCLUSIONS

Antepartum stillbirth is a complex syndrome associated with several risk factors. Although small babies are at higher risk, current growth restriction detection strategies only modestly reduced the rate of stillbirth.

TWEETABLE ABSTRACT

International stillbirth study finds individual risks poor predictors of death but combinations promising.

COMT and DAT1 genes are associated with hyperactivity and inattention traits in the 1993 Pelotas Birth Cohort: evidence of sex-specific combined effect

BACKGROUND

Attention-deficit/hyperactivity disorder (ADHD) symptoms are dimensionally distributed in the population. This study aimed to assess the role of the catechol-O-methyltransferase (COMT) and of the dopamine transporter (DAT1) genes on ADHD symptoms in the general population.

METHODS

We investigated 4101 individuals from the 1993 Pelotas Birth Cohort Study using the parent version of the Strengths and Difficulties Questionnaire (SDQ) at ages 11 and 15 years. The SDQ hyperactivity/inattention scores were the main outcomes.

RESULTS

Linear regression analyses demonstrated that the increasing number of COMT158Val and DAT1 10R alleles significantly predicted increasing SDQ hyperactivity/inattention scores in boys at both 11 and 15 years of age (β coefficient = 0.049, t = 2.189, p = 0.029, R² = 0.012, and β coefficient = 0.064, t = 2.832, p = 0.005, R² = 0.008, respectively). The presence of both COMT158Val and DAT1 10R alleles was also associated with full categorical ADHD diagnosis at 18 years of age in boys (χ² = 4.561, p = 0.033, odds ratio 2.473, 95% confidence interval 1.048-5.838) from this cohort. We did not observe these associations in girls.

LIMITATIONS

Our analyses of SDQ hyperactivity/inattention scores were not corrected for SDQ scores of conduct problems because these variables were highly correlated.

CONCLUSION

This study demonstrates a role for COMT and DAT1 genes on hyperactivity/inattention symptoms and provides further support for ADHD as the extreme of traits that vary in the population. It also confirms previous evidence for sexual dimorphism on COMT and DAT1 gene expression.

Adiposity during adolescence and carotid intima-media thickness in adulthood: Results from the 1993 Pelotas Birth Cohort

Background and aims

Although several studies have examined the association between adiposity and cardiovascular risk markers, few have explored the issue prospectively in young populations. We sought to test whether higher levels of body mass index (BMI) and subscapular skinfold at different stages of adolescence were associated with carotid intima-media thickness (cIMT) in young adulthood.

Methods

In a prospective cohort, we assessed BMI and subscapular skinfold at 11, 15 and 18 years and measured cIMT at 18 years in 3264 individuals. Traditional cardiovascular risk factors and fat mass-mediating effects on cIMT were also assessed.

Results

Both BMI and subscapular skinfolds were significantly associated with higher cIMT in a cummulative fashion: after controlling for confounders, males and females who persisted overweight/obese at all three assessments, had a mean higher cIMT (5.2 and 3.1 μm, respectively) compared to males and females with normal/healthy BMI at each evaluation (p < 0.001). Moreover, male and females that presented increased fatness in all assessments had a similar pattern of higher cIMT compared to normal/healthy fatness/skinfold at 18 years (mean cIMT 4.6 and 3.0 μm for males and females, respectively; p < 0.001). Associations between adiposity and cIMT were both direct and indirect. Indirect effects were chiefly mediated by fat mass and diastolic blood pressure.

Conclusions

Our results suggest adiposity exerts direct and indirect effects during adolescence that result in higher cIMT in young adulthood.

•

High BMI and subscapular skinfolds during adolescence are associated with higher cIMT at 18 years.

•

Adiposity exerts direct and indirect effects on cIMT.

•

Indirect effects are chiefly mediated by fat mass and diastolic blood pressure.

Relationship between Body Composition and Pulmonary Function in Early Adult Life: A Cross-Sectional Analysis Nested in Two Birth Cohort Studies

BACKGROUND

Overweight/obesity has been reported to worsen pulmonary function (PF). This study aimed to examine the association between PF and several body composition (BC) measures in two population-based cohorts.

METHODS

We performed a cross-sectional analysis of individuals aged 18 and 30 years from two Pelotas Birth Cohorts in southern Brazil. PF was assessed by spirometry. Body measures that were collected included body mass index, waist circumference, skinfold thickness, percentages of total and segmented (trunk, arms and legs) fat mass (FM) and total fat-free mass (FFM). FM and FFM were measured by air-displacement plethysmography (BODPOD) and by dual-energy x-ray absorptiometry (DXA). Associations were verified through linear regressions stratified by sex, and adjusted for weight, height, skin color, and socioeconomic, behavioral, and perinatal variables.

RESULTS

A total of 7347 individuals were included in the analyses (3438 and 3909 at 30 and 18 years, respectively). Most BC measures showed a significant positive association between PF and FFM, and a negative association with FM. For each additional percentage point of FM, measured by BOD POD, the forced vital capacity regression coefficient adjusted by height, weight and skin color, at 18 years, was -33 mL (95% CI -38, -29) and -26 mL (95% CI -30, -22), and -30 mL (95% CI -35, -25) and -19 mL (95% CI -23, -14) at 30 years, in men and women, respectively. All the BOD POD regression coefficients for FFM were the same as for the FM coefficients, but in a positive trend (p<0.001 for all associations).

CONCLUSIONS

All measures that distinguish FM from FFM (skinfold thickness-FM estimation-BOD POD, total and segmental DXA measures-FM and FFM proportions) showed negative trends in the association of FM with PF for both ages and sexes. On the other hand, FFM showed a positive association with PF.

Breastfeeding and mental health in adulthood: A birth cohort study in Brazil

BACKGROUND

Breastfeeding is negatively associate with behavioral and internalization problems, psychological stress, and depressive/anxiety symptoms. However, studies evaluating specific mental health disorders are scarce. We aimed to assess the association between breastfeeding and mental health outcomes in young adults.

METHODS

In 1982, hospital deliveries in Pelotas (Southern Brazil) were identified; liveborns were examined and their mothers interviewed (n=5914). Information on breastfeeding was collected in early childhood. In 2012-13, at 30 years of age, we used the Mini International Neuropsychiatric Interview (MINI) for the diagnosis of major depression (MD), generalized anxiety disorder (GAD) and social anxiety disorder (SAD). In addition, we used the Beck Depression Inventory (BDI-II) and the Self-reported Questionnaire (SRQ-20), to evaluate depressive symptoms severity and common mental disorders (CMD), respectively. We used multivariable regression models to evaluate the association between breastfeeding and mental health outcomes.

RESULTS

We evaluated 3657 individuals. Prevalence of CMD, MD, GAD and SAD was 24.3%, 7.9%, 12.7% and 3.6%, respectively. In multivariable models the odds of having a more severe case of depression (BDI-II) was smaller among those breastfed for 6 or more months (OR=0.69 95%CI [0.53-0.89]). We observed a similar pattern for MD and CMD, however, confidence intervals included the reference.

LIMITATIONS

We had no information on home environment characteristics during childhood. Lack of power and a small effect size could explain why we did not detect an association between breastfeeding and MD.

CONCLUSION

Breastfeeding reduced the odds of having more severe depressive symptoms.

Genomic ancestry and the social pathways leading to major depression in adulthood: the mediating effect of socioeconomic position and discrimination

BACKGROUND

Evidence suggests that there is an association between ethnicity/skin color and depression; however, many contextual and individual variables, like sense of discrimination and socioeconomic position (SEP), might influence the direction of this association. We assessed the association between African ancestry and major depression among young adults that have been followed-up since birth in a Southern Brazilian city, and the mediating effect of SEP and discrimination.

METHODS

In 1982, all hospital deliveries in Pelotas (Southern Brazil) were identified; liveborns were examined and their mothers interviewed (n = 5914). In 2012-13, at 30 years of age, we used the Mini International Neuropsychiatric Interview (MINI) for major depression diagnosis. In addition, DNA samples were genotyped for approximately 2.5 million single nucleotide polymorphisms (SNPs) using Illumina (CA, USA) HumanOmni2.5-8v1 array. Genomic ancestry estimation was based on approximately 370 000 single nucleotide polymorphisms (SNPs) mutually available for the Pelotas cohort and selected samples (used as reference panels) of the HapMap and Human Genome Diversity (HGDP). We estimated prevalence ratios (PR) using Poisson regression models and evaluated the association between percentage of African ancestry and major depression. We used G-computation for mediation analysis.

RESULTS

At 30 years, 3576 individuals were evaluated for major depression (prevalence = 7.9 %). Only individuals in the highest SEP, who had a percentage of African ancestry between >5-30 % and >30 % had a prevalence of major depression 2.16 (PR = 2.16 95 % CI [1.05-4.45]) and 2.74 (PR = 2.74 95 % CI [1.06-7.06]) times higher, than those with 5 % or less, respectively. Among these subjects, sense of discrimination by skin color, captured 84 % of the association between African ancestry and major depression.

CONCLUSION

SEP is an important effect modifier of the positive association between African ancestry and major depression. In addition, this association is predominantly mediated by the sense of feeling discriminated by skin color.

Congenital Zika virus syndrome in Brazil: a case series of the first 1501 livebirths with complete investigation

BACKGROUND

In November, 2015, an epidemic of microcephaly was reported in Brazil, which was later attributed to congenital Zika virus infection. 7830 suspected cases had been reported to the Brazilian Ministry of Health by June 4, 2016, but little is known about their characteristics. We aimed to describe these newborn babies in terms of clinical findings, anthropometry, and survival.

METHODS

We reviewed all 1501 liveborn infants for whom investigation by medical teams at State level had been completed as of Feb 27, 2016, and classified suspected cases into five categories based on neuroimaging and laboratory results for Zika virus and other relevant infections. Definite cases had laboratory evidence of Zika virus infection; highly probable cases presented specific neuroimaging findings, and negative laboratory results for other congenital infections; moderately probable cases had specific imaging findings but other infections could not be ruled out; somewhat probable cases had imaging findings, but these were not reported in detail by the local teams; all other newborn babies were classified as discarded cases. Head circumference by gestational age was assessed with InterGrowth standards. First week mortality and history of rash were provided by the State medical teams.

FINDINGS

Between Nov 19, 2015, and Feb 27, 2015, investigations were completed for 1501 suspected cases reported to the Brazilian Ministry of Health, of whom 899 were discarded. Of the remainder 602 cases, 76 were definite, 54 highly probable, 181 moderately probable, and 291 somewhat probable of congenital Zika virus syndrome. Clinical, anthropometric, and survival differences were small among the four groups. Compared with these four groups, the 899 discarded cases had larger head circumferences (mean Z scores -1·54 vs -3·13, difference 1·58 [95% CI 1·45-1·72]); lower first-week mortality (14 per 1000 vs 51 per 1000; rate ratio 0·28 [95% CI 0·14-0·56]); and were less likely to have a history of rash during pregnancy (20·7% vs 61·4%, ratio 0·34 [95% CI 0·27-0·42]). Rashes in the third trimester of pregnancy were associated with brain abnormalities despite normal sized heads. One in five definite or probable cases presented head circumferences in the normal range (above -2 SD below the median of the InterGrowth standard) and for one third of definite and probable cases there was no history of a rash during pregnancy. The peak of the epidemic occurred in late November, 2015.

INTERPRETATION

Zika virus congenital syndrome is a new teratogenic disease. Because many definite or probable cases present normal head circumference values and their mothers do not report having a rash, screening criteria must be revised in order to detect all affected newborn babies.

FUNDING

Brazilian Ministry of Health, Pan American Health Organization, and Wellcome Trust.

LBW and IUGR temporal trend in 4 population-based birth cohorts: the role of economic inequality

Background

Low/medium income countries, with health inequalities present high rates of neonates having low birthweight and/or are small for the gestational age. This study aims to analyze the absolute and relative income inequality in the occurrence of low birthweight and small size for gestational age among neonates in four birth cohorts from southern Brazil in 1982, 1993, 2004, and 2011.

Methods

The main exhibit was monthly family income. The outcomes were birth with low birthweight or small for the gestational age. The inequalities were calculated using the Slope Index of Inequality and the Relative Index of Inequality adjusted for maternal skin color, schooling, age, and marital status.

Results

In all birth cohorts, poorer mothers were at greater odds of having neonates with low birthweight or small for the gestational age. There was a tendency to decrease the prevalence of small for gestational age in poorer families associated with the reduction of inequalities over the past decades, which was not observed regarding low birthweight.

Conclusions

Economic inequalities occurred in neonates with low birthweight and with intrauterine growth restriction in the four studies, with a higher incidence of inadequate neonatal outcomes in the poorer families.

Attention-Deficit/Hyperactivity Disorder Trajectories From Childhood to Young Adulthood: Evidence From a Birth Cohort Supporting a Late-Onset Syndrome

IMPORTANCE

The requirement of a childhood onset has always been a key criterion for the diagnosis of attention-deficit/hyperactivity disorder (ADHD) in adults, but recently this requirement has become surrounded by controversy.

OBJECTIVE

To investigate whether impaired young adults with ADHD symptoms always have a childhood-onset disorder in a population-based longitudinal study.

DESIGN, SETTING, AND PARTICIPANTS

Participants belonged to the 1993 Pelotas Birth Cohort Study, including 5249 individuals born in Pelotas, Brazil, in 1993. They were followed up to 18 to 19 years of age, with 81.3% retention. The data analysis was performed between August 8, 2015, and February 5, 2016.

MAIN OUTCOMES AND MEASURES

The ADHD status was first ascertained at 11 years of age using a screening instrument (hyperactivity subscale of the Strength and Difficulties Questionnaire) calibrated for a DSM-IV ADHD diagnosis based on clinical interviews with parents using the Development and Well-Being Assessment. At 18 to 19 years of age, ADHD diagnosis was derived using DSM-5 criteria, except age at onset. We estimated the overlap between these groups assessed at 11 and 18 to 19 years of age and the rates of markers of impairment in these 2 groups compared with those without ADHD.

RESULTS

At 11 years of age, childhood ADHD (C-ADHD) was present in 393 individuals (8.9%). At 18 to 19 years of age, 492 individuals (12.2%) fulfilled all DSM-5 criteria for young adult ADHD (YA-ADHD), except age at onset. After comorbidities were excluded, the prevalence of YA-ADHD without comorbidities decreased to 256 individuals (6.3%). Children with C-ADHD had a male preponderance not observed among children without ADHD (251 [63.9%] vs 1930 [47.9%] male, P < .001), whereas the YA-ADHD group had a female preponderance (192 [39.0%] vs 1786 [50.4%] male, P < .001). Both groups had increased levels of impairment in adulthood, as measured by traffic incidents, criminal behavior, incarceration, suicide attempts, and comorbidities. However, only 60 children (17.2%) with ADHD continued to have ADHD as young adults, and only 60 young adults (12.6%) with ADHD had the disorder in childhood.

CONCLUSIONS AND RELEVANCE

The findings of this study do not support the assumption that adulthood ADHD is necessarily a continuation of childhood ADHD. Rather, they suggest the existence of 2 syndromes that have distinct developmental trajectories.

Lifetime overweight and obesity and body composition in adulthood: the 1982 Pelotas (Brazil) birth cohort study

This study aimed to assess the association between overweight/obesity at different moments in the life cycle and body composition in early adulthood. Data were used from the 1982 Pelotas (Brazil) birth cohort study, which has followed live born children of families residing in the urban area of Pelotas at different ages. At 30 years of age, 3,701 cohort members were interviewed and body composition was assessed using Bod Pod, 2,219 cohort members had at least one weight and height measurement taken in the three periods (childhood, adolescence, and adulthood), 24% never presented overweight, and 68.6% were never classified as obese. Elevated body mass index (BMI) and percent body fat at 30 years of age were associated with individuals classified as overweight in all three periods or in adolescence and adulthood, while those with overweight/obesity only in childhood or adolescence showed mean BMI and percent body fat similar to those who had never presented overweight/obesity. The results indicate the benefit of early interruption of overweight/obesity.

Neonatal ventilatory support and respiratory diseases in children up to six years of age: the 2004 Pelotas (Brazil) Birth Cohort study

The study's objective was to evaluate the association between neonatal ventilatory support and the subsequent occurrence of respiratory diseases in children up to six years of age. This was a population-based birth cohort study. The main exposure was ventilatory support at birth, defined as the use of nasal continuous positive airway pressure (NCPAP) and/or mechanical ventilation (MV) for more than three hours from the time of hospitalization at birth until the first 28 days of life. Outcomes were: chest wheezing in the twelve months prior to the follow-up interview, medical diagnosis of asthma any time in the child´s life, and occurrence of pneumonia up to six years of age. Crude and adjusted analyses for potential confounding variables were performed using Poisson regression. 3,624 children were analyzed. NCPAP plus MV or MV alone was associated with higher frequency of medical diagnosis of asthma, even after adjusting for maternal and child characteristics (PR = 2.24; 95%CI: 1.27-3.99). The results highlight medium-term respiratory complications associated with neonatal ventilatory support.

Gestational weight gain standards based on women enrolled in the Fetal Growth Longitudinal Study of the INTERGROWTH-21st Project: a prospective longitudinal cohort study

OBJECTIVE

To describe patterns in maternal gestational weight gain (GWG) in healthy pregnancies with good maternal and perinatal outcomes.

DESIGN

Prospective longitudinal observational study.

SETTING

Eight geographically diverse urban regions in Brazil, China, India, Italy, Kenya, Oman, United Kingdom, and United States, April 2009 to March 2014.

PARTICIPANTS

Healthy, well nourished, and educated women enrolled in the Fetal Growth Longitudinal Study component of the INTERGROWTH-21(st) Project, who had a body mass index (BMI) of 18.50-24.99 in the first trimester of pregnancy.

MAIN OUTCOME MEASURES

Maternal weight measured with standardised methods and identical equipment every five weeks (plus/minus one week) from the first antenatal visit (<14 weeks' gestation) to delivery. After confirmation that data from the study sites could be pooled, a multilevel, linear regression analysis accounting for repeated measures, adjusted for gestational age, was applied to produce the GWG values.

RESULTS

13,108 pregnant women at <14 weeks' gestation were screened, and 4607 met the eligibility criteria, provided consent, and were enrolled. The variance within sites (59.6%) was six times higher than the variance between sites (9.6%). The mean GWGs were 1.64 kg, 2.86 kg, 2.86 kg, 2.59 kg, and 2.56 kg for the gestational age windows 14-18(+6) weeks, 19-23(+6) weeks, 24-28(+6) weeks, 29-33(+6) weeks, and 34-40(+0) weeks, respectively. Total mean weight gain at 40 weeks' gestation was 13.7 (SD 4.5) kg for 3097 eligible women with a normal BMI in the first trimester. Of all the weight measurements, 71.7% (10,639/14,846) and 94.9% (14,085/14,846) fell within the expected 1 SD and 2 SD thresholds, respectively. Data were used to determine fitted 3rd, 10th, 25th, 50th, 75th, 90th, and 97th smoothed GWG centiles by exact week of gestation, with equations for the mean and standard deviation to calculate any desired centiles according to gestational age in exact weeks.

CONCLUSIONS

Weight gain in pregnancy is similar across the eight populations studied. Therefore, the standards generated in this study of healthy, well nourished women may be used to guide recommendations on optimal gestational weight gain worldwide.

Association between breastfeeding and intelligence, educational attainment, and income at 30 years of age: a prospective birth cohort study from Brazil

Background

Breastfeeding has clear short-term benefits, but its long-term consequences on human capital are yet to be established. We aimed to assess whether breastfeeding duration was associated with intelligence quotient (IQ), years of schooling, and income at the age of 30 years, in a setting where no strong social patterning of breastfeeding exists.

Methods

A prospective, population-based birth cohort study of neonates was launched in 1982 in Pelotas, Brazil. Information about breastfeeding was recorded in early childhood. At 30 years of age, we studied the IQ (Wechsler Adult Intelligence Scale, 3rd version), educational attainment, and income of the participants. For the analyses, we used multiple linear regression with adjustment for ten confounding variables and the G-formula.

Findings

From June 4, 2012, to Feb 28, 2013, of the 5914 neonates enrolled, information about IQ and breastfeeding duration was available for 3493 participants. In the crude and adjusted analyses, the durations of total breastfeeding and predominant breastfeeding (breastfeeding as the main form of nutrition with some other foods) were positively associated with IQ, educational attainment, and income. We identified dose-response associations with breastfeeding duration for IQ and educational attainment. In the confounder-adjusted analysis, participants who were breastfed for 12 months or more had higher IQ scores (difference of 3·76 points, 95% CI 2·20–5·33), more years of education (0·91 years, 0·42–1·40), and higher monthly incomes (341·0 Brazilian reals, 93·8–588·3) than did those who were breastfed for less than 1 month. The results of our mediation analysis suggested that IQ was responsible for 72% of the effect on income.

Interpretation

Breastfeeding is associated with improved performance in intelligence tests 30 years later, and might have an important effect in real life, by increasing educational attainment and income in adulthood.

Funding

Wellcome Trust, International Development Research Center (Canada), CNPq, FAPERGS, and the Brazilian Ministry of Health.

Secular trends in smoking during pregnancy according to income and ethnic group: four population-based perinatal surveys in a Brazilian city

OBJECTIVES

To assess socioeconomic and ethnic inequalities in smoking during pregnancy over three decades (1982-2011).

SETTING

Population-based study in Pelotas City, Brazil.

PARTICIPANTS

All urban women giving birth in the city hospitals in 1982 (5909), 1993 (5223) and 2004 (4201), plus all urban and rural women delivering from January 2011 to April 2012 (6275).

PRIMARY OUTCOME

Self-reported smoking during pregnancy.

RESULTS

The prevalence of smoking during pregnancy fell from 35.7% in 1982 to 21.0% in 2011. In each survey, prevalence decreased with increasing income (p<0.001). In the poorest quintile, smoking fell by 27.4% in the period studied compared to 67.1% in the wealthiest quintile. In all surveys, prevalence was lower among white women than among those who classified themselves as black or brown (p<0.001). Over time, smoking declined by 50.0% among the former and 30.7% among the latter. Absolute and relative inequalities both increased over time.

CONCLUSIONS

The reduction in smoking during pregnancy was primarily due to a decline among white, high-income women. Further efforts are needed to reduce smoking among all population groups.

Low resting heart rate is associated with violence in late adolescence: a prospective birth cohort study in Brazil

Background : Youth violence is a major global public health problem. Three UK and Swedish studies suggest that low resting heart rate predicts male youth violence, but this has not been tested in other social settings nor for females.

Methods : A prospective, population-based birth cohort study was conducted in Pelotas, Brazil. Heart rate was measured using a wrist monitor at ages 11, 15 and 18 years. Violent crime and non-violent crime were measured at age 18 in self-reports and official records ( N  = 3618). Confounding variables were assessed in the perinatal period and at age 11, in interviews with mothers and children. Logistic regression was used to estimate associations between quartiles of heart rate at each age, and violent and non-violent crime at age 18, separately for males and females.

Results : Lower resting heart rate was a robust correlate of violent and non-violent crime for males. Comparing males in the lowest and top quartiles of heart rate at age 15 years, adjusted odds ratios were 1.9 for violent crime [95% confidence interval (CI) 1.4–2.7] and 1.7 for non-violent crime (95% CI 1.1–2.6). For females, crime outcomes were associated only with low resting heart rate at age 18. Associations were generally linear across the four heart rate quartiles. There was no evidence that associations differed according to socioeconomic status at age 15.

Conclusions : Low resting heart rate predicted violent and non-violent crime for males, and was cross-sectionally associated with crime for females. Biological factors may contribute to individual propensity to commit crime, even in a middle-income setting with high rates of violence.

Are fetal growth impairment and preterm birth causally related to child attention problems and ADHD? Evidence from a comparison between high-income and middle-income cohorts

Background

Cross-cohort comparison is an established method for improving causal inference. This study compared 2 cohorts, 1 from a high-income country and another from a middle-income country, to (1) establish whether birth exposures may play a causal role in the development of childhood attention problems; and (2) identify whether confounding structures play a different role in parent-reported attention difficulties compared with attention deficit hyperactivity disorder (ADHD) diagnoses.

Methods

Birth exposures included low birth weight (LBW), small-for-gestational age (SGA), small head circumference (HC) and preterm birth (PTB)). Outcomes of interest were attention difficulties (Strengths and Difficulties Questionnaire, SDQ) and ADHD (Development and Well-Being Assessment, DAWBA). Associations between exposures and outcomes were compared between 7-year-old children from the Avon Longitudinal Study of Parents and Children (ALSPAC) in the UK (N=6849) and the 2004 Pelotas cohort in Brazil (N=3509).

Results

For attention difficulties (SDQ), the pattern of association with birth exposures was similar between cohorts: following adjustment, attention difficulties were associated with SGA (OR=1.59, 95% CI 1.20 to 2.19) and small HC (OR=1.64, 95% CI 1.11 to 2.41) in ALSPAC and SGA (OR=1.35, 95% CI 1.04 to 1.75) in Pelotas. For ADHD, however, the pattern of association following adjustment differed markedly between cohorts. In ALSPAC, ADHD was associated with LBW (OR=2.29, 95% CI 1.09 to 4.80) and PTB (OR=2.33, 95% CI 1.23 to 4.42). In the Pelotas cohort, however, ADHD was associated with SGA (OR=1.69, 95% CI 1.02 to 2.82).

Conclusions

The findings suggest that fetal growth impairment may play a causal role in the development of attention difficulties in childhood, as similar associations were identified across both cohorts. Confounding structures, however, appear to play a greater role in determining whether a child meets the full diagnostic criteria for ADHD.

Sugar Consumption and Changes in Dental Caries from Childhood to Adolescence

There are no prospective studies investigating the effects of sugar-related feeding practices on changes in dental caries from early childhood to young adulthood. The aim of this study was to assess whether sugar-related feeding practices affect dental caries between the ages of 6 and 18 y. This birth cohort study was initiated in 1993 in Pelotas, Brazil. There were 3 dental clinical assessments; at ages 6 y (n = 359), 12 y (n = 339), and 18 y (n = 307). Sugar-related feeding practices were assessed at ages 4, 15, and 18 y. Covariates included sex and life course variables, such as family income, breast-feeding, mother's education, regularity of dental visit, and child's toothbrushing habits. Group-based trajectory analysis was performed to characterize trajectories of time-varying independent variables that had at least 3 time points. We fitted a generalized linear mixed model assuming negative binomial distribution with log link function on 3-time repeated dental caries assessments. One in 5 participants was classified as "high" sugar consumers, and nearly 40% were "upward consumers." "Low consumers" accounted for >40% of the sample. High and upward sugar consumers had higher dental caries prevalence and mean DMFT in all cohort waves when compared with low sugar consumers. Caries occurred at a relatively constant rate over the period of study, but in all sugar consumption groups, the increment of dental caries was slightly higher between ages 6 and 12 y than between 12 and 18 y. Adjusted analysis showed that dental caries increment ratio between ages 6 and 18 y was 20% and 66% higher in upward and high sugar consumer groups as compared with low consumers. The higher the sugar consumption along the life course, the higher the dental caries increment. Even the low level of sugar consumption was related to dental caries, despite the use of fluoride.

Sex differences in the association between foetal growth and child attention at age four: specific vulnerability of girls

BACKGROUND

Recent evidence suggests that impaired foetal growth may provide an early indication of increased risk of child attention problems. However, despite both foetal growth and child attention problems differing by sex, few studies have examined sex differences in this association. Furthermore, no studies have been conducted in low- and middle-income countries, where there are higher rates of perinatal problems. This study aimed to test for sex differences in the association between foetal growth indices and attention problems at age four, in a large, prospective birth cohort from a middle-income country.

METHODS

A total of 3,749 neonates from the 2004 Pelotas birth cohort (Brazil) with foetal growth indices collected at birth [low birthweight (LBW), small-for-gestational age (SGA), head circumference (HC), head circumference-to-abdominal circumference ratio (HC/AC) and ponderal index (PI)], were assessed for attention problems using the Child Behaviour Checklist at age four. Ordinal logistic regression with successive adjustment for maternal, demographic, gestational, perinatal and child nutrition/mother-child morbidity, was conducted separately for girls and boys.

RESULTS

In girls, attention difficulties were associated with being born SGA (OR = 1.40, CI = 1.08-1.82, p = .012), with a small HC (OR = 1.52, CI = 1.11-2.08, p = .009), or with a low PI (OR = 1.29, CI = 1.08-1.54, p = .005). There were no associations identified between attention difficulties and any foetal growth indices in boys.

CONCLUSIONS

Our results show that girls with impaired foetal growth may be particularly at risk of attention difficulties in childhood. This is consistent with emerging research that female foetuses may be more vulnerable to certain suboptimal intrauterine environments, inducing epigenetic changes that lead to disturbed growth and long-term developmental impairment.

Short Maternal Stature Increases Risk of Small-for-Gestational-Age and Preterm Births in Low- and Middle-Income Countries: Individual Participant Data Meta-Analysis and Population Attributable Fraction

BACKGROUND

Small-for-gestational-age (SGA) and preterm births are associated with adverse health consequences, including neonatal and infant mortality, childhood undernutrition, and adulthood chronic disease.

OBJECTIVES

The specific aims of this study were to estimate the association between short maternal stature and outcomes of SGA alone, preterm birth alone, or both, and to calculate the population attributable fraction of SGA and preterm birth associated with short maternal stature.

METHODS

We conducted an individual participant data meta-analysis with the use of data sets from 12 population-based cohort studies and the WHO Global Survey on Maternal and Perinatal Health (13 of 24 available data sets used) from low- and middle-income countries (LMIC). We included those with weight taken within 72 h of birth, gestational age, and maternal height data (n = 177,000). For each of these studies, we individually calculated RRs between height exposure categories of < 145 cm, 145 to < 150 cm, and 150 to < 155 cm (reference: ≥ 155 cm) and outcomes of SGA, preterm birth, and their combination categories. SGA was defined with the use of both the International Fetal and Newborn Growth Consortium for the 21st Century (INTERGROWTH-21st) birth weight standard and the 1991 US birth weight reference. The associations were then meta-analyzed.

RESULTS

All short stature categories were statistically significantly associated with term SGA, preterm appropriate-for-gestational-age (AGA), and preterm SGA births (reference: term AGA). When using the INTERGROWTH-21st standard to define SGA, women < 145 cm had the highest adjusted risk ratios (aRRs) (term SGA-aRR: 2.03; 95% CI: 1.76, 2.35; preterm AGA-aRR: 1.45; 95% CI: 1.26, 1.66; preterm SGA-aRR: 2.13; 95% CI: 1.42, 3.21). Similar associations were seen for SGA defined by the US reference. Annually, 5.5 million term SGA (18.6% of the global total), 550,800 preterm AGA (5.0% of the global total), and 458,000 preterm SGA (16.5% of the global total) births may be associated with maternal short stature.

CONCLUSIONS

Approximately 6.5 million SGA and/or preterm births in LMIC may be associated with short maternal stature annually. A reduction in this burden requires primary prevention of SGA, improvement in postnatal growth through early childhood, and possibly further intervention in late childhood and adolescence. It is vital for researchers to broaden the evidence base for addressing chronic malnutrition through multiple life stages, and for program implementers to explore effective, sustainable ways of reaching the most vulnerable populations.

Objectively measured physical activity and sedentary-time are associated with arterial stiffness in Brazilian young adults

OBJECTIVE

To examine the associations between objectively measured physical activity and sedentary time with pulse wave velocity (PWV) in Brazilian young adults.

METHODS

Cross-sectional analysis with participants of the 1982 Pelotas (Brazil) Birth Cohort who were followed-up from birth to 30 years of age. Overall physical activity (PA) assessed as the average acceleration (mg), time spent in moderate-to-vigorous physical activity (MVPA - min/day) and sedentary time (min/day) were calculated from acceleration data. Carotid-femoral PWV (m/s) was assessed using a portable ultrasound. Systolic and diastolic blood pressure (SBP/DBP), waist circumference (WC) and body mass index (BMI) were analyzed as possible mediators. Multiple linear regression and g-computation formula were used in the analyses.

RESULTS

Complete data were available for 1241 individuals. PWV was significantly lower in the two highest quartiles of overall PA (0.26 m/s) compared with the lowest quartile. Participants in the highest quartile of sedentary time had 0.39 m/s higher PWV (95%CI: 0.20; 0.57) than those in the lowest quartile. Individuals achieving ≥30 min/day in MVPA had lower PWV (β = -0.35; 95%CI: -0.56; -0.14). Mutually adjusted analyses between MVPA and sedentary time and PWV changed the coefficients, although results from sedentary time remained more consistent. WC captured 44% of the association between MVPA and PWV. DBP explained 46% of the association between acceleration and PWV.

CONCLUSIONS

Physical activity was inversely related to PWV in young adults, whereas sedentary time was positively associated. Such associations were only partially mediated by WC and DBP.

The Effect of Fetal and Childhood Growth over Depression in Early Adulthood in a Southern Brazilian Birth Cohort

BACKGROUND

Poor nutrition and growth during fetal life and childhood might be associated with depression in adulthood; however, studies evaluating these associations present controversial results, especially when comparing studies using different proxies for fetal growth. We evaluated the association of fetal and childhood growth/nutrition with depression, in adulthood, using different approaches and measurement methods.

METHOD

In 1982, hospital births (n = 5914) in Pelotas, southern Brazil, were examined and have been prospectively followed. At 30 years, the presence of major depression and depressive symptoms severity was evaluated using the Mini International Neuropsychiatric Interview (MINI) and Beck Depression Inventory (BDI-II). The present study assessed their association with birth weight, premature birth, small for gestational age (SGA), stunting and conditional growth during childhood.

RESULTS

At 30 years, 3576 individuals were evaluated and 7.9% had major depression. Low birth weight (PR = 1.01 95%CI [0.64-1.60]), having been born SGA (PR = 0.87 95%CI [0.64-1.19]) and premature birth (PR = 1.22 95%CI [0.72-2.07]) were not associated with major depression in multivariable models. However, those born SGA who were also stunted in childhood had a higher prevalence of major depression (PR = 1.87 95%CI [1.06-3.29]) and greater odds of scoring a higher level of depression in the BDI-II (OR = 2.18 95%CI [1.34-3.53]).

CONCLUSION

In this Brazilian cohort of young adults, those born SGA who were also stunted during childhood had a higher risk of depression in adulthood. Our results show that the effect of growth impairment on depression is cumulative.

Gene-Environment Interaction in Youth Depression: Replication of the 5-HTTLPR Moderation in a Diverse Setting

OBJECTIVE

Replication of scientific findings is a major challenge in biomedical research. In psychiatry, the identification of measured gene-environment interactions (G×E) has promoted a heated debate over the past decade, with controversial results about its influence on disorders such as major depression. The authors sought to replicate a 2003 study on G×E in youth depression in a large birth cohort from a diverse setting.

METHOD

Using data from the 1993 Pelotas Birth Cohort Study, and adopting a design as similar as possible to that of the original study, the authors tested whether the relationship between childhood maltreatment and a subsequent depressive episode diagnosis was moderated by 5-HTTLPR genotype. Of 5,249 individuals assessed at birth and followed up to age 18, data on the evaluation for depressive episodes in early adulthood, on childhood maltreatment, and on genotype were available for 3,558 participants, of whom 2,392 remained after conservative screening for previous depressive symptoms. Associations were investigated with logistic regression analyses and controlling for potential confounders.

RESULTS

The results replicated important findings of the original study, this time in a sample of young adults from a middle-income country: there was a differential dose-response relationship between childhood maltreatment and major depression according to 5-HTTLPR genotype.

CONCLUSIONS

After following a research strategy as comparable as possible to that of the original study, the results corroborated the existence of a measured G×E, now in a large sample from a different sociocultural context. These findings provide further evidence that a genetic variant in the 5-HTTLPR moderates the link between childhood maltreatment and youth depression.

Cesarean sections in Brazil: will they ever stop increasing?

OBJECTIVE

To describe trends, geographic distribution, and risk factors for cesarean deliveries in Brazil in 2000-2011, and to determine if efforts to curtail rates have had a measurable impact.

METHODS

This was an observational study using nationwide information from the Department of Informatics of the Unified Health System (DATASUS). Individual level analyses were based on data regarding maternal education, age, parity, and skin color. Ecological analyses at the level of 431 health districts investigated the relationships with health facility density and poverty level.

RESULTS

Cesarean rates increased markedly, from 37.9% in 2000 to 53.9% in 2011. Preliminary results from 2012 showed a rate of 55.8%, with the richest geographic areas showing the highest rates. Rates at the municipal level varied from 9%-96%. Cesareans were more common in women with higher education, white skin color, older age, and in primi- paras. In the ecological analyses, the number of health facilities per 1 000 population was strongly and positively correlated with cesarean rates, with an increase of 16.1 percentage points (95% Confidence Interval [95%CI] = 4.3-17.8) for each facility. An increase of 1 percentage point in the poverty rate was associated with a decline of 0.5 percentage point in cesarean rates (95%CI = 0.5-0.6).

CONCLUSIONS

The strong associations with maternal education and health facility density suggest that the vast majority of cesareans are not medically indicated. A number of policies and programs have been launched to counteract this trend, but have had virtually no impact.

Perinatal and sociodemographic factors at birth predicting conduct problems and violence to age 18 years: comparison of Brazilian and British birth cohorts

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.

Anthropometric Characterization of Impaired Fetal Growth: Risk Factors for and Prognosis of Newborns With Stunting or Wasting

IMPORTANCE

Stunting (short length for age) and wasting (low body mass index [BMI] for age) are widely used to assess child nutrition. In contrast, newborns tend to be assessed solely based on their weight.

OBJECTIVE

To use recent international standards for newborn size by gestational age to assess how stunted and wasted newborns differ in terms of risk factors and prognoses.

DESIGN, SETTING, AND PARTICIPANTS

A cross-sectional study with follow-up until hospital discharge was conducted at urban sites in Brazil, China, India, Italy, Kenya, Oman, England, and the United States that are participating in the INTERGROWTH-21st Project. The study was conducted from April 27, 2009, to March 2, 2014, and the final dataset for analyses was locked on March 19, 2014.

EXPOSURES

Sociodemographic and behavioral maternal risk factors, previous pregnancy history, and maternal and fetal conditions during pregnancy were investigated as risk factors for stunting and wasting. Anthropometry at birth was used to predict for neonatal prognosis.

MAIN OUTCOMES AND MEASURES

Newborn stunting and wasting were defined as birth length and BMI for gestational age below the third centiles of the INTERGROWTH-21st standards. Prognosis was assessed through mortality before hospital discharge, admission to neonatal intensive care units, and newborn complications.

RESULTS

From the 60 206 singleton live births during the study period, we selected all newborns between 33 weeks' and 42 weeks 6 days' gestation at birth (51 200 [85%]) with reliable ultrasound dating. Stunting affected 3.8% and wasting 3.4% of all newborns; both conditions were present in 0.7% of the sample. Of the 26 conditions studied, five were more strongly associated with stunting than with wasting (reported as odds ratios [OR]; 95% CI): short maternal height (6.7; 5.1-9.0), younger maternal age (0.7; 0.5-0.9), smoking (2.8; 2.3-3.3), illicit drug use (2.3; 1.5-3.6), and clinically suspected intrauterine growth restriction (5.2; 4.5-6.0). Wasting was more strongly related than stunting with 4 newborn outcomes (neonatal intensive care stay, 6.7 [5.5-8.1]; respiratory distress syndrome, 4.0 [3.3-4.9]; transient tachypnea, 2.1 [1.5-2.9]; and no oral feeding for >24 hours, 5.0 [3.9-6.5]). Maternal gestational diabetes mellitus was protective against wasting (0.6; 0.5-0.8) but not against stunting (0.9; 0.7-1.1).

CONCLUSIONS AND RELEVANCE

Although newborn stunting and wasting share some common determinants, they are distinct phenotypes with their own risk factors and neonatal prognoses. To be consistent with the literature on infant and child nutrition, newborns should be classified using the 2 phenotypes of stunting and wasting. The distinction will help to prioritize preventive interventions and focus the management of fetal undernutrition.

Gestational age and newborn size according to parental social mobility: an intergenerational cohort study

Background

We examined the associations between socioeconomic trajectories from birth to adulthood and gestational age and birth size in the next generation, using linked data from two population-based birth cohorts carried out in a Brazilian city. By comparing socioeconomic trajectories of mothers and fathers, we attempted to identify-specific effects of maternal and paternal socioeconomic trajectory on offspring birth weight, birth length, head circumference and gestational age at birth.

Methods

2 population-based birth cohort studies were carried out in 1982 and 2004 in Pelotas (Brazil); 156 mothers and 110 fathers from the earlier cohort had children in 2004. Gestational age and birth length, weight and head circumference were measured. Analyses were carried out separately for mothers and fathers. Mediation analyses assessed the role of birth weight and adult body mass index (BMI).

Results

Among mothers, but not for fathers, childhood poverty was strongly associated with smaller size in the next generation (about 400 g in weight and 1.5 cm in height) and shorter gestations (about 2 weeks). Adult poverty did not play a role. For mothers, the associations with gestational age, birth length and weight—but not with head circumference—persisted after adjusting for maternal birth weight and for the height and weight of the grandmother. Maternal birth weight did not mediate the observed associations, but high maternal BMI in adulthood was partly responsible for the association with gestational age.

Conclusions

Strong effects of early poverty on gestational age and birth size in the next generation were observed among mothers, but not among fathers. These findings suggest a specific maternal effect of socioeconomic trajectory, and in particular of early poverty on offspring size and duration of pregnancy.

Breastfeeding and bone mass at the ages of 18 and 30: prospective analysis of live births from the Pelotas (Brazil) 1982 and 1993 cohorts

OBJECTIVE

To evaluate the effect of total breastfeeding, breastfeeding duration and type of breastfeeding at 3 months of age on bone mass at 18 and 30 years.

STUDY DESIGN

A prospective, longitudinal study was conducted with two birth cohorts (1982 and 1993) in Pelotas, Southern Brazil. Measurements of bone mineral content (BMC) and bone mineral density (BMD) at 18 and 30 years of age were obtained by dual-energy X-ray absorptiometry (DXA). Information on breastfeeding was collected during the first 4 years of life. Analyses were performed by linear regression and stratified by sex.

RESULTS

A total of 1109 and 3226 participants provided complete information on breastfeeding in early life and bone mass at 18 and 30 years, respectively. No association between breastfeeding and bone mass was observed in women at both ages nor among men at age 30. Among men at the age of 18, BMC and BMD were higher among those breastfed regardless of duration (p=0.032 and p=0.043, respectively).

CONCLUSIONS

Despite a very weak positive effect of breastfeeding (yes/no) on BMC and BMD at age 18 in men, most findings pointed to a lack of association between breastfeeding and bone mass until young adulthood.