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1.  Dietary intake patterns of children aged 6 years and their association with socioeconomic and demographic characteristics, early feeding practices and body mass index 
BMC Public Health  2016;16:1055.
Background
Dietary intake patterns of children from the 2004 Pelotas birth cohort study have been described at 12, 24 and 48 months of age, but there is no information about dietary patterns of these children at 6 years. Then, we aimed to identify and describe dietary intake patterns of children aged 6 years as well as to assess their association with socioeconomic and demographic characteristics, early feeding practices and BMI z-score at 6 years.
Methods
We used principal components analysis to identify dietary intake patterns of 3,427 children from the 2004 Pelotas (Brazil) birth cohort study. We used multiple linear regression models to evaluate whether socioeconomic and demographic characteristics (socioeconomic position, mother’s age at birth, and child’s sex and skin colour), early feeding practices (exclusive breastfeeding duration and age of introduction of complementary foods), and BMI z-score at 6 years were associated with dietary intake patterns.
Results
We identified seven dietary components of children’s dietary intake patterns, namely: fruits and vegetables, snacks and treats, coffee and bread, milk, cheese and processed meats, rice and beans and carbohydrates. Dietary patterns were socially patterned, since six dietary components were associated with socioeconomic position. Moreover, high intake of snacks and treats and less fruits and vegetables were associated with children born to teenage mothers, with those exclusively breastfed for less than one month, and with those who started on complementary feeding before 4 months. Finally, overweight and obese children at 6 years presented lower intake of four out of seven dietary components, but we need to be cautious in interpretation due to limitations on food consumption reporting and due to possible reverse causality.
Conclusion
Dietary intake patterns in children are strongly influenced by socioeconomic characteristics. Other factors such as younger maternal age at birth, and both early weaning and early introduction of complementary feeding appear to be related with ‘unhealthier’ patterns. Overweight and obese children presented lower intake of four out of seven dietary components, but further studies would be interesting to understand the longitudinal effect of children’s feeding practices on BMI and adiposity.
Electronic supplementary material
The online version of this article (doi:10.1186/s12889-016-3725-2) contains supplementary material, which is available to authorized users.
doi:10.1186/s12889-016-3725-2
PMCID: PMC5052805  PMID: 27716197
Dietary intake; Principal component analysis; Cohort studies; Nutrition assessment
2.  Patient health questionnaire-9 versus Edinburgh postnatal depression scale in screening for major depressive episodes: a cross-sectional population-based study 
BMC Research Notes  2016;9:453.
Background
Major depressive episodes (MDE) are frequent at the population level and are generally associated with severe symptoms that impair performance of activities of daily living of individuals suffering from this condition. The aim of this study was to compare the accuracy of two tests that separately showed suitable properties in screening for MDE: the Patient Health Questionnaire-9 (PHQ-9) and the Edinburgh postnatal depression scale (EPDS).
Methods
In a previous study, the sensitivity and specificity of the PHQ-9 and the EPDS in screening for MDE were compared with a structured diagnostic interview conducted by psychiatrics and psychologists using the Mini International Neuropsychiatric Interview as the gold standard. In a sample of adults living in the community in Pelotas, Brazil, the PHQ-9 and EPDS were applied at the same interview and the gold standard on a median of 17 days later. The interviews were carried out at the participant’s home.
Results
447 individuals (191 men and 256 women) were assessed. The PHQ-9 and the EPDS results were concordant in 87.5 % of the respondents, with a moderate agreement beyond what was expected by chance alone (kappa = 0.61). The areas below the ROC curves were not statistically different (82.1 % for PHQ-9 and 83.5 % for EPDS) (p = 0.291), thus indicating that the two tests had similar moderate accuracy.
Conclusions
PHQ-9 and EPDS may be applied with equal confidence in screening for MDE in the community.
doi:10.1186/s13104-016-2259-0
PMCID: PMC5037593  PMID: 27677844
Patient health questionnaire-9; Edinburgh postnatal depression scale; Major depressive episode; Screening; Accuracy
3.  Intellectual Disability in a Birth Cohort: Prevalence, Etiology, and Determinants at the Age of 4 Years 
Public Health Genomics  2016;19(5):290-297.
Background
Intellectual disability (ID), characterized by impairments in intellectual function and adaptive behavior, affects 1-3% of the population. Many studies investigated its etiology, but few are cohort studies in middle-income countries.
Aims
To estimate prevalence, etiology, and factors related to ID among children prospectively followed since birth in a Southern Brazilian city (Pelotas).
Methods
In 2004, maternity hospitals were visited daily and births were identified. Live-born infants (n = 4,231) whose family lived in the urban area have been followed for several years. At the age of 2 and 4 years, performances in development and intelligence tests were evaluated using the Battelle Developmental Inventory and Wechsler Intelligence Scale, respectively. Children considered as having developmental delay were invited to attend a genetic evaluation.
Results
At 4 years of age, the prevalence of ID was 4.5%, and the etiology was classified into 5 groups: environmental (44.4%), genetic (20.5%), idiopathic (12.6%), neonatal sequelae (13.2%), other diseases (9.3%). Most children presented impairment in two or more areas of adaptive behavior. There was no difference in prenatal care attendance or maternal schooling among the groups.
Conclusion
For about 40% of children, ID was attributed to nonbiological factors, suggesting that the rate may be reduced with appropriate interventions early in life.
doi:10.1159/000448912
PMCID: PMC5079101  PMID: 27595410
Cohort studies; Developmental delay; Intellectual disability; Mental retardation; Prevalence
4.  LBW and IUGR temporal trend in 4 population-based birth cohorts: the role of economic inequality 
BMC Pediatrics  2016;16:115.
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.
doi:10.1186/s12887-016-0656-0
PMCID: PMC4966743  PMID: 27473678
Inequality; Income; Preterm; Low birthweight; Small for the gestational age; Intrauterine growth restriction; Poverty
5.  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.
doi:10.1136/jech-2015-206222
PMCID: PMC4941187  PMID: 26767410
Cohort studies; MATERNAL & CHILD CG; PERINATAL EPIDEMIOLOGY
6.  Genetic causes of intellectual disability in a birth cohort: A population‐based study 
Intellectual disability affects approximately 1–3% of the population and can be caused by genetic and environmental factors. Although many studies have investigated the etiology of intellectual disability in different populations, few studies have been performed in middle‐income countries. The present study estimated the prevalence of genetic causes related to intellectual disability in a cohort of children from a city in south Brazil who were followed from birth. Children who showed poor performance in development and intelligence tests at the ages of 2 and 4 were included. Out of 4,231 liveborns enrolled in the cohort, 214 children fulfilled the inclusion criteria. A diagnosis was established in approximately 90% of the children evaluated. Genetic causes were determined in 31 of the children and 19 cases remained unexplained even after extensive investigation. The overall prevalence of intellectual disability in this cohort due to genetic causes was 0.82%. Because this study was nested in a cohort, there were a large number of variables related to early childhood and the likelihood of information bias was minimized by collecting information with a short recall time. This study was not influenced by selection bias, allowing identification of intellectual disability and estimation of the prevalence of genetic causes in this population, thereby increasing the possibility of providing appropriate management and/or genetic counseling. © 2015 The Authors. American Journal of Medical Genetics Part A Published by Wiley Periodicals, Inc.
doi:10.1002/ajmg.a.37011
PMCID: PMC4863139  PMID: 25728503
intellectual disability; mental retardation; genetics causes of diseases; population‐based studies; birth defects
7.  Relationship between maternal pre‐pregnancy body mass index, gestational weight gain and childhood fatness at 6–7 years by air displacement plethysmography 
Maternal & Child Nutrition  2015;11(4):606-617.
Abstract
This study aims to investigate the effect of maternal pre‐pregnancy body mass index (BMI) and gestational weight gain (GWG) on offspring body composition. In this prospective cohort study, offspring body composition at 6 years of age was obtained through air displacement plethysmography. Linear regression was used to obtain crude and adjusted coefficients. Information regarding offspring body composition and maternal pre‐pregnancy BMI was available for 3156 children and on offspring body composition and GWG for 3129 children. There was a direct association of maternal pre‐pregnancy BMI and GWG with offspring's fat mass (FM), fat‐free mass (FFM), fat mass index (FMI), fat‐free mass index (FFMI) and body fat percent (BF%) in crude and adjusted analyses. After adjustment for co‐variables, for each kg m−2 of maternal pre‐pregnancy BMI increase, there was a mean increment of 0.13 kg in the offspring FFM, 0.06 kg m−2 in FFMI, 0.11 kg in FM, 0.07 kg m−2 in FMI and 0.18% in BF%. For each kilogram of maternal GWG increase, there was a mean increment of 0.08 kg in offspring's FM, 0.05 kg m−2 in FMI, 0.04 kg in FFM, 0.01 kg m−2 in FFMI and 0.18 % in BF%. Mothers with a higher pre‐pregnancy BMI or GWG tend to have children with greater adiposity at age 6 years. Fetal overnutrition is more likely among mothers with greater BMI during pregnancy; as a consequence, it can accelerate the childhood obesity epidemic.
doi:10.1111/mcn.12186
PMCID: PMC4832361  PMID: 25850519
body composition; pregnancy; children; fatness; women's weight; weight gain
8.  Short Sleep Duration in the First Years of Life and Obesity/Overweight at Age 4 Years: A Birth Cohort Study 
The Journal of Pediatrics  2016;168:99-103.e3.
Objective
To investigate whether short sleep duration from the first year of life influenced weight at an early age.
Study design
During 2004, children born in Pelotas, Brazil, were enrolled in a cohort study. Sleeping habits during the previous 2 weeks were assessed, and the children were weighed and measured at 1-, 2-, and 4-year follow-ups. Overweight and obesity at 4 years were defined according to World Health Organization z-scores for body mass index for age. Short sleep duration was defined as fewer than 10 hours of sleep per night at any follow-up.
Results
Out of the 4263 live births, 4231 were recruited. The prevalence of short sleep duration at any follow-up from 1-4 years of age was 10.1%. At 4 years of age, 201 children were obese (5.3%), and 302 (8%) were overweight. Among short sleepers, the prevalence ratio for overweight/obesity after adjusting for maternal and children's characteristics was 1.32 (1.03; 1.70).
Conclusions
Children who slept for fewer than 10 hours per night at any follow-up from 1-4 years of age were more likely to be overweight or obese at 4 years of age, despite their sociodemographic and sleep characteristics.
doi:10.1016/j.jpeds.2015.09.074
PMCID: PMC4691233  PMID: 26541426
BMI, Body mass index; PR, Prevalence ratio
9.  Effects of exercise in the whole spectrum of chronic kidney disease: a systematic review 
Clinical Kidney Journal  2015;8(6):753-765.
Chronic kidney disease (CKD) is a public health problem. Although physical activity is essential for the prevention and treatment of most chronic diseases, exercise is rarely prescribed for CKD patients. The objective of the study was to search for and appraise evidence on the effectiveness of exercise interventions on health endpoints in CKD patients. A systematic review was performed of randomized clinical trials (RCTs) designed to compare exercise with usual care regarding effects on the health of CKD patients. MEDLINE, EMBASE, Cochrane Central, Clinical Trials registry, and proceedings of major nephrology conference databases were searched, using terms defined according to the PICO (Patient, Intervention, Comparison and Outcome) methodology. RCTs were independently evaluated by two reviewers. A total of 5489 studies were assessed for eligibility, of which 59 fulfilled inclusion criteria. Most of them included small samples, lasted from 8 to 24 weeks and applied aerobic exercises. Three studies included only kidney transplant patients, and nine included pre-dialysis patients. The remaining RCTs allocated hemodialysis patients. The outcome measures included quality of life, physical fitness, muscular strength, heart rate variability, inflammatory and nutritional markers and progression of CKD. Most of the trials had high risk of bias. The strongest evidence is for the effects of aerobic exercise on improving physical fitness, muscular strength and quality of life in dialysis patients. The benefits of exercise in dialysis patients are well established, supporting the prescription of physical activity in their regular treatment. RCTs including patients in earlier stages of CKD and after kidney transplantation are urgently required, as well as studies assessing long-term outcomes. The best exercise protocol for CKD patients also remains to be established.
doi:10.1093/ckj/sfv099
PMCID: PMC4655802  PMID: 26613036
chronic kidney disease; dialysis; exercise; physical activity
10.  Diet quality of preschool children aged 2 to 5 years living in the urban area of Pelotas, Brazil 
Revista Paulista de Pediatria  2015;33(3):310-317.
Abstract
Objective:
To assess the dietary quality of preschool children in the urban area of Pelotas, Rio Grande do Sul, southern Brazil.
Methods:
Dietary quality was measured according to the Healthy Eating Index (HEI), adapted to Brazil. Food consumption was obtained using the Food Frequency Questionnaire (FFQ). The index score was obtained by a score, ranging from 0 to 100, distributed in 13 food groups that characterize different components of a healthy diet. The better the quality of the diet, the closer the score is to 100.
Results:
Dietary quality was evaluated in 556 preschoolers. The mean HEI score value was 74.4 points, indicating that diets need improvement. The mean scores were significantly higher among girls and in children from families with income between one and less than three minimum wages.
Conclusions:
The children showed vegetable consumption below the recommended level, while foods of the food group of oils and fats, as well as the group of sugars, candies, chocolates and snacks, were consumed in excess. It is important to reinforce guidelines to promote healthier eating habits, which may persist later in life.
doi:10.1016/j.rpped.2015.05.002
PMCID: PMC4620958  PMID: 26122208
Preschool; Indexes; Food habits; Diet
11.  Excessive crying at 3 months of age and behavioural problems at 4 years age: a prospective cohort study 
Background
Excessive crying in early infancy has been associated with behavioural problems among preschool children from high income countries but studies in low income and middle income countries are scarce.
Methods
The 2004 Pelotas Birth Cohort is a population-based study planned to enrol all live births occurring in Pelotas that year and comprises 4231 children who so far have been followed up at 3, 12, 24, 48 and 72 months of age. Several familial, maternal and child characteristics were gathered in every follow-up. At the 3-month follow-up, infants whose mothers perceived them as crying more than others of the same age were classified as ‘crying babies’. Child behavioural problems were assessed through the Child Behavior Checklist (CBCL) applied to the mother at the 48-month follow-up. Crude and adjusted ORs with 95% CIs were calculated by logistic regression.
Results
Prevalence of excessive crying at 3 months was 11.9% (10.9% to 13.0%). Among children with excessive crying at 3 months the proportion in the clinical range for CBCL total, internalising and externalising problems at 4 years of age was 31.2%, 12.9% and 37.5%, respectively, against 20.6%, 6.8% and 29.6%, respectively, among non-crying babies. After controlling for confounders crying babies presented increased risk of being in clinical range of CBCL total (OR=1.34; 1.03 to 1.74), internalising (OR=1.55; 1.09 to 2.21) and externalising problems (OR=1.29; 1.01 to 1.64) than infants without excessive crying.
Conclusions
Excessive crying in early infancy may represent one important risk factor for developing behavioural problems in later phases of early childhood.
doi:10.1136/jech-2014-204568
PMCID: PMC4484259  PMID: 25700531
CHILD HEALTH; Cohort studies; EPIDEMIOLOGY; PRIMARY HEALTH CARE; PUBLIC HEALTH
12.  Determinants of out-of-pocket health expenditure on children: an analysis of the 2004 Pelotas Birth Cohort 
Background
The present study aimed to examine the impact of socioeconomic, demographic, and health status-related factors on out-of-pocket expenditure on health care for children.
Methods
Data were obtained from a birth cohort study conducted in the city of Pelotas, state of Rio Grande do Sul (RS), southern Brazil, in 2004. The final sample is a result of adjusts made in order to keep in the analysis only those that attended to 3 follow-ups (at 12, 24 and 48 months of age). Estimates were carried out using the Panel Data Tobit Model with random effects.
Results
The study showed that expenditure on medicines was 20 % less likely in those considered healthy children by their mothers and, if there was any expenditure with healthy children, the expected expenditure was reduced by 58 %. A 1 % increase in household income increased the expected expenditure on medicines by 16 %, and by 23 % in children with private health insurance coverage.
Conclusions
All types of health care expenditures examined were higher for children covered by private health insurance. Although total health care expenditure was higher for children of better-off families, it represented a lower share of these families’ income evidencing income inequality in health care expenditures.
Electronic supplementary material
The online version of this article (doi:10.1186/s12939-015-0180-0) contains supplementary material, which is available to authorized users.
doi:10.1186/s12939-015-0180-0
PMCID: PMC4467315  PMID: 26051372
Determinants; Health expenditure; Children; Health economics; Inequality
13.  Linear spline multilevel models for summarising childhood growth trajectories: A guide to their application using examples from five birth cohorts 
Childhood growth is of interest in medical research concerned with determinants and consequences of variation from healthy growth and development. Linear spline multilevel modelling is a useful approach for deriving individual summary measures of growth, which overcomes several data issues (co-linearity of repeat measures, the requirement for all individuals to be measured at the same ages, and bias due to missing data). Here, we outline the application of this methodology to model individual trajectories of length/height and weight, drawing on examples from five cohorts from different generations and different geographical regions with varying levels of economic development. We describe the unique features of the data within each cohort that have implications for the application of linear spline multilevel models, e.g. differences in the density and inter-individual variation in measurement occasions, and multiple sources of measurement with varying measurement error. After providing example Stata syntax and a suggested workflow for the implementation of linear spline multilevel models, we conclude with a discussion of the advantages and disadvantages of the linear spline approach compared with other growth modelling methods such as fractional polynomials, more complex spline functions and other non-linear models.
doi:10.1177/0962280213503925
PMCID: PMC4074455  PMID: 24108269
child; growth; height; longitudinal; multilevel models; spline; weight; ALSPAC; Born in Bradford; Generation XXI; Pelotas; PROBIT
14.  Trajectories of maternal depression and offspring psychopathology at 6 years: 2004 Pelotas cohort study 
Journal of Affective Disorders  2015;174:424-431.
Background
Few studies have addressed the course and severity of maternal depression and its effects on child psychiatric disorders from a longitudinal perspective. This study aimed to identify longitudinal patterns of maternal depression and to evaluate whether distinct depression trajectories predict particular psychiatric disorders in offspring.
Methods
Cohort of 4231 births followed-up in the city of Pelotas, Brazil. Maternal depressive symptoms were assessed with the Edinburgh Postnatal Depression Scale (EPDS) at 3, 12, 24 and 48 months and 6 years after delivery. Psychiatric disorders in 6-year-old children were evaluated through the development and well-being assessment (DAWBA) instrument. Trajectories of maternal depression were calculated using a group-based modelling approach.
Results
We identified five trajectories of maternal depressive symptoms: a “low” trajectory (34.8%), a “moderate low” (40.9%), a “increasing” (9.0%), a “decreasing” (9.9%), and a “high-chronic” trajectory (5.4%). The probability of children having any psychiatric disorder, as well as both internalizing and externalizing problems, increased as we moved from the “low” to the “high-chronic” trajectory. These differences were not explained by maternal and child characteristics examined in multivariate analyses.
Limitations
Data on maternal depression at 3-months was available on only a sub-sample. In addition, we had to rely on maternal report of child’s behavior alone.
Conclusions
The study revealed an additive effect on child outcome of maternal depression over time. We identified a group of mothers with chronic and severe symptoms of depression throughout the first six years of the child life and for this group child psychiatric outcome was particularly compromised.
Highlights
•Maternal postnatal depressive symptomatology was modeled using group-based approach.•5 maternal trajectories were identified from 3 months through 6 years postpartum.•Offspring psychiatric disorders were assessed at age 6 years.•Psychiatric disorders increased from the “low” to the “high-chronic” trajectory.•We revealed an additive effect on child outcome of maternal depression over time.
doi:10.1016/j.jad.2014.12.012
PMCID: PMC4351190  PMID: 25553403
DAWBA, development and well-being assessment; EPDS, Edinburgh Post-natal Depression Scale; LMP, last menstrual period; C-section, caesarean section; OR, odds ratio, 95% CI, 95% confidence interval.; Maternal postnatal depression; Group-based modelling; Development and well-being assessment; Mental health; Children; Cohort study
15.  The association of birth order with later body mass index and blood pressure: a comparison between prospective cohort studies from the UK and Brazil 
Background
Previous studies have found greater adiposity and cardiovascular risk in first born children. The causality of this association is not clear. Examining the association in diverse populations may lead to improved insight.
Methods
We examine the association between birth order and body mass index (BMI), systolic and diastolic blood pressure (SBP/DBP) in the 2004 Pelotas cohort from southern Brazil and the Avon Longitudinal Study of Parents and Children (ALSPAC) from Bristol, south west England, restricting analysis to families with two children in order to remove confounding by family size.
Results
No consistent differences in BMI, SBP or DBP were observed comparing first and second born children. Within the Pelotas 2004 cohort, first born females were thinner, with lower SBP and DBP; e.g. mean difference in SBP comparing first with second born was -0.979 (95% confidence interval -2.901 to 0.943). In ALSPAC, first born females had higher BMI, SBP and DBP. In both cohorts, associations tended to be in the opposite direction in males, although no statistical evidence for gender interactions was found.
Conclusions
The findings do not support an association between birth order and BMI or blood pressure. Differences to previous studies may be explained by differences in populations and/or confounding by family size in previous studies.
doi:10.1038/ijo.2013.189
PMCID: PMC4024316  PMID: 24097298
ALSPAC; birth order; blood pressure; body mass index; cardiovascular; obesity; Pelotas; siblings
16.  Early life determinants of low IQ at age 6 in children from the 2004 Pelotas Birth Cohort: a predictive approach 
BMC Pediatrics  2014;14:308.
Background
Childhood intelligence is an important determinant of health outcomes in adulthood. The first years of life are critical to child development. This study aimed to identify early life (perinatal and during the first year of life) predictors of low cognitive performance at age 6.
Methods
A birth cohort study started in the city of Pelotas, southern Brazil, in 2004 and children were followed from birth to age six. Information on a broad set of biological and social predictors was collected. Cognitive ability—the study outcome—was assessed using the Wechsler Intelligence Scale for Children (WISC). IQ scores were standardized into z-scores and low IQ defined as z < −1. We applied bootstrapping methods for internal validation with a multivariate logistic regression model and carried out external validation using a second study from the 1993 Pelotas Birth Cohort.
Results
The proportion of children with IQ z-score < −1 was 16.9% (95% CI 15.6–18.1). The final model included the following early life variables: child’s gender; parents’ skin color; number of siblings; father’s and mother’s employment status; household income; maternal education; number of persons per room; duration of breastfeeding; height-for-age deficit; head circumference-for-age deficit; parental smoking during pregnancy; and maternal perception of the child’s health status. The area under the ROC curve for our final model was 0.8, with sensitivity of 72% and specificity of 74%. Similar results were found when testing external validation by using data from the 1993 Pelotas Birth Cohort.
Conclusions
The study results suggest that a child’s and her/his family’s social conditions are strong predictors of cognitive ability in childhood. Interventions for promoting a healthy early childhood development are needed targeting children at risk of low IQ so that they can reach their full cognitive potential.
Electronic supplementary material
The online version of this article (doi:10.1186/s12887-014-0308-1) contains supplementary material, which is available to authorized users.
doi:10.1186/s12887-014-0308-1
PMCID: PMC4272809  PMID: 25510879
Child development; Birth cohort; Intelligence; Cognition; Social determinants of health; Brazil
17.  Physical Activity during Pregnancy and Offspring Neurodevelopment and IQ in the First 4 Years of Life 
PLoS ONE  2014;9(10):e110050.
Background
Maternal physical activity during pregnancy could alter offspring's IQ and neurodevelopment in childhood.
Methods
Children belonging to a birth cohort were followed at 3, 12, 24 and 48 months of age. Physical activity during pregnancy was assessed retrospectively at birth. Neurodevelopment was evaluated by Battelle's Development Inventory (12, 24 and 48 months) and IQ by the Weschler's Intelligence Scale (48 months). Neurodevelopment was based on Battelles' (90th percentile) and also analyzed as a continuous outcome. IQ was analyzed as a continuous outcome. Potential confounders were: family income, mother's age, schooling, skin color, number of previous births and smoking; and newborns': preterm birth, sex and low birth weight.
Results
From birth to 48 months, sample size decreased from 4231 to 3792. Crude analysis showed that IQ at 48 months was slightly higher (5 points) among children from active women. The Battelle's score at 12 and 24 months was higher among offspring from active mothers. After controlling for confounders, physical activity during pregnancy was positively associated to the Battelle's Inventory at 12 months IQ, however, at 48 months no association was observed.
Conclusion
Physical activity during pregnancy does not seem to impair children's neurodevelopment and children from active mothers presented better performance at 12 months.
doi:10.1371/journal.pone.0110050
PMCID: PMC4211660  PMID: 25350666
18.  Validation of the Edinburgh postnatal depression scale (EPDS) for screening of major depressive episode among adults from the general population 
BMC Psychiatry  2014;14:284.
Background
Standardized questionnaires designed for the identification of depression are useful for monitoring individual as well as population mental health. The Edinburgh Postnatal Depression Scale (EPDS) has originally been developed to assist primary care health professionals to detect postnatal depression, but several authors recommend its use outside of the postpartum period. In Brazil, the use of the EPDS for screening depression outside the postpartum period and among non-selected populations has not been validated. The present study aimed to assess the validity of the EPDS as a screening instrument for major depressive episode (MDE) among adults from the general population.
Methods
This is a validation study that used a population-based sampling technique to select the participants. The study was conducted in the city of Pelotas, Brazil. Households were randomly selected by two stage conglomerates with probability proportional to size. EPDS was administered to 447 adults (≥20 years). Approximately 17 days later, participants were reinterviewed by psychiatrics and psychologists using a structured diagnostic interview (Mini International Neuropsychiatric Interview, MINI). We calculated the sensitivity and specificity of each cutoff point of EPDS, and values were plotted as a receiver operator characteristic curve.
Results
The best cutoff point for screening depression was ≥8, with 80.0% (64.4 - 90.9%) sensitivity and 87.0% (83.3 - 90.1%) specificity. Among women the best cutoff point was ≥8 too with values of sensitivity and specificity of 84.4% (67.2 – 94.7%) and 81.3% (75.5 – 86.1%), respectively. Among men, the best cutoff point was ≥7 (75% sensitivity and 89% specificity).
Conclusions
The EPDS was shown to be suitable for screening MDE among adults in the community.
doi:10.1186/s12888-014-0284-x
PMCID: PMC4203969  PMID: 25293375
Major depressive episode; Validity of tests; Sensitivity and specificity; Adult; EPDS test; Depression
19.  Antenatal and postnatal maternal mood symptoms and psychiatric disorders in pre-school children from the 2004 Pelotas Birth Cohort 
Journal of Affective Disorders  2014;164(100):112-117.
Background
Maternal mood symptoms have been associated with psychiatric disorders in children. This study aimed to assess critical periods when maternal symptoms would be more deleterious.
Methods
Cohort of 4231 births followed-up in the city of Pelotas, Brazil. Mood symptoms during pregnancy were self-reported by mothers at perinatal interview; and at 3-months postpartum, mothers answered the Self-Reporting Questionnaire. Psychiatric disorders in 6-year-old children were evaluated through the Development and Well-Being Assessment instrument. Odds ratios with 95% confidence intervals (95% CI) were calculated by logistic regression.
Results
Prevalence of mood symptoms in pregnancy was 24.6% (23.2–26.0%) and at three months postpartum 22.5% (21.1–23.9%). Prevalence of mental disorders in children was 13.3% (12.2–14.4%). After adjustment for confounders children of mothers with mood symptoms during pregnancy were 82% more likely of presenting psychiatric disorders than children of mothers that did not (1.82; 1.48–2.25); and the chance of having mental disorders among children whose mothers had positive SRQ-20 at three months postpartum was 87% greater than the observed among children whose mothers had it negative (1.87; 1.50–2.33).
Limitations
Because maternal anxiety/depression may interfere with interpretation of the child behavior, child׳s mental health being obtained by interviewing the mother is a limitation of this study. Lack of information on other risk factors may have lead to residual confounding on the effect of maternal mood symptoms at three months postpartum.
Conclusions
Children of mothers presenting mood symptoms during pregnancy and in the first months postpartum are more likely to present psychiatric disorders at 6 years of age.
doi:10.1016/j.jad.2014.04.033
PMCID: PMC4051989  PMID: 24856563
DAWBA, Development and Well- Being Assessment; EPDS, Edinburgh Post-natal Depression Scale; LBW, low birth weight; LMP, last menstrual period; OR, odds ratio; MW, minimum wages; SRQ-20, self-reporting questionnaire; 95% CI, 95% confidence interval; Mood disorders; Self-reporting questionnaire; Development and Well-Being Assessment; Cohort study; Preschool children
20.  Cohort Profile Update: 2004 Pelotas (Brazil) Birth Cohort Study. Body composition, mental health and genetic assessment at the 6 years follow-up 
International Journal of Epidemiology  2014;43(5):1437-1437f.
This is an update of the 2004 Pelotas Birth Cohort profile, originally published in 2011. In view of the high prevalence of overweight and mental health problems among Brazilian children, together with the availability of state-of-the-art equipment to assess body composition and diagnostic tests for mental health in childhood, the main outcomes measured in the fifth follow-up (mean age 6.8 years) included child body composition, mental health and cognitive ability. A total of 3722 (90.2%) of the original mothers/carers were interviewed and their children examined in a clinic where they underwent whole-body dual X-ray absorptiometry (DXA), air displacement plethysmography and a 3D photonic scan. Saliva samples for DNA were obtained. Clinical psychologists applied the Development and Well-Being Assessment questionnaire and the Wechsler Intelligence Scale for Children to all children. Results are being compared with those of the two earlier cohorts to assess the health effects of economic growth and full implementation of public policies aimed at reducing social inequalities in the past 30 years. For further information visit the programme website at [http://www.epidemio-ufpel.org.br/site/content/coorte_2004/questionarios.php]. Applications to use the data should be made by contacting 2004 cohort researchers and filling in the application form available at [http://www.epidemio-ufpel.org.br/site/content/estudos/formularios.php].
doi:10.1093/ije/dyu144
PMCID: PMC4190519  PMID: 25063002
21.  Prevalence and comorbidity of psychiatric disorders among 6-year-old children: 2004 Pelotas Birth Cohort 
Purpose
Most studies published on the prevalence of psychiatric disorders in children were conducted in high-income countries despite the fact that nearly 90 % of the world’s population aged under 18 live in low- and middle-income countries. The study aimed to assess the prevalence of psychiatric disorders among children of 6 years of age, to examine the distribution of psychiatric disorders by gender and socioeconomic status and to evaluate the occurrence of psychiatric comorbidities.
Methods
The 2004 Pelotas Birth Cohort originally comprised 4,231 live births from Pelotas, southern Brazil. A total of 3,585 (84.7 % of 4,231 births) children aged 6 years were assessed using the Development and Well-Being Assessment (DAWBA).
Results
Nearly 13 % of the children presented a psychiatric diagnosis according to DSM-IV, being more prevalent among males than females (14.7 and 11.7 %, respectively, p = 0.009). Anxiety disorders were the most prevalent of all disorders (8.8 %) and specific phobias (5.4 %) and separation anxiety disorder (3.2 %) were the most common subtypes. Attention deficit hyperactivity disorder (2.6 %), oppositional defiant disorder/conduct disorder (2.6 %), and depression (1.3 %) were also diagnosed. More than one psychiatric disorder was presented by 17 % of children. Socioeconomically disadvantaged children had a higher prevalence of psychiatric disorders.
Conclusion
Our findings underline the early onset of psychiatric disorders among children and the frequent occurrence of psychiatric comorbidity. Early prevention is needed in the field of mental health in Brazil and should start during infancy.
doi:10.1007/s00127-014-0826-z
PMCID: PMC4028510  PMID: 24488152
Prevalence; Cohort studies; Mental disorders; Mental health; Child
22.  Patterns of deliveries in a Brazilian birth cohort: almost universal cesarean sections for the better-off 
Revista de saude publica  2011;45(4):635-643.
OBJECTIVE
To describe the patterns of deliveries in a birth cohort and to compare vaginal and cesarean section deliveries.
METHODS
All children born to mothers from the urban area of Pelotas, Brazil, in 2004, were recruited for a birth cohort study. Mothers were contacted and interviewed during their hospital stay when extensive information on the gestation, the birth and the newborn, along with maternal health history and family characteristics was collected. Maternal characteristics and childbirth care financing – either private or public healthcare (SUS) patients - were the main factors investigated along with a description of C-sections distribution according to day of the week and delivery time. Standard descriptive techniques, χ2 tests for comparing proportions and Poisson regression to explore the independent effect of C-section predictors were the methods used.
RESULTS
The overall C-section rate was 45%, 36% among SUS and 81% among private patients, where 35% of C-sections were reported elective. C-sections were more frequent on Tuesdays and Wednesdays, reducing by about a third on Sundays, while normal deliveries had a uniform distribution along the week. Delivery time for C-sections was markedly different among public and private patients. Maternal schooling was positively associated with C-section among SUS patients, but not among private patients.
CONCLUSIONS
C-sections were almost universal among the wealthier mothers, and strongly related to maternal education among SUS patients. The patterns we describe are compatible with the idea that C-sections are largely done to suit the doctor’s schedule. Drastic action is called for to change the current situation.
PMCID: PMC3794425  PMID: 21670862
Parturition; Cesarean Section, trends; Perinatal Care; Obstetrics; Socioeconomic Factors; Cohort Studies.
23.  Prevalence of sun exposure and its associated factors in southern Brazil: a population-based study* 
Anais Brasileiros de Dermatologia  2013;88(4):554-561.
BACKGROUND
Sunlight exposure is responsible for a large number of dermatological diseases.
OBJECTIVE
We estimated the prevalence of sunlight exposure and its associated factors in adults from southern Brazil in a cross-sectional, population-based study.
METHODS
We investigated a representative sample of individuals aged ≥ 20 years (n=3,136). Sunlight exposure and its associated factors were evaluated in two distinct situations: at leisure time and at work. The time period investigated ranged from December 2004 to March 2005, comprising 120 days of the highest ultraviolet index in the urban area of the city of Pelotas, in southern Brazil. The participants were asked about sunlight exposure for at least 20 minutes between 10 A.M. and 4 P.M. The analysis was stratified by sex, and sunlight exposure was grouped into five categories.
RESULTS
Among the 3,136 participants, prevalence of sunlight exposure at the beach was 32.8% (95% CI, 30.3 - 35.2) and 26.3% (95% CI, 24.2 28.3) among men and women, respectively. The prevalence at work was 39.8% (95% CI, 37.2 - 42.4) among men and 10.5% (95% CI, 9.1 - 12.0) among women. Age was inversely associated with sunlight exposure. Family income and achieved schooling were positively associated with sunlight exposure at leisure time and inversely associated with sunglight exposure at work. Self-reported skin color was not associated. Knowledge of any friend or relative who has been affected by skin cancer was positively associated with sunlight exposure among men at work.
CONCLUSION
Despite the media campaigns on the harmful effects of excessive sunlight exposure, we found a high prevalence of sunlight exposure during a period of high ultraviolet index.
doi:10.1590/abd1806-4841.20132122
PMCID: PMC3760930  PMID: 24068126
Environment and public health; Precancerous conditions; Public health practice; Skin neoplasms; Sunbathing
24.  Prognostic factors for low birthweight repetition in successive pregnancies: a cohort study 
Background
To identify prognostic factors associated with recurrence of low birthweight (LBW) in successive gestations, a study was carried out with a subsample of mothers enrolled in the 2004 Pelotas Birth Cohort.
Methods
Data were collected by hospital-based interviews. Newborns were weighed and measured. Gestational age was defined according to the date of last menstrual period, ultra-sound scan before the 20th week of pregnancy or the Dubowitz method. Mothers who reported at least one LBW newborn in the two previous gestations were included. Prevalence ratios (PR) and 95% confidence intervals were estimated from Poisson Regression. All estimates were adjusted for parity.
Results
A total of 4558 births were identified in 2004, and 565 met inclusion criteria, out of which 86 (15.2%) repeated LBW in 2004. Among mothers with two LBW babies before 2004, 47.9% presented LBW recurrence. Belonging to the highest socio-economic stratum (PR 0.89; 0.01-0.46) and gaining ≥ 10 kg during pregnancy (PR 0.09; 0.01-0.77) were protective against LBW recurrence. Higher risk of LBW recurrence was observed among mothers with higher parity (≥3 previous deliveries; PR=1.93; 95% CI 1.23-3.02); who had given birth to a previous preterm baby (PR=4.01; 2.27-7.10); who delivered a female newborn in current gestation (PR=2.61; 1.45-4.69); and that had not received adequate antenatal care (PR=2.57; 1-37-4.81).
Conclusion
Improved quality of antenatal care and adequate maternal weight gain during pregnancy may be feasible strategies to prevent LBW repetition in successive pregnancies.
doi:10.1186/1471-2393-13-20
PMCID: PMC3558483  PMID: 23342985
Prognostic factors; Low birthweight recurrence; Low birthweight; Preterm; Antenatal care
25.  Use of Medicines with Unknown Fetal Risk among Parturient Women from the 2004 Pelotas Birth Cohort (Brazil) 
Journal of Pregnancy  2012;2012:257597.
Background. To estimate the exposure to medicines with unknown fetal risk during pregnancy and to analyze the maternal characteristics associated with it. Methods. A questionnaire was administered to 4,189 mothers of children belonging to the 2004 Pelotas (Brazil) birth cohort study about use of any medicine during gestation. We evaluated the associations between use of medicines with unknown fetal risk and the independent variables through logistic regression models. Unknown fetal risk was defined as medicines in which studies in animals have revealed adverse effects on the fetus, and no controlled studies in women, or studies in women and animals, are available. Results. Out of the 4,189 women, 52.5% used at least one medicine from unknown fetal risk. Use of these medicines was associated with white skin color, high schooling, high income, six or more antenatal care consultations, hospital admission during pregnancy, and morbidity during gestation. Conclusion. The use of unknown fetal risk medicines is high, suggesting that their use must be addressed with caution with the aim of restricting their use to cases in which the benefits are greater than the potential risks.
doi:10.1155/2012/257597
PMCID: PMC3549362  PMID: 23346403

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