Etiologically Based Functional Taxonomy of the Preterm Birth Syndrome

Preterm birth (PTB) is a complex syndrome traditionally defined by a single parameter, namely, gestational age at birth (ie, ˂37 weeks). This approach has limitations for clinical usefulness and may explain the lack of progress in identifying cause-specific effective interventions. The authors offer a framework for a functional taxonomy of PTB based on (1) conceptual principles established a priori; (2) known etiologic factors; (3) specific, prospectively identified obstetric and neonatal clinical phenotypes; and (4) postnatal follow-up of growth and development up to 2 years of age. This taxonomy includes maternal, placental, and fetal conditions routinely recorded in data collection systems.

Evaluation of genomic factors and early childhood stimulation on intelligence in children from a Brazilian birth cohort: The primary role of independent factors

BACKGROUND

Childhood cognitive abilities are a predictor of health outcomes and adult income potential. Identifying factors associated with childhood intelligence and their interactions is essential in behavioral research. We assessed the impact of genetic variants and early child stimulation (ECS) on child intelligence and examined their possible interaction as potential modifiers of IQ in a population-based longitudinal study.

METHODS

Participants of the 2004 Pelotas Birth Cohort study (N = 4231) underwent intelligent quotient (IQ) by WISC-III assessment at 6 years of age. At 24 and 48-months, mothers answered five ECS marker questions, whose sum was used to create a score. The polygenic score for intelligence (IQ-PGS) was constructed from the GWAS-weighted estimate of cognition. Association was assessed using multiple linear regression models adjusted for maternal, family, and child confounding variables. To explore the possible influence of skin color and ethnoracial classification, the regression models were stratified according to the skin color variable, as a sensitivity analysis.

RESULTS

In the adjusted analysis, IQ-PGS (β = 0.79, 95% confidence interval [95% CI] 0.26;1.31) as well as ECS (β = 2.34; 95% CI: 1.76;2.92) were associated with IQ in this sample. The association between IQ-PGS and IQ was significant only in the white Brazilian group in the sensitivity analysis. However, there was no interaction between IQ-PGS and ECS on IQ (p(IQ-PGS x ECS) = 0.46).

CONCLUSIONS

ECS did not modify the impact of genetic potential on intellectual development during childhood, suggesting that genetic factors and ECS exert independent effects on the IQ levels of children.

[Association between birth conditions and bone mineral density in adults from the 1982 and 1993 birth cohorts in Pelotas, Rio Grande do Sul State, Brazil]

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

Maternal vaccination against COVID-19 and neonatal outcomes during Omicron: INTERCOVID-2022 study

BACKGROUND

In early 2023, when Omicron was the variant of concern, we showed that vaccinating pregnant women decreased the risk for severe COVID-19-related complications and maternal morbidity and mortality.

OBJECTIVE

This study aimed to analyze the impact of COVID-19 during pregnancy on newborns and the effects of maternal COVID-19 vaccination on neonatal outcomes when Omicron was the variant of concern.

STUDY DESIGN

INTERCOVID-2022 was a large, prospective, observational study, conducted in 40 hospitals across 18 countries, from November 27, 2021 (the day after the World Health Organization declared Omicron the variant of concern) to June 30, 2022, to assess the effect of COVID-19 in pregnancy on maternal and neonatal outcomes and to assess vaccine effectiveness. Women diagnosed with laboratory-confirmed COVID-19 during pregnancy were compared with 2 nondiagnosed, unmatched women recruited concomitantly and consecutively during pregnancy or at delivery. Mother-newborn dyads were followed until hospital discharge. The primary outcomes were a neonatal positive test for COVID-19, severe neonatal morbidity index, severe perinatal morbidity and mortality index, preterm birth, neonatal death, referral to neonatal intensive care unit, and diseases during the neonatal period. Vaccine effectiveness was estimated with adjustment for maternal risk profile.

RESULTS

We enrolled 4707 neonates born to 1577 (33.5%) mothers diagnosed with COVID-19 and 3130 (66.5%) nondiagnosed mothers. Among the diagnosed mothers, 642 (40.7%) were not vaccinated, 147 (9.3%) were partially vaccinated, 551 (34.9%) were completely vaccinated, and 237 (15.0%) also had a booster vaccine. Neonates of booster-vaccinated mothers had less than half (relative risk, 0.46; 95% confidence interval, 0.23-0.91) the risk of being diagnosed with COVID-19 when compared with those of unvaccinated mothers; they also had the lowest rates of preterm birth, medically indicated preterm birth, respiratory distress syndrome, and number of days in the neonatal intensive care unit. Newborns of unvaccinated mothers had double the risk for neonatal death (relative risk, 2.06; 95% confidence interval, 1.06-4.00) when compared with those of nondiagnosed mothers. Vaccination was not associated with any congenital malformations. Although all vaccines provided protection against neonatal test positivity, newborns of booster-vaccinated mothers had the highest vaccine effectiveness (64%; 95% confidence interval, 10%-86%). Vaccine effectiveness was not as high for messenger RNA vaccines only. Vaccine effectiveness against moderate or severe neonatal outcomes was much lower, namely 13% in the booster-vaccinated group (all vaccines) and 25% and 28% in the completely and booster-vaccinated groups, respectively (messenger RNA vaccines only). Vaccines were fairly effective in protecting neonates when given to pregnant women ≤100 days (14 weeks) before birth; thereafter, the risk increased and was much higher after 200 days (29 weeks). Finally, none of the neonatal practices studied, including skin-to-skin contact and direct breastfeeding, increased the risk for infecting newborns.

CONCLUSION

When Omicron was the variant of concern, newborns of unvaccinated mothers had an increased risk for neonatal death. Neonates of vaccinated mothers had a decreased risk for preterm birth and adverse neonatal outcomes. Because the protective effect of COVID-19 vaccination decreases with time, to ensure that newborns are maximally protected against COVID-19, mothers should receive a vaccine or booster dose no more than 14 weeks before the expected date of delivery.

Premorbid intelligence quotient and school failure as risk markers for bipolar disorder and major depressive disorder

Mood disorders significantly impact global health, with MDD ranking as the second leading cause of disability in the United States and BD ranking 18th. Despite their prevalence and impact, the relationship between premorbid intelligence and the subsequent development of BD and MDD remains inconclusive. This study investigates the potential of premorbid Intelligence Quotient (IQ) and school failure frequency as risk factors for Bipolar Disorder (BD) and Major Depressive Disorder (MDD) in a birth cohort setting. We analyze data from the Pelotas population-based birth cohort study, comprising 3580 participants aged 22, who had no prior mood disorder diagnoses. Utilizing regression models and accounting for potential confounders, we assess the impact of IQ and school failure, measured at age 18, on the emergence of BD and MDD diagnoses at age 22, using individuals without mood disorders as comparators. Results reveal that lower IQ (below 70) at 18 is associated with an increased risk of BD (Adjusted Odds Ratio [AOR] 1.75, 95%CI: 1.00-3.09, p < 0.05), while higher IQ (above 120) is linked to MDD (AOR 2.16, 95%CI: 1.24-3.75, p < 0.001). Moreover, an elevated number of school failures is associated with increased BD risk (AOR 1.23, 95%CI: 1.11-1.41, p < 0.001), particularly for BD type 1 (AOR 1.36, 95% CI: 1.17-1.58, p < 0.001). These findings offer insights into the distinct premorbid intellectual characteristics of BD and MDD and contribute to a deeper understanding of their developmental trajectories, potentially informing the development of risk assessment tools for mood disorders.

Relationship between sleep problems and headaches among adolescents: Pelotas 2004 Birth cohort

Objective

To investigate the cross-sectional association between sleep problems (the exposure) and headaches (the outcome) among 15-year-olds from the Pelotas 2004 Birth Cohort, a population-based study in the south of Brazil.

Method

The occurrence of headaches was obtained through the question: "Do you usually suffer headaches?" and the ICHD-3 criteria were used to classify as: tension-type headache, headache with characteristics of migraine with or without aura, or other. Regarding sleep, the weekly frequency in the last month of insomnia and bad dreams/nightmares, and self-reported sleep quality were investigated. Unadjusted and adjusted prevalence ratios (PR) with 95% confidence intervals were calculated using Poisson regression with robust variance.

Results

A total of 1916 adolescents were analyzed. The prevalence of headaches was 51.6% (69.0% in females and 34.8% in males): 31.8% (39.7% vs. 24.1%) reported tension-type headache; 14.7% (21.9% vs. 7.8%), headaches with characteristics of migraines without aura; 3.6%, headaches with characteristics of migraines with aura; and 1.5% (5.1% vs. 2.3%), other types. Adolescents with insomnia ≥3 times/week presented higher probability of headaches (PR = 1.54; 95%CI 1.23-1.93), compared with those with no problems falling asleep or maintaining sleep. Among those who classified their sleep as poor/very poor, the probability of headaches was 33% higher (PR = 1.33; 95%CI 1.13-1.57) than among those who classified their sleep as very good.

Conclusions

Headaches were highly prevalent among the adolescents and were related to sleep problems even after allowing for several confounders.

Pathways from maternal depression to child resilience: Socioeconomic, family, and individual factors in the 2004 Pelotas (Brazil) birth cohort

Background

The negative impacts of maternal depression on child mental health outcomes are well-documented. However, some children show adaptive functioning following exposure to maternal depression, demonstrating resilience. In a large birth cohort from Brazil, a middle-income country, we examined direct and indirect pathways, considering socioeconomic, family, and individual factors, contributing to the development of resilience.

Methods

Using data from the 2004 Pelotas Birth Cohort (N = 4231), we restricted the sample to those exposed to maternal depression up to age 6 years (depression present at ≥2 out of 5 assessment waves; n = 1132; 50% boys). Resilience was defined as scoring below or equal to the mean of the unexposed group on all four problem subscales of the parent-report Strengths and Difficulties Questionnaire at age 11 years. We examined pathways from socioeconomic status (SES; measured at birth) to resilience via cognitive stimulation (CS) (at 24 and 48 months) and Intelligence quotient (IQ) (at 6 years), and from CS to resilience via IQ, using counterfactual mediation.

Results

A minority of children exposed to maternal depression showed resilience (12.4%). There was evidence of indirect pathways from SES to resilience via CS (odds ratio (OR) = 1.76, 95% confidence interval (CI) 1.02-3.38) and IQ (OR = 1.19, 95% CI 1.01-1.42), such that higher SES was associated with resilience via both higher levels of CS and higher IQ, which, in turn, were each positively associated with resilience. Furthermore, there was evidence of a direct (OR = 1.86, 95% CI 1.01-3.76) and total effect (OR = 1.94, 95% CI 1.05-3.89) of CS on resilience, even after controlling for SES. However, these effects varied depending on how persistent and severe depression was defined.

Conclusions

These findings suggest that CS in early childhood may represent a modifiable protective factor for children exposed to maternal depression and a promising intervention target to promote child resilience in the context of maternal depression exposure.

Normative spatiotemporal fetal brain maturation with satisfactory development at 2 years

Maturation of the human fetal brain should follow precisely scheduled structural growth and folding of the cerebral cortex for optimal postnatal function1. We present a normative digital atlas of fetal brain maturation based on a prospective international cohort of healthy pregnant women2, selected using World Health Organization recommendations for growth standards3. Their fetuses were accurately dated in the first trimester, with satisfactory growth and neurodevelopment from early pregnancy to 2 years of age4,5. The atlas was produced using 1,059 optimal quality, three-dimensional ultrasound brain volumes from 899 of the fetuses and an automated analysis pipeline6-8. The atlas corresponds structurally to published magnetic resonance images9, but with finer anatomical details in deep grey matter. The between-study site variability represented less than 8.0% of the total variance of all brain measures, supporting pooling data from the eight study sites to produce patterns of normative maturation. We have thereby generated an average representation of each cerebral hemisphere between 14 and 31 weeks' gestation with quantification of intracranial volume variability and growth patterns. Emergent asymmetries were detectable from as early as 14 weeks, with peak asymmetries in regions associated with language development and functional lateralization between 20 and 26 weeks' gestation. These patterns were validated in 1,487 three-dimensional brain volumes from 1,295 different fetuses in the same cohort. We provide a unique spatiotemporal benchmark of fetal brain maturation from a large cohort with normative postnatal growth and neurodevelopment.

[Birth conditions and attention deficit/hyperactivity disorders (ADHD) in adults in the Pelotas (Brazil) birth cohorts of 1982 and 1993]

This study evaluates the association of birth conditions with attention deficit/hyperactivity disorders (ADHD) in adults using data from two birth cohorts in the city of Pelotas Rio Grande do Sul State, Brazil. In 1982 and 1993 all births in the city were identified and have been prospectively monitored. In the follow-ups at 30 and 22 years of the 1982 (n = 3,574) and 1993 (n = 3,780) cohorts, respectively, participants were examined, and trained psychologists applied the Mini-International Neuropsychiatric Interview (M.I.N.I.). Those individuals who met the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) diagnostic criteria were defined as positive for ADHD. Poisson regression with robust variance adjustment was used to estimate the prevalence ratio (PR) adjusted for sex, maternal skin color, family income, maternal age, maternal schooling during pregnancy, maternal marital status, parity, and maternal smoking during pregnancy. The prevalence of adult ADHD was 4.4% and 4.5% in the 1982 and 1993 cohorts, respectively. The prevalence of ADHD was higher in those born with lower weight, but no linear trend was observed, and those born with weight between 3,000 and 3,499 grams (PR = 1.40; 95%CI: 1.05-1.86) had the highest risk. For gestational age, we observed an inversely proportional relationship for the presence of ADHD: preterm infants had a 33% higher risk (95%CI: 0.90-1.96) of being considered as having ADHD than those born at 39 or more weeks, but as the confidence interval included nullity, this association may have occurred at random. These results indicate that birth weight and gestational age may be associated with adult ADHD.

Socioeconomic inequalities related to maternal perception of children's oral health at age 4: Results of a birth cohort

OBJECTIVES

To estimate socioeconomic inequalities in the maternal perception of children's oral health from a birth cohort study in Brazil.

METHODS

The data from this study were collected through perinatal interviews and at the 48-month follow-up from the 2015 Pelotas Birth Cohort Study. The main outcome was the maternal perception of children's oral health, dichotomized into positive (good/very good) and negative (fair/bad/very bad). The secondary outcome was untreated dental caries (absence and presence, according to the ICDAS index - International Caries Detection and Assessment System). For the statistical analysis, the absolute inequality index (Slope Index of Inequality - SII) and the relative concentration index (Concentration Index - CIX) were used. Analyses were stratified by maternal educational level, family income and wealth index.

RESULTS

The prevalence of outcomes was 19.4% (95% CI 18.2; 20.7) for the negative maternal perception of children's oral health and 15.6% (95% CI 14.4; 16.8) for untreated dental caries. Socioeconomics inequalities were observed in negative maternal perception of children's oral health in both absolute and relative terms. A SII of -16.6 (95% CI -20.8; -12.5) was observed for family income, with higher prevalence in poor families. A higher prevalence of the negative maternal perception of children's oral health was observed in mothers without any educational level or a few years of study (CIX -21.1 [95% CI -24.5; -17.7]).

CONCLUSIONS

This study demonstrates socioeconomics disparities in the maternal perception of children's oral health and in the prevalence of untreated caries in children. A higher concentration of negative maternal perception of children's oral health was identified among the most socioeconomically vulnerable individuals. The findings reinforce the presence of socioeconomic inequalities in subjective measures about children's oral health.

Maternal depression trajectories in childhood, subsequent maltreatment, and adolescent emotion regulation and self-esteem: the 2004 Pelotas birth cohort

This study aimed to examine the impact of maternal depressive symptoms trajectories on 15-year-old adolescents' self-esteem and emotion regulation and test the mediating role of child maltreatment in this association. The 2004 Pelotas Birth Cohort is an ongoing cohort study originally comprised of 4231 live births in a southern Brazilian city. We examined a subsample of 1949 adolescents at age 15 years. Maternal depressive symptoms were assessed using the Edinburgh Postnatal Depression Scale. Trajectories of maternal depression from 3 months until the 11-year follow-up were calculated using a group-based modeling approach. Child maltreatment at age 11 years was measured using the parent-report version of the Parent-Child Conflict Tactics Scale. Adolescent outcomes at age 15 years were assessed by the self-report version of the Rosenberg Self-esteem Scale and the Emotion Regulation Index for Children and Adolescents. Path model analysis was conducted using a structural equation modeling framework in Mplus software. All maternal depression trajectories were negatively associated with offspring self-esteem and emotion regulation compared to the reference group (low depression trajectory). There was a significant indirect effect of maternal depression trajectories on emotion regulation mediated via child maltreatment. No evidence of moderation by sex was found for any pathway. The effects of maternal depression on adolescents' emotion regulation are partly mediated by child maltreatment at age 11.

Association between preterm infant size at 1 year and ADHD later in life: data from 1993 and 2004 Pelotas Birth Cohorts

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

Two decades of socioeconomic inequalities in the prevalence of untreated dental caries in early childhood: Results from three birth cohorts in southern Brazil

OBJECTIVES

To estimate the socioeconomic disparities in untreated dental caries in early childhood according to socioeconomic characteristics in three birth cohorts in Southern Brazil.

METHODS

The socioeconomic data to this study were collected at the 48-month follow-up and oral health studies of 1993, 2004 and 2015 Pelotas birth cohort studies. The outcome was untreated dental caries in children aged 6 (1993 cohort), 5 (2004 cohort) and 4 years (2015 cohort), dichotomized into absence/presence. Analyses were stratified by maternal skin colour/race, maternal education and family income. For statistical purposes, the prevalence difference, relative risk and absolute and relative indices of health inequality (Slope Index of Inequality-SII and Concentration Index-CIX) were used.

RESULTS

The prevalence of untreated dental caries in primary dentition was 63.4%, 45.5% and 15.6%, in 1993, 2004 and 2015 cohorts, respectively. The prevalence of untreated dental caries was concentrated in the poorest quintile and lower maternal education group in both absolute (SII) and relative (CIX) measures of inequality, being characterized as a pro-poor event. A higher risk of untreated caries was found in the poorest quintile of family income compared with the richest quintile in the 1993 cohort (RR 1.44 [95% CI 1.05; 1.98]). That risk was higher considering the 2004 Cohort (RR 1.78 [95% CI 1.42; 2.23]) and 2015 cohort (RR 4.20 [95% CI 2.97; 5.94]) data.

CONCLUSIONS

Over the course of two decades, a higher prevalence of untreated dental caries is concentrated among the most socioeconomically deprived children.

Machine learning for accurate estimation of fetal gestational age based on ultrasound images

Accurate estimation of gestational age is an essential component of good obstetric care and informs clinical decision-making throughout pregnancy. As the date of the last menstrual period is often unknown or uncertain, ultrasound measurement of fetal size is currently the best method for estimating gestational age. The calculation assumes an average fetal size at each gestational age. The method is accurate in the first trimester, but less so in the second and third trimesters as growth deviates from the average and variation in fetal size increases. Consequently, fetal ultrasound late in pregnancy has a wide margin of error of at least ±2 weeks' gestation. Here, we utilise state-of-the-art machine learning methods to estimate gestational age using only image analysis of standard ultrasound planes, without any measurement information. The machine learning model is based on ultrasound images from two independent datasets: one for training and internal validation, and another for external validation. During validation, the model was blinded to the ground truth of gestational age (based on a reliable last menstrual period date and confirmatory first-trimester fetal crown rump length). We show that this approach compensates for increases in size variation and is even accurate in cases of intrauterine growth restriction. Our best machine-learning based model estimates gestational age with a mean absolute error of 3.0 (95% CI, 2.9-3.2) and 4.3 (95% CI, 4.1-4.5) days in the second and third trimesters, respectively, which outperforms current ultrasound-based clinical biometry at these gestational ages. Our method for dating the pregnancy in the second and third trimesters is, therefore, more accurate than published methods.

Child and Maternal Mental Health Before and During the COVID-19 Pandemic: Longitudinal Social Inequalities in a Brazilian Birth Cohort

OBJECTIVE

The coronavirus disease 2019 (COVID-19) pandemic has caused major stress for families and children, particularly in the context of prolonged school closures. Few longitudinal studies are available on young children's mental health, including data both before and during the pandemic. This study examined experiences that might increase risk for mental health problems among caregivers and young children during the COVID-19 pandemic and inequalities driven by pre-pandemic disadvantage.

METHOD

This prospective, population-based birth cohort study in Pelotas, Brazil, analyzed 2,083 children and caregivers with data from before the pandemic in 2019, when children were 4 years old, and again in 2020, when schools were closed for a long period during the pandemic. Child conduct problems, emotional problems, and hyperactivity-inattention problems were assessed using the Strengths and Difficulties Questionnaire. Family financial hardship, relationship difficulties, caregiver mental health, parenting practices, and child fears and isolation were considered as potential risk factors.

RESULTS

Across the whole population, the only significant increase in mental health problems from before to during the pandemic was found for maternal depression. However, poorer families were at far greater risk of experiencing serious financial problems, food shortages, increased conflict in adult relationships, parenting problems, and child worries about food availability during the pandemic. In turn, these difficulties were associated with increases in multiple mental health problems for both caregivers and children. Increased child mental health problems were most strongly associated with concurrent maternal anxiety (β > 0.20, p < .001, for each of child conduct, emotional, and hyperactivity problems), maternal depression (β = 0.26, p < .001, for child emotional problems), partner criticism (β = 0.21, p < .001, for child conduct problems), and harsh parenting (β > 0.20, p < .001, for both child conduct and hyperactivity problems). Child worry about COVID-19 was associated with increased emotional problems (β = 0.14, p < .001), but children's isolation was not associated with their mental health.

CONCLUSION

Overall, the impact of the COVID-19 pandemic on mental health is a mixed picture, but for families in poverty, marked material and interpersonal difficulties were associated with increases in mental health problems among children and caregivers.

Linear growth and relative weight gain in childhood and bone mass in adolescence: findings from the Pelotas (Brazil) 2004 birth cohort

With the objective to investigate the relationship of weight and height growth with bone mass at 11 years, we found that boys who grew in weight and height, especially at 48 months, and girls, who grew in weight at 24 months and height at 11 years, gained more bone mass.

PURPOSE

To investigate independent relationships of linear growth and relative weight gain during defined periods of infancy, childhood, and early adolescence with areal bone mineral density (aBMD) of three sites at 11 years.

METHODS

Data on weight and length/height were obtained at birth, 3, 12, and 24 months, and the ages of 4, 6, and 11. The outcome was whole body, femoral neck, and lumbar spine aBMD (g/cm2) measured at 11 years using dual-energy X-ray absorptiometry. The effects of weight gain and linear growth were analyzed using conditional relative weight and conditional length/height. Associations between conditional growth and outcomes were analyzed using linear regression, adjusted for multiple confounders.

RESULTS

Individuals with data available for exposures and bone outcomes were 2875 and comprised the sample. For boys, the greatest magnitude of increase for whole body and height gain was at 48 months (β 0.014, 95% CI 0.010; 0.018). For girls, higher aBMD was observed for those with greater height gain at 11 years, representing for lumbar spine an increase of 0.056 g/cm2 (95% CI 0.050; 0.062). For body weight, among boys, the greatest magnitude in the whole body was also associated with weight gain at 48 months (β 0.014, 95% CI 0.010; 0.018). For girls, the highest coefficient was at 24 months, representing for lumbar spine an increase of 0.028 g/cm2, (95% CI 0.021; 0.035).

CONCLUSION

Positive associations were demonstrated between length/height and weight gain and aBMD in both sexes, with emphasis on girls' aBMD in response to the linear growth achieved mainly at 11 years.

Preeclampsia prediction with blood pressure measurements: A global external validation of the ALSPAC models

OBJECTIVE

The prediction of preeclampsia in pregnancy has resulted in a plethora of prognostic models. Yet, very few make it past the development stage and most fail to influence clinical practice. The timely identification of high-risk pregnant women could deliver a tailored antenatal care regimen, particularly in low-resource settings. This study externally validated and calibrated previously published models that predicted the risk of preeclampsia, based on blood pressure (BP) at multiple time points in pregnancy, in a geographically diverse population.

METHODS

The prospective INTERBIO-21st Fetal Study included 3,391 singleton pregnancies from Brazil, Kenya, Pakistan, South Africa, Thailand and the UK, 2012-2018. Preeclampsia prediction was based on baseline characteristics, BP and deviation from the expected BP trajectory at multiple time points in pregnancy. The prediction rules from the Avon Longitudinal Study of Parents and Children (ALSPAC) were implemented in the INTERBIO-21st cohort.

RESULTS

Model discrimination was similar to the development cohort. Performance was best with baseline characteristics and a BP measurement at 34 weeks' gestation (AUC 0.85, 95 % CI 0.80-0.90). The ALSPAC models largely overestimated the true risk of preeclampsia incidence in the INTERBIO-21st cohort.

CONCLUSIONS

After recalibration, these prediction models could potentially serve as a risk stratifying tool to help identify women who might benefit from increased surveillance during pregnancy.

Prevalence and predictors of anti-SARS-CoV-2 serology in a highly vulnerable population of Rio de Janeiro: A population-based serosurvey

Background

COVID-19 serosurveys allow for the monitoring of the level of SARS-CoV-2 transmission and support data-driven decisions. We estimated the seroprevalence of anti-SARS-CoV-2 antibodies in a large favela complex in Rio de Janeiro, Brazil.

Methods

A population-based panel study was conducted in Complexo de Manguinhos (16 favelas) with a probabilistic sampling of participants aged ≥1 year who were randomly selected from a census of individuals registered in primary health care clinics that serve the area. Participants answered a structured interview and provided blood samples for serology. Multilevel regression models (with random intercepts to account for participants’ favela of residence) were used to assess factors associated with having anti-S IgG antibodies. Secondary analyses estimated seroprevalence using an additional anti-N IgG assay.

Findings

4,033 participants were included (from Sep/2020 to Feb/2021, 22 epidemic weeks), the median age was 39·8 years (IQR:21·8-57·7), 61% were female, 41% were mixed-race (Pardo) and 23% Black. Overall prevalence was 49·0% (95%CI:46·8%-51·2%) which varied across favelas (from 68·3% to 31·4%). Lower prevalence estimates were found when using the anti-N IgG assay. Odds of having anti-S IgG antibodies were highest for young adults, and those reporting larger household size, poor adherence to social distancing and use of public transportation.

Interpretation

We found a significantly higher prevalence of anti-S IgG antibodies than initially anticipated. Disparities in estimates obtained using different serological assays highlight the need for cautious interpretation of serosurveys estimates given the heterogeneity of exposure in communities, loss of immunological biomarkers, serological antigen target, and variant-specific test affinity.

Funding

Fundação Oswaldo Cruz, Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), Fundação de Amparo a Pesquisa do Estado do Rio de Janeiro (FAPERJ), the European Union's Horizon 2020 research and innovation programme, Royal Society, Serrapilheira Institute, and FAPESP.

Association between fetal abdominal growth trajectories, maternal metabolite signatures early in pregnancy, and childhood growth and adiposity: prospective observational multinational INTERBIO-21st fetal study

BACKGROUND

Obesity predominantly affects populations in high-income countries and those countries facing epidemiological transition. The risk of childhood obesity is increased among infants who had overweight or obesity at birth, but in low-resource settings one in five infants are born small for gestational age. We aimed to study the relationships between: (1) maternal metabolite signatures; (2) fetal abdominal growth; and (3) postnatal growth, adiposity, and neurodevelopment.

METHODS

In the prospective, multinational, observational INTERBIO-21st fetal study, conducted in maternity units in Pelotas (Brazil), Nairobi (Kenya), Karachi (Pakistan), Soweto (South Africa), Mae Sot (Thailand), and Oxford (UK), we enrolled women (≥18 years, with a BMI of less than 35 kg/m², natural conception, and a singleton pregnancy) who initiated antenatal care before 14 weeks' gestation. Ultrasound scans were performed every 5±1 weeks until delivery to measure fetal growth and feto-placental blood flow, and we used finite mixture models to derive growth trajectories of abdominal circumference. The infants' health, growth, and development were monitored from birth to age 2 years. Early pregnancy maternal blood and umbilical cord venous blood samples were collected for untargeted metabolomic analysis.

FINDINGS

From Feb 8, 2012, to Nov 30, 2019, we enrolled 3598 pregnant women and followed up their infants to 2 years of age. We identified four ultrasound-derived trajectories of fetal abdominal circumference growth that accelerated or decelerated within a crucial 20-25 week gestational age window: faltering growth, early accelerating growth, late accelerating growth, and median growth tracking. These distinct phenotypes had matching feto-placental blood flow patterns throughout pregnancy, and different growth, adiposity, vision, and neurodevelopment outcomes in early childhood. There were 709 maternal metabolites with positive effect for the faltering growth phenotype and 54 for the early accelerating growth phenotype; 31 maternal metabolites had a negative effect for the faltering growth phenotype and 76 for the early accelerating growth phenotype. Metabolites associated with the faltering growth phenotype had statistically significant odds ratios close to 1·5 (ie, suggesting upregulation of metabolic pathways of impaired fetal growth). The metabolites had a reciprocal relationship with the early accelerating growth phenotype, with statistically significant odds ratios close to 0.6 (ie, suggesting downregulation of fetal growth acceleration). The maternal metabolite signatures included 5-hydroxy-eicosatetraenoic acid, and 11 phosphatidylcholines linked to oxylipin or saturated fatty acid sidechains. The fungicide, chlorothalonil, was highly abundant in the early accelerating growth phenotype group.

INTERPRETATION

Early pregnancy lipid biology associated with fetal abdominal growth trajectories is an indicator of patterns of growth, adiposity, vision, and neurodevelopment up to the age of 2 years. Our findings could contribute to the earlier identification of infants at risk of obesity.

FUNDING

Bill & Melinda Gates Foundation.

Effects of early-life poverty on health and human capital in children and adolescents: analyses of national surveys and birth cohort studies in LMICs

The survival and nutrition of children and, to a lesser extent, adolescents have improved substantially in the past two decades. Improvements have been linked to the delivery of effective biomedical, behavioural, and environmental interventions; however, large disparities exist between and within countries. Using data from 95 national surveys in low-income and middle-income countries (LMICs), we analyse how strongly the health, nutrition, and cognitive development of children and adolescents are related to early-life poverty. Additionally, using data from six large, long-running birth cohorts in LMICs, we show how early-life poverty can have a lasting effect on health and human capital throughout the life course. We emphasise the importance of implementing multisectoral anti-poverty policies and programmes to complement specific health and nutrition interventions delivered at an individual level, particularly at a time when COVID-19 continues to disrupt economic, health, and educational gains achieved in the recent past.

Complex Perinatal Syndromes Affecting Early Human Growth and Development: Issues to Consider to Understand Their Aetiology and Postnatal Effects

Complex perinatal syndromes (CPS) affecting pregnancy and childhood, such as preterm birth, and intra- and extra-uterine growth restriction, have multiple, diverse contexts of complexity and interaction that determine the short- and long-term growth, health and development of all human beings. Early in life, genetically-guided somatic and cerebral development occurs alongside a psychism "in statu nascendi," with the neural structures subjected to the effects of the intra- and extra-uterine environments in preparation for optimal postnatal functioning. Different trajectories of fetal cranial and abdominal growth have been identified before 25 weeks' gestation, tracking differential growth and neurodevelopment at 2 years of age. Similarly, critical time-windows exist in the first 5-8 months of postnatal life because of interactions between the newborn and their environment, mother/care-givers and feeding practices. Understanding these complex relational processes requires abandoning classical, linear and mechanistic interpretations that are placed in rigid, artificial biological silos. Instead, we need to conduct longitudinal, interdisciplinary research and integrate the resulting new knowledge into clinical practice. An ecological-systemic approach is required to understand early human growth and development, based on a dynamic multidimensional process from the molecular or genomic level to the socio-economic-environmental context. For this, we need theoretical and methodological tools that permit a global understanding of CPS, delineating temporal trajectories and their conditioning factors, updated by the incorporation of new scientific discoveries. The potential to optimize human growth and development across chronological age and geographical locations - by implementing interventions or "treatments" during periods of greatest instability or vulnerability - should be recognized. Hence, it is imperative to take a holistic view of reproductive and perinatal issues, acknowledging at all levels the complexity and interactions of CPS and their sensitive periods, laying the foundations for further improvements in growth and development of populations, to maximize global human potential. We discuss here conceptual issues that should be considered for the development and implementation of such a strategy aimed at addressing the perinatal health problems of the new millenium.

Association between Polygenic Risk Scores for ADHD and Asthma: A Birth Cohort Investigation

OBJECTIVE

Shared genetic mechanisms have been hypothesized to explain the comorbidity between ADHD and asthma. To evaluate their genetic overlap, we relied on data from the 1982 Pelotas birth cohort to test the association between polygenic risk scores (PRSs) for ADHD (ADHD-PRSs) and asthma, and PRSs for asthma (asthma-PRSs) and ADHD.

METHOD

We analyzed data collected at birth, 2, 22, and 30 years from 3,574 individuals.

RESULTS

Subjects with ADHD had increased risk of having asthma (OR 1.92, 95% CI 1.01-3.66). The association was stronger for females. Our results showed no evidence of association between ADHD-PRSs and asthma or asthma-PRSs and ADHD. However, an exploratory analysis suggested that adult ADHD might be genetically associated with asthma.

CONCLUSION

Our results do not support a shared genetic background between both conditions. Findings should be viewed in light of important limitations, particularly the sample size and the self-reported asthma diagnosis. Studies in larger datasets are required to better explore the genetic overlap between adult ADHD and asthma.

Social and racial inequity in self-rated oral health in adults in Southern Brazil

This study aimed to estimate social and racial inequalities in self-rated oral health in adults from the Brazilian birth cohort study. This study belongs to 1982 Pelotas (Brazil) birth cohort study. Data from this study was collected for oral health conditions 31 years old (Oral Health Study). The outcome was self-rated oral health, dichotomized into positive (good/very good) and negative (regular/bad/very bad). Analyses were stratified by gender, racial/skin color groups, schooling level and income. For statistical analysis, the slope index of inequality (SII) and the concentration index (CIX) were used. The prevalence of negative self-rated oral health was 36.1%. Social inequalities were observed in self-rated oral health in both absolute and relative terms. A SII of -30.0 (95%CI: -43.6; -16.4) was observed for income, and -27.7 (95%CI: -41.9; -13.4) for schooling level. Both the individuals’ income and the schooling level had negative CIX (CIXincome -14.6 [95%CI: -21.2; -8.0] and CIXschooling level -14.1 [95%CI: -20.7; -7.5]). Furthermore, the prevalence of negative self-rated oral health in black/brown/indigenous individuals from the highest income/schooling level was comparable to prevalence of the outcome in the white individuals belonging to the lowest income/schooling levels. This study results demonstrate racial disparities in oral health regardless of income and schooling levels. Furthermore, a higher concentration of negative self-rated oral health was identified among the most socioeconomically vulnerable individuals. Our findings reinforce the presence of racial and socioeconomic inequalities in oral health.

Population-level seropositivity trend for SARS-Cov-2 in Rio Grande do Sul, Brazil

OBJECTIVE

To describe the evolution of seropositivity in the State of Rio Grande do Sul, Brazil, through 10 consecutive surveys conducted between April 2020 and April 2021.

METHODS

Nine cities covering all regions of the State were studied, 500 households in each city. One resident in each household was randomly selected for testing. In survey rounds 1–8 we used the rapid WONDFO SARS-CoV-2 Antibody Test (Wondfo Biotech Co., Guangzhou, China). In rounds 9–10, we used a direct ELISA test that identifies IgG to the viral S protein (S-UFRJ). In terms of social distancing, individuals were asked three questions, from which we generated an exposure score using principal components analysis.

RESULTS

Antibody prevalence in early April 2020 was 0.07%, increasing to 10.0% in February 2021, and to 18.2% in April 2021. In round 10, self-reported whites showed the lowest seroprevalence (17.3%), while indigenous individuals presented the highest (44.4%). Seropositivity increased by 40% when comparing the most with the least exposed.

CONCLUSIONS

The proportion of the population already infected by SARS-Cov-2 in the state is still far from any perspective of herd immunity and the infection affects population groups in very different levels.

Conditional cash transfers and adolescent mental health in Brazil: Evidence from the 2004 Pelotas Birth Cohort

BACKGROUND

Young people living in poverty are at higher risk of mental disorders, but whether interventions aimed to reduce poverty have lasting effects on mental health has not been well established. We examined whether exposure to Brazil's conditional cash transfers programme (CCT), Bolsa Família (BFP), during childhood reduces the risk of mental health problems in early adolescence.

METHODS

We used data from 2063 participants in the 2004 Pelotas Birth Cohort study. Propensity score matching (PSM) estimated the association between BFP participation at age 6 and externalising problems (Strengths and Difficulties Questionnaire - SDQ and violent behaviour) and socio-emotional competencies (Development and Well-Being Assessment questionnaire, and the Nowick-Strickland Internal-External Scale) at age 11.

RESULTS

PSM results suggest that programme participation at age of six was not significantly associated with externalising problems (P = 0.433), prosocial behaviour (P = 0.654), violent behaviour (P = 0.342), social aptitudes (P = 0.281), positive attributes (P = 0.439), or locus of control (P = 0.148) at the age of 11 years.

CONCLUSIONS

Participation in BFP during childhood was not associated with improved or worsened mental health in early adolescence. While we cannot fully discard that findings may be due to adverse selection, results suggest that CCTs alone may not be sufficient to improve mental health outcomes and would be prudent to assess whether mental health interventions as an addition to CCTs may be helpful.

[Prevalence of antibodies against SARS-CoV-2 according to socioeconomic and ethnic status in a nationwide Brazilian surveyPrevalência de anticorpos contra o SARS-CoV-2 de acordo com o status socioeconômico e étnico em uma pesquisa nacional no Brasil]

OBJECTIVES

To investigate socioeconomic and ethnic group inequalities in prevalence of antibodies against SARS-CoV-2 in the 27 federative units of Brazil.

METHODS

In this cross-sectional study, three household surveys were carried out on May 14-21, June 4-7, and June 21-24, 2020 in 133 Brazilian urban areas. Multi-stage sampling was used to select 250 individuals in each city to undergo a rapid antibody test. Subjects answered a questionnaire on household assets, schooling and self-reported skin color/ethnicity using the standard Brazilian classification in five categories: white, black, brown, Asian or indigenous. Principal component analyses of assets was used to classify socioeconomic position into five wealth quintiles. Poisson regression was used for the analyses.

RESULTS

25 025 subjects were tested in the first, 31 165 in the second, and 33 207 in the third wave of the survey, with prevalence of positive results equal to 1.4%, 2.4%, and 2.9% respectively. Individuals in the poorest quintile were 2.16 times (95% confidence interval 1.86; 2.51) more likely to test positive than those in the wealthiest quintile, and those with 12 or more years of schooling had lower prevalence than subjects with less education. Indigenous individuals had 4.71 (3.65; 6.08) times higher prevalence than whites, as did those with black or brown skin color. Adjustment for region of the country reduced the prevalence ratios according to wealth, education and ethnicity, but results remained statistically significant.

CONCLUSIONS

The prevalence of antibodies against SARS-CoV-2 in Brazil shows steep class and ethnic gradients, with lowest risks among white, educated and wealthy individuals.

Association between cesarean section and human capital in adulthood: 1982 and 1993 Pelotas birth cohorts, Rio Grande do Sul State, Brazil

This study aims to assess the association between mode of delivery and human capital among young adults enrolled in the 1982 and 1993 Pelotas birth cohorts, Rio Grande do Sul State, Brasil. In 1982 and 1993, the maternity hospitals of the municipality were daily visited, the births identified, and those live births, whose family lived in the urban area of Pelotas, were examined and their mothers interviewed. Information on mode of delivery, vaginal or cesarean, was provided by the mother in the perinatal study. Performance in intelligence tests achieved schooling and income were evaluated in the 30 years visit at the 1982 cohort. At the 1993 cohort, schooling and income were assessed at the 22 years visit, whereas IQ was evaluated at 18 years. Tobacco smoking in adulthood and type of school was used as negative outcomes to strength causal inference. Initially, cesarean section was positively associated with human capital at adulthood, with the exception of income in the 1993 cohort. After controlling for confounders, the magnitude of the associations was strongly reduced, and the regression coefficients were close to the null value. The negative outcome analysis showed that, after controlling for confounding variables, the mode of delivery was not associated with tobacco smoking and type of school. Suggesting that the variables included in the regression model to control for confounding, provided an adequate adjustment and it is unlikely that the results are due to residual confounding by socioeconomic status. On the other hand, considering the short- and long-term risks and the epidemic of cesarean sections, measures should be implemented to reduce its prevalence.

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

OBJECTIVE

This study aimed to evaluate the relationship between sleep duration trajectories from adolescence to early adulthood and working memory, schooling and income at 22 years in the Pelotas 1993 Birth Cohort.

METHODS

Sleep duration was self-reported at ages 11, 18 and 22. Sleep trajectories were identified using finite mixture models. Schooling was recorded as the number of completed years of education. Working memory was evaluated using The Digit Span test and income was recorded for who reported have a job and received a payment for this in the previous month. All analyses were stratified by sex.

RESULTS

We used crude and adjusted (for demographic, health and behavior characteristics measured at perinatal and 11-years) linear or quantile regression analyses. A total of 2915 individuals were included. Three trajectories for males were used: "increase and maintenance" (3.4%), "fast reduction and maintenance" (45.0%) and "constant reduction" (51.6%). For females, we used the trajectories: "increase and decrease" (2.4%), "fast reduction and maintenance" (25.6%) and "constant reduction" (72.0%). Males from "increase and maintenance" and females from "increase and decrease" trajectories scored, on average, 1.6 and 1.8 points lower, respectively, in working memory test. They presented a median of 1.4 and 2.6 fewer schooling years, respectively, compared to individuals from the "fast reduction and maintenance" trajectory. Regarding income, no significant association was observed.

CONCLUSION

Sleep duration during adolescence could affect cognitive and educational outcomes in early adulthood. Individuals who presented the expected sleep trajectory (decrease of sleep duration across adolescence) presented better outcomes.

Time-dependent decay of detectable antibodies against SARS-CoV-2: A comparison of ELISA with two batches of a lateral-flow test

BACKGROUND

Large-scale epidemiological studies of seroprevalence of antibodies against SARS-CoV-2 often rely on point-of-care tests that provide immediate results to participants. Yet, little is known on how long rapid tests remain positive after the COVID-19 episode, or how much variability exists across different brands and even among batches of the same test.

METHODS

In November 2020, we assessed the sensitivity of three tests applied to 133 individuals with a previous positive PCR result between April and October. All subjects provided finger prick blood samples for two batches (A and B) of the Wondfo lateral-flow IgG/IgM test, and dried blood spot samples for the S-UFRJ ELISA test.

RESULTS

Overall sensitivity levels were 92.5% (95% CI 86.6-96.3), 63.2% (95% CI 54.4-71.4) and 33.8% (95% CI 25.9-42.5) for the S-UFRJ test, Wondfo A and Wondfo B tests, respectively. There was no evidence of a decline in the positivity of S-UFRJ with time since the diagnosis, but the two Wondfo batches showed sharp reductions to as low as 41.9% and 19.4%, respectively, for subjects with a positive PCR in June or earlier. Positive results for batch B of the rapid test were 35% to 54% lower than for batch A at any given month of diagnosis.

INTERPRETATION

Whereas the ELISA test showed high sensitivity and stability of results over the five months of the study, both batches of the rapid test showed substantial declines, with one of the batches consistently showing lower sensitivity levels than the other. ELISA tests based on dried-blood spots are an inexpensive alternative to rapid lateral-flow tests in large-scale epidemiological studies.

FUNDING

The study was funded by the "Todos Pela Saúde" initiative, Instituto Serrapilheira, Brazilian Ministry of Health, Brazilian Collective Health Association (ABRASCO) and the JBS S.A. initiative 'Fazer o Bem Faz Bem'.

Slow Spread of SARS-CoV-2 in Southern Brazil Over a 6-Month Period: Report on 8 Sequential Statewide Serological Surveys Including 35 611 Participants

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

COVID-19 and social distancing among children and adolescents in Brazil

OBJECTIVE

To estimate the prevalence of SARS-CoV-2 antibodies and the adherence to measures of social distancing in children and adolescents studied in three national surveys conducted in Brazil between May-June 2020.

METHODS

Three national serological surveys were conducted in 133 sentinel cities located in all 27 Federative Units. Multistage probability sampling was used to select 250 individuals per city. The total sample size in age ranges 0-9 and 10-19 years old are of 4,263 and 8,024 individuals, respectively. Information on children or adolescents was gathered with a data collection app, and a rapid point-of-case test for SARS-CoV-2 was conducted on a finger prick blood sample.

RESULTS

The adjusted prevalence of antibodies was 2.9% (2.2-3.6) among children 0-9 years, 2.2% (1.8-2.6) among adolescents 10-19 years, and 3.0% (2.7-3.3) among adults 20+years. Prevalence of antibodies was higher among poor children and adolescents compared to those of rich families. Adherence to social distancing measures was seen in 72.4% (71.9-73.8) of families with children, 60.8% (59.6-61.9) for adolescents, and 57.4% (56.9-57.8) for adults. For not leaving the house except for essential matters the proportions were 81.7% (80.5-82.9), 70.6% (69.6-61.9), and 65.1% (64.7-65.5), respectively. Among children and adolescents, social distancing was strongly associated with socioeconomic status, being much higher in the better-off families.

CONCLUSIONS

The prevalence of antibodies against SARS-CoV-2 showed comparable levels among children, adolescents, and adults. Adherence to social distancing measures was more prevalent in children, followed by adolescents. There were important socioeconomic differences in the adherence to social distancing among children and adolescents.

High prevalence of symptoms among Brazilian subjects with antibodies against SARS-CoV-2

Since the beginning of the pandemic of COVID-19, there has been a widespread assumption that most infected persons are asymptomatic. Using data from the recent wave of the EPICOVID19 study, a nationwide household-based survey including 133 cities from all states of Brazil, we estimated the proportion of people with and without antibodies for SARS-CoV-2 who were asymptomatic, which symptoms were most frequently reported, number of symptoms and the association with socio-demographic characteristics. We tested 33,205 subjects using a rapid antibody test previously validated. Information was collected before participants received the test result. Out of 849 (2.7%) participants positive for SARS-CoV-2 antibodies, only 12.1% (95% CI 10.1-14.5) reported no symptoms, compared to 42.2% (95% CI 41.7-42.8) among those negative. The largest difference between the two groups was observed for changes in smell/taste (56.5% versus 9.1%, a 6.2-fold difference). Changes in smell/taste, fever and body aches were most likely to predict positive tests as suggested by recursive partitioning tree analysis. Among individuals without any of these three symptoms, only 0.8% tested positive, compared to 18.3% of those with both fever and changes in smell or taste. Most subjects with antibodies against SARS-CoV-2 are symptomatic, even though most present only mild symptoms.

Influenza vaccination in older adults during the COVID-19 pandemic: a population-based study in 133 Brazilian cities

Routine immunization during pandemics can be harmed. This study estimated the influenza vaccination coverage in older adults during the COVID-19 through the EPICOVID-19, a population-based study conducted in 133 cities from the 26 Brazilian states and Federal District. We selected 25 census tracts per city, with probability proportional to the tract's size, ten households by census tract, and one random individual interviewed. A total of 8,265 older adults (≥60 years old) were interviewed and asked whether they had been vaccinated against flu in 2020. Vaccination coverage was 82.3% (95% CI: 80.1-84.2) with no difference by gender, age, and region; higher vaccination coverage was observed among the wealthiest (84.7% versus 80.1% in the poorest) and among the more educated (87.3% versus 83.2% less educated); lower coverage among indigenous (56.9% versus > 80% among other ethnic groups). A positive association was identified with the number of comorbidities among men but not among women. Most of the population was vaccinated (97.5%) in the public health system. The private network was chosen mainly in the South by the wealthiest and more educated. Vaccination coverage was seven percentage points lower than the government target (90%), and inequalities should be reversed in future campaigns.

Association of the length of time using computers and mobile devices with low back, neck and mid-back pains: findings from a birth cohort

OBJECTIVES

Neck and low back pains are the leading causes of years lived with disability, and using computers or mobile devices in excess could be risk factors for back pain. Our aim was to evaluate the association of the length of time using computers and mobile devices with neck, mid-back and low back pains and the number of regions with pain.

STUDY DESIGN

Cross-sectional study nested in the 1993 Pelotas birth cohort with young adults aged 22 years.

METHODS

Outcomes analyzed were neck, mid-back and low back pains and the number of regions with pain. Exposures were the number of daily hours using computers and mobile devices. Crude and adjusted analyses were performed to estimate prevalence ratios using Poisson regression.

RESULTS

Almost half of the sample reported having back pain, the low back pain being the most prevalent. Compared with individuals using mobile devices for less than one hour, the prevalence of neck pain was 1.41 and 1.81 times higher among individuals using mobile devices from three to seven hours and for seven or more hours per day, respectively. Neck pain prevalence was 1.47 times higher among individuals using computers for more than two hours than among those not using computers. Using mobile devices for seven hours or more was associated to 1.19 times higher prevalence of low back pain.

CONCLUSION

Using mobile devices in excess was associated to neck and low back pains, while the use of computers in excess was associated only to neck pain. It is important that guidelines are developed to recommend the adequate length of time that computers and mobile devices should be used to prevent back pain.

Patterns of Growth in Childhood in Relation to Adult Schooling Attainment and Intelligence Quotient in 6 Birth Cohorts in Low- and Middle-Income Countries: Evidence from the Consortium of Health-Oriented Research in Transitioning Societies (COHORTS)

BACKGROUND

Growth faltering has been associated with poor intellectual performance. The relative strengths of associations between growth in early and in later childhood remain underexplored.

OBJECTIVES

We examined the association between growth in childhood and adult human capital in 5 low- and middle-income countries (LMICs).

METHODS

We analyzed data from 9503 participants in 6 prospective birth cohorts from 5 LMICs (Brazil, Guatemala, India, the Philippines, and South Africa). We used linear and quasi-Poisson regression models to assess the associations between measures of height and relative weight at 4 age intervals [birth, age ∼2 y, midchildhood (MC), adulthood] and 2 dimensions of adult human capital [schooling attainment and Intelligence Quotient (IQ)].

RESULTS

Meta-analysis of site- and sex-specific estimates showed statistically significant associations between size at birth and height at ∼2 y and the 2 outcomes (P < 0.001). Weight and length at birth and linear growth from birth to ∼2 y of age (1 z-score difference) were positively associated with schooling attainment (β: 0.13; 95% CI: 0.08, 0.19, β: 0.17; 95% CI: 0.07, 0.32, and β: 0.25, 95% CI: 0.10, 0.40, respectively) and adult IQ (β: 0.74, 95% CI: 0.35, 1.14, β: 0.73, 95% CI: 0.35, 1.10, and β: 1.52, 95% CI: 0.96, 2.08, respectively). Linear growth from age 2 y to MC and from MC to adulthood was not associated with higher school attainment or IQ. Change in relative weight in early childhood, MC, and adulthood was not associated with either outcome.

CONCLUSIONS

Linear growth in the first 1000 d is a predictor of schooling attainment and IQ in adulthood in LMICs. Linear growth in later periods was not associated with either of these outcomes. Changes in relative weight across the life course were not associated with schooling and IQ in adulthood.

Association Between Preterm-Birth Phenotypes and Differential Morbidity, Growth, and Neurodevelopment at Age 2 Years: Results From the INTERBIO-21st Newborn Study

IMPORTANCE

The etiologic complexities of preterm birth remain inadequately understood, which may impede the development of better preventative and treatment measures.

OBJECTIVE

To examine the association between specific preterm-birth phenotypes and clinical, growth, and neurodevelopmental differences among preterm newborns compared with term newborns up to age 2 years.

DESIGN, SETTING, AND PARTICIPANTS

The INTERBIO-21st study included a cohort of preterm and term newborn singletons enrolled between March 2012 and June 2018 from maternity hospitals in 6 countries worldwide who were followed up from birth to age 2 years. All pregnancies were dated by ultrasonography. Data were analyzed from November 2019 to October 2020.

EXPOSURES/INTERVENTIONS

Preterm-birth phenotypes.

MAIN OUTCOMES AND MEASURES

Infant size, health, nutrition, and World Health Organization motor development milestones assessed at ages 1 and 2 years; neurodevelopment evaluated at age 2 years using the INTERGROWTH-21st Neurodevelopment Assessment (INTER-NDA) tool.

RESULTS

A total of 6529 infants (3312 boys [50.7%]) were included in the analysis. Of those, 1381 were preterm births (mean [SD] gestational age at birth, 34.4 [0.1] weeks; 5148 were term births (mean [SD] gestational age at birth, 39.4 [0] weeks). Among 1381 preterm newborns, 8 phenotypes were identified: no main maternal, fetal, or placental condition detected (485 infants [35.1%]); infections (289 infants [20.9%]); preeclampsia (162 infants [11.7%]); fetal distress (131 infants [9.5%]); intrauterine growth restriction (110 infants [8.0%]); severe maternal disease (85 infants [6.2%]); bleeding (71 infants [5.1%]); and congenital anomaly (48 infants [3.5%]). For all phenotypes, a previous preterm birth was a risk factor for recurrence. Each phenotype displayed differences in neonatal morbidity and infant outcomes. For example, infants with the no main condition detected phenotype had low neonatal morbidity but increased morbidity and hospitalization incidence at age 1 year (odds ratio [OR], 2.2; 95% CI, 1.8-2.7). Compared with term newborns, the highest risk of scoring lower than the 10th centile of INTER-NDA normative values was observed in the fine motor development domain among newborns with the fetal distress (OR, 10.6; 95% CI, 5.1-22.2) phenotype.

CONCLUSIONS AND RELEVANCE

Results of this study suggest that phenotypic classification may provide a better understanding of the etiologic factors and mechanisms associated with preterm birth than continuing to consider it an exclusively time-based entity.

RPS Brazilian Birth Cohorts Consortium (Ribeirão Preto, Pelotas and São Luís): history, objectives and methods

This paper describes the history, objectives and methods used by the nine Brazilian cohorts of the RPS Brazilian Birth Cohorts Consortium (Ribeirão Preto, Pelotas and São Luís) Common thematic axes are identified and the objectives, baseline periods, follow-up stages and representativity of the population studied are presented. The Consortium includes three birth cohorts from Ribeirão Preto, São Paulo State (1978/1979, 1994 and 2010), four from Pelotas, Rio Grande do Sul State (1982, 1993, 2004 and 2015), and two from São Luís, Maranhão State (1997 and 2010). The cohorts cover three regions of Brazil, from three distinct states, with marked socioeconomic, cultural and infrastructure differences. The cohorts were started at birth, except for the most recent one in each municipality, where mothers were recruited during pregnancy. The instruments for data collection have been refined in order to approach different exposures during the early phases of life and their long-term influence on the health-disease process. The investigators of the nine cohorts carried out perinatal studies and later studied human capital, mental health, nutrition and precursor signs of noncommunicable diseases. A total of 17,636 liveborns were recruited in Ribeirão Preto, 19,669 in Pelotas, and 7,659 in São Luís. In the studies starting during pregnancy, 1,400 pregnant women were interviewed in Ribeirão Preto, 3,199 in Pelotas, and 1,447 in São Luís. Different strategies were employed to reduce losses to follow-up. This research network allows the analysis of the incidence of diseases and the establishment of possible causal relations that might explain the health outcomes of these populations in order to contribute to the development of governmental actions and health policies more consistent with reality.

Fetal cerebellar growth and Sylvian fissure maturation: international standards from Fetal Growth Longitudinal Study of INTERGROWTH-21st Project

OBJECTIVE

To construct international ultrasound-based standards for fetal cerebellar growth and Sylvian fissure maturation.

METHODS

Healthy, well nourished pregnant women, enrolled at < 14 weeks' gestation in the Fetal Growth Longitudinal Study (FGLS) of INTERGROWTH-21^st , an international multicenter, population-based project, underwent serial three-dimensional (3D) fetal ultrasound scans every 5 ± 1 weeks until delivery in study sites located in Brazil, India, Italy, Kenya and the UK. In the present analysis, only those fetuses that underwent developmental assessment at 2 years of age were included. We measured the transcerebellar diameter and assessed Sylvian fissure maturation using two-dimensional ultrasound images extracted from available 3D fetal head volumes. The appropriateness of pooling data from the five sites was assessed using variance component analysis and standardized site differences. For each Sylvian fissure maturation score (left or right side), mean gestational age and 95% CI were calculated. Transcerebellar diameter was modeled using fractional polynomial regression, and goodness of fit was assessed.

RESULTS

Of those children in the original FGLS cohort who had developmental assessment at 2 years of age, 1130 also had an available 3D ultrasound fetal head volume. The sociodemographic characteristics and pregnancy/perinatal outcomes of the study sample confirmed the health and low-risk status of the population studied. In addition, the fetuses had low morbidity and adequate growth and development at 2 years of age. In total, 3016 and 2359 individual volumes were available for transcerebellar-diameter and Sylvian-fissure analysis, respectively. Variance component analysis and standardized site differences showed that the five study populations were sufficiently similar on the basis of predefined criteria for the data to be pooled to produce international standards. A second-degree fractional polynomial provided the best fit for modeling transcerebellar diameter; we then estimated gestational-age-specific 3^rd , 50^th and 97^th smoothed centiles. Goodness-of-fit analysis comparing empirical centiles with smoothed centile curves showed good agreement. The Sylvian fissure increased in maturation with advancing gestation, with complete overlap of the mean gestational age and 95% CIs between the sexes for each development score. No differences in Sylvian fissure maturation between the right and left hemispheres were observed.

CONCLUSION

We present, for the first time, international standards for fetal cerebellar growth and Sylvian fissure maturation throughout pregnancy based on a healthy fetal population that exhibited adequate growth and development at 2 years of age. © 2020 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Prematurity and body composition at 6, 18, and 30 years of age: Pelotas (Brazil) 2004, 1993, and 1982 birth cohorts

Background

We aimed to investigate the association between preterm birth and body composition at 6, 18, and 30 years of age using data from three population-based birth cohort studies.

Methods

Gestational age (GA), defined by the date of the last menstrual period (categorized in ≤33, 34–36, and ≥ 37 weeks), was gathered in the first 24-h after delivery for all live births occurring in the city of Pelotas, Brazil, in 2004, 1993 and 1982. Body composition was assessed by air-displacement plethysmography. Outcomes included fat mass (FM, kg), percent FM (%FM), FM index (FMI, kg/m²), fat-free mass (FFM, kg); percent FFM (%FFM), FFM index (FFMI, kg/m²), body mass index (BMI, kg/m² at 18 years in the 1993 cohort and 30 years in the 1982 cohort), and BMI Z-score (at 6 years in the 2004 cohort). We further explored the association of birth weight for GA with body composition indicators and BMI. Crude and adjusted linear regressions provided beta coefficients with 95% confidence intervals (95%CI).

Results

A total of 3036, 3027, and 3369 participants, respectively, from the 2004, 1993, and 1982 cohorts were analyzed. At 6 years, preterm boys (born at 34–36 weeks) presented lower adjusted mean of FM (β = − 0.80 kg, − 1.45;-0.16, p = 0.046), %FM (β = − 2.39%, − 3.90;-0.88, p = 0.008), FMI (β = − 0.70 kg/m², − 1.13;-0.27, p = 0.004) as well as lower FFM (β = − 0.4 kg, − 0.77; − 0.12, p = 0.010) and FFMI (β = − 0.3 kg/m², − 0.46;-0.10, p < 0.001), and BMI Z-score (β = − 0.69,; − 0.99;-0.40, p < 0.001); but higher %FFM (β = 2.4%, 0.87;-3.90, p = 0.008), when compared to boys born at term (≥37). At 30 years, FM (15.7 kg, 0.25;31.1, p = 0.102) was higher among males born at ≤33 weeks. No association was observed for females from the three cohorts and for 18-year-old males. The association of birth weight for GA with body composition and BMI was not significant in any cohort. At 6 years, SGA boys had lower FFMI than boys AGA.

Conclusions

Our results suggest that preterm birth is associated with decreased body fat and fat-free mass in childhood but higher fat mass in adulthood. Nevertheless, results were only significant for males. SGA boys also showed lower FFMI.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-021-10368-w.

Dental caries and depression in pregnant women: The role of oral health self-perception as mediator

OBJECTIVE

This study investigated the role of oral health self-perception as mediator of association between dental caries and depression among pregnant women from the 2015 Pelotas Birth Cohort Study, Brazil.

MATERIALS AND METHODS

Overall, 2,496 pregnant women participated of this oral health sub-study. Data related to demographic and socioeconomic conditions, lifetime and current depression, and oral health self-perception were collected. Participants were also assessed for dental caries (DMF-T index). Depression was assessed using the Edinburgh Postnatal Depression Scale. For analysis, six outcomes related to dental caries experience were considered. Causal mediation analysis was performed using parametric regression models.

RESULTS

When it was assumed that all subjects had poor perception about oral health, it was observed that the presence of moderate/severe depressive signals and symptoms was higher in subjects with dental caries experience (OR 1.13; CI 95% 1.06-1.20), with severity of untreated dental caries (OR 2.08; CI 95% 1.16-3.78), untreated dental caries (OR 1.18; 95% CI 1.07-1.29), tooth loss (OR 1.08; 95% CI 1.02-1.14), and filled tooth (OR 1.07; 95% CI 1.02-1.16).

CONCLUSIONS

Our findings show the effect of dental caries on depression is mediated by self-perception about oral health in pregnant women.

Fetal growth velocity standards from the Fetal Growth Longitudinal Study of the INTERGROWTH-21st Project

BACKGROUND

Human growth is susceptible to damage from insults, particularly during periods of rapid growth. Identifying those periods and the normative limits that are compatible with adequate growth and development are the first key steps toward preventing impaired growth.

OBJECTIVE

This study aimed to construct international fetal growth velocity increment and conditional velocity standards from 14 to 40 weeks' gestation based on the same cohort that contributed to the INTERGROWTH-21st Fetal Growth Standards.

STUDY DESIGN

This study was a prospective, longitudinal study of 4321 low-risk pregnancies from 8 geographically diverse populations in the INTERGROWTH-21st Project with rigorous standardization of all study procedures, equipment, and measurements that were performed by trained ultrasonographers. Gestational age was accurately determined clinically and confirmed by ultrasound measurement of crown-rump length at <14 weeks' gestation. Thereafter, the ultrasonographers, who were masked to the values, measured the fetal head circumference, biparietal diameter, occipitofrontal diameter, abdominal circumference, and femur length in triplicate every 5 weeks (within 1 week either side) using identical ultrasound equipment at each site (4-7 scans per pregnancy). Velocity increments across a range of intervals between measures were modeled using fractional polynomial regression.

RESULTS

Peak velocity was observed at a similar gestational age: 16 and 17 weeks' gestation for head circumference (12.2 mm/wk), and 16 weeks' gestation for abdominal circumference (11.8 mm/wk) and femur length (3.2 mm/wk). However, velocity growth slowed down rapidly for head circumference, biparietal diameter, occipitofrontal diameter, and femur length, with an almost linear reduction toward term that was more marked for femur length. Conversely, abdominal circumference velocity remained relatively steady throughout pregnancy. The change in velocity with gestational age was more evident for head circumference, biparietal diameter, occipitofrontal diameter, and femur length than for abdominal circumference when the change was expressed as a percentage of fetal size at 40 weeks' gestation. We have also shown how to obtain accurate conditional fetal velocity based on our previous methodological work.

CONCLUSION

The fetal skeleton and abdomen have different velocity growth patterns during intrauterine life. Accordingly, we have produced international Fetal Growth Velocity Increment Standards to complement the INTERGROWTH-21st Fetal Growth Standards so as to monitor fetal well-being comprehensively worldwide. Fetal growth velocity curves may be valuable if one wants to study the pathophysiology of fetal growth. We provide an application that can be used easily in clinical practice to evaluate changes in fetal size as conditional velocity for a more refined assessment of fetal growth than is possible at present (https://lxiao5.shinyapps.io/fetal_growth/). The application is freely available with the other INTERGROWTH-21st tools at https://intergrowth21.tghn.org/standards-tools/.

Trajectories of maternal depressive symptoms and offspring's risk behavior in early adolescence: data from the 2004 Pelotas birth cohort study

BACKGROUND

This longitudinal study explored the relationship between trajectories of maternal depressive symptoms and offspring's risk behavior in adolescence contributing to an extremely scarce literature about the impacts of maternal depression trajectories on offspring risk behaviors.

METHODS

We included 3437 11-year-old adolescents from the 2004 Pelotas Birth Cohort Study. Trajectories of maternal depressive symptoms were constructed using Edinburgh Postnatal Depression Scale (EDPS) from age 3 months to 11 years. We identified five trajectories of maternal depressive symptoms: "low" "moderate low", "increasing", "decreasing", and "chronic high". The following adolescent outcomes were identified via self-report questionnaire and analyzed as binary outcome -yes/no: involvement in fights and alcohol use at age 11. We used logistic regression models to examine the effects of trajectories of maternal depressive symptoms on offspring's risk behavior adjusting for potential confounding variable.

RESULTS

Alcohol use and/or abuse as well as involvement in fights during adolescence, were not significantly associated with any specific trajectory of maternal depressive symptoms neither in the crude nor in the adjusted analyses.

CONCLUSION

Alcohol use and involvement in fights at age 11 were not associated with any specific trajectory of maternal depression.

Periodontal disease and preterm birth: Findings from the 2015 Pelotas birth cohort study

OBJECTIVES

To verify the association between periodontal conditions and preterm birth.

MATERIALS AND METHODS

This study used data from the 2015 Pelotas Birth Cohort Study, Brazil. Pregnant women expected to give birth in 2015 were interviewed and dentally examined by a trained dentist, with periodontal measures collected in all teeth, six sites per tooth. Exposure was periodontal disease. Outcomes were preterm birth (all births <37 weeks of gestational age) and early preterm birth (<34 weeks). Analysis was carried out using Poisson regression according to a directed acyclic graph.

RESULTS

A total of 2,474 women participated in the study. Incidence of preterm births was 10.2% and of early preterm births was 3.5%. Frequency of gingivitis was 21.7%, and periodontitis was 14.9%. Periodontitis was associated with a risk almost two times higher of having early preterm delivery compared with healthy pregnant women (RR 1.93; 95% CI 1.09-3.43). Presence of 5+ mm periodontal pocket with bleeding on probing was also associated with higher risk for early preterm delivery.

CONCLUSIONS

The association between periodontal disease in pregnancy and the occurrence of preterm delivery is sensitive to the case definitions. Periodontal disease increased the risk of early preterm delivery.

Second generation of the 1993 birth cohort, Pelotas (Brazil): Aims, design, preliminary results

BACKGROUND AND AIMS

Longitudinal cohort studies examining different generations can explain how health problems can be transmitted through genetic and environmental mechanisms and their effects on the health of offspring. This study aimed to present the design and to describe the characteristics of the baseline sample of a second generation cohort.

METHODS

The 93Cohort-II is a dynamic prospective cohort composed of a second generation from the original 1993 Pelotas Birth Cohort (offspring), whose parents had their last follow-up at 22 years old. Biological parents were asked to answer questions addressing the type of birth, general health status, family composition, dietary habits, breastfeeding habits, and child-caregiver(s), among others, and the children's anthropometric measurements were evaluated.

RESULTS

Of 1650 children identified, 1212 were evaluated (response rate, 73.4%), and 21 died before the baseline assessment. The age of the offspring ranged from 0 to 10 years (mean [±SD], 2.9 ± 2.1 years); most children (65.6%) lived with both parents and were born to young mothers and poor families. One-third of the children were breastfed until 6 months of age, one-half were born by cesarean section, 63.9% had used medication in the previous 15 days, 26.4% experienced hospitalization at least once since birth, and 14% had no updated vaccination; asthma/bronchitis (20.4%) and bronchiolitis (13.4%) were the most frequently reported diseases. More than 60% consumed ultra-processed foods, and the prevalence of overweight among those <5 and ≥6 years of age was 10.2% and 18.9%, respectively. The mean total Child Behavior Checklist score was 44.1 ± 23.61 (≥16 months), and the mean intellectual quotient score in children ≥6 years of age was 97.9 ± 15.4.

CONCLUSION

Despite the difficulties in conducting intergenerational cohort studies, the results of the present investigation provide evidence supporting the feasibility of performing these types of studies in middle-income countries.

Early identification of bipolar disorder among young adults - a 22-year community birth cohort

OBJECTIVE

We set forth to build a prediction model of individuals who would develop bipolar disorder (BD) using machine learning techniques in a large birth cohort.

METHODS

A total of 3748 subjects were studied at birth, 11, 15, 18, and 22 years of age in a community birth cohort. We used the elastic net algorithm with 10-fold cross-validation to predict which individuals would develop BD at endpoint (22 years) at each follow-up visit before diagnosis (from birth up to 18 years). Afterward, we used the best model to calculate the subgroups of subjects at higher and lower risk of developing BD and analyzed the clinical differences among them.

RESULTS

A total of 107 (2.8%) individuals within the cohort presented with BD type I, 26 (0.6%) with BD type II, and 87 (2.3%) with BD not otherwise specified. Frequency of female individuals was 58.82% (n = 150) in the BD sample and 53.02% (n = 1868) among the unaffected population. The model with variables assessed at the 18-year follow-up visit achieved the best performance: AUC 0.82 (CI 0.75-0.88), balanced accuracy 0.75, sensitivity 0.72, and specificity 0.77. The most important variables to detect BD at the 18-year follow-up visit were suicide risk, generalized anxiety disorder, parental physical abuse, and financial problems. Additionally, the high-risk subgroup of BD showed a high frequency of drug use and depressive symptoms.

CONCLUSIONS

We developed a risk calculator for BD incorporating both demographic and clinical variables from a 22-year birth cohort. Our findings support previous studies in high-risk samples showing the significance of suicide risk and generalized anxiety disorder prior to the onset of BD, and highlight the role of social factors and adverse life events.

International values for haemoglobin distributions in healthy pregnant women

BACKGROUND

Anaemia in pregnancy is a global health problem with associated morbidity and mortality.

METHODS

A secondary analysis of prospective, population-based study from 2009 to 2016 to generate maternal haemoglobin normative centiles in uncomplicated pregnancies in women receiving optimal antenatal care. Pregnant women were enrolled <14 weeks' gestation in the Fetal Growth Longitudinal Study (FGLS) of the INTERGROWTH-21st Project which involved eight geographically diverse urban areas in Brazil, China, India, Italy, Kenya, Oman, United Kingdom and United States. At each 5 ± 1 weekly visit until delivery, information was collected about the pregnancy, as well as the results of blood tests taken as part of routine antenatal care that complemented the study's requirements, including haemoglobin values.

FINDINGS

A total of 3502 (81%) of 4321 women who delivered a live, singleton newborn with no visible congenital anomalies, contributed at least one haemoglobin value. Median haemoglobin concentrations ranged from 114.6 to 121.4 g/L, 94 to 103 g/L at the 3rd centile, and from 135 to 141 g/L at the 97th centile. The lowest values were seen between 31 and 32 weeks' gestation, representing a mean drop of 6.8 g/L compared to 14 weeks' gestation. The percentage variation in maternal haemoglobin within-site was 47% of the total variance compared to 13% between sites.

INTERPRETATION

We have generated International, gestational age-specific, smoothed centiles for maternal haemoglobin concentration compatible with better pregnancy outcomes, as well as adequate neonatal and early childhood morbidity, growth and development up to 2 years of age.

FUNDING

Bill & Melinda Gates Foundation Grant number 49038.

SARS-CoV-2 antibody prevalence in Brazil: results from two successive nationwide serological household surveys

BACKGROUND

Population-based data on COVID-19 are essential for guiding policies. There are few such studies, particularly from low or middle-income countries. Brazil is currently a hotspot for COVID-19 globally. We aimed to investigate severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody prevalence by city and according to sex, age, ethnicity group, and socioeconomic status, and compare seroprevalence estimates with official statistics on deaths and cases.

METHODS

In this repeated cross-sectional study, we did two seroprevalence surveys in 133 sentinel cities in all Brazilian states. We randomly selected households and randomly selected one individual from all household members. We excluded children younger than 1 year. Presence of antibodies against SARS-CoV-2 was assessed using a lateral flow point-of-care test, the WONDFO SARS-CoV-2 Antibody Test (Wondfo Biotech, Guangzhou, China), using two drops of blood from finger prick samples. This lateral-flow assay detects IgG and IgM isotypes that are specific to the SARS-CoV-2 receptor binding domain of the spike protein. Participants also answered short questionnaires on sociodemographic information (sex, age, education, ethnicity, household size, and household assets) and compliance with physical distancing measures.

FINDINGS

We included 25 025 participants in the first survey (May 14-21) and 31 165 in the second (June 4-7). For the 83 (62%) cities with sample sizes of more than 200 participants in both surveys, the pooled seroprevalence increased from 1·9% (95% CI 1·7-2·1) to 3·1% (2·8-3·4). City-level prevalence ranged from 0% to 25·4% in both surveys. 11 (69%) of 16 cities with prevalence above 2·0% in the first survey were located in a stretch along a 2000 km of the Amazon river in the northern region. In the second survey, we found 34 cities with prevalence above 2·0%, which included the same 11 Amazon cities plus 14 from the northeast region, where prevalence was increasing rapidly. Prevalence levels were lower in the south and centre-west, and intermediate in the southeast, where the highest level was found in Rio de Janeiro (7·5% [4·2-12·2]). In the second survey, prevalence was similar in men and women, but an increased prevalence was observed in participants aged 20-59 years and those living in crowded conditions (4·4% [3·5-5·6] for those living with households with six or more people). Prevalence among Indigenous people was 6·4% (4·1-9·4) compared with 1·4% (1·2-1·7) among White people. Prevalence in the poorest socioeconomic quintile was 3·7% (3·2-4·3) compared with 1·7% (1·4-2·2) in the wealthiest quintile.

INTERPRETATION

Antibody prevalence was highly heterogeneous by country region, with rapid initial escalation in Brazil's north and northeast. Prevalence is strongly associated with Indigenous ancestry and low socioeconomic status. These population subgroups are unlikely to be protected if the policy response to the pandemic by the national government continues to downplay scientific evidence.

FUNDING

Brazilian Ministry of Health, Instituto Serrapilheira, Brazilian Collective Health Association, and the JBS Fazer o Bem Faz Bem.

Prevalence of antibodies against SARS-CoV-2 according to socioeconomic and ethnic status in a nationwide Brazilian survey

OBJECTIVES

To investigate socioeconomic and ethnic group inequalities in prevalence of antibodies against SARS-CoV-2 in the 27 federative units of Brazil.

METHODS

In this cross-sectional study, three household surveys were carried out on May 14-21, June 4-7, and June 21-24, 2020 in 133 Brazilian urban areas. Multi-stage sampling was used to select 250 individuals in each city to undergo a rapid antibody test. Subjects answered a questionnaire on household assets, schooling and self-reported skin color/ethnicity using the standard Brazilian classification in five categories: white, black, brown, Asian or indigenous. Principal component analyses of assets was used to classify socioeconomic position into five wealth quintiles. Poisson regression was used for the analyses.

RESULTS

25 025 subjects were tested in the first, 31 165 in the second, and 33 207 in the third wave of the survey, with prevalence of positive results equal to 1.4%, 2.4%, and 2.9% respectively. Individuals in the poorest quintile were 2.16 times (95% confidence interval 1.86; 2.51) more likely to test positive than those in the wealthiest quintile, and those with 12 or more years of schooling had lower prevalence than subjects with less education. Indigenous individuals had 4.71 (3.65; 6.08) times higher prevalence than whites, as did those with black or brown skin color. Adjustment for region of the country reduced the prevalence ratios according to wealth, education and ethnicity, but results remained statistically significant.

CONCLUSIONS

The prevalence of antibodies against SARS-CoV-2 in Brazil shows steep class and ethnic gradients, with lowest risks among white, educated and wealthy individuals.