Search

Background: Early growth faltering accounts for one-third of child deaths, and adversely impacts the health and human capital of surviving children. Social as well as biological factors contribute to growth faltering, but their relative strength and interrelations in different contexts have not been fully described.Objective: The aim of this study was to use structural equation modelling to explore social and biological multidetermination of child height at age 2 y in longitudinal data from 4 birth cohort studies in low- and middle-income countries.Methods: We analyzed data from 13,824 participants in birth cohort studies in Brazil, India, the Philippines, and South Africa. We used exploratory structural equation models, with height-for-age at 24 mo as the outcome to derive factors, and path analysis to estimate relations among a wide set of social and biological variables common to the 4 sites.Results: The prevalence of stunting at 24 mo ranged from 14.0% in Brazil to 67.7% in the Philippines. Maternal height and birthweight were strongly predictive of height-for-age at 24 mo in all 4 sites (all P values <0.001). Three social-environmental factors, which we characterized as "child circumstances," "family socioeconomic status," and "community facilities," were identified in all sites. Each social-environmental factor was also strongly predictive of height-for-age at 24 mo (all P values <0.001), with some relations partly mediated through birthweight. The biological pathways accounted for 59% of the total explained variance and the social-environmental pathways accounted for 41%. The resulting path coefficients were broadly similar across the 4 sites.Conclusions: Early child growth faltering is determined by both biological and social factors. Maternal height, itself a marker of intergenerational deprivation, strongly influences child height at 2 y, including indirect effects through birthweight and social factors. However, concurrent social factors, many of which are modifiable, directly and indirectly contribute to child growth. This study highlights opportunities for interventions that address both biological and social determinants over the long and short term. [ABSTRACT FROM AUTHOR]

Background: The role that childhood stunting plays in the development of overweight and obesity later in life is not well understood, particularly in adolescence and young adulthood, because most studies have only followed up through midchildhood.Objective: The objective of this study was to examine the relation between stunting and age-specific patterns of overweight and obesity incidence from early childhood to young adulthood in the context of a country in the process of the nutrition transition while these children were growing up.Methods: We analyzed data from 895 participants in the Birth-to-Twenty Plus Cohort (Bt20+), an urban South African birth cohort initiated in 1990. Anthropometric data were collected at multiple ages and participants were included if they provided height at age 24 mo and ≥1 measure of body mass index [BMI; weight (kg)/height (m)2] in each of the following time periods: 4-8 y, 11-12 y, 13-15 y, 16-18 y, and 22-24 y. We defined stunting at age 24 mo as height-for-age z score <2 and overweight as BMI z score (BMIZ) >1 in childhood (4-8 y) and adolescence (11-12 y, 13-15 y, and 16-18 y) and BMI ≥25 in young adulthood (22-24 y). We compared BMI, BMIZ, and the prevalence of overweight by stunting status, stratified by sex.Results: Our sample was 93% black and 51% female. The prevalence of stunting at 24 mo was 26% in males and 19% in females. In young adulthood, the prevalence of overweight and obesity was 15.5% (men) and 47.5% (women). Among both males and females, neither mean BMI nor a combined measure of overweight and obesity in any subsequent period differed by stunting status at 24 mo (P ≥ 0.05).Conclusion: Stunting at 24 mo was not related to the risk of overweight or obesity in this cohort. Stunting may not be an important contributor to the increasing obesity rates in urban South Africa. [ABSTRACT FROM AUTHOR]

Background: Birth weight is an important determinant of an infant's immediate and future health.Aim: This study examined associations between selected maternal psychosocial and environmental risk factors during pregnancy and subsequent infant birth weight, utilising data from the South African Birth to Twenty Plus (Bt20+) birth cohort study.Subjects: Exposure to nine maternal risks were assessed in 1228 women who completed an antenatal questionnaire and whose infants were delivered within a seven-week period.Outcome Measures: The outcome of interest was infant birth weight. Birth weight z-scores (BWZ) were calculated using the World Health Organization Child Growth Standards. Bivariate analyses and multiple regression models were used to identify significant risk factors.Results: The mean infant birth weight was 3139g (SD 486g), with a significant advantage in mean birth weight for male infants of 73g (p=0.008). Being unsure or not wanting the pregnancy was associated with a ~156g reduction in infant birth weight (β=-0.32; 95% CI -0.51; -0.14). Tobacco use during pregnancy was also negatively associated with BWZ (β=-0.32; 95% CI -0.59; -0.05). Exposure to both significant risk factors (tobacco use and pregnancy wantedness) was associated with cumulative reductions in birth weight, particularly among boys.Conclusions: This study reinforces the importance of risks related to maternal attitudes and behaviours during pregnancy, namely unwanted pregnancy and tobacco use, which significantly lowered birth weight. Both identified risks are amenable to public health policy and programme intervention. [ABSTRACT FROM AUTHOR]

Summary: Background: Prospective data spanning childhood and adolescence are needed to better understand obesity incidence among children and to identify important periods for intervention. Objective: To describe gender differences in overweight and obesity from infancy to late adolescence in a South African cohort. Methods: We analysed body mass index at 1–2 years, 4–8 years, 11–12 years, 13–15 years and 16–18 years among 1172 participants in the South African Birth‐to‐Twenty cohort. Results: Among boys, overweight and obesity prevalence declined from age 1–2 years to 16–18 years. Among girls, overweight and obesity prevalence increased from 4–8 years to 16–18 years. Obesity incidence was highest from 4–8 years to 11–12 years in boys (6.8 cases per 1000 person‐years) and from 11–12 years to 13–15 years in girls (11.2 cases per 1000 person‐years). Among girls, obesity at 16–18 years was associated with overweight (odds ratio [OR] = 3.6; 95% confidence interval [CI] 1.8–7.2) or obesity (OR = 8.0; 95% CI 3.7–17.6) at 1–2 years and overweight (OR = 6.8; 95% CI 3.3–13.9) or obesity (OR = 42.3; 95% CI 15.0–118.8) at 4–8 years; for boys, obesity at 16–18 years was associated with overweight at 1–2 years (OR = 5.6; 95% CI 1.7–18.0) and obesity at 4–8 years (OR = 19.7; 95% CI 5.1–75.9). Conclusions: Among girls, overweight and obesity increased throughout childhood. Overweight and obesity were not widely prevalent among boys. Early childhood and post‐puberty may be important periods for intervention among girls. [ABSTRACT FROM AUTHOR]