The authors declare they have no competing interests.
RLL designed, developed, and conducted the research study and wrote the first draft of the manuscript. SW performed the structural equation modelling and contributed to the interpretation of the data and manuscript draft. KBB and AGL contributed to the analysis and interpretation of the blood and stool specimens, respectively. LAH provided oversight of the analytical procedures and contributed to the interpretation of the data. HCR and APM recruited the daycare centres and provided oversight to the data collection in Salvador, assisted by DBL. RSG contributed to the design and oversight of the project in Brazil, and in the data interpretation and revision of the manuscript. All authors have read and approved the final manuscript.
Earlier we reported on growth and adiposity in a cross-sectional study of disadvantaged Brazilian preschoolers. Here we extend the work on these children, using structural equation modelling (SEM) to gather information on the complex relationships between the variables influencing height and adiposity. We hope this information will help improve the design and effectiveness of future interventions for preschoolers.
In 376 preschoolers aged 3–6 years attending seven philanthropic daycares in Salvador, we used SEM to examine direct and indirect relationships among biological (sex, ethnicity, birth order, maternal height and weight), socio-economic, micronutrient (haemoglobin, serum selenium and zinc), and environmental (helminths, de-worming) variables on height and adiposity, as reflected by Z-scores for height-for-age (HAZ) and body mass index (BMIZ).
Of the children, 11 % had HAZ < −1, 15 % had WHZ < −1, and 14 % had BMIZ > 1. Of their mothers, 8 % had short stature, and 50 % were overweight or obese. Based on standardized regression coefficients, significant direct effects (p < 0.05) for HAZ were maternal height (0.39), being white (−0.07), having helminth infection (−0.09), and serum zinc (−0.11). For BMIZ, significant direct effects were maternal weight (0.21), extremely low SES (−0.15), and haemoglobin (0.14). Indirect (p < 0.05) effects for HAZ were sex (being male) (−0.02), helminth infection (−0.01), de-worming treatment (0.01), and serum selenium (−0.02), and for BMIZ were extremely low SES (−0.001), helminth infection (−0.004), and serum selenium (0.02).
Of the multiple factors influencing preschoolers’ growth, helminth infection was a modifiable risk factor directly and indirectly affecting HAZ and BMIZ, respectively. Hence the WHO de-worming recommendation should include preschoolers living in at-risk environments as well as school-aged children.