Understanding the complex determinants of height and adiposity in disadvantaged daycare preschoolers in Salvador, NE Brazil through structural equation modelling.

BACKGROUND: 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. METHODS: 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). RESULTS: 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). CONCLUSIONS: 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.

Disadvantaged pre-schoolers attending day care in Salvador, Northeast Brazil have a low prevalence of anaemia and micronutrient deficiencies.

OBJECTIVE: To examine the micronutrient status of disadvantaged pre-schoolers from Northeast Brazil, following the introduction of pro-poor policies, by assessing the prevalence of anaemia and micronutrient deficiencies and the role of sociodemographic factors, genetic Hb disorders and parasitic infections. DESIGN: In a cross-sectional study, data on sociodemographic status, health, growth, genetic Hb disorders, parasites and nutrient supply from day-care meals were obtained. Fasting blood samples were collected and analysed for Hb, serum ferritin, transferrin receptor, folate, vitamin B12, retinol, Zn and Se. SETTING: Seven philanthropic day-care centres serving urban slums in Salvador, Northeast Brazil. SUBJECTS: Pre-schoolers aged 3-6 years from disadvantaged households. RESULTS: Of the 376 sampled children, 94 % were of black or mixed race; 33 % and 29 % had at least one genetic Hb disorder and intestinal parasite, respectively. Stunting and underweight were ≤5 %; 14 % were overweight. Day-care centres supplied micronutrient-dense meals and snacks each weekday. Less than 10 % of pre-schoolers had anaemia and micronutrient deficiencies. Predictors (P < 0·05) of Hb were α(3·7) thalassaemia, Se and retinol (but not ferritin). Micronutrient predictors (P < 0·05) were: elevated α1-glycoprotein for ferritin, Hb AS and BMI Z-score >1 for transferrin receptor, Zn and elevated α1-glycoprotein for retinol, sex and helminths for Se, helminths for vitamin B12, and Giardia intestinalis infection for serum folate. CONCLUSIONS: Impaired growth, anaemia and micronutrient deficiencies were uncommon among these disadvantaged pre-schoolers attending day care. A range of interventions including provision of micronutrient-dense, fortified day-care meals, deworming and vitamin A supplementation likely contributed to improved micronutrient status, suggesting expanded coverage of these programmes.