The nutritional status of disadvantaged preschool children attending daycares in Salvador, Northeast Brazil: a cross-sectional study

Abstract

In the poor Northeast region of Brazil, grave concerns exist regarding the prevalence of anaemia and vitamin A deficiency, and the increasing risk of overweight among preschool children. Brazil has introduced pro-poor social policies, such as preschool daycare programmes, yet comprehensive studies of the growth, health, and micronutrient status of disadvantaged daycare children in NE Brazil are lacking.

We conducted a cross-sectional study of 376 disadvantaged preschoolers aged three to six years in seven philanthropic daycares in Salvador, NE Brazil and assessed their growth and biomarkers of morbidity and micronutrient status; explored potential predisposing factors to parasitic infections, micronutrient deficiencies, and poor iron status; and examined multiple factors associated with their somatic growth by a structural equation model (SEM). Our results showed nearly half of the households were classified as having extremely low SES and the remainder low SES. The prevalence of underweight, wasting, and stunting in the preschoolers was low (< 10%), although 13% had BMIZ-scores > 1SD. The energy density of the daycare meals was low (0.79 kcal/g), yet the nutrient supply was enhanced by iron and folic acid fortification and was adequate, except for calcium, vitamin A, and thiamine. Nearly 30% were infected with >1 parasite, with boys and children from extremely low SES having more than twice the risk of helminth infections (p<0.05). Helminths negatively impacted on selenium and vitamin B-12 biomarkers (p<0.05), whereas Giardia intestinalis was positively associated with serum folate (p<0.05). Deworming treatment and vitamin A supplements were inversely associated with helminths and Giardia, respectively. Anaemia and zinc, selenium, folate, vitamin A, and B-12 deficiencies were low (<10%), although nearly a third of children had evidence of chronic inflammation (AGP > 1 g/L). More than 30% had a genetic haemoglobin disorder. A significant inverse association was found between haemoglobin and α3.7 thalassemia (p<0.001). The major positive predictors of haemoglobin were serum selenium, retinol, and zinc, although the latter association was modest. Elevated AGP was the only positive and significant predictor of serum ferritin (p=0.001). However, serum soluble transferrin receptor was positively associated with Hb AS and BMIZ > 1SD (p<0.05). Based on the SEM, the significant positive direct effect on HAZ-scores was maternal height (p<0.001), and the major negative associations were being male, white, of high birth order, and having a helminth infection. Similarly, the main positive predictor of BMIZ-scores was maternal weight (p<0.001), whereas extremely low SES and being male were the significant negative direct effects on BMIZ-scores (p<0.05). In conclusion, our findings highlight the susceptibility of disadvantaged preschoolers to both under- and overnutrition and the need for effective deworming strategies. Overall adequate nutritional status appears to be associated with some pro-poor initiatives, such as vitamin A supplementation and preschool daycare programmes. The latter provided a protective environment, by supplying fortified foods and a micronutrient-rich diet. Thus, we endorse expansion of daycare programme coverage, with some improvements to increase the energy density and reduce deficits in the nutrient supply of meals, provision of nutrition education for the caregivers, and treatment of parasitic infections.