RESUMO

Home fortification with multiple micronutrient powder (MNP) is effective in the prevention of anemia in young children. However, the impact on their vitamin A status remains controversial. This study aimed to evaluate the effect of MNP on vitamin A status in young Brazilian children. A multicenter pragmatic, controlled trial was carried out in primary health centers in four Brazilian cities. In the beginning of the study, the control group (CG) consisted of children 11-14 months old (n = 395) attending in routine pediatric health care. In parallel, the intervention group (IG) was composed of children 6-8 months old (n = 399), in the same health centers, who followed the intervention with MNP for 2-3 months. The analysis of the effect of MNP on vitamin A status was performed by comparing the IG with the CG after a 4- to 6-month follow-up when IG children had reached the age of the controls. The prevalence of vitamin A deficiency (VAD; serum retinol <0.70 µmol/L) in the CG was 16.2%, while in the IG was 7.5%-a 55% reduction in the VAD [prevalence ratio (95% confidence interval) = 0.45 (0.28; 0.72)]. This reduction was also significant when stratifying the study centers by coverage of the Brazilian Vitamin A Supplementation Program. The adjusted mean of vitamin A serum concentrations improved in the IG compared with CG children, with a shift to the right in the vitamin A distribution. Home fortification with MNP was effective in reducing VAD among young Brazilian children.

Assuntos

Anemia Ferropriva/epidemiologia , Alimentos Fortificados , Micronutrientes/administração & dosagem , Deficiência de Vitamina A/epidemiologia , Vitamina A/administração & dosagem , Adulto , Anemia Ferropriva/prevenção & controle , Biomarcadores/sangue , Brasil/epidemiologia , Feminino , Serviços de Saúde , Hemoglobinas/metabolismo , Humanos , Lactente , Masculino , Estado Nutricional , Pós , Prevalência , Vitamina A/sangue , Deficiência de Vitamina A/prevenção & controle , Adulto Jovem

RESUMO

In Colombia's bottom socio-economic strata, 46.6% of children under two are anaemic. A prevalence of above 20% falls within the WHO guidelines for daily supplementation with multiple micronutrient powder (MNP). To evaluate the effect of daily MNP supplementation on anaemia amongst Colombian children aged 12-24 months we ran a cluster RCT (n=1440). In previous work, we found the intervention had no impact on haemoglobin or anaemia in this population. In this current paper, we investigate this null result and find it cannot be explained by an underpowered study design, inaccurate measurements, low adoption of and compliance with the intervention, or crowding out through dietary substitution. We conclude that our intervention was ineffective at reducing rates of childhood anaemia because MNP itself was inefficacious in our population, rather than poor implementation of or adherence to the planned intervention. Further analysis of our data and secondary data suggests that the evolution with age of childhood anaemia in Colombia, and its causes, appear different from those in settings where MNP has been effective. Firstly, rates of anaemia peak at much earlier ages and then fall rapidly. Secondly, anaemia that remains after the first year of life is relatively, and increasingly as children get older, unrelated to iron deficiency. We suggest that factors during gestation, birth, breastfeeding and early weaning may be important in explaining very high rates of anaemia in early infancy. However, the adverse effects of these factors appear to be largely mitigated by the introduction of solid foods that often include meat. This renders population wide MNP supplementation, provided after a diet of solid foods has become established, an ineffective instrument with which to target Colombia's childhood anaemia problem.