Nutritional Status as a modifier of the effect of Vitamin A or Zinc Supplementation on Gastrointestinal Parasite Infections in Mexican Children

Childhood nutritional status may modify the efficacy of micronutrient supplementation on infectious disease outcomes. Our study evaluated whether nutritional status, as indicated by height‐for age z scores (HAZ) and weight‐for‐age z scores (WAZ), modifies A. lumbricoides, E. Histolytica, and G. lamblia infection durations among vitamin A or zinc supplemented Mexican children. A total of 707 children living in a periurban community of Mexico City, between 6 and 15 months of age, were randomized to receive vitamin A, zinc, a combined vitamin A and zinc supplement, or a placebo. Changes in infection durations for the 3 parasites determined in monthly collected stools were modelled for 4 categories of HAZ and WAZ using parametric regression. In the vitamin A treatment arm, A. lumbricoides infection durations were significantly increased in children with the lowest HAZ scores (18.67 ± 29.18 days) and reduced in children with the highest HAZ scores (1 ± 0 days, p<0.01). In vitamin A‐zinc treatment arm, G. lamblia infection durations were significantly increased in children with the highest HAZ scores (p<0.01) and reduced in children with the and highest WAZ scores (p<0.01). Our results suggest that childhood nutritional status modifies the effect zinc or vitamin A supplementation has on gastrointestinal parasite outcomes.