The influence of zinc supplementation on morbidity due to Plasmodium falciparum: A randomized trial in preschool children in Papua New Guinea

Zinc is crucial for normal immune function and can reduce morbidity from mu ltiple infectious diseases. To determine the influence of zinc on malaria m orbidity we conducted a randomized placebo-controlled trial of daily zinc s upplementation in children residing in a malaria endemic region of Papua Ne w Guinea. A total of 274 preschool children aged 6 to 60 months were given 10 mg elemental zinc (n = 136) or placebo (n = 138) for 6 days a week for 4 6 weeks. Slide-confirmed malaria episodes were detected by surveillance of cases self-reporting to a local health center. Cross-sectional surveys were conducted at the beginning, middle, and end of the study to assess infecti on rates, parasite density, spleen enlargement, and hemoglobin levels. Zinc supplementation resulted in a 38% (95% CI 3-60, P = 0.037) reduction in Pl asmodium falciparum health center-based episodes, defined as parasitemia gr eater than or equal to 9200 parasites/mul with axial temperature greater th an or equal to 37.5 degreesC or reported fever. Episodes accompanied by any parasitemia were also reduced by 38% (95% CI 5-60, P = 0.028), and episode s with parasitemia greater than or equal to 100,000/mul were reduced by 69% (95% CI 25-87, P = 0.009). There was no evidence of the effects of zinc on Plasmodium vivax morbidity or on health center attendance for causes other than P. falciparum. Zinc had no consistent effect on cross-sectional malar iometric indices. Although P. falciparum prevalence tended to be lower at t he end of the study in children given the placebo, such changes were absent at the mid-study survey. These results suggest that improved dietary zinc intake may reduce morbidity due to P. falciparum.