Vitamin A, infectious disease, and childhood mortality: a 2 solution?

Vitamin A was first discovered in 1913. Its deficiency was soon associated in animal models and case reports with stunting, infection, and ocular changes (xerophthalmia) resulting in blindness. The ocular consequences dominated clinical interest through the early 1980s. A longitudinal prospective study of risk factors contributing to vitamin A deficiency and xerophthalmia revealed a close, dose-response relationship between the severity of mild preexisting vitamin A deficiency and the subsequent incidence of respiratory and diarrheal infection (relative risk [RR], 2.0-3.0) and, most dramatically, death (RR, 3.0-10.0). Subsequent community-based prophylaxis trials of varying design confirmed that vitamin A supplementation of deficient populations could reduce childhood (1-5 years old) mortality by an average of 35%. Concurrent hospital-based treatment trials with vitamin A in children with measles revealed a consistent reduction in measles-associated mortality in Africa of at least 50%. It is now estimated that improving the vitamin A status of all deficient children worldwide would prevent 1-3 million childhood deaths annually.