Interrelationship between diarrhea and vitamin A deficiency: is vitamin A deficiency a risk factor for diarrhea?

A cross-sectional study, a follow-up study and an evaluation of impact of community-based distribution of vitamin A capsules (200,000 IU) were conducted in Omdurman (Sudan) between November, 1988, and March, 1989. In the cross-sectional survey 1441 children less than 5 years of age participated, which established the baseline values for plasma retinol-binding protein. During the follow-up period 290 cases of diarrhea occurred. Low concentrations of plasma retinol-binding protein (less than 1.85 mg/dl) proved to be a risk factor for diarrhea, especially in girls. The relative risk increased after the second year of life. Children who received vitamin A supplementation before commencement of the study had a lower incidence of diarrhea. The protective effect of vitamin A supplementation was greater in girls (relative risk, 0.297; 95% confidence interval, 0.240 to 0.368) than in boys (relative risk, 0.404; 95% confidence interval, 0.352 to 0.464).