Poor micronutrient status is associated with diarrheal illness, but it is not known whether low folate and/or cobalamin status are independent risk factors for diarrhea. We measured the association between plasma folate and cobalamin and subsequent diarrheal morbidity in a prospective cohort study of 2296 children aged 6-30 mo in New Delhi, India. Plasma concentrations of folate, cobalamin, total homocysteine (tHcy), and methylmalonic acid were determined at baseline. Whether a child had diarrhea was recorded during weekly visits in a 4-mo zinc supplementation trial. Diarrhea episodes lasting <7, ≥7, and ≥14 d were classified as acute, prolonged, and persistent, respectively. There was a total of 4596 child periods with acute, 633 with prolonged, and 117 with persistent diarrhea during follow-up. Children with plasma folate concentrations in the lowest quartile had higher odds of persistent diarrhea than children in the other quartiles [adjusted OR = 1.77 (95% CI = 1.14, 2.75); P = 0.01]. This effect differed between boys [adjusted OR = 2.51 (95% CI = 1.47, 4.28)] and girls [adjusted OR = 1.03 (95% CI = 0.53, 2.01); P-interaction = 0.030]. We found a small but significant association between high plasma tHcy concentration and acute diarrhea [adjusted OR = 1.14 (95% CI = 1.04, 1.24); P = 0.006]. Plasma cobalamin concentration was not a predictor of diarrheal morbidity. In conclusion, poor folate status was an independent predictor of persistent diarrhea in this population.
Trial registration: ClinicalTrials.gov NCT00272116.