Micronutrients and oral clefts: a case-control study.

Little is known about oral clefts in developing countries. We aimed to identify micronutrient-related and environmental risk factors for oral clefts in Thailand. We tested hypotheses that maternal exposure during the periconceptional period to multivitamins or liver consumption would decrease cleft lip with or without cleft palate (CL ± P) risk and that menstrual regulation supplements would increase CL ± P risk. We conducted a multisite hospital-based case-control study in Thailand. We enrolled cases with CL ± P and 2 live births as controls at birth from the same hospital. Mothers completed a questionnaire. Conditional logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs). Eighty-six cases and 172 controls were enrolled. Mothers who took a vitamin (adjusted OR, 0.39; 95% CI: 0.16, 0.94) or ate liver (adjusted OR, 0.26; 95% CI: 0.12, 0.57) were less likely than those who did not to have an affected child. Mothers who took a menstrual regulation supplement were more likely than mothers who did not to have an affected child. Findings did not differ for infants with a family history of other anomalies or with isolated CL ± P. If replicated, our finding that liver decreases CL ± P risk could offer a low-cost primary prevention strategy.