Maternal Intake of Vitamin E and Birth Defects, National Birth Defects Prevention Study, 1997 to 2005

BACKGROUND In a recent study, high maternal periconceptional intake of vitamin E was found to be associated with risk of congenital heart defects (CHDs). To explore this association further, we investigated the association between total daily vitamin E intake and selected birth defects. METHODS: We analyzed data from 4525 controls and 8665 cases from the 1997 to 2005 National Birth Defects Prevention Study. We categorized estimated periconceptional energy-adjusted total daily vitamin E intake from diet and supplements into quartiles (referent, lowest quartile). Associations between quartiles of energy-adjusted vitamin E intake and selected birth defects were adjusted for demographic, lifestyle, and nutritional factors. RESULTS: We observed a statistically significant association with the third quartile of vitamin E intake (odds ratio [OR], 1.17; 95% confidence interval [CI], 1.01-1.35) and all CHDs combined. Among CHD sub-types, we observed associations with left ventricular outflow tract obstruction defects, and its sub-type, coarctation of the aorta and the third quartile of vitamin E intake. Among defects other than CHDs, we observed associations between anorectal atresia and the third quartile of vitamin E intake (OR, 1.66; 95% CI, 1.01-2.72) and hypospadias and the fourth quartile of vitamin E intake (OR, 1.42; 95% CI, 1.09-1.87). CONCLUSION: Selected quartiles of energy-adjusted estimated total daily vitamin E intake were associated with selected birth defects. However, because these few associations did not exhibit exposure-response patterns consistent with increasing risk associated with increasing intake of vitamin E, further studies are warranted to corroborate our findings. (C) 2014 Wiley Periodicals, Inc.