Periconceptional vitamin use, dietary folate, and the occurrence of neural tube defects

• Published in: Epidemiology (Cambridge, Mass.) Vol. 6; no. 3; p. 219
• Main Authors: Shaw, G M, Schaffer, D, Velie, E M, Morland, K, Harris, J A
• Format: Journal Article
• Language: English
• Published: United States 01.05.1995
• Subjects: Adult; California - epidemiology; Case-Control Studies; Demography; Diet; Energy Intake; Ethnic Groups; Female; Folic Acid - administration & dosage; Humans; Infant, Newborn; Interviews as Topic; Neural Tube Defects - epidemiology; Neural Tube Defects - ethnology; Neural Tube Defects - prevention & control; Odds Ratio; Preconception Care; Pregnancy; Pregnancy Trimester, First; Risk Factors; Vitamins - administration & dosage; Vitamins - therapeutic use; California
• ISSN: 1044-3983
• DOI: 10.1097/00001648-199505000-00005

With a case-control study, we investigated whether periconceptional intake of supplemental or dietary folate reduced the risk of having a neural tube defect (NTD)-affected pregnancy. Mothers of 549 (88% of eligible) cases and 540 (88%) controls were interviewed in person about vitamin supplements used in either the 3 months before or the 3 months after conception and also about usual diet in the 3 months before conception. Women with any use of a folic acid-containing vitamin in the 3 months before conception had a lower risk of having an NTD-affected pregnancy [odds ratio (OR) = 0.65; 95% confidence interval (CI) = 0.45-0.94]. ORs were similar for 3 levels (< 0.4, 0.4-0.9, and > 0.9 mg per day) of average daily intake of folic acid. Any level of use in the first 3 months after conception resulted in a lowered risk as well (OR = 0.60; 95% CI = 0.46-0.79). Reduced risks were less marked for Hispanics and were not observed among women who graduated from college. Modest reduced risks were noted among non-vitamin users whose estimated daily dietary intake of folate was more than 0.227 mg. We observed decreasing risk with increasing folate intake from combined dietary sources and vitamin supplements. A reduction in NTD risk associated with folate intake is consistent with other studies; however, the reduced risk may be particular to subsets of the population, primarily non-Hispanic women and women whose education does not exceed high school.