title: Periconceptional nutrient intakes and risks of neural tube defects in California.
abstract: BACKGROUND
  This study investigated the association of neural tube defects (NTDs) with maternal periconceptional intake of folic acid-containing supplements and dietary nutrients, including folate, among deliveries that occurred after folic acid fortification in selected California counties.
  
  
  METHODS
  The population-based case-control study included fetuses and live born infants with spina bifida (189) or anencephaly (141) and 625 nonmalformed, live born controls delivered from 1999 to 2003. Mothers reported supplement use during telephone interviews, which included a 107-item food frequency questionnaire. For dietary nutrients, intakes <25th, 25th to <75th (reference), and > or =75th percentile were compared, based on control distributions.
  
  
  RESULTS
  After adjustment for potential confounders, any versus no supplement intake resulted in ORs of 0.8 (95% CI, 0.5-1.3) for anencephaly and 0.8 (95% CI, 0.6-1.2) for spina bifida. After stratification by maternal intake of vitamin supplements, most factors in the glycemic pathway were not associated with either NTD, with the exception of low levels of fructose and glucose that were significantly associated with anencephaly. Some nutrients that contribute to one-carbon metabolism showed lowered risks (folate, riboflavin, vitamins B(6) and B(12)); others did not (choline, methionine, zinc). Antioxidant nutrients tended to be associated with lowered risks (vitamins C, E, A, beta-carotene, lutein).
  
  
  CONCLUSIONS
  Mothers' intake of vitamin supplements was modestly if at all associated with a lowered risk of NTDs. Dietary intake of several nutrients contributing to one-carbon metabolism and oxidative stress were associated with reduced NTD risk.
authors.affiliation: California Research Division, March of Dimes Foundation, Oakland, California 94609-1673, USA. SCarmichael@marchofdimes.com
authors.forename: Suzan L
authors.initials: SL
authors.lastname: Carmichael
authors.forename: Wei
authors.initials: W
authors.lastname: Yang
authors.forename: Gary M
authors.initials: GM
authors.lastname: Shaw
mesh_terms: D000328:Adult; D000975:Antioxidants / Q000008:administration & dosage; D002140:California / Q000453:epidemiology; D002244:Carbon / Q000378:metabolism; D016022:Case-Control Studies; D004032:Diet; D019587:Dietary Supplements; D002149:Energy Intake; D005260:Female; D005492:Folic Acid / Q000008:administration & dosage*; D005632:Fructose / Q000032:analysis; D005947:Glucose / Q000032:analysis; D006801:Humans; D009436:Neural Tube Defects / Q000453:epidemiology* / Q000517:prevention & control; D011247:Pregnancy; D012306:Risk; D055815:Young Adult
chemical_list: D000975:Antioxidants; D005632:Fructose; D002244:Carbon; D005492:Folic Acid; D005947:Glucose