title: Folic acid supplements and risk of facial clefts: national population based case-control study.
abstract: OBJECTIVE
  To explore the role of folic acid supplements, dietary folates, and multivitamins in the prevention of facial clefts.
  
  
  METHODS
  National population based case-control study.
  
  
  METHODS
  Infants born 1996-2001 in Norway.
  
  
  METHODS
  377 infants with cleft lip with or without cleft palate; 196 infants with cleft palate alone; 763 controls.
  
  
  METHODS
  Association of facial clefts with maternal intake of folic acid supplements, multivitamins, and folates in diet.
  
  
  RESULTS
  Folic acid supplementation during early pregnancy (> or =400 microg/day) was associated with a reduced risk of isolated cleft lip with or without cleft palate after adjustment for multivitamins, smoking, and other potential confounding factors (adjusted odds ratio 0.61, 95% confidence interval 0.39 to 0.96). Independent of supplements, diets rich in fruits, vegetables, and other high folate containing foods reduced the risk somewhat (adjusted odds ratio 0.75, 0.50 to 1.11). The lowest risk of cleft lip was among women with folate rich diets who also took folic acid supplements and multivitamins (0.36, 0.17 to 0.77). Folic acid provided no protection against cleft palate alone (1.07, 0.56 to 2.03).
  
  
  CONCLUSIONS
  Folic acid supplements during early pregnancy seem to reduce the risk of isolated cleft lip (with or without cleft palate) by about a third. Other vitamins and dietary factors may provide additional benefit.
authors.affiliation: Epidemiology Branch, National Institute of Environmental Health Sciences/NIH, Durham, NC 27709, USA. wilcox@niehs.nih.gov
authors.forename: Allen J
authors.initials: AJ
authors.lastname: Wilcox
authors.forename: Rolv Terje
authors.initials: RT
authors.lastname: Lie
authors.forename: Kari
authors.initials: K
authors.lastname: Solvoll
authors.forename: Jack
authors.initials: J
authors.lastname: Taylor
authors.forename: D Robert
authors.initials: DR
authors.lastname: McConnaughey
authors.forename: Frank
authors.initials: F
authors.lastname: Abyholm
authors.forename: Hallvard
authors.initials: H
authors.lastname: Vindenes
authors.forename: Stein Emil
authors.initials: SE
authors.lastname: Vollset
authors.forename: Christian A
authors.initials: CA
authors.lastname: Drevon
mesh_terms: D016022:Case-Control Studies; D002971:Cleft Lip / Q000517:prevention & control*; D002972:Cleft Palate / Q000517:prevention & control*; D019587:Dietary Supplements; D005260:Female; D005492:Folic Acid / Q000008:administration & dosage*; D006801:Humans; D007231:Infant, Newborn; D009664:Norway; D016742:Preconception Care / Q000379:methods*; D011247:Pregnancy; D011295:Prenatal Care / Q000379:methods*; D014815:Vitamins
chemical_list: D014815:Vitamins; D005492:Folic Acid