title: The association between periconceptional folic acid supplementation and congenital heart defects: a case-control study in China.
abstract: OBJECTIVE
  This study aims to evaluate the association between folic acid (FA) supplementation and congenital heart defects (CHDs).
  
  
  METHODS
  This hospital-based case-control study initiated in 2010 in China analyzed 358 cases and 422 controls. The adjusted odds ratio (AOR) calculated using a logistic model was used to assess the association between FA supplementation and CHDs.
  
  
  RESULTS
  Compared with a mother who reported no FA supplementation, mothers who reported FA supplementation were less likely to have offspring with isolated CHD(s) (AOR=0.52, 0.34-0.78) and multiple complex conditions (AOR=0.27, 0.14-0.55). However, mothers who reported FA supplementation for less than 1 month regardless of the start time of supplementation, did not have a significantly lower risk of having an offspring with isolated or multiple complex conditions. Mothers who reported FA supplementation for ≧3 months beginning before conception had a significantly lower risk of having children with isolated CHD(s) (AOR=0.31, 0.18-0.54).
  
  
  CONCLUSIONS
  FA-supplementation is associated with reduced risk of CHDs. The earlier FA supplementation begins before pregnancy and the longer supplementation lasts, the lower the risk of CHDs is.
authors.affiliation: National Center for Birth Defect Monitoring, West China Second University Hospital, Sichuan University, Chengdu 610041, China.
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Li
authors.forename: Shengli
authors.initials: S
authors.lastname: Li
authors.forename: Dezhi
authors.initials: D
authors.lastname: Mu
authors.forename: Zhen
authors.initials: Z
authors.lastname: Liu
authors.forename: Yanli
authors.initials: Y
authors.lastname: Li
authors.forename: Yuan
authors.initials: Y
authors.lastname: Lin
authors.forename: Xinlin
authors.initials: X
authors.lastname: Chen
authors.forename: Fengzhi
authors.initials: F
authors.lastname: You
authors.forename: Nana
authors.initials: N
authors.lastname: Li
authors.forename: Kui
authors.initials: K
authors.lastname: Deng
authors.forename: Ying
authors.initials: Y
authors.lastname: Deng
authors.forename: Yanping
authors.initials: Y
authors.lastname: Wang
authors.forename: Jun
authors.initials: J
authors.lastname: Zhu
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D002681:China; D019587:Dietary Supplements; D005260:Female; D005492:Folic Acid / Q000008:administration & dosage*; D006330:Heart Defects, Congenital / Q000517:prevention & control*; D006801:Humans; D016742:Preconception Care; D011247:Pregnancy; D014803:Vitamin B Complex / Q000008:administration & dosage*; D055815:Young Adult
chemical_list: D014803:Vitamin B Complex; D005492:Folic Acid