title: Association between maternal use of folic acid supplements and risk of autism spectrum disorders in children.
abstract: OBJECTIVE
  Prenatal folic acid supplements reduce the risk of neural tube defects in children, but it has not been determined whether they protect against other neurodevelopmental disorders.
  
  
  OBJECTIVE
  To examine the association between maternal use of prenatal folic acid supplements and subsequent risk of autism spectrum disorders (ASDs) (autistic disorder, Asperger syndrome, pervasive developmental disorder-not otherwise specified [PDD-NOS]) in children.
  
  
  METHODS
  The study sample of 85,176 children was derived from the population-based, prospective Norwegian Mother and Child Cohort Study (MoBa). The children were born in 2002-2008; by the end of follow-up on March 31, 2012, the age range was 3.3 through 10.2 years (mean, 6.4 years). The exposure of primary interest was use of folic acid from 4 weeks before to 8 weeks after the start of pregnancy, defined as the first day of the last menstrual period before conception. Relative risks of ASDs were estimated by odds ratios (ORs) with 95% CIs in a logistic regression analysis. Analyses were adjusted for maternal education level, year of birth, and parity.
  
  
  METHODS
  Specialist-confirmed diagnosis of ASDs.
  
  
  RESULTS
  At the end of follow-up, 270 children in the study sample had been diagnosed with ASDs: 114 with autistic disorder, 56 with Asperger syndrome, and 100 with PDD-NOS. In children whose mothers took folic acid, 0.10% (64/61,042) had autistic disorder, compared with 0.21% (50/24,134) in those unexposed to folic acid. The adjusted OR for autistic disorder in children of folic acid users was 0.61 (95% CI, 0.41-0.90). No association was found with Asperger syndrome or PDD-NOS, but power was limited. Similar analyses for prenatal fish oil supplements showed no such association with autistic disorder, even though fish oil use was associated with the same maternal characteristics as folic acid use.
  
  
  CONCLUSIONS
  Use of prenatal folic acid supplements around the time of conception was associated with a lower risk of autistic disorder in the MoBa cohort. Although these findings cannot establish causality, they do support prenatal folic acid supplementation.
authors: Norwegian Institute of Public Health, PO Box 4404, Nydalen, N-0403 Oslo, Norway. pal.suren@fhi.no
authors: Pål
authors: P
authors: Surén
authors: Christine
authors: C
authors: Roth
authors: Michaeline
authors: M
authors: Bresnahan
authors: Margaretha
authors: M
authors: Haugen
authors: Mady
authors: M
authors: Hornig
authors: Deborah
authors: D
authors: Hirtz
authors: Kari Kveim
authors: KK
authors: Lie
authors: W Ian
authors: WI
authors: Lipkin
authors: Per
authors: P
authors: Magnus
authors: Ted
authors: T
authors: Reichborn-Kjennerud
authors: Synnve
authors: S
authors: Schjølberg
authors: George
authors: G
authors: Davey Smith
authors: Anne-Siri
authors: AS
authors: Øyen
authors: Ezra
authors: E
authors: Susser
authors: Camilla
authors: C
authors: Stoltenberg
mesh_terms: D000293:Adolescent; D002648:Child; D002659:Child Development Disorders, Pervasive / Q000453:epidemiology* / Q000517:prevention & control*; D002675:Child, Preschool; D015331:Cohort Studies; D019587:Dietary Supplements; D005260:Female; D005492:Folic Acid / Q000627:therapeutic use*; D006801:Humans; D008297:Male; D009664:Norway / Q000453:epidemiology; D016017:Odds Ratio; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D011295:Prenatal Care; D011297:Prenatal Exposure Delayed Effects; D012044:Regression Analysis; D012306:Risk; D014803:Vitamin B Complex / Q000627:therapeutic use*; D055815:Young Adult
chemical_list: D014803:Vitamin B Complex; D005492:Folic Acid
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