title: Advanced parental age and autism risk in children: a systematic review and meta-analysis.
abstract: OBJECTIVE
  Advanced parental age has raised additional concern as a risk factor of autism. We conducted a meta-analysis of observational studies investigating the association between advanced parental age and risk of autism.
  
  
  METHODS
  PubMed, EMBASE, and Web of Science were searched for reports published up to November 11, 2015. Risk estimates from individual studies were pooled using random-effects models.
  
  
  RESULTS
  Twenty-seven studies were included in the meta-analysis. Compared with the reference points, the lowest parental age category was associated with a reduced risk of autism in the offspring, with adjusted odds ratios (ORs) 0.89 (95% confidence intervals [CIs] 0.75-1.06) and 0.81 (95% CI 0.73-0.89) for mother and father, respectively, and the highest parental age category was associated with an increased risk of autism in the offspring, with adjusted ORs 1.41 (95% CI 1.29-1.55) and 1.55 (95% CI 1.39-1.73) for mother and father respectively. Dose-response meta-analysis indicated that an increase of 10 years in maternal and paternal age was associated with an 18% and 21% higher risk of autism.
  
  
  CONCLUSIONS
  Advanced parental age was associated with an increased risk of autism in the offspring. More mechanistic studies are needed to further explain this positive association.
authors.affiliation: Research Center for Clinical and Translational Medicine, Beijing 302 Hospital, Beijing, China.
authors.forename: S
authors.initials: S
authors.lastname: Wu
authors.affiliation: Department of General Surgery, The 309th Hospital of PLA, Beijing, China.
authors.forename: F
authors.initials: F
authors.lastname: Wu
authors.affiliation: Department of Medical Microbiology and Parasitology, Second Military Medical University, Shanghai, China.
authors.forename: Y
authors.initials: Y
authors.lastname: Ding
authors.affiliation: Research Center for Clinical and Translational Medicine, Beijing 302 Hospital, Beijing, China.
authors.forename: J
authors.initials: J
authors.lastname: Hou
authors.affiliation: Research Center for Clinical and Translational Medicine, Beijing 302 Hospital, Beijing, China.
authors.forename: J
authors.initials: J
authors.lastname: Bi
authors.affiliation: Research Center for Clinical and Translational Medicine, Beijing 302 Hospital, Beijing, China.
authors.forename: Z
authors.initials: Z
authors.lastname: Zhang
mesh_terms: D001321:Autistic Disorder / Q000453:epidemiology*; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D064887:Observational Studies as Topic; D016017:Odds Ratio; D010290:Parents; D012307:Risk Factors
keywords: autism spectrum disorders; child; maternal age; paternal age