Independent and dependent contributions of advanced maternal and paternal ages to autism risk

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Abstract

Reports on autism and parental age have yielded conflicting results on whether mothers, fathers, or both, contribute to increased risk. We analyzed restricted strata of parental age in a 10-year California birth cohort to determine the independent or dependent effect from each parent. Autism cases from California Department of Developmental Services records were linked to State birth files (1990-1999). Only singleton births with complete data on parental age and education were included (n = 4,947,935, cases = 12,159). In multivariate logistic regression models, advancing maternal age increased risk for autism monotonically regardless of the paternal age. Compared with mothers 25-29 years of age, the adjusted odds ratio (aOR) for mothers 401 years was 1.51 (95% CI: 1.35-1.70), or compared with mothers <25 years of age, aOR = 1.77 (95% CI, 1.56-2.00). In contrast, autism risk was associated with advancing paternal age primarily among mothers <30: aOR = 1.59 (95% CI, 1.37-1.85) comparing fathers 40+ vs. 25-29 years of age. However, among mothers >30, the aOR was 1.13 (95% CI, 1.01-1.27) for fathers 40+ vs. 25-29 years of age, almost identical to the aOR for fathers <25 years. Based on the first examination of heterogeneity in parental age effects, it appears that women's risk for delivering a child who develops autism increases throughout their reproductive years whereas father's age confers increased risk for autism when mothers are <30, but has little effect when mothers are past age 30. We also calculated that the recent trend towards delayed childbearing contributed approximately a 4.6% increase in autism diagnoses in California over the decade.

Original languageEnglish (US)
Pages (from-to)30-39
Number of pages10
JournalAutism Research
Volume3
Issue number1
DOIs
StatePublished - Feb 2010

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Keywords

  • Advanced maternal age
  • Advanced paternal age
  • Attributable risk
  • Autism
  • Effect measure modification
  • Interaction
  • Maternal age
  • Paternal age

ASJC Scopus subject areas

  • Neuroscience(all)
  • Clinical Neurology
  • Genetics(clinical)

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