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This Article Figures Only Full Text Full Text (PDF) All Versions of this Article: AJPH.2008.149021v1 99/9/1673    most recent Submit a response View Shopping Cart Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by King, M. D. Articles by Bearman, P. S. PubMed PubMed Citation Articles by King, M. D. Articles by Bearman, P. S. Related Collections Disability Epidemiology Social Science Birth Outcomes

Marissa D. King, PhD, Christine Fountain, PhD, Diana Dakhlallah, BA and Peter S. Bearman, PhD

At the time of the study, the authors were with the Institute for Social and Economic Research and Policy, Columbia University, New York, NY. Christine Fountain was also with the Department of Sociology at the University of South Carolina, Columbia. Peter S. Bearman was also with the Department of Sociology, Columbia University, New York.

Correspondence: Correspondence should be sent to Peter S. Bearman, PhD, Paul Lazarsfeld Center for the Social Sciences, Columbia University, 420 West 118th Street, IAB Building Room 803, MC 3355, New York, NY, 10027 (e-mail: psb17{at}columbia.edu). Reprints can be ordered at http://www.ajph.org by clicking the "Reprints/Eprints" link.

Objectives. We sought to estimate the risk for autism associated with maternal and paternal age across successive birth cohorts.

Methods. We linked birth records and autism diagnostic records from the California Department of Developmental Services for children born in California between 1992 and 2000 to calculate the risk associated with maternal and paternal age for each birth cohort as well as for the pooled data.

Results. The categorical risks associated with maternal age over 40 years ranged from a high of 1.84 (95% confidence interval [CI] = 1.37, 2.47) to a low of 1.27 (95% CI = 0.95, 1.69). The risk associated with paternal age ranged from 1.29 (95% CI = 1.03, 1.6) to 1.71 (95% CI = 1.41, 2.08).

Conclusions. Pooling data across multiple birth cohorts inflates the risk associated with paternal age. Analyses that do not suffer from problems produced by pooling across birth cohorts demonstrated that advanced maternal age, rather than paternal age, may pose greater risk. Future research examining parental age as a risk factor must be careful to avoid the paradoxes that can arise from pooling data, particularly during periods of social demographic change.