'Studies of season of birth or season of conception can provide clues about etiology. We investigated whether certain months or seasons of conception are associated with increased risk of autism spectrum disorders, for which etiology is particularly obscure,' investigators in Davis, United States report.
'The study population comprises 6,604,975 children born from 1990 to 2002 in California. Autism cases (n = 19,238) were identified from 1990 through 2008 in databases of the California Department of Developmental Services, which coordinates services for people with developmental disorders. The outcome in this analysis was autism diagnosed before the child's sixth birth date. The main independent variables were month of conception and season of conception (winter, spring, summer, and fall). Multivariate logistic regression models were used to estimate odds ratios (ORs) with their 95% confidence intervals (CIs) for autism by month of conception. Children conceived in December (OR = 1.09 [95% CI = 1.02-1.17]), January (1.08 [1.00-1.17]), February (1.12 [1.041.20]), or March (1.16 [1.08-1.24]) had higher risk of developing autism compared with those conceived in July. Conception in the winter season (December, January, and February) was associated with a 6% (OR = 1.06, 95% CI = 1.02-1.10) increased risk compared with summer,' wrote O. Zerbo and colleagues, University of California.
The researchers concluded: 'Higher risks for autism among those conceived in winter months suggest the presence of environmental causes of autism that vary by season.'
Zerbo and colleagues published their study in Epidemiology (Month of Conception and Risk of Autism. Epidemiology, 2011;22(4):469-475).
For additional information, contact O. Zerbo, University of California, Dept. of Public Health Science, School Medical, MS1C, Davis, CA 95616, United States.
The publisher of the journal Epidemiology can be contacted at: Lippincott Williams & Wilkins, 530 Walnut St., Philadelphia, PA 19106-3621, USA.
Keywords: City:Davis, State:California, Country:United States, Region:North and Central America, Neurology, Pediatrics, Developmental Disabilities
This article was prepared by Pediatrics Week editors from staff and other reports. Copyright 2011, Pediatrics Week via NewsRx.com.
