Season of Birth and Autistic Disorder in Israel

Barak, Yoram
Ring, Aliza
Sulkes, Juliet
Gabbay, Uri
Elizur, Avner

Received Nov. 17, 1993; revisions received April 7 and July 14, 1994; accepted Aug. 18, 1994. From the Yehuda Abarbanel Mental Health Center and Belinson Medical Center--Epidemiology Unit, Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel. Address reprint requests to Dr. Barak, Yehuda Abarbanel Mental Health Center, 15, Keren-Kayemet St., Bat-Yam, Israel.

American Journal of Psychiatry 152(5):p 798-800, May 1995.

Objective

Variations in month of birth were examined in patients with infantile autism to test the hypothesis that birth in a particular month may be a risk factor for this disorder. Method: Data for autistic patients registered with the National League for Autism in Israel (N=188) during the years 1964-1986 were compared with data on monthly distribution of live births in Israel for the corresponding period. Results: After risk ratio estimates were computed for children born with infantile autism for each month, a significant increase was observed for children born in March and August. This association was true for each year throughout the study. An additional finding was a significantly higher rate of birth of autistic children in the years 1970-1976. Conclusions: This study, although made in a different climatic area than three earlier studies, further emphasizes the earlier findings that March and August births are a risk factor for development of autistic disorder. (Am J Psychiatry 1995; 152:798-800)