Prevalence and incidence of autism spectrum disorders among national health insurance enrollees in Taiwan from 1996 to 2005.

The authors used a national database to examine the prevalence and incidence of autism spectrum disorders. The National Health Research Institute provided a database of 1,000,000 random participants for study. A population-based sample of 372,642 aged younger than 18 was obtained as a dynamic cohort. Those study participants who had at least one service claim from 1996 to 2005 with a principal diagnosis of autism spectrum disorders were identified. The cumulative prevalence of autism spectrum disorders increased from 1.79 to 28.72 per 10 000 from 1996 to 2005. The annual incidence of autism spectrum disorders increased from 0.91 to 4.41 per 10,000 per year from 1997 to 2005. Higher incidence was detected in the 0 to 5 age group, in males, and in those who lived in northern, southern, and eastern regions and urban areas. Our findings suggest increases in the prevalence and incidence of treated autism spectrum disorders in Taiwan.