Comparative mortality in mentally retarded patients in California, with and without Down's syndrome, 1986-1991

The large database of the California Department of Developmental Services provides a data source for mortality rates in persons with mental retardation by age, sex, severity, cause and associated conditions.

Data for 1986-1991 were used to determine age-related mortality rates in cases with and without Down's Syndrome, in three severity levels of mental retardation. Distribution data for the data-base population are also given.

In both Down's and non-Down's patient groups excess mortality increased with severity of mental retardation at all ages. In both groups excess mortality tended to decrease with advancing age to age 35-39 years, and to increase at the older ages. The age increase in excess death rate at age 40 years and up was steeper in the patients with Down's Syndrome.