Mortality of people with mental retardation in California with and without Down syndrome, 1986-1991.

Mortality of people with mental retardation receiving services in California was examined. The large population (N = 118,653) enabled us to work directly with mortality rates at specific ages. Up to about age 35, mortality rates of people with Down syndrome were comparable to those of people with mental retardation due to other causes. Subsequently, the increase was much more rapid in the group with Down syndrome. Mortality rates of individuals with Down syndrome doubled every 6.4 years compared to 9.6 years for people without Down syndrome. Life tables were constructed; the remaining life expectancy of a 1-year-old child with Down syndrome with mild/moderate retardation was 55 years and with profound mental retardation, 43 years.