Trends in Stroke Prevalence in the United States Population Age 25-74, 1971-1994.
Mortality from stroke in the United States (US) has declined since 1900. Primary prevention was credited for much of this decline through the 1970s; however, observational studies have indicated that stroke incidence did not decline during the 1980s. In contrast, improvement in stroke survival has been noted in the 1970s and 1980s. The effect of these secular trends on the prevalence and number of stroke survivors in the US has not been determined. The prevalence and number of non-institutionalized stroke survivors in the US was estimated through self-report for three time periods, 1971-1975, 1976-1980, and 1988-1994, using data from the National Health and Nutrition Examination Survey (NHANES) I, II, and III, respectively. Prevalence and number of stroke survivors were analyzed for the overall US population and by age (25-59, 60-74), race (White and African-American), and sex. Estimates were limited to the US population age 25-74 years old because NHANES I and II did not interview persons 75 years of age and older. The age, race, and sex adjusted prevalence of stroke increased from 1.41 to1.69 to 1.87; an average increase of 7.5% (95% confidence interval, CI: -2%, 18%) for each 5-year period between NHANES I, II, and III. Additionally, the number of stroke survivors increased from 1.5 to 2.4 million across this same time period. The prevalence of stroke among the US population age 60-74 years of age increased from 4.2% to 5.0% to 5.2% from NHANES I to III; an average increase of 6.4% for each 5 years (95% CI: -3%, +17%) during the period analyzed. In contrast, among persons age 25-59 the prevalence of stroke was less than 1% in all three-time periods and a secular trend was not present. Although stroke prevalence increased 28% for each 5-year period among African-American females (95% CI: +3%, +56%) and +12% among White males (95% CI: -2%, +29%) it did not change among African-American males or White females. In contrast, the number of stroke survivors increased among all age, race and sex sub-groups. Despite the absence of strong trends in stroke prevalence, the number of non-institutionalized stroke survivors under age 75 years of age increased substantially.