The incidence of stroke in the United States during the past 50 years has declined, although the severity of stroke has not, according to a study in published in the Journal of the American Medical Association.
Raphael Carandang, MD, of Boston University, and colleagues examined data from the Framingham Study (health study, with participants initially recruited in 1948) to determine long-term trends in the incidence, lifetime risk, severity, and 30-day risk of death from clinical stroke. This study included 9,152 Framingham Study original participants and offspring undergoing follow-up for up to 50 years over three consecutive time-periods (1950-1977, 1978-1989, and 1990-2004), with ascertainment of stroke risk factor data every 2 years and active surveillance for occurrence of stroke or death.
The researchers found that the age-adjusted annual incidence of clinical stroke and atherothrombotic brain infarctions (ABI) in participants age 55 to 94 years decreased during the three periods. The incidence of clinical stroke decreased significantly. Across the three periods, the lifetime risk of clinical stroke (by age 90 years) decreased from 19.5% to 14.5% in men age 65 years and from 18% to 16.1% in women. Age-adjusted stroke severity did not vary across periods; however, death within 30 days of stroke decreased significantly in men (from 23% to 14%) but not significantly in women (from 21% to 20%).
“The severity of stroke has not decreased and 30-day mortality has decreased significantly only in men, perhaps due to an older age at onset of stroke and more severe strokes in women. These sobering trends emphasize that while improved control of risk factors has lowered incidence of stroke, there is a need for greater primary prevention efforts to reduce the lifetime risk, severity, and 30-day mortality following stroke,” the authors conclude.
More than 750,000 new strokes occur each year in the United States. It is the third leading cause of death behind heart disease and cancer and the leading neurologic cause of long-term disability, according to background information in the article.