U.S. Stroke Incidence Has Declined Over Past 50 Years

TUESDAY, Dec. 26 (HealthDay News) -- Over the past 50 years there has been a decline in the incidence of stroke in the United States, but lifetime risk has not declined, possibly due to longer life expectancies, researchers report in the Dec. 27 issue of the Journal of the American Medical Association.

Philip A. Wolf, M.D., of Boston University School of Medicine, and colleagues analyzed data on 9,152 men and women who had not had a stroke at baseline and who were followed up at three periods during the course of 50 years. This amounted to 174,917 person-years of follow-up. Data on stroke risk factors and surveillance for incidence of stroke were conducted every two years.

During the course of follow-up, there were 1,030 strokes, of which 629 (61 percent) were atherothrombotic brain infarctions. Men accounted for 450 (44 percent) of the cases. In men, the age-adjusted stroke incidence was 7.6 per 1000 person-years in 1950-1977, 6.2 in 1978-1989, and 5.3 in 1990-2004. The incidence for women over the same three periods was 6.2 per 1000 person-years, 5.8 and 5.1, respectively. There was a decline in lifetime risk at age 65, from 19.5 percent to 14.5 percent for men and from 18.0 percent to 16.1 percent for women, but it was not statistically significant.

"The results of this study suggest that improved control of risk factors has lowered stroke incidence but emphasize the need for continued primary prevention efforts," the authors conclude.

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