Twenty-Four-Year Trends in the Incidence of Ischemic Stroke in Sweden From 1987 to 2010

Abstract

The incidence of stroke in Sweden increased between 1989 and 2000 among people aged ≤65 years, but more recent data on those aged >65 years are lacking. Through the Swedish Hospital Discharge and Cause of Death registries, we identified all cases of nonfatal and fatal ischemic stroke (IS) among people aged 18 to 84 years during 1987-2010 in Sweden. Of the 391 081 stroke cases identified, 1.6% were 18 to 44 years, 16.7% were 45 to 64 years, and 81.7% were 65 to 84 years. Among people aged 18 to 44 years, there was a continuous increase in the incidence of stroke of 1.3% (95% confidence interval, 0.8%-1.8%) per year for men and 1.6% (1.0%-2.3%) per year for women. Among men and women aged 45 to 64 years, slightly declining rates were observed from the late 1990s, with a mean annual decrease of 0.4% (0.1%-0.7%) among men and 0.6% (0.2%-1.0%) among women. Among men aged 65 to 84 years, a decrease of 3.7% in IS (3.4%-4.0%) per year was observed from the late 1990s. This was more marked in women, where an initial decrease of 2.5% (2.1%-2.9%) per year was followed by an accelerated decrease of 5.1% (4.4%-5.8%) after 2005. Mortality from IS decreased markedly in all age groups. The incidence of IS in elderly people in Sweden is now decreasing, whereas the decline in IS incidence in the middle-aged people is much less steep. The increasing incidence of stroke in the young, particularly if carried forward to an older age, is concerning.