Twenty-four-year trends in the incidence of ischemic stroke in Sweden from 1987 to 2010

Abstract

Background and purpose: 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.

Methods: 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.

Results: 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.

Conclusions: 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.

Keywords: epidemiology; incidence; ischemic; mortality; stroke.