Incidence of stroke in a Finnish prospective population study.

The incidence of stroke was investigated in a large Finnish prospective population study. The study population consisted of 11,984 men and 11,682 women aged 15 years and over drawn from four geographical regions of the country. In a mean follow-up time of six years, 174 men and 169 women suffered a fatal or non-fatal stroke. The age-adjusted mean annual incidence of stroke in men, 4.0/1000, was statistically significantly higher than the annual incidence in women, 3.3/1000. In twelve percent of the cases stroke was caused by subarachnoid hemorrhage and in ten percent by cerebral hemorrhage. In 30 percent of the cases, cerebral infarction was ascertained as the cause of the stroke; while in 49 percent of the cases, the type of stroke could not be specified with certainty. The incidence of stroke was significantly higher in non-attendants than in attendants at the initial survey. The incidence of cerebral infarction appeared to be higher in men from eastern Finland than in men from southwestern Finland.