Risk-factor profile for the incidence of subarachnoid and intracerebral haemorrhage, cerebral infarction, and unspecified stroke during 21 years' follow-up in men

Aims: To study the risk-factor profile for the incidence of non-fatal and fatal stroke among middle-aged men according to the stroke subtypes subarachnoid or intracerebral haemorrhage, cerebral infarction, and unspecified stroke. Methods: The study design is a prospective cohort study. A total of 16,209 men aged 40-49 years resident in Oslo were screened for cardiovascular disease risk factors in 1972-73. Of these, 14,403 men had no cardiovascular symptoms or diseases or diabetes. The incidence of stroke after 21 years of follow-up of all men was extracted from hospital records and linkage to Statistics Norway. Results: A total of 429 non-fatal and 107 fatal stroke events were registered. Case fatality within 28 days (number and percentage of cases) was 51% (41, 7.7%) for subarachnoid haemorrhage, 39% (67, 12.6%) for cerebral haemorrhage, 10% (246, 46.3%) for cerebral infarct, and 19% (177, 33.4%) for unspecified stroke. Risk of stroke ( not subarachnoid haemorrhage) increased with the presence of symptoms or a history of cardiovascular disease or diabetes. In multivariate analysis of men without CVD or diabetes, high blood pressure was a risk factor for all subtypes of stroke; furthermore, daily smoking was a risk factor for all subtypes except subarachnoid haemorrhage. Serum cholesterol and glucose concentrations and height (inverse association) were independently associated with cerebral infarction. Smoking was a significantly stronger predictor of fatal than non-fatal events. Conclusions: The risk-factor profile differed according to the underlying subtype of stroke. Cerebral infarction clearly shared with myocardial infarction the classical risk factors, including non-fasting glucose concentration.