Level of fibrinogen and risk of fatal and non-fatal stroke. Eurostroke: A collaborative study among research centres in Europe. (Research Report).(Statistical Data Included)

Background: It is well established that raised levels of fibrinogen increase the risk of coronary heart disease. For stroke, however, data are much more limited and restricted to overall stroke. This study investigated the association between fibrinogen and fatal, non-fatal, haemorrhagic and ischaemic stroke in three European cohorts participating in EUROSTROKE.

Methods: EUROSTROKE is a collaborative project among ongoing European cohort studies on incidence and risk factors of stroke. EUROSTROKE is designed as a nested case-control study. For each stroke case, two controls were sampled. Strokes were classified according to MONICA criteria or reviewed by a panel of four neurologists. Recently, data on stroke and fibrinogen became available from cohorts in Cardiff (79 cases/194 controls), Kuopio (74/124), and Rotterdam (62/203). Results were adjusted for age, sex, smoking, and systolic blood pressure.

Results: The risk of stroke gradually increased with increasing fibrinogen levels: the odds ratios per quartile increase were 1.08 (95% CI 0.63 to 1.84), 1.91 (1.12 to 3.26) and 2.78 (1.64 to 4.72), respectively. This association was similar for ischaemic (n=138) and haemorrhagic stroke (n=25) Associations between fibrinogen and stroke were similar across strata of smoking, diabetes mellitus, previous myocardial infarction, and HDL cholesterol. The odds ratio, however, tended to increase with increasing systolic blood pressure: from 1.21 among those with a systolic pressure <120 mm Hg to 1.99 among subjects with a systolic pressure of 160 mm Hg or above.

Conclusion: This analysis of the EUROSTROKE project indicates that fibrinogen is a powerful predictor of stroke. Results did not disclose a differential in this relation of fibrinogen and fatal or non-fatal stroke, or with type of stroke (ischoemic or hoemorrhagic).

It is well established that raised levels of fibrinogen increase the risk of coronary heart disease. This has convincingly been shown in population-based studies among apparently healthy subjects. (1-6) Also, among subjects with a history of coronary heart disease fibrinogen is an important predictor of future coronary events. (7) Studies on the association between fibrinogen and stroke are, however, limited.(1 3 8) These studies were based on a limited number of events and in general restricted to overall stroke without subtyping the stroke events.

We evaluated the association between fibrinogen and fatal, non-fatal, haemorrhagic and ischaemic stroke combining data obtained in three European cohorts participating in EURO-STROKE.

METHODS

The rationale and design of EUROSTROKE have been described in detail elsewhere. (9) In short, EUROSTROKE is a collaborative study among European research centres to investigate (1) the variation in incidence of fatal and non-fatal ischaemic and haemorrhagic stroke among populations in different European countries; (2) whether the observed differences in stroke incidence across countries can be explained by differences in prevalence of established cardiovascular risk factors; (3) the relative importance of smoking and some selected dietary factors (potassium intake, alcohol consumption), haemostatic disturbances (fibrinogen) and comorbidity (rheumatic heart disease, atrial fibrillation) compared with established risk factors as determinants of the occurrence of ischaemic and haemorrhagic stroke. The EURO STROKE database is drawn from ongoing European population-based prospective follow up studies (cohorts) and is designed as a case-control study nested within these ongoing studies. For each stroke case, two co ntrols were sampled. Controls were matched on day of baseline examination only. Apart from its objectives, the EUROSTROKE database allows for aetiological analyses looking into various risk factors for stroke. EUROSTROKE formally started on 1 January 1994. At present, fibrinogen data from three cohorts were available for analysis.

Finland

The Finnish contribution to EUROSTROKE comes from the Kuopio Ischemic Heart Disease Risk Factor study, which is a population-based prospective cohort study comprised of an age stratified random sample of 2682 men aged 42, 48, 54, and 60 years. The baseline examination was performed between 1984 and 1989.(10) Fatal and non-fatal stroke cases were collected through the national mortality statistics and the FINMONICA stroke registries. Stroke was defined according to FINMONICA criteria and definitions." Case ascertainment from the baseline examination to 1 January 1993 revealed 74 stroke cases. Controls subjects (n=148) were randomly drawn from the cohort that remained free from stroke during follow up. Fibrinogen was measured in 61 cases and 124 controls.

The Netherlands

The Dutch contribution to EURO …