Level of fibrinogen and risk of fatal and non-fatal stroke. EUROSTROKE: a collaborative study among research centres in Europe

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 become 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 (ischaemic or haemorrhagic).