Long-term effects of hemostatic variables on fatal coronary heart disease: 30-year results from the first prospective Northwick Park Heart Study (NPHS-I)


Tom Meade, Department of Epidemiology and Population Health, Non-Communicable Disease Epidemiology Unit, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1 7HT, UK.
Tel.: +44 20 7927 2182; fax: +44 20 7580 6897; e-mail: tom.meade@lshtm.ac.uk


Background: The long-term associations of established risk factors for coronary heart disease (CHD), for example cholesterol, are well known, but not for the less familiar hemostatic variables. Objectives: To establish whether associations between hemostatic variables and CHD first identified nearly three decades ago have persisted long-term. Methods: The first Northwick Park Heart Study (NPHS-I) recruited 2167 white men and 941 white women, average age at entry 48 years, on whom measures of factor (F) VII activity (VIIc) and plasma fibrinogen were carried out, both at entry and at follow-up approximately 6 years later. Results: During a median follow-up of 29 years, 231 male and 36 female CHD deaths were recorded from notifications by the Office for National Statistics. VIIc at recruitment was significantly related to CHD mortality, corrected rate ratio, RR, per 1 SD increase 1.56 (95% CI 1.29, 1.88) in men and RR 1.78 (95% CI 1.17, 2.72) in women. Recruitment fibrinogen was also strongly related to CHD mortality in men, RR 1.63 (95% CI 1.33, 1.99) but not in women, RR 0.75 (95% CI 0.40, 1.43). The associations persisted after controlling for confounders and were confirmed using 6-year follow-up measurements and in analyses omitting deaths within 10 years of recruitment. Conclusions: The hemostatic system contributes to CHD mortality, and its effect is stable over time. For VIIc, the effect was similar in men and women, while for fibrinogen it appeared to be present only in men.