Hematocrit and the risk of coronary heart disease mortality in the TAMRISK study, a 28-year follow-up

Objective. To evaluate whether hematocrit (HCT) is associated with coronary heart disease (CHD) mortality in men over 55 years of age in Finland. Methods. Health survey data were recorded in 1980 from 670 men, aged 55 years. The causes of deaths during a 28-year follow-up were obtained from official records. Statistical comparisons were done by Cox proportional hazard regression model after dividing the men into two groups, one with HCT < 50% and the other, HCT >= 50%. Results. There were altogether 412 deaths of all causes, including 140 from CHD. In men having HCT < 50%, the crude CHD mortality rate per 10,000 population was 2203, while in men with HCT >= 50%, the corresponding figure was 4255. Men with HCT >= 50% were 2.4 times (95% CI 1.6-3.5) more likely to die from CHD than were men with HCT < 50%. After adjusting for established coronary risk factors, the increased risk remained 1.8-fold (95 % CI, 1.1-2.7). Conclusions. Borderline polycythemia was associated with increased CHD mortality. The cut-off Value in our study was >= 50%, proposing that for men over 55 years of age such HCT levels might be an additional risk factor. (C) 2009 Elsevier Inc. All rights reserved.