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> or =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> or =50%, the corresponding figure was 4255. Men with HCT> or =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 > or =50%, proposing that for men over 55 years of age such HCT levels might be an additional risk factor.