Serum total cholesterol and mortality in a Japanese population

Abstract

Although the relation between serum total cholesterol and coronary heart disease is well established, the relation with mortality from non-coronary disease is controversial. Inverse relations of serum cholesterol with hemorrhagic stroke and cancer have stimulated the examination of cholesterol-non-coronary mortality associations. The population surveyed is 12,187 men and women aged 40–69 years living in Yao City, a suburb of Osaka, who undertook baseline examinations between 1975 and 1984 and had no history of stroke and coronary heart disease at baseline. The subjects were followed on average 8.9 years until the end of 1988 using systematic mortality surveillance. During the follow-up, there were 343 deaths, comprising 170 cancer deaths ( International Classification of Death 9th edition: ICD-9, 140–239), 21 coronary heart disease deaths (ICD-9, 410–414), 67 other cardiovascular deaths (ICD-9, 390–458 excluding 410–414), and 85 non-cardiovascular, non-cancer deaths. There was a significant inverse association of serum cholesterol with total and cancer mortality for men, and no significant association for women. The cholesterol-disease association, although not significant, was positive for coronary heart disease and other cardiovascular disease deaths, and inverse for non-cardiovascular, non-cancer deaths in both sexes. The inverse association of serum cholesterol with total and cancer mortality for men remained significant after controlling for age, job classification, hypertension category, usual alcohol intake, cigarette smoking, and relative weight index. A 34 mg/dl (1 SD) lower serum cholesterol level was associated with a 21% (95% confidence interval (CI) = 4–42%) higher risk of total mortality and a 26% (95% CI interval = 2–56%) higher risk of cancer death. These inverse associations were stronger in current heavy drinkers (≧ 56 g ethanol per day) than in the other men. The inverse association between serum cholesterol and cancer was also significant when deaths within the first 5 years were excluded from the analysis. Whether the inverse association is explained by other factors or whether this association is causal requires further investigation.