Risk of Hypercholesterolemia for Cardiovascular Disease and the Population Attributable Fraction in a 24-year Japanese Cohort Study

Aims: The population-attributable fraction (PAF) is an indicator of the disease burden. In Western countries, the PAF of hypercholesterolemia in cardiovascular disease (CVD) is the highest among that for traditional risk factors; however, data for Asian populations are limited. Methods: A 24-year cohort study was conducted among 9,209 randomly selected participants who were not taking statins. We estimated the hazard ratio (HR) after adjusting for covariates and PAF associated with the serum total cholesterol (TC) levels in relation to CVD mortality. Results: The TC level was found to be positively associated with an increased risk of CVD, coronary heart disease (CHD) and cardiac death (CHD plus heart failure), with an HR of 1.08 (95% confidence interval [CI]: 1.00-1.16), 1.33 (95% CI: 1.14-1.55) and 1.21 (95% CI: 1.08-1.35) for a 1-SD increment in the serum TC level, respectively. Similar positive associations between the TC level and both CHD and cardiac death were observed after classifying the patients by age and sex. Furthermore, the highest serum TC level (>= 6.72 mmol/L) was positively associated with CVD death, with an HR of 1.76 (95% CI: 1.25-2.47), as well as both CHD death and cardiac death. In contrast, no significant relationships were observed between the serum TC level and stroke. Meanwhile, the PAF for CVD, CHD, and cardiac deaths due to hypercholesterolemia (serum TC level >= 5.69 mmol/L, defined by the Japan Atherosclerosis Society) was 1.7%, 10.6% and 5.6%, respectively. Conclusions: The estimated PAF of CVD death due to hypercholesterolemia is moderately high, but lower than that for other risk factors, such as hypertension.