Serum total cholesterol levels and all-cause mortality in a home-dwelling elderly population: a six-year follow-up

Objective. To investigate the association between serum total cholesterol and all-cause mortality in elderly individuals aged >= 75 years. Design. A prospective cohort study with a six-year follow-up. Setting and subjects. A random sample (n = 700) of all persons aged >= 75 years living in Kuopio, Finland. After exclusion of participants living in institutional care and participants using lipid-modifying agents or missing data on blood pressure and cholesterol levels, the final study population consisted of 490 home-dwelling elderly persons with clinical examination. We used the Cox proportional hazard model and the propensity score (PS) method. Main outcome measure. All-cause mortality. Results. In an age-and sex-adjusted analysis, participants with S-TC >= 6mmol/l had the lowest risk of death (hazard ratio, HR = 0.48, 95% CI 0.33-0.70) compared with those with S-TC < 5 mmol/l. HR of death for a 1 mmol increase in S-TC was 0.78. In multivariate analyses, the HR of death for a 1 mmol increase in S-TC was 0.82 and using S-TC < 5 mmol/l as a reference, the HR of death for S-TC >= 6 mmol/l was 0.59 (95% CI 0.39-0.89) and for S-TC 5.0-5.9 mmol/l, the HR was 0.62 (95% CI 0.42-0.93). In a PS-adjusted model using S-TC < 5 mmol/l as a reference, the HR of death for S-TC >= 6 mmol/l was 0.42 (95% CI 0.28-0.62) and for S-TC 5.0-5.9 mmol/l, the HR was 0.57 (95% CI 0.38-0.84). Conclusions. Participants with low serum total cholesterol seem to have a lower survival rate than participants with an elevated cholesterol level, irrespective of concomitant diseases or health status.