Cholesterol and all-cause mortality in elderly people from the Honolulu Heart Program: a cohort study

Background A generally held belief is that cholesterol concentrations shoul d be kept low to lessen the risk of cardiovascular disease. However, studie s of the relation between serum cholesterol and all-cause mortality in elde rly people have shown contrasting results. To investigate these discrepanci es, we did a longitudinal assessment of changes in both lipid and serum cho lesterol concentrations over 20 years, and compared them with mortality. Methods Lipid and serum cholesterol concentrations were measured in 3572 Ja panese/American men (aged 71-93 years) as part of the Honolulu Heart Progra m. We compared changes in these concentrations over 20 years with all-case mortality using three different Cox proportional hazards models. Findings Mean cholesterol fell significantly with increasing age. Age-adjus ted mortality rates were 68.3, 48.9, 41.1, and 43.3 for the first to fourth quartiles of cholesterol concentrations, respectively. Relative risks for mortality were 0.72 (95% CI 0.60-0.87), 0.60 (0.49-0.74), and 0.65 (0.53-0. 80), in the second, third, and fourth quartiles, respectively, with quartil e 1 as reference. A Cox proportional hazard model assessed changes in chole sterol concentrations between examinations three and four. Only the group w ith low cholesterol concentration at both examinations had a significant as sociation with mortality (risk ratio 1.64, 95% CI 1.13-2.36). Interpretation We have been unable to explain our results. These data cast doubt on the scientific justification for lowering cholesterol to very low concentrations (<4.65 mmol/L) in elderly people.