Serum lipids and their association with mortality in the elderly: a prospective cohort study

Abstract

To determine whether high levels of serum total cholesterol and low levels of high-density lipoprotein cholesterol (HDLc) are associated with increased mortality in the elderly. Prospective cohort study of 1032 non-institutionalized people aged 70 in the city of Turku, Southern Finland. The cohort population was recruited as part of a larger longitudinal aging study, the Turku Elderly Study. Fasting serum levels of total cholesterol, HDL-c and triglycerides were measured, and the amount of low-density lipoprotein cholesterol was calculated at baseline. The cohort was followed for mortality for 12 years, and the causes of death were recorded and further classified into cardiovascular and other causes of death. The hazard ratios of dying for subjects in various cholesterol quartiles were computed by the Cox proportional hazards model, adjusting for cardiovascular risk factors and pre-existing medical conditions. Low levels of serum total cholesterol and HDL-c were associated with a greater risk of death over a follow-up of 12 years. After adjustment for several cardiovascular risk factors, the association between total cholesterol and survival changed. All-cause mortality seemed to be highest in the highest quartile of total cholesterol and nearly as high in the lowest quartile of total cholesterol, suggesting a U-shaped connection, but the differences were not statistically significant. However, cardiovascular mortality was significantly lowest in the lowest quartile of total cholesterol and significantly highest in the lowest quartile of HDL-c. High levels of serum total cholesterol and particularly low levels of HDL-c seem to be risk factors for cardiovascular mortality even in the elderly population.