Plasma lipid concentrations and survival in geriatric population A retrospective cohort study

Plasma lipids in mid-life are important predictors for cardiovascular events and deaths. However, the association between plasma lipid concentrations and mortality in late life is controversial. Recent studies showed that older people with extremely low total cholesterol (TC) have poor survival outcome, but this conclusion was drawn mostly from Western cohorts. Our study investigated association between plasma lipid concentrations and mortality in Taiwanese elderly population. A retrospective cohort study was conducted among the 69,824 elderly people who participated in the Taipei City Geriatric Health Examination between 2006 and 2010, with a mean follow-up of 3.6 years. The measurements of TC, high density lipoprotein (HDL) and triglycerides were obtained from the records of the participants. Low density lipoprotein (LDL) was calculated using Friedewald formula in 69,088 participants. All lipid components were categorized into quartiles. Males and females were analyzed separately using multivariate Cox proportional hazards models. The elderly with the lowest quartile of TC (<175mg/dL), HDL cholesterol (<43mg/dL) and LDL cholesterol (<100.4 mg/dL) were at higher risk of all-cause mortality. Older females with the lowest quartile of TC and LDL cholesterol had higher cardiovascular mortality. Older females with the lowest quartile of HDL had higher mortality from cardiovascular and cerebrovascular diseases. We concluded that TC, mostly attributed to LDL cholesterol, was inversely related to all-cause mortality. HDL remained to be protective against both cardiovascular and stroke mortality in older females. The target levels of plasma lipids in people older than 65 years should be different from that in younger adults.