Serum high-density lipoprotein cholesterol levels, their relationship with baseline functional and cognitive status, and their utility in predicting mortality in nonagenarians

Little is known about the role of high-density lipoprotein cholesterol (HDL-C) in oldest-old subjects. The aim of this study is to evaluate the association between HDL-C levels and physical and cognitive performance indicators in nonagenarians, and also to determine the influence of HDL-C levels on the 3-year mortality risk.

The data analyzed were taken from the NonaSantfeliu Study. Functional status was determined by the Lawton-Brody Index (LI) for instrumental activities of daily living (IADL) and the Barthel Index (BI) for basic activities (BADL). Cognition was assessed using the Spanish version of the Mini-Mental State Examination (MEC).

The sample consisted of 49 women (79%) and 13 men, aged 94.3 ± 2.6 years. Mean HDL-C levels were 60 ± 16 mg/dL, and 16 subjects (25.8%) had low HDL-C values. HDL-C levels did correlate with BI (r = 0.28, P = 0.02) and LI (r = 0.32, P = 0.01), but not with MEC (r = 0.18, P = 0.15). Normal HDL-C levels at baseline were significantly associated with higher BI scores (P < 0.006, odds ratio [OR] = 1.03, 95% confidence interval [CI] = 1.01-1.05) and a lower number of prescription drugs used (P < 0.04, OR = 0.71, 95% CI = 0.49-0.99). Baseline HDL-C levels were significantly lower among the group of nonagenarians who died within the 3 years of follow up (P = 0.02). However, after adjusting for potential confounders, the association between HDL-C and mortality lost significance.

Higher levels of HDL-C correlate with better functional status and less use of prescribed drugs in nonagenarians. However, the relationship between low HDL-C levels and long-term mortality in this population remains unclear.