Low levels of low-density lipoprotein cholesterol in older adults are inversely associated with the incidence of coronary artery disease and all-cause mortality: the Shizuoka Kokuho Database study.

purposeThe risk of ischemic heart disease mortality increases linearly with increasing levels of low-density lipoprotein cholesterol (LDL-C). However, low LDL-C has been suggested as associated with mortality in older adults. Thus, further studies in Asian populations with relatively lower LDL-C levels may provide insight into the LDL-C paradox. Accordingly, this study aimed to clarify the association between low LDL-C levels and poor outcomes in Japanese older adults.

methodsThis retrospective cohort study analyzed 283,289 community residents aged 65-90 years (mean age: 72.7 ± 6.0 years). Clinical characteristics, including cholesterol levels, were obtained from annual health checkup data. The incidence of cardiovascular disease, functional disability, and all-cause mortality was determined using health insurance data.

resultsThe mean follow-up time was 6.3 years. Low LDL-C levels (< 80 mg/dL) were positively associated with the incidence of functional disability (hazard ratio [HR] = 1.31) and all-cause mortality (HR = 1.57) and inversely associated with the coronary artery disease incidence (HR = 0.56) (all, P < 0.001). Similar results were observed in analyses of subpopulations by age (≥ 75 or < 75 years), sex, and lipid-lowering medication use, as well as in an analysis excluding participants with severe comorbidity at baseline. The combination of low LDL-C and low high-density lipoprotein cholesterol (< 40 mg/dL) showed a higher HR for functional disability (1.46) and all-cause mortality (1.85) (all, P < 0.001).

conclusionsLow LDL-C in older adults was a protective factor for coronary artery disease but a risk factor for functional disability and all-cause mortality.