Combining LDL-C and HDL-C to predict survival in late life: The InChianti study

Abstract

Background: While the relationship between total cholesterol (TC) and cardiovascular disease (CVD) progressively weakens with aging, several studies have shown that low TC is associated with increased mortality in older individuals. However, the possible additive/synergic contribution of the two most important cholesterol rich fractions (LDL-C and HDL-C) to mortality risk has not been previously investigated. Our study aimed to investigate the relationship between baseline LDL-C and HDL-C, both separately and combined, and 9-years mortality in a sample of community dwelling older individuals from the InCHIANTI study.

Methods and findings: 1044 individuals over 64 years were included. CVD and cancer mortality were defined by ICD-9 codes 390-459 and 140-239, respectively. LDL-C <130 mg/dL (3.36 mmol/L) was defined as "optimal/near optimal". Low HDL-C was defined as <40/50 mg/dL (1.03/1.29 mmol/L) in males/females, respectively. Nine-years mortality risk was calculated by multivariate Cox proportional hazards model. We found that, compared to subjects with high LDL-C and normal HDL-C (reference group), total mortality was significantly increased in subjects with optimal/near optimal LDL-C and low HDL-C (H.R.:1.58; 95%CI:1.11-2.25). As regards the specific cause of death, CVD mortality was not affected by LDL-C/HDL-C levels, while cancer mortality was significantly increased in all subjects with optimal/near optimal LDL-C (with normal HDL-C: H.R.: 2.49; with low HDL-C: H.R.: 4.52). Results were unchanged after exclusion of the first three years of follow-up, and of subjects with low TC (<160 g/dL-4.13 mmol/L).

Conclusions: Our findings suggest that, in community dwelling older individuals, the combined presence of optimal/near optimal LDL-C and low HDL-C represents a marker of increased future mortality.

Fig 1. 9 years cumulative survival curves by multivariate Cox proportional hazards model, in 1044 community dwelling older subjects, according to combined levels of plasma LDL-C and HDL-C (adjusted for age, gender, statin therapy, years of school, smoking, alcohol consumption, BMI, creatinine, uric acid, IL-6 plasma levels, serum albumin, hypertension, diabetes,CHD, stroke, CHF, weight loss >4.5 kg in the last year, and diagnosis of cancer).