Low-density lipoprotein cholesterol and mortality in older people.

OBJECTIVES

To investigate the role of low-density lipoprotein cholesterol (LDL-C) as a predictor of mortality in elderly subjects.

DESIGN

Population-based prospective cohort study.

SETTING

Two communities in northern Italy.

PARTICIPANTS

Three thousand one hundred twenty Caucasian subjects aged 65 and older recruited in for the Cardiovascular Study in the Elderly and followed up for 12 years.

MEASUREMENTS

Anthropometric measures: fasting plasma total cholesterol, triglyceride, high-density lipoprotein cholesterol, LDL-C, glucose, creatinine, and body mass index. Clinical measures: medical assessment, diabetes mellitus, hypertension, stroke, coronary disease, heart failure, and smoking and drinking habits. Vital status measures: death certificates from the Registry Office and causes of death according to the International Classification of Diseases. After plotting mortality rates using quartiles of LDL-C, relative hazard rates (RHRs) were calculated using multivariate Cox regression analyses. When the trend was nonlinear, the RHRs were further calculated for the 25th, 50th, and 75th percentiles of the distribution to confirm curvilinearity.

RESULTS

The distribution of risk of total mortality in women and of fatal heart failure in all subjects was curvilinear (non J-shaped), decreasing nonlinearly with LDL-C. For total mortality in men and cardiovascular mortality in both sexes, the relationship with LDL-C was J-shaped. The risk of fatal myocardial infarction was J-shaped in men, whereas it increased linearly with higher LDL-C in women. In both sexes, the association between stroke mortality and LDL-C was not significant.

CONCLUSION

This study adds to the uncertainty of the role of elevated levels of LDL-C as a risk factor for mortality in old people.