Prognostic significance of serum cholesterol, lathosterol, and sitosterol in old age; a 17-year population study.

BACKGROUND. Low serum total cholesterol is frequently associated with worse survival in older people, but mechanisms of this association are poorly understood. AIMS. Characteristics of cholesterol metabolism were related to survival in a random 75 + population sample. METHODS. Serum cholesterol and lathosterol, and sitosterol were measured in random persons (n = 623) of birth cohorts (1904, 1909, and 1914) in 1990, and all persons were followed for 17 years. RESULTS. Total cholesterol declined in old age, and low cholesterol was associated with poor health and multi-morbidity. Cholesterol below 5.0 mmol/L was associated with accelerated all-cause mortality (age- and gender-adjusted hazard ratio (HR) 1.54; 95% CI 1.21-1.97; P < 0.001) and vascular mortality (HR 2.13 (1.42-3.07); P < 0.001). Lathosterol (indicating cholesterol synthesis) and sitosterol (indicating cholesterol absorption) also decreased with deteriorating health. Low lathosterol, sitosterol, and cholesterol predicted mortality additively and independently of each other. When all three sterols were high (> median) or low, the age- and gender-adjusted survival was 9.9 and 5.6 years (P < 0.001). CONCLUSION. Lower synthesis and absorption of cholesterol, and low serum cholesterol level are associated with deteriorating health and indicate impaired survival in old age.