In subjects older than 75 years of age being in the lowest quartile of cholesterol is associated with increased mortality. - GreenMedInfo Summary

Increasing comorbidity with aging reduces the predictive power of cardiovascular risk factors. From the age of 70 onward, total cholesterol levels decrease, perhaps associated with changes in the composition of some lipoprotein fractions. In subjects older than 75 years, being in the lowest quartile of cholesterol, insulinemia or serum albumin concentrations is associated with increased mortality. Cholesterol levels below 189 mg/dL in subjects older than 75 years should be considered an early sign of unidentified comorbidity or of rapid functional decline. HDL cholesterol levels, rather than total or LDL cholesterol, were inversely associated with increased mortality from ischemic coronary disease and stroke appears to rise as HDL cholesterol levels fall, rather than total or LDL cholesterol. On the other hand, LDL concentrations below 106 mg/dL and HDL concentrations below 36 mg/dL were associated with an increased risk of death from infectious disease. Stroke incidence, in particular, ischemic stroke, is highest in subjects older than 75 years. HDL cholesterol levels above 35 mg/dL appear to have a protective effect against ischemic stroke in subjects younger than 70 years. Two interventional drug studies investigating the effects of two statins (simvastatin and pravastatin) found that in subgroups of subjects older than 75 these drugs were associated with a reduction in all-cause mortality and cardiovascular morbidity, regardless of total cholesterol levels, but had no short-term effect on cognitive function.