High-density lipoprotein cholesterol levels of very old people in the diagnosis of dementia.

Serum cholesterol fractions and triglycerides were determined in 68 female hospital patients over 90 years of age with senile dementia of Alzheimer type (AD; n = 22) with multi-infarct dementia (MID; n = 23) or without dementia (n = 23). There were no significant differences in serum HDL cholesterol levels between the three groups, but the ratio of high-density lipoprotein cholesterol (HDLC) to total cholesterol was lower in MID patients than in patients without dementia. In all three groups the concentrations of serum cholesterol, low-density lipoprotein cholesterol (LDLC) and triglycerides were relatively low and the concentration of HDLC was normal. The concentrations of serum triglycerides and very-low-density lipoprotein (VLDL) cholesterol were significantly (P less than 0.05) higher in MID patients than in AD patients. The mean levels of serum total cholesterol and LDLC were significantly (P less than 0.001) higher in MID patients than in patients without dementia. The mean levels of LDLC of AD patients were higher than in patients without dementia. The results do not support the suggestion that HDLC levels may be of diagnostic value in multi-infarct dementia.