SERUM TOTAL CHOLESTEROL, APOLIPOPROTEIN-E EPSILON-4 ALLELE, AND ALZHEIMERS-DISEASE

The epsilon 4 allele of the apolipoprotein E (apoE) is associated with Alzheimer's disease (AD) and also with elevated serum total cholester ol and low-density lipoprotein levels, However, the interrelationships between apoE genotype, plasma cholesterol levels and AD risk have bee n studied very little. We examined the possible role of serum total ch olesterol in the pathogenesis of AD in a population-based sample of 44 4 men, aged 70-89 years, who were survivors of the Finnish cohorts of the Seven Countries Study, Previous high serum cholesterol level (mean level greater than or equal to 6.5 mmol/l) was a significant predicto r of the prevalence of AD (odds ratio = 3.1, 95% confidence interval = 1.2, 8.5) after controlling for age and the presence of apoE epsilon 4 allele. In men who subsequently developed AD the cholesterol level d ecreased before the clinical manifestations of AD. We conclude that hi gh serum total cholesterol may be an independent risk factor for AD an d some of the effect of the apoE epsilon 4 allele on risk of AD might be mediated through high serum cholesterol.