ASSOCIATION BETWEEN FEATURES OF THE INSULIN-RESISTANCE SYNDROME AND ALZHEIMERS-DISEASE INDEPENDENTLY OF APOLIPOPROTEIN E4 PHENOTYPE - CROSS-SECTIONAL POPULATION-BASED STUDY

Objective: To determine the association between features of the insuli n resistance syndrome and Alzheimer's disease. Design: Cross sectional population based study. Subjects: 980 people aged 69 to 78 (349 men, 631 women). Setting: Population of Kuopio, eastern Finland. Main outco me measures: Presence of features of the insulin resistance syndrome a nd diagnosis of Alzheimer's disease by detailed neurological and neuro psychological evaluation. Results: 46 (4.7%) subjects were classified as having probable or possible Alzheimer's disease. In univariate anal yses, apolipoprotein E4 phenotype (odds ratio; 95% confidence interval 3.24: 1.77 to 5.92), age (1.16; 1.05 to 1.29), low level of education (0.82; 0.72 to 0.93), low total cholesterol concentration (0.77; 0.59 to 1.00), high systolic blood pressure (1.01; 1.00 to 1.03), high fas ting and 2 hour plasma glucose concentrations (1.11; 1.01 to 1.23 and 1.08; 1.03 to 1.13, respectively), high fasting and 2 hour insulin con centrations (1.05; 1.02 to 1.08 and 1.003; 1.00 to 1.01, respectively) , and abnormal glucose tolerance (1.86; 1.23 to 2.80) were significant ly associated with Alzheimer's disease. In multivariate analysis inclu ding apolipoprotein E4 phenotype, age, education, systolic blood press ure, total cholesterol concentration, fasting glucose concentration, a nd insulin concentration, apolipoprotein E4 phenotype, age, education, total cholesterol, and insulin were significantly associated with Alz heimer's disease. In 532 non-diabetic subjects without the e4 allele h yperinsulinaemia was associated with an increased risk for Alzheimer's disease (prevalence of disease 7.5% v 1.4% in normoinsulinaemic subje cts, P = 0.0004). In contrast, in the 228 with the e4 allele hyperinsu linaemia had no effect on the risk of disease (7.0% v 7.1%, respective ly). Conclusion: Features of the insulin resistance syndrome are assoc iated with Alzheimer's disease independently of apolipoprotein E4 phen otype.