Late life insulin resistance and Alzheimer's disease and dementia: The Kuakini Honolulu heart program.

INTRODUCTION: Recent findings outline negative effects of brain insulin signaling on memory due to hyperinsulinemia. We investigated the association between insulin resistance (IR) with AD and dementia. METHODS: Later life Japanese men (N = 1544, mean age = 79.9 years) with normal cognitive function were followed from exam 4 to 5 of the Kuakini Honolulu Asia Aging Study. Subjects underwent physical exams, blood draws, and neuropsychological testing. IR status was determined at exam 4 using the McAuley and HOMA indices. Subjects with prevalent diabetes and dementia were excluded. Incident dementia and AD cases were determined at exam 5. RESULTS: IR was associated with decreased odds of AD and dementia using both IR indices. Carriers of the APOE ε4 allele had 15% increased odds of AD and dementia. DISCUSSION: Our findings provide insight regarding possible inverse relationship between IR and AD in elderly Japanese men, and support biologic studies showing short term hyperinsulinemia improves memory and cognitive function.