Insulin-degrading enzyme haplotypes affect insulin levels but not dementia risk.

Background: Insulin-degrading enzyme (IDE) polymorphism is hypothesized to regulate insulin levels as well as processes involved in neuronal compromise found in dementia.

Methods: We examined the association of IDE haplotypes with dementia and insulin levels in a single well-characterized cohort of Japanese-American men born between 1900 and 1919 and followed since 1965. In 1991, a fasting insulin was obtained; dementia cases were ascertained in 1991 and 1994 in a multi-stage procedure, diagnoses were made according to international guidelines.