TYPE-II DIABETES AND COGNITIVE FUNCTION - A POPULATION-BASED STUDY OFNATIVE-AMERICANS

OBJECTIVE - To explore the relationship between type II diabetes and c ognitive function in older Native Americans and to assess the effects of other selected risk factors for cognitive dysfunction on this relat ionship. RESEARCH DESIGN AND METHODS - Cognitive function was assessed in 80 diabetic and 81 nondiabetic Native Americans who were 45-76 yea rs of age in a cross-sectional population-based sub-study of the Stron g Heart Study. Thirteen cognitive function tests were administered dur ing a personal interview. Information about six other risk factors for cognitive dysfunction, including depressive symptoms, physical functi on, alcoholism, current alcohol use, hypertension, and myocardial infa rction, was ascertained from interviews and from abstraction of medica l records. RESULTS - Diabetes was associated with impairment on only t wo tests of cognitive function: verbal fluency (P = 0.004) and similar ities (P = 0.010). Depressive symptoms were related to verbal fluency (P = 0.004), but did not explain the diabetes-related difference in pe rformance. The effects of hypertension, depressive symptoms, and curre nt alcohol use explained the diabetes-related performance difference o n similarities. Cognitive function was not related to metabolic contro l (HbA(1c) level). CONCLUSIONS - We found little evidence that type II diabetes in this population of Native Americans is associated with de crement in cognitive function. Some of the cognitive impairment previo usly attributed to diabetes may be related, at least in part, to the i nfluence of other risk factors. This should be considered in the desig n of future studies in other populations.