Type 2 diabetes and cognitive function in community-dwelling elderly women

OBJECTIVE - To examine the relationship of type 2 diabetes to cognitive fun ction in community-dwelling women. RESEARCH DESIGN AND METHODS - From 1995 to 1999, we administered four rests of cognitive function (Telephone Interview of Cognitive Status [TICS], imm ediate and delayed recall of the East Boston Memory Test, and verbal fluenc y) by telephone to 2,374 participants (70-78 years of age) of the Nurses' H ealth Study. Information on diabetes was collected biennially beginning in 1976; 82 women reported type 2 diabetes before their cognitive testing. We used linear and logistic regression models to calculate multivariate-adjust ed mean differences in scores and relative risks of a low score (bottom 10% of the distribution) for diabetic women compared with nondiabetic women. RESULTS - After multivariate adjustment, women with type 2 diabetes scored lower on all our cognitive tests than women without diabetes. On the genera l rest of cognition (TICS), the mean difference in score between women with and without diabetes was - 0.60 (95% CL - 1.18 to -0.03, P = 0.04) and the relative risk of a low TICS score was 1.98 (95% CI 1.06 to 3.69). On a glo bal score combining results of the four tests, the mean for diabetic women was lower than that among women without diabetes (adjusted difference in sc ore -0.73, 95% CI -1.42 to -0.04, P = 0.04), and the relative risk of a low global score was 2.16 (95% CI 1.10 to 4.21). Relative to women without dia betes, longer duration of diabetes was associated with lower scores. Few di abetic women were pharmacologically treated (n = 31), but those taking medi cation had scores similar to those of women without diabetes. CONCLUSIONS - In these women, diabetes was related to lower scores on sever al aspects of cognitive function. Longer duration of diabetes may be associ ated with poorer scares, but hypoglycemic therapy may ameliorate scores.