Diabetes and cognitive function in a middle-aged cohort: findings from the Whitehall II study.
OBJECTIVE
To compare cognitive performance in those with diabetes, impaired glucose tolerance, and normoglycemia in a middle-aged cohort.


METHODS
The authors analyzed data from a prospective occupational cohort study begun in 1985-1988 (baseline). Diabetes was classified from oral glucose tolerance tests that were performed in 1992-1993 (phase 3) and 1997-1999 (phase 5) and self reported diagnosis of diabetes from questionnaire at baseline, 1989 (phase 2), phase 3, 1995 (phase 4), and phase 5 of the study. A battery of cognitive tests (memory, Alice Heim 4 [AH 4], Mill Hill vocabulary test, phonemic fluency, and categorical fluency) were measured at phase 5 in 4,020 men and 1,627 women with a mean age of 56 and free of symptoms of stroke.


RESULTS
At phase 5, a total of 208 (5%) men and 101 (6%) women had diabetes while 405 (10%) men and 192 (12%) women had impaired glucose tolerance. Those with diabetes were at increased risk of poor performance in AH 4 compared to those without (men: OR, 2.45; 95% CI, 1.77 to 3.38; women: OR, 1.83; 95% CI, 1.09 to 3.08). These effects were independent of age, social position, vascular problems, and health-related behaviors. Impaired glucose tolerance was not related to any measure of cognition.


CONCLUSIONS
Type 2 diabetes is associated with poor performance in some aspects of cognition in middle-aged men and women.
Kumari
Meena
M
Department of Epidemiology and Public Health, International Centre for Health and Society, London, UK. M.Kumari@ucl.ac.uk
Marmot
Michael
M
D000368:Aged; D000428:Alcohol Drinking / Q000453:epidemiology; D001921:Brain / Q000378:metabolism / Q000503:physiopathology; D002318:Cardiovascular Diseases / Q000453:epidemiology; D015984:Causality; D003072:Cognition Disorders / Q000175:diagnosis / Q000453:epidemiology* / Q000523:psychology; D015331:Cohort Studies; D015897:Comorbidity; D048909:Diabetes Complications / Q000453:epidemiology* / Q000378:metabolism / Q000503:physiopathology; D003924:Diabetes Mellitus, Type 2 / Q000175:diagnosis / Q000453:epidemiology*; D005260:Female; D006801:Humans; D006943:Hyperglycemia / Q000150:complications / Q000503:physiopathology; D006946:Hyperinsulinism / Q000150:complications / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D010809:Physical Fitness / Q000502:physiology / Q000523:psychology; D011446:Prospective Studies; D012737:Sex Factors; D011795:Surveys and Questionnaires