Diabetes and function in different cognitive systems in older individuals without dementia.
OBJECTIVE
To examine the relation of type 2 diabetes to the level of function in five different cognitive systems in older individuals without dementia.


METHODS
Participants were 882 older men and women without dementia participating in the Rush Memory and Aging Project, a longitudinal clinical-pathological study of aging and dementia. They underwent uniform evaluations, which included clinical classification of dementia, and detailed cognitive function testing from which previously established summary measures of episodic memory, semantic memory, working memory, perceptual speed, visuospatial ability, and global cognition were derived. Diabetes was identified by history and direct medication inspection.


RESULTS
Diabetes was present in 116 (13%) participants. In separate linear regression models controlling for age, sex, and education, diabetes was associated with lower levels of semantic memory (P < 0.001) and perceptual speed (P = 0.005), but not with episodic memory, working memory, or visuospatial ability or with a measure of global cognition. The associations of diabetes with cognition were reduced when controlling for several vascular variables, and the associations were substantially stronger in current smokers than in individuals who never smoked or formerly smoked.


CONCLUSIONS
These results suggest that type 2 diabetes is associated with cognitive impairment, especially in semantic memory and perceptual speed and that these effects may be modified by smoking status.
Arvanitakis
Zoe
Z
Rush Alzheimer's Disease Center, Rush University Medical Center, 600 South Paulina St., Suite 1020, Chicago, IL 60612, USA. zoe_arvanitakis@rush.edu
Wilson
Robert Smith
RS
Li
Yan
Y
Aggarwal
Neelum Thanik
NT
Bennett
David Alan
DA
D000368:Aged; D000369:Aged, 80 and over; D003071:Cognition; D003430:Cross-Sectional Studies; D003924:Diabetes Mellitus, Type 2 / Q000523:psychology*; D005260:Female; D006801:Humans; D008297:Male; D008568:Memory; D016571:Neural Networks, Computer; D012907:Smoking; D013037:Spatial Behavior; D014792:Visual Acuity