Linking glycemic control and executive function in rural older adults with diabetes mellitus.

OBJECTIVES To examine the association between glycemic control and the executive functioning domain of cognition and to identify risk factors for inadequate glycemic control that may explain this relationship. DESIGN Cross-sectional study. SETTING In-person interviews conducted in participants' homes. PARTICIPANTS Ninety-five rural older African Americans, American Indians, and whites with diabetes mellitus (DM) from three counties in south-central North Carolina. MEASUREMENTS Participants underwent uniform evaluations. Glycemic control was measured using a validated method, and executive function was assessed using a previously established set of measures and scoring procedure. Information pertaining to medication for treatment of DM, knowledge of DM, and DM self-care behaviors were obtained. RESULTS In linear regression models adjusting for sex, age, education, ethnicity, duration of DM, and depressive symptoms, executive function was significantly associated with glycemic control. A 1-point higher executive function score was associated with a 0.47 lower glycosylated hemoglobin value (P=.01). The association between glycemic control and executive function became nonsignificant (P=.08) when controlling for several glycemic control risk factors, including use of DM medication and DM knowledge. CONCLUSION These results suggest that poor glycemic control is associated with impairments in performance on composite measures of executive function and that modifiable risk factors for glycemic control such as use of DM medication and DM knowledge may explain this relationship.