Long-term change in physiological markers and cognitive performance in type 2 diabetes: the Look AHEAD Study.

CONTEXT The effects of physiological improvements on cognitive function among persons with type 2 diabetes mellitus (T2DM) are not fully understood. OBJECTIVE To determine whether improvements in physiological markers (body weight, blood sugar control, and physical activity) during intensive lifestyle intervention (ILI) are associated with enhancements in cognitive function in older adults with T2DM. DESIGN Multi-site randomized controlled trial. SETTING Academic research centers. PATIENTS OR OTHER PARTICIPANTS Participants were aged 45-76 years with T2DM. INTERVENTION The Action for Health in Diabetes (Look AHEAD) study, a randomized controlled clinical trial of ILI. MAIN OUTCOME MEASURE Two to three cognitive assessments were collected from 1089 participants, the first and last occurring a mean [standard deviation] of 8.6 [1.0] and 11.5 [.7] years after enrollment. RESULTS Greater improvements in blood sugar control were associated with better cognitive scores (fasting glucose and Rey Auditory Verbal Learning Test, AVLT: p=.0148, fasting glucose and Digit Symbol Coding, DSC: p=.0360, HbA1C and DSC: p=.0477) , but weight loss had mixed associations with cognitive scores (greater BMI reduction and worse AVLT overall: p=.0053; greater BMI reduction and better DSC scores among those overweight but not obese at baseline: p=.010). Associations were strongest among those who were overweight (not obese) at baseline; and among those with a history of cardiovascular disease (CVD) at baseline. CONCLUSIONS Improvements in glycemic control, but not necessarily weight status, during ILI may be associated with better subsequent cognitive performance. These associations may differ by adiposity and CVD history.