Adiposity predicts cognitive decline in older persons with diabetes: a 2-year follow-up.

BACKGROUND: The mechanisms related to cognitive impairment in older persons with Type 2 diabetes (DM) remains unclear. We tested if adiposity parameters and body fat distribution could predict cognitive decline in older persons with DM vs. normal glucose tolerance (NGT). METHODOLOGY: 693 older persons with no dementia were enrolled: 253 with DM in good metabolic control; 440 with NGT (age range:65-85 years). Longitudinal study comparing DM and NGT individuals according to the association of baseline adiposity parameters (body mass index (BMI), waist-hip-ratio (WHR), waist circumference (WC) and total body fat mass) to cognitive change (Mini Mental State Examination (MMSE), a composite score of executive and attention functioning (CCS) over time. FINDINGS: At baseline, in DM participants, MMSE correlated with WHR (beta = -0.240; p = 0.043), WC (beta = -0.264; p = 0.041) while CCS correlated with WHR (beta = -0.238; p = 0.041), WC (beta = -0.326; p = 0.013) after adjusting for confounders. In NGT subjects, no significant correlations were found among any adiposity parameters and MMSE, while CCS was associated with WHR (beta = -0.194; p = 0.036) and WC (beta = -0.210; p = 0.024). Participants with DM in the 3(rd) tertile of total fat mass showed the greatest decline in cognitive performance compared to those in 1(st) tertile (tests for trend: MMSE(p = 0.007), CCS(p = 0.003)). Logistic regression models showed that 3(rd) vs. 1(st) tertile of total fat mass, WHR, and WC predicted an almost two-fold decline in cognitive function in DM subjects at 2(nd) yr (OR 1.68, 95%IC 1.08-3.52). CONCLUSIONS: Total fat mass and central adiposity predict an increased risk for cognitive decline in older person with DM.