ETHNIC DIFFERENCES IN RISK FACTORS FOR COGNITIVE DECLINE AND DEMENTIA, IN INDIVIDUALS WITH DIABETES: RESULTS FROM THE ADVANCE TRIAL

Abstract

Objective: Ethnic differences in risk factors for dementia remain underexplored. This project will estimate ethnic differences on the associations between risk factors, and treatment effects, with cognitive decline (CD) and/or dementia, in individuals with type 2 diabetes (T2D). Design and method: This study uses the Action in Diabetes and Vascular Disease: Preterax and Diamicron Modified Release Controlled Evaluation (ADVANCE) trial of 11,140 individuals with T2D from 20 countries. Multivariable adjusted multinomial logistic regression models were used to examine the associations between baseline characteristics and odds of subsequent CD/dementia, by Asian and non-Asian ethnicity. Results: There were 4242 (38%) participants of Asian ethnicity. During 5-years (median) follow-up, 1827 participants (40% Asian) had CD/dementia (1718 with CD only (41% Asian); 21 with dementia only (19% Asian); 88 with CD and dementia (32% Asian)), and 929 (30% Asian) died without CD/dementia. Participants of Asian ethnicity had a higher odds of CD/dementia than non-Asians (odds ratio [OR] [95% confidence interval (CI)], 1.25 [1.09, 1.44]). In both Asians and non-Asians, older age, longer diabetes duration was associated with greater odds of CD/dementia; higher years at education completion and taller stature reduced the odds of CD/dementia. Higher baseline cognitive function was associated with a lower odds of CD/dementia in non-Asians 0.93 [0.90, 0.96], but not in Asians 1.01 [0.97, 1.04]. Stroke/transient ischaemic attack, retinal disease, higher body mass index, waist circumference, and current smoker (vs. never), were associated with a higher odds of CD/dementia in non-Asians but not in Asians. Moderate/vigorous physical activity vs none/mild was associated with a higher odds of CD/dementia in Asians 1.26 [1.10, 1.45] but a lower odds in non-Asians 0.81 [0.68, 0.97]. There was no evidence that intensive glucose control (vs. standard control) or blood pressure lowering (vs. placebo) conferred a lower risk of CD/dementia, overall nor by ethnicity. Conclusions: People of Asian ethnicity had a 25% higher risk of CD/dementia than non-Asians in this study. There were some differential effects of risk factors for CD/dementia by ethnicity. More data from Asian populations are required to verify ethnic differences and the mechanisms that underlie these differences.