Glycemic control predicts the development of dementia in type 2 diabetes

Abstract

Aim: Epidemiological and biological evidence support a link between type 2 diabetes mellitus and cognitive decline. Our study aims to determine the incidence and risk factors associated with the development of dementia in a Chinese population. Methods: A retrospective cohort of 7111 Chinese type 2 diabetic subjects, aged 70 years or above, with no known dementia, and being followed up under ambulatory care clinics in the Hong Kong West Cluster, were included. All cases of incident dementia were identified and based on the commencement of anti-dementia pharmacotherapy during follow-up. Demographics, co-morbidities, metabolic parameters, and the use of other concomitant medications at baseline were considered as possible confounders. Results: After a median follow-up of 5 years, 198 (2.8%) subjects were commenced on anti-dementia pharmacotherapy. Compared to controls, subjects with incident dementia were older (78.9±4.9 years vs. 77.2±5.3; p<0.001), with a greater proportion of female gender (70.7% vs. 56.9; p<0.001), and had higher hemoglobin A1c levels (7.37±1.84% vs. 6.85±2.02; p=0.004). Notably, there was no significant difference in their baseline lipid profiles, the prevalence of cardiovascular co-morbidities at baseline, and the use of other concomitant medications, including anti-diabetic drugs, anti-hypertensive drugs and lipid lowering agents. On multivariable logistic regression analysis, age (Odds ratio [OR] 1.89, 95% confidence interval = 1.21-2.93; p=0.005), female gender (OR 1.14, 95% confidence interval = 1.03-1.26; p=0.015) and their baseline hemoglobin A1c levels (OR 1.06, 95% confidence interval = 1.01-1.10; p=0.009) were independent predictors for the development of dementia. Conclusions: A1c, other than non-modifiable risk factors like age and gender, is a modifiable risk factor that is associated with incident dementia in our Chinese cohort over 5 years, highlighting the need of good glycaemic control in preventing the development of dementia.