Associations of the Glycaemic Control of Diabetes with Dementia and Physical Function in Rural-Dwelling Older Chinese Adults: A Population-Based Study

Purpose: To examine the associations of impaired fasting glucose (IFG) and glycaemic control of diabetes with dementia, global cognitive function and physical function among rural-dwelling Chinese older adults. Patients and Methods: This population-based cross-sectional study included 4583 participants (age >= 65 years, 57.3% women) living in Yanlou Town, Yanggu County, western Shandong Province, China. In 2018, data were collected through interviews, clinical examinations, neuropsychological tests, and laboratory tests. Diabetes status was defined by self-reported physician-diagnosed diabetes, current use of antidiabetic agents, and fasting blood glucose tests. Global cognitive function was assessed using the Mini-Mental State Examination. Dementia was diagnosed following DSM-IV criteria, and Alzheimer's disease (AD) was diagnosed following the National Institute on Aging-Alzheimer's Association criteria. Physical function was assessed by the Short Physical Performance Battery. Data were analysed using multiple logistic and general linear regression models. Results: IFG was found in 267 participants, and diabetes was diagnosed in 658 participants (257 with well-controlled diabetes, 401 with poorly controlled diabetes). Dementia was diagnosed in 166 participants (116 with AD), and physical functional impairment was found in 1973 participants. The multi-adjusted odds ratio (OR) of dementia associated with poorly controlled diabetes (vs without IFG or diabetes) was 2.41 (95% CI 1.52-3.84), and the OR of AD associated with poorly controlled diabetes was 2.32 (1.34-4.04). In addition, the adjusted OR of physical functional impairment was 1.40 (1.06-1.85) for well-controlled diabetes and 1.69 (1.35-2.12) for poorly controlled diabetes. However, IFG was not associated with cognitive or physical function. Conclusion: The glycaemic control status of diabetes patients was associated with cognitive impairment and physical functional impairment.