The association of hyperglycemia and kidney dysfunction with cognitive impairment in community‐dwelling older adults in Taiwan

Abstract

AbstractBackgroundDiabetes was considered one of the risk factors for dementia. However, one‐third of diabetic patients also suffer from kidney disease. It remains unclear the intercorrelation between blood sugar and kidney function that affects the occurrence of mild cognitive impairment for people with normal blood sugar levels. This study aimed to explore the relationship between hyperglycemia and kidney dysfunction (KD) on cognitive impairment in older adults.MethodThis is an eight‐year cohort study (2011‐2019). A total of 509 non‐demented older adults were recruited from the elderly health checkup program at baseline (2011‐2013) with three biannual follow‐ups. Global and domain‐specific (memory, attention, executive function, and language) cognition were assessed by the Taiwanese version of Montreal Cognitive Assessment (MoCA‐T) and a battery of neuropsychological tests, respectively. MCI was defined as a MoCA‐T score of 22 or 23. Hyperglycemia was defined as fasting blood glucose greater than 100 mg/dL. KD was defined as having either glomerular filtration rate < 60 ml/min/1.73 m2 or proteinuria. The generalized linear mixed model was utilized to examine the effects of hyperglycemia and KD on cognitive performance.ResultThe prevalence of MCI was 9.4% at baseline. Hyperglycemia [adjusted odds ratio (aOR) = 1.91] and KD (aOR = 1.98) were significantly associated with the risk of MCI over eight years after adjusting for covariates, respectively. In addition, hyperglycemia and KD were significantly associated with poor performance of logical memory (β:‐0.51 to ‐0.01), executive function (β:‐0.25 to ‐0.003), attention (β:‐0.07 to ‐0.03), and verbal fluency (β:‐0.08 to ‐0.005). Hyperglycemia and KD was associated with an increased risk of MCI participants aged less than 75 years (aOR = 2.19–2.21) and in APOE ε4 non‐carriers (aOR = 2.02–2.15).ConclusionOur finding indicated that poor glycemic control and kidney function were associated with an increased risk of MCI or poor performance of cognitive domains in older adults. Cognitive impairment may be reversible through optimal management of glycemia and kidney disease; interventions (e.g., self‐management education, dietary restriction, and sufficient physical activity, etc.) at the early stage will be helpful to prevent dementia.