The Association of Late-Life Diabetes Status and Hyperglycemia With Incident Mild Cognitive Impairment and Dementia: The ARIC Study

Abstract

We sought to examine associations in older adults among diabetes, glycemic control, diabetes duration, and biomarkers of hyperglycemia with incident mild cognitive impairment (MCI) and incident dementia. RESEARCH DESIGN AND METHODS We conducted a prospective analysis of 5,099 participants from the Atherosclerosis Risk in Communities (ARIC) Study who attended the fifth (2011-2013) exam. Cognitive status was assessed during follow-up via telephone calls, death certificate codes, surveillance, and a follow-up examination (2016-2017). We defined incident cognitive impairment as incident MCI or incident dementia in persons dementiafree at the index examination; we also examined each outcome separately. Diabetes was defined using self-report, medications, or HbA 1c ‡6.5%; poor glycemic control in persons with diabetes was defined as HbA 1c ‡7%. We examined the following biomarkers of hyperglycemia: HbA 1c , fructosamine, glycated albumin, and 1,5-anhydroglucitol. RESULTS Mean age at baseline was 76 years, 59% were female, and 21% were black. Diabetes (hazard ratio [HR] 1.14 [95% CI 1.00, 1.31]), poor glycemic control in persons with diabetes (HR 1.31 [95% CI 1.05, 1.63]), and longer diabetes duration (‡5 vs. <5 years; HR 1.59 [95% CI 1.23, 2.07]) were significantly associated with incident cognitive impairment. We found a J-shaped association between HbA 1c and incident dementia. Glycated albumin and fructosamine were also associated with incident dementia, independently of HbA 1c. HbA 1c and fructosamine were also associated with incident MCI. CONCLUSIONS Diabetes status, poor glycemic control, and longer diabetes duration were associated with worse cognitive outcomes over a median follow-up of 5 years. The U.S. population is rapidly aging. In 2012, 14% of the U.S. population was 65 years and older, and this proportion is expected to climb to .20% by 2030, representing .70 million people (1). Among older adults, the prevalence of diabetes is 22%, and the prevalence of prediabetes is 24% (2). Studies have documented that persons with

Factors associated with poor glycaemic control in type 2 diabetic elderly patients with mild cognitive impairment

“…This study shows that 83.9% type 2 diabetic elderly patients with MCI have poor glycaemic control. This observation is novel in the Polish population, and the result is consistent with other studies which presented high associations between poor glycaemic control and cognitive impairment in diabetics worldwide [21,22,23]. Data from cross-sectional studies agree that a chronic hyperglycaemic state causes cognitive function deficit.…”

Risk of mini-mental state examination (MMSE) decline in the elderly with type 2 diabetes: a Chinese community-based cohort study

“…This suggests that poor glycemic control is an important factor related to cognitive decline. But the studies using high HbA1c levels to measure this have shown some conflicting results [ 4 , 14 – 17 ]. Therefore, at the moment, the association between HbA1c and cognitive decline in patients with T2DM remains unclear.…”

Mechanisms of diabetes and dementia

“…An increase of HbA 1c by 1mmol/mol was associated with a significantly increased rate of decline in cognitive scores and executive function . More recent data from the ARIC study (Atherosclerosis Risk in Communities) found an increased incidence of mild cognitive impairment and dementia in patients with longer diabetes duration (over five years) and poor glycaemic control, further adding support to the hyperglycaemia theory …”