Aims: Given that diabetes is associated with cognitive impairment and dementia in later life, we aimed to investigate the relationship between glycated haemoglobin (HbA 1c), diabetes and domain-specific neuropsychological performance in older adults. Methods: Cross-sectional cohort study using data from the Trinity-Ulster-Department of Agriculture (TUDA) study. Participants underwent detailed cognitive and neuropsychological assessment using the Mini-Mental State Examination (MMSE), Frontal Assessment Battery (FAB) and Repeatable Assessment for Neuropsychological Status (RBANS). Linear regression was used to assess associations between HbA 1c, diabetes status and neuropsychological performance, with adjustment for important clinical covariates. Results: Of 4938 older adults (74.1 ± 8.3 years; 66.9% female), 16.3% (n = 803) had diabetes (HbA 1c ≥ 6.5%; 48 mmol/mol), with prediabetes (HbA 1c ≥ 5.7%–6.4%; 39–47 mmol/mol) present in 28.3% (n = 1395). Increasing HbA 1c concentration was associated with poorer overall performance on the FAB [β: −0.01 (−0.02, −0.00); p = 0.04 per % increase] and RBANS [β = −0.66 (−1.19, −0.13); p = 0.02 per % increase]. Increasing HbA 1c was also associated with poorer performance on immediate memory, visuo-spatial, language and attention RBANS domains. Diabetes was associated poorer performance on neuropsychological tests of immediate memory, language, visual-spatial and attention. Conclusions: Both increasing HbA 1c and the presence of diabetes were associated with poorer cognitive and domain-specific performance in older adults. HbA 1c, and not just diabetes status per se, may represent an important target in the promotion of optimal brain health in older adults.
Bibliographical noteFunding Information:
The Trinity‐Ulster‐Department of Agriculture (TUDA) study was supported by government funding from the Irish Department of Agriculture, Food and the Marine and Health Research Board (under the Food Institutional Research Measure to H.M) and from the Northern Ireland Department for Employment and Learning (under its Strengthening the All‐Island Research Base initiative). The authors wish to acknowledge all of the TUDA study participants. Dr Dyer additionally wishes to acknowledge the support of the Wellcome‐HRB Clinical Research Facility at St James’s Hospital.
© 2021 The Authors. Diabetic Medicine published by John Wiley & Sons Ltd on behalf of Diabetes UK.
- glycated haemoglobin