Serum high‐density lipoprotein cholesterol is a protective predictor of executive function in older patients with diabetes mellitus

AIMS/INTRODUCTION: Older people with diabetes mellitus are at high risk for cognitive impairment or dementia. The clinical predictors for cognitive decline in older people with diabetes mellitus were elucidated. MATERIALS AND METHODS: This was a secondary analysis of a vitamin B(12) intervention trial in older people with diabetes mellitus. A total of 271 non‐demented individuals were followed up at 9‐month intervals for 27 months. We explored the association between baseline clinical features with changes in cognitive measures (Clinical Dementia Rating scale, Neuropsychological Test Battery including executive function z‐scores, psychomotor speed z‐scores and memory z‐scores). RESULTS: A total of 152 participants had normal cognition (Clinical Dementia Rating 0) and 119 had cognitive impairment (Clinical Dementia Rating 0.5) at baseline. After 27 months, 41 participants had cognitive decline, 36 of whom were cognitively normal at baseline. Multiple logistic regression showed no significant clinical predictor of global cognitive decline. Higher high‐density lipoprotein cholesterol (HDL‐C) was associated with better executive performance at month 27 (β = 0.359, P < 0.001). Multilevel modeling showed that the highest tertile of HDL‐C was associated with better executive function z‐scores than the lowest tertile of HDL‐C at all time‐points. CONCLUSIONS: Among older people with diabetes mellitus, higher serum HDL‐C was associated with better executive function.