Good cholesterol tied to better memory, executive function in older diabetic patients

High levels of high-density lipoprotein (HDL) cholesterol appear to correlate with better changes in memory and executive function in older adults with diabetes mellitus, according to a recent China study.

Researchers conducted a follow-up analysis of a previous randomized, placebo-controlled trial. A total of 145 diabetes mellitus patients who had received a 27-month course of vitamin B12 supplementation were assessed after 72 months using cognitive tests, such as the Neuropsychological Test Battery (NTB) and Clinical Dementia Rating scale. A subset of patients who had brain magnetic resonance imaging scans at various time points was also evaluated.

General linear regression analysis showed that HDL cholesterol levels were significantly and positively associated with NTB results, particularly with the executive function domain at months 18 (β, 0.330; p=0.014), 27 (β, 0.444; p<0.001), 36 (β, 0.496; p=0.001), and 45 (β, 323; p=0.039). At the final follow-up at month 72, however, such an interaction had been weakened substantially (β, 0.009; p=0.966).

In addition, HDL cholesterol likewise correlated with better memory scores at months 9 (β, 0.283; p=0.042), 27 (β, 0.384; p=0.012), and 36 (β, 0.374; p=0.025), as well as with psychomotor speed at months 36 (β, 0.737; p=0.002) and 45 (β, 0.609; p=0.018).

Of note, these impacts of HDL cholesterol were independent of its cholesterol efflux capacity (CEC), which did not show any significant interaction with any cognitive outcome measure at any time point.

“We concluded that higher serum HDL cholesterol was associated with more favourable changes in executive and memory function in older people with diabetes mellitus,” the researchers said.

“However, HDL function, as estimated by adenosine-binding cassette transporter A1-mediated CEC, was not significantly associated with cognitive function or structural brain changes in older people with diabetes mellitus,” they added.