The necessity of strengthening glycemic and lipid metabolism management for improving brain structure and cognitive function in people with diabetes: A retrospective study based on UK Biobank

Abstract

Objective

To investigate the relation of glycemic and lipid metabolism with brain structure and cognitive function in people with diabetes, so as to improve cognitive function in these individuals.

Methods

Based on the UK Biobank, 26,394 patients, who were diagnosed with diabetes by doctors between 2006 and 2010, were included in the study. The demographic information, clinical data of glycemic and lipid metabolism and cognitive function (brain MRI and cognitive function scores) were collected. Multiple linear regression and non-restricted cubic spline analyses were used to investigate the relations of glycemic and lipid metabolism with brain structure and cognitive function.

Results

In this study, the mean age of people with diabetes (containing 39 % females) was 59.58 ± 7.21 years. Higher random blood glucose (β = −0.116, p < 0.001) and glycosylated hemoglobin (HbA1c) (β = −0.062, p = 0.051) were associated with a smaller brain volume. Higher HbA1c (β = 0.036, p < 0.001; β = 0.023, p = 0.021) was related with worse cognitive function. Further analysis showed that HbA1c < 6.5 % had a protective effect on cognitive function, and HbA1c = 6.5 %∼8.5 % and >8.5 % was unrelated and negatively related with cognitive function, respectively. Different types of lipids had varying effects on cognitive function. Higher total cholesterol (TC) (β = 0.125, p = 0.008), low density lipoprotein-cholesterol (LDL-C) (β = 0.086, p = 0.025), and ApoB (β = 0.092, p = 0.026) were associated with more significant brain structural abnormalities. Conversely, triglyceride (TG) = 0.75∼8.0 mmol/L was positively correlated with cognitive function (β = −0.036, p < 0.001; β = −0.044, p < 0.001; β = 0.058, p = 0.001), and higher ApoA (β = −0.032, p < 0.001; β = −0.033, p < 0.001; β = 0.047, p = 0.004) was associated with better cognitive function. The age-stratified analysis revealed that the impact of lipids on cognitive function was age-dependent. TC and LDL-C were related to brain structural abnormalities in the 55–60 age group, while TG had a stronger protective effect on cognitive function in older adults, particularly those aged 65–70 years.

Conclusion

In people with diabetes, higher HbA1c (>8.5 %), as well as elevated TC, LDL-C, and ApoB, are associated with worse brain structure and cognitive function. Conversely, HbA1c < 6.5 % and elevated TG within the range of 0.75∼8.0 mmol/L have a protective effect on cognitive function, and the later exhibited more evident impact in older adults. To prevent or delay the onset of dementia in people with diabetes, it may be necessary to intensify glycemic control, targeting an HbA1c level of <6.5 %. Additionally, the age-specific lipid-lowering strategies shall be considered, with more flexible triglyceride-lowering goals for elderly patients.