Reduced Serum Levels of Brain-Derived Neurotrophic Factor Are Related to Mild Cognitive Impairment in Chinese Patients with Type 2 Diabetes Mellitus

Background: Brain-derived neurotrophic factor (BDNF) is involved in obesity, type 2 diabetes mellitus (T2DM), and cognitive dysfunction. The present study sought to assess the role of serum levels of BDNF in the pathophysiological process of mild cognitive impairment (MCI), a preclinical phase of dementia in 715 Chinese patients with T2DM.

Methods: Cross-sectional data were obtained from 715 patients with T2DM recruited from a Chinese diabetes center. Serum levels of BDNF were measured with sandwich enzyme-linked immunosorbent assay. The influence of BDNF on MCI was examined using univariate and multivariate binary logistic regression analyses.

Results: In univariate and multivariate logistic regression analyses, for each one-unit increase of BDNF, the unadjusted and adjusted risk of MCI decreased by 9% (OR 0.91; 95% CI 0.88-0.93, p < 0.001) and 6% (0.94; 0.87-0.98, p < 0.001) respectively. In multivariate models comparing the first (Q1), second and third quartiles against the fourth quartile of BDNF, BDNF in Q1 and Q2 were associated with MCI, and increased risk of MCI by 275% (OR 3.75; 95% CI 2.38-6.03) and 155% (2.55; 1.32-4.02). These results suggested that for each 1 ng/mL increase of serum level of BDNF, the association became stronger among obese diabetic patients (OR 0.91, 95% CI 0.85-0.96; p < 0.001) versus nonobese diabetic patients (OR 0.95, 95% CI 0.86-0.98; p = 0.001).

Conclusion: The present data demonstrated that reduced serum levels of BDNF were associated with increased risk of MCI and might be useful for identifying diabetic patients at risk of dementia for early prevention strategies.