Association between BDNF Polymorphism and Depressive Symptoms in Patients Newly Diagnosed with Type 2 Diabetes Mellitus

Purpose Little is known about the relationship between brain-derived neurotrophic factor (BDNF) gene polymorphisms and psychiatric symptoms in diabetes patients. We investigated the effects of BDNF Val/66/Met polymorphism, glucose status, psychological susceptibility, and resilience on anxiety and depression symptoms in patients newly diagnosed with type 2 diabetes mellitus (T2DM). Materials and Methods We examined biochemical factors and BDNF polymorphism in 89 patients who were newly diagnosed with T2DM. Psychiatric symptoms were investigated with the Hospital Anxiety and Depression Scale (HADS), and the Connor-Davidson Resilience Scale (CD-RISC) and Impact of Event Scale (IES) were used to assess psychological resilience and susceptibility to psychological distress, respectively. Logistic regression analyses were conducted to investigate factors associated with psychiatric symptoms. Results We determined that 62 patients (70%) were Met-carriers. No significant differences were found between the Val/Val homozygous and Met-carrier groups regarding age, sex, body mass index, and clinical factors related to glycemic control and lipid profiles. HADS-anxiety and HADS-depression scores and IES factor scores were higher in the Met-carrier than the Val/Val homozygous group. Hemoglobin A1c (HbA1c) level was significantly inversely correlated with the severity of depressive symptoms. Resilience factors showed significant inverse correlations, and IES factors showed positive correlations with depressive symptom severity. In the logistic regression analysis model, depressive symptoms were significantly associated with HbA1c and BDNF polymorphism, whereas only the hyperarousal factor of the IES scale was associated with anxiety. Conclusion Depressive symptoms are associated with the presence of the Met-carriers and lower HbA1c in patients newly diagnosed with T2DM.