Relationship between serum apolipoprotein B levels and depressive symptoms in elderly Chinese patients with mild cognitive impairment: A large-scale cross-sectional and five-year follow-up study

Background: Patients with mild cognitive impairment (MCI) often have depressive symptoms. The purpose of this study was to investigate the effects of depressive symptoms on lipid metabolism and future cognitive function in patients with MCI. Methods: A total of 1014 patients with MCI were included. Their demographic data, clinical data, and lipid parameters were collected. Meanwhile, they also completed a series of scale assessments, including Geriatric depression scale (GDS), Ability of Daily Living (ADL), Montreal cognitive assessment (MoCA) and Block Design Test (BDT). Then these patients were also followed for five years. Results: Patients with depressive symptoms had lower serum apolipoprotein B (ApoB) levels, lower BDT scores and higher ADL scale scores. Correlation analysis showed that GDS was significantly associated with BDT and ADL. Moreover, logistic regression analysis found that ApoB was associated with depressive symptoms. Cox regression analysis showed that only baseline MoCA scores could predict the risk of future MCI transition to dementia. Conclusions: Our results suggest low serum ApoB levels may be associated with depressive symptoms in patients with MCI. However, depressive mood or lipids alone may not predict the risk of MCI transition to dementia.