Serum Low-Density Lipoprotein Cholesterol Levels and Depressive Mood in Korean Adults: A Nationwide Population-Based Study

Background: The association between serum cholesterol levels and depression has been studied extensively; however, results are inconsistent. This study aimed to investigate the association between low-density lipoprotein cholesterol (LDL-C) levels and depressive symptoms among Korean adults. Methods: This cross-sectional study used data obtained from the 2007-2015 Korea National Health and Nutrition Examination Survey. In total, 40,904 adults were included in the final analysis. Participants were categorized into five groups according to their LDL-C levels, using the Korean guidelines for dyslipidemia. Symptoms of depression were evaluated using a self-reported questionnaire. Weighted logistic regression was used to examine the relationship between LDL-C levels and self-reported depressive symptoms. Results: Compared with the intermediate category, the lowest (<70 mg/dL) and highest (>= 160 mg/dL) LDL-C categories were associated with depressive symptoms, after adjusting for potential confounding factors (odds ratio [OR], 1.191; 95% confidence interval [CI], 1.008-1.409; OR, 1.241; 95% CI, 1.073-1.435, respectively). The highest LDL-C category was positively associated with depressive symptoms in those who were middle-aged, female, had a low body mass index, and taking or not taking dyslipidemia medications. Conclusion: A U-shaped association was identified between LDL-C categories and self-reported depressive symptoms. Our findings suggest that LDL-C levels that are too low or too high are associated with self-reported depressive symptoms. Further prospective studies are needed to determine the causal relationship of this association.