Serum lipid levels in depression and suicidality: The Korea National Health and Nutrition Examination Survey (KNHANES) 2014

Background: The level of serum lipids has been reported to be associated with depression and suicidality, but the exact relationship between these factors remains controversial. The aim of this study was to investigate the association between lipid levels and depression with suicidality in large sample. Methods: We examined the association between serum lipid levels and the existence of mild depression measured using Patient Health Questionnaire 9 (PHQ-9) in a national sample of Korean. The data of 2055 men and 2894 women who participated in the 6th Korea National Health and Nutrition Examination Survey (KNHNES VI) were used. The serum concentration of high-density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C), triglyceride, and total cholesterol were dichotomized and complex samples logistic regression was employed in the analysis. Results: There was a significant association between high level of HDL-C (>= 40 mg/dl) and depression in adult men, and between high level of triglyceride (>= 150 mg/dl) and depression in adult women. In middle-aged adults 45-64 year), increased level of depression and suicidality was related to high level of triglyceride, respectively. (depression, OR=2.20 (95% CI 1.26-3.85); suicidality, OR=3.66 (95% CI 1.41-9.51). Furthermore, we found that the increased number of abnormal lipids level was significantly associated with the increased prevalence of depression in women (OR =1.34, 95% CI =1.12-1.60) and in middle-aged adults (OR=1.43, 95% CI =1.12-1.82). Limitations: As this study had a cross-sectional design, it was hard to investigate causation between lipid levels and depression, and the assessment of suicidality needs more validation. Conclusion: Our findings support a significant association between the high level of HDL-C, triglyceride and depression in large sample data. Triglyceride was highly associated with suicidality in younger and middle-aged adults, but not in elderly adults. Further assessment could delineate relationship between serum lipid levels and depression with suicidality in other ethnic groups.