Relationship between Lipid Ratio and Depression: Cross-sectional Study

This study investigated the relationship between depression and three lipid ratios: TC / HDL-C, LDL-C / HDL-C, and TG / HDL-C. The results showed a link between TG / HDL-C in men and depression. However, TC / HDL-C and LDL-C / HDL-C were not associated with depression in both men and women.

Previous studies have mainly focused on the relationship between the above lipid ratios and cardiovascular disease and insulin resistance.^{13,14,15,16 16}.. However, no previous studies have been conducted to analyze the association between these ratios and depression.Several studies have shown that the TC / HDL-C ratio is an important marker of cardiovascular risk and is primarily associated with insulin resistance.^{13,14,16 16,17 17}.. As indicated by the flamingham risk score, the risk of coronary artery disease increases with increasing TG / HDL-C ratio.¹².. In addition, the high TG / HDL-C ratio predicts the presence of small, dense LDL particles and helps diagnose the development of insulin resistance and metabolic syndrome.^{18 18}..

Previous studies have shown that low TC and LDL-C levels correlate with the development of depression.^{15,16 16,19 19,20}.. There are some plausible explanations for this relationship.First, depression reduces a patient’s appetite and lowers serum TC levels.^{19 19}..Second, activation of cytokines that interfere with cholesterol synthesis occurs in depression^{twenty one}..Third, low cholesterol levels reduce the availability of serotonin and make patients more susceptible to depression.^{16 16}..

A study conducted on 8390 people using data from the US National Health Survey showed an association between depression and cholesterol levels. Depression was diagnosed using PHQ-9 and LDL-C levels were divided into three groups: <169 mg / dL, 169–221 mg / dL, and ≥222 mg / dL. The results show that the OR of depression is 5.13 (1.74–15.09) in the low group (<169 mg / dL) and 2.28 (1.07–4.86) in the high group compared to the moderate group (169–221 mg / dL). ). A group showing a U-shaped relationship (222 mg / dL or higher).However, LDL-C and HDL-C were not associated with moderate depression.¹⁵.. Although LDL-C levels are known to be associated with depression, our study identified the relationship between cholesterol ratios and depression and demonstrated the importance of assessing lipid ratios. ..

Low cholesterol levels are associated with indicators of mental health. The association between low cholesterol levels and depression has been consistently proven in laboratory studies.In addition, studies of animals with low cholesterol levels have observed less favorable or depressive behavior.^{twenty two,twenty three}..Previous reports showed that patients who used cholesterol-lowering medications for a long time showed signs of depression.²⁰.. These findings can be explained by the previously reported significant correlation between plasma serotonin and low cholesterol levels.^{2,twenty four}..

Similar to current studies, some previous studies have shown that depression is associated with high TG and low HDL-C levels.^{twenty five,26}..A recent meta-analysis conducted to investigate whether lipid parameters differ between healthy individuals and patients with major depressive disorder in the first episode showed elevated TG and decreased HDL-C levels. Revealed to be associated with major depressive disorder in the first episode^{twenty five}.. Although TG and HDL-C levels are known to be associated with depression, our study has identified a relationship between TG / HDL-C ratios and depression, and assessment of lipid ratios is important. I made it clear that there is.

Serum lipid levels in people with depression and suicidal ideation have been analyzed in previous studies using KNHANES data, and the results show a significant association between high HDL-C and TG levels and depression. rice field.²⁶.. However, unlike this study, it was performed using 2014 KNHANES data and depression was diagnosed with a PHQ-9 score of 5 or higher.

Their association with potential mediators of lipid or lipoprotein depression and symptom heterogeneity has been investigated in previous studies.²⁷.. The results showed that melancholic features were independently associated with low HDL-C levels, whereas atypical depression was independently associated with high TC and LDL-C levels.²⁷..

The results of this study are consistent with the results of previous studies suggesting that depression is associated with metabolic syndrome. Research on the relationship between metabolic syndrome and depression has been actively conducted in recent years.^{6,28 28,29}.. There are several possible mechanisms behind this correlation between metabolic syndrome and depression. People with depression are more likely to engage in unhealthy behaviors such as smoking, drinking alcohol, unhealthy diets and lifestyles, and non-compliance with treatment than those who do not.²⁹..In addition, depression causes hypothalamic-pituitary-adrenal axis dysregulation, which may explain its association with metabolic syndrome.³⁰.. Studies have analyzed whether CRP and TG were associated with attempted suicide in patients with major depressive disorder. The results of the study showed that CRP was significantly higher in suicide attempts than in depressed patients and healthy controls who did not attempt suicide. TG levels were significantly higher in depressed patients compared to healthy controls³¹..

In this study, the PHQ-9 score was used to analyze the presence of depression. The usefulness of the PHQ-9 score as a diagnostic criterion for depression has already been tested in South Korea and other countries.^7,8,9.. However, the scores used as diagnostic criteria vary from study to study.In this study, PHQ-9 score≧Ten were diagnosed with depression. In a study by Kroenke et al.^{19 19}The 9-point cutoff had 95% high sensitivity and 84% specificity. However, 10 points that are easy to remember and easy to apply in actual clinical practice are proposed as the optimal cutoff points.³²..

The review journal reports that the association between depression and lipid profile leads to some conclusions.^{33 33}.. That is, some studies have reported that lower cholesterol levels have a negative effect on depression, while others have reported that they are not relevant. Our results cannot assume an association between lipid profile and depression, but at least TG / HDL-C can be assumed to be associated with weight gain or poor lifestyle-mediated depression. I can do it.

This study is meaningful because it is the first study to analyze the association between lipid ratios and depression in a large population. The results of this study show that TC / HDL-C and LDL-C / HDL-C are not associated with depression. However, the results of this study may have been influenced by the sample size, design, and participants in this study. Therefore, large-scale prospective clinical trials in the future are needed to validate this conclusion.

This study has some limitations. First, we used data from studies that measured depression and lipid levels only once. Depression and cholesterol levels can fluctuate over time. Therefore, failure to explain these fluctuations may have clouded the observed relevance. Second, the data used in the survey came from a large government survey, with some limitations in statistical analysis. The degree and characteristics of depression and the existence of suicidal ideation / attempt were not investigated. In addition, psychotropic drug administration and cognitive therapy have not been investigated. Third, because this was a cross-sectional study, it was difficult to determine the relationship between low cholesterol levels and depression.