The curvilinear relationship between hepatic steatosis index and depression: Findings from the NHANES.

Background: Previous studies have established a link between depression and fatty liver disease, yet the relationship with the Hepatic Steatosis Index (HSI) has not been thoroughly investigated. This study aims to explore the potential association between HSI and depression.

Methods: We investigated the association between HSI and depression (PHQ-9 depression score ≥ 10) using a weighted multiple logistic regression model and stratified analysis. Non-linear associations were explored using fitted smooth curves. A recursive method was employed to identify inflection points and construct a two-part linear regression model. Subgroup analysis was conducted to examine the differences in this association within various subgroups.

Results: Our study included 43,888 participants. The mean HSI was 37.06, with a range of 0 to 135.92. Multivariate logistic regression analysis, showed that the OR for the association between HSI and depression was 1.02 (95 % CI: 1.01, 1.02). This means that there is 2 % increase likelihood of depression for each unit increase in HSI. A nonlinear relationship was observed, with an inflection point identified at an HSI value of 29.72, indicating a negative correlation below the threshold and a positive correlation above it. Stratified analysis indicated that, aside from participants with BMI ≥ 30 who displayed a linear positive association, HSI showed a curvilinear association with depression in other groups are similar to that observed in the overall sample. In subgroup analyses, statistically significant interactions were observed between HSI and depression within groups defined by education level and smoking status.

Conclusion: We found a curvilinear relationship between HSI and Depression.