# Neutrophil-to-high-density lipoprotein cholesterol ratio (NHR) mediates the relationship between abdominal fat index and depression in a cross-sectional study

## TL;DR

This study finds that abdominal fat is linked to depression, with the neutrophil-to-HDL cholesterol ratio partially explaining this connection.

## Contribution

The study introduces NHR as a potential mediator linking abdominal fat and depression.

## Key findings

- Subcutaneous and visceral adipose tissue indices are positively correlated with depression.
- NHR partially mediates the relationship between abdominal fat and depression.
- Visceral fat shows a linear link to depression, while subcutaneous fat shows a nonlinear link.

## Abstract

Investigate the link between abdominal adipose tissue index and depression, and assess the mediating effect of the neutrophil-to-high-density lipoprotein cholesterol ratio (NHR) in this association.

Participants were chosen using datasets from the National Health and Nutrition Examination Survey (NHANES). To assess the associations between abdominal adipose tissue index and depression, a weighted logistic regression analysis was conducted. Adjusted logistic regression models and restricted cubic splines were used to examine the relationship between subcutaneous and visceral adipose tissue index and depression, with subgroup analyses conducted according to demographic characteristics, personal habits, and comorbidities. The mediation model assessed the potential role of NHR as a mediator in the relationship between abdominal adipose tissue index and depression. Depression was defined using the PHQ-9 screening questionnaire (cut-off ≥ 10), this reflects a screening result and not a clinical diagnosis.

The weighted prevalence of depression was determined to be 8.10%. The average participant age was 38.81 years, with females making up 47.86% of the sample and showing a higher prevalence of depression than males. The three weighted binary logistic regression models revealed significant positive correlations between Subcutaneous Adipose Tissue Index (SATI), Visceral Adipose Tissue Index (VATI), and depression. Restricted cubic splines (RCS) analysis showed a linear relationship between VATI and depression (P-overall<0.001, P-nonlinear>0.05), whereas SATI exhibited a nonlinear relationship with depression (P-overall<0.001, P-nonlinear<0.05). Mediation analyses indicated that the associations between SATI, VATI, and depression were partially mediated by NHR.

This study elucidates the associations between SATI, VATI and depression, proposing that these relationships may be partially mediated by NHR. These findings offer a novel perspective on the interplay between fat distribution and mental health, and suggest potential biological markers for future preventive and interventional strategies aimed at addressing depression.

The online version contains supplementary material available at 10.1186/s12888-025-07498-5.