Abstract
This study explored the non-linear relationship between pan-immune inflammation value (PIV) and probable depression using NHANES data (2005-2018, n = 27,049). Restricted cubic spline analysis identified an optimal PIV cutoff (5.74). Weighted logistic regression revealed that individuals with PIV > 5.74 had 14% higher risk of probable depression (OR=1.14, 95% CI:1.02-1.28). Gender-stratified analyses showed significant PIV and probable depression associations in females (OR=1.20, 95% CI:1.03-1.40) but not in males. In males, higher PIV interacted with age, education, and alcohol consumption to influence probable depression risk (interaction P < 0.05), whereas no such interactions occurred in females. The findings suggest PIV may serve as a sex-specific biomarker for probable depression risk, with more stable associations in females. Further research is needed to elucidate the mechanisms underlying these gender differences and validate these findings before any clinical application.