Chronic Inflammation and Hearing Loss: Key Biomarkers and Subgroup Differences by Gender and BMI in a National Cohort.

Background: Hearing loss (HL) significantly impacts quality of life and economic status worldwide. Chronic inflammation is suggested to influence hearing, yet the connection with inflammation-related indexes in the general population is not well understood.

Methods: This cross-sectional study analyzed data from 7231 adults from six cycles (2005-2012 and 2015-2018) of the National Health and Nutrition Examination Survey (NHANES). It examined the correlation between systemic immune-inflammatory biomarkers (NLR, SII, PLR, and LMR) and auditory threshold shifts/HL using multivariable logistic regression models. Smooth curve fitting visualized the association, and log-likelihood ratio tests determined the existence of thresholds in biomarker effects, supplemented by subgroup analyses.

Results: After adjustments, significant associations were found for low-frequency HL with ln-transformed NLR (OR = 1.29, 95% CI: 1.06-1.56, p = 0.0116), ln-SII (OR = 1.31, 95% CI: 1.08-1.59, p = 0.0065), and ln-LMR (OR = 0.74, 95% CI: 0.60-0.91, p = 0.00043). For high-frequency HL, similar patterns were observed for ln-SII (OR = 1.25, 95% CI: 1.05-1.48, p = 0.0105) and ln-LMR (OR = 0.76, 95% CI: 0.64-0.90, p = 0.007); however, the association with ln-NLR did not reach statistical significance (OR = 1.18, 95% CI: 1.00-1.40, p = 0.0562). NLR and SII positively correlated with HL, while LMR showed a negative correlation. No significant association was noted with PLR. Dose-response relationships were observed, particularly between LMR and all categorized frequencies of HL and between SII and high-frequency HL. Subgroup analyses indicated that NLR and SII are risk factors for HL in healthy BMI males, with LMR being more protective in males, the elderly, and diabetics.

Conclusions: Systemic inflammation-related indexes, especially SII, are predictive of both high- and low-frequency HL, highlighting the role of inflammatory homeostasis in hearing health. LMR may offer protective effects, particularly in specific subgroups. These findings suggest potential targets for HL treatment by regulating inflammation, warranting further investigation into their clinical application.