The association between composite inflammatory indicators and noise-induced hearing loss: a cross-sectional study (Preprint)

BACKGROUND Occupational noise-induced hearing loss (ONIHL) is a progressive and irreversible form of sensorineural hearing loss. Composite inflammatory indicators, such as the neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and systemic immune inflammation index (SII), have been confirmed as prognostic indicators for various cancers and diseases; however, their relationship with hearing loss in workers exposed to occupational noise remains unclear. OBJECTIVE This study aimed to analyze the factors influencing noise-induced hearing loss and explore the relationship between composite inflammatory indicators (SII, PLR, and NLR) and hearing loss at the population level, providing suggestions for the prevention and treatment of hearing loss among workers. METHODS This cross-sectional study included 22,433 workers exposed to noise. Binary logistic regression was used to analyze the factors influencing speech frequency and high-frequency hearing loss (HFHL) among the workers. Multivariate logistic regression and subgroup analyses were used to analyze the correlation between inflammatory indicators and hearing loss. RESULTS The abnormal rate of HFHL was 27.80%, and that of speech-frequency hearing loss (SFHL) was 5.28%. The results of binary logistic regression analysis showed that male sex and age were common risk factors for HFHL and SFHL (P<.05). Smoking was a risk factor for SFHL (Odds Ratio [OR]1.201, 95% Confidence Interval [CI] 1.036-1.392). Working in small (OR 1.392, 95%CI 1.235-1.570) and micro (OR 1.430, 95% CI 1.307-1.564) enterprises were risk factors for HFHL among workers. For each unit increase in a worker’s Body Mass Index, the risk of HFHL increased by 0.7% (OR, 1.007, 95% CI 1.001-1.014). In the unadjusted model, both NLR and PLR were significantly correlated with HFHL and SFHL, whereas SII was not significantly correlated with hearing loss. The OR for the PLR was 0.628 (95% CI 0.599-0.658), which was significantly and negatively correlated with HFHL. The OR of NLR was 1.135 (95% CI 1.053-1.225), which was significantly and positively correlated with HFHL. For SFHL, the OR of PLR was 0.676 (95% CI 0.614-0.745), and that of NLR was 1.282 (95% CI 1.104-1.489). After adjusting for age, length of service, sex, Body Mass Index, and hypertension, PLR was significantly negatively correlated with HFHL (OR 0.698, 95%CI 0.665-0.733) and SFHL (OR 0.704, 95% CI 0.637-0.777). Subgroup analysis indicated that the negative correlation between the PLR and HFHL was particularly significant among people aged <50 years and smokers, whereas there was a significant negative correlation between the PLR and SFHL in people aged <50 years (P for interaction<.05). CONCLUSIONS The inflammatory indicators, NLR and PLR, are significantly associated with hearing loss. These easily accessible blood indicators can serve as biomarkers to assist in identifying workers at high risk of ONIHL. These results provide insights for the development of early warning and targeted prevention strategies for ONIHL.