Conicity Index Associated with Adult Hearing Impairment: A Cross-Sectional Study Based on the National Health and Nutrition Examination Survey (2001–2018)

Abstract

Objective: This study aimed to evaluate the association of conicity index (C-index), a marker of abdominal obesity, with hearing impairment (HI) in US adults using data from the National Health and Nutrition Examination Survey (NHANES). Methods: We conducted a cross-sectional investigation using data from nine NHANES cycles spanning from 2001 to 2018. The C-index was used as the independent variable, whereas HI—defined as a pure-tone average hearing threshold exceeding 25 dB HL—was the outcome measure. Multivariable logistic regression models were used to assess the association between C-index and HI, adjusting for potential confounders including age, sex, race/ethnicity, hypertension, diabetes, total cholesterol, haemoglobin and blood urea nitrogen. Dose–response relationships were evaluated using trend tests (P for trend) and restricted cubic spline (RCS) analysis. Subgroup analyses were performed to assess potential interaction effects. Results: A total of 7394 adults aged 20–69 were included. Higher C-index values were significantly associated with an increased prevalence of HI. In the fully adjusted model, each unit increase in C-index was associated with 7.35-fold higher odds of HI (95% CI: 3.03–17.82, P 0.05). Conclusion: Higher C-index values are independently associated with greater odds of HI. Given the rising burden of obesity and its metabolic consequences, the C-index may serve as a practical tool for HI risk assessment, especially in populations with cardiometabolic risk factors.

Keywords

• conicity index
• cross-sectional analysis
• hearing impairment
• obesity
• nhanes