Individual-level and area-level socioeconomic inequalities in hearing impairment among Chinese adults: a population-based study

Background: It is unclear whether individual-level and area-level socioeconomic status (SES) is associated with hearing impairment (HI). This study determines an association of individual SES, area SES and their interaction with HI among working-aged adults. Methods: Data were obtained from the large, population-based sample of the Second China National Sample Survey on Disability, a cross-sectional study conducted in China. A total of 1 333 528 participants aged 25–59 years were included. HI was measured by pure-tone audiometry (PTA) and audiologists further ascertained for a final diagnosis. Individual SES was defined as a summed of z-scored of education level and household income per capita, and area SES was calculated as a summed of z-scored of county-level income per capita, high school rate, poverty rate and rate of upper-class occupation. Multilevel logistic regression was used. Results: Individual and area SES were associated with HI among Chinese working-aged adults. A 1-SD increase in individual SES was associated with decreased risk of HI (OR=0.3, 95% CI: 0.3 to 0.3). Area SES was positively related to HI (OR=1.2, 95%CI: 1.2 to 1.3). The cross-level interaction on individual and area SES was significantly associated with HI, indicating that among those who lived in higher SES areas, participants with lower SES had a greater likelihood to develop HI. Conclusions: Significant individual and area socioeconomic inequalities were observed in HI among Chinese working-aged adults. Lower SES adults who resided in prosperous areas may face more deprivation on hearing health than those with higher SES