Association between individual-level and area-level socioeconomic status and hearing impairment among working-age Australians: a longitudinal study
Hearing loss is the fourth major cause of disability worldwide and has a significant adverse effect on a person’s cognitive, physical and social functioning and performance in the workplace. One in six Australians is living with hearing loss. By 2050, this estimate is expected to increase to one in four. Differences in socioeconomic status, defined as socioeconomic inequality, are identified as significant risk factors for hearing impairment; however, this association has not yet been investigated among working-age Australians. To address this gap, this study examines the longitudinal association between socioeconomic status and hearing impairment among working-age Australians. The analysis is based on a nationally representative sample of 10,722 participants from the Household, Income and Labour Dynamics in Australia (HILDA) survey. The association between hearing impairment and socioeconomic status was examined using multivariate logistic regression models fitted at the baseline. A variable selection procedure was applied to clean, select and retain the most significant covariates in the model. Marginal effects modelling was used to predict and quantify the incremental risk of hearing impairment associated with each socioeconomic measure. To draw causal inference, a hierarchical Cox proportional hazard model was used. Model fit was assessed using Akaike Information Criteria (AIC) and Bayesian Information Criteria (BIC). A proportional hazard test was used to test for the proportional odds assumption. The results provide strong evidence that there was a significant inverse association between individual-level and area-level socioeconomic status and hearing impairment. Multivariate analysis at baseline showed that lower educational attainment, occupational status, income and area-level socioeconomic status were independently associated with greater odds of hearing impairment. Longitudinal analysis by the Cox proportional hazard model gave identical results with a slightly higher predictive power. Overall, the findings support the conceptual model developed in this study and suggest a direction for future research on the association between hearing impairment and socioeconomic status.