Associations between hearing impairment and mortality risk in older persons: the Blue Mountains Hearing Study

Abstract

Purpose: To assess whether hearing loss predicts an increased risk of mortality.

Methods: The Blue Mountains Hearing Study examined 2956 persons (49+ years) during 1997 to 2000. The Australian National Death Index was used to identify deaths until 2005. Hearing loss was defined as the pure-tone average (0.5-4 kHz) of air-conduction hearing thresholds greater than 25 dB HL. Associations between hearing loss and mortality risk were estimated using Cox regression and structural equation modeling (SEM).

Results: When we used Cox regression, we discovered that hearing loss was associated with increased risk of cardiovascular (hazard ratio [HR] 1.36, 95% confidence interval [CI] 1.08-1.84) and all-cause (AC) mortality (HR 1.39, 95% CI 1.11-1.79) after adjustment for age and sex but not after multivariable adjustment. SEM pathway analysis, however, revealed a greater AC mortality risk (HR 2.58, 95% CI 1.64-4.05) in persons with hearing loss, which was mediated: cognitive impairment (HR 1.45, 95% CI 1.08-1.94) and walking disability (HR 1.63, 95% CI 1.24-2.15). These variables increased mortality both directly and indirectly through effects on self-rated health.

Conclusions: Hearing loss was associated with increased AC mortality via three mediating variables: disability in walking, cognitive impairment, and self-rated health. It is important to recognize that persons with combined disabilities are at increased risk of cardiovascular and AC mortality.