The Prevalence, risk factors and impacts of hearing impairment in an older Australian community: the Blue Mountains Hearing Study. Libby Harricks memorial oration

There have been few recent large population-based studies to estimate the prevalence, risk factors and impacts of age-related hearing impairment. Our study aimed to provide these data for the cohort of older persons attending 5-year examinations of the Blue Mountains Study, in a defined area, west of Sydney, Australia.Of 2696 eligible residents, 2015 persons (75%) aged 55-99(mean 70 years) were examined. A detailed questionnaire was administered and air and bone-conduction audio metric thresholds measured from 0.25 to 8KHz. Thresholds were higher in men than in women and in left compared with right ears. Hearing loss,defined as >25dBHL in the better ear averaged over 4 frequencies,was found in 39.3% of subjects. It was mild (>25 to ≤40 dBHL) in25.9%, moderate (40 to ≤60 dBHL) in 11.2%, marked (60 to≤90dBHL) in 2.3% and profound (>90 dBHL) in 0.4%. After adjusting for gender, the odds for hearing loss doubled with each increasing decade of age. Hearing loss was independently associated with both the duration and severity of reported work-related noise exposure (70% increased risk), the presence and duration of type2 diabetes (50% increased risk), current smoking (40% increased risk), together with lower educational attainment and past history of stroke. Regular alcohol consumption was associated with a slightly reduced risk of hearing loss. Hearing impairment also impacted negatively on participants’ perception of their general health and was independently associated with a higher use of community support services and a higher rate of nursing home placement Persons with hearing loss were more likely to also have visual impairment. This study has demonstrated important epidemiologic findings about age-related hearing loss that support and extend recent U.S. findings. Follow-up of this cohort is soon to commence and will assess the 5-year incidence and progression of hearing loss in this community.