The contribution of family history to hearing loss in an older population

OBJECTIVES: Although it has been well established that the prevalence of and severity of hearing loss increase with age, the contribution of familial factors to age-related hearing loss cannot be quantified. This is largely because hearing loss in older people has both genetic and environmental contributions. As environmental factors play an increasing role with age, it is difficult to delineate the separate contribution of genetic factors to age-related hearing loss. In a population-based survey of hearing loss in a representative older Australian community, we attempted to overcome this using logistic regression analysis, accounting for known factors associated with hearing loss including age, sex, noise exposure at work, diabetes, and current smoking. DESIGN: We tested hearing thresholds using pure tone audiometry and used a forced choice questionnaire to determine the nature of family history in a population of individuals aged 50 yrs or older in a defined region, west of Sydney, Australia (N = 2669). We compared the characteristics of participants with and without family history of hearing loss. Of those reporting a positive family history, we compared subgroups for age, gender and severity of hearing loss, and trends by the severity of hearing loss. Logistic regression was used to obtain odds ratios (ORs) with 95% confidence intervals (CIs) that compared the chances of having hearing loss in participants with and without family history, after adjusting for other factors known associated with hearing loss. RESULTS: Our findings indicate that family history was most strongly associated with moderate to severe age-related hearing loss. We found a strong association between maternal family history of hearing loss and moderate to severe hearing loss in women (adjusted OR 3.0; 95% CI 1.6-5.6 in women with without a maternal history). Paternal family history of hearing loss was also significantly, though less strongly, associated with moderate-severe hearing loss in men (adjusted OR 2.0; CI 1.01-3.9 in men with than without a paternal history). CONCLUSIONS: Findings from this study are important in the identification of individuals whose auditory system may be genetically susceptible to aging and environmental insult. Genetic counseling may assist in ameliorating the effects of hearing loss.