Improved hearing in Swedish 70-year olds-a cohort comparison over more than four decades (1971-2014)

Abstract

Objective: the world population is ageing rapidly. In light of these demographic changes, it is of interest to generate current data regarding the prevalence and characteristics of age-related hearing loss. The purpose of this study was to investigate hearing acuity and the prevalence of hearing loss in a contemporary age-homogenous cohort of old adults, and to assess secular trends in hearing function during the last half-century (1971-2014). Methods: we performed a prospective population-based cohort comparison study of unscreened populations. As part of a geriatric population-based study (H70), a new cohort of 70-year olds (n = 1,135) born in 1944 was tested with computerised automated pure-tone audiometry. The hearing thresholds were compared to three earlier born cohorts of 70-year olds, born in 1901-02 (n = 376), 1906-07 (n = 297) and 1922 (n = 226), respectively. Results: significant improvements in median pure-tone thresholds were seen at several frequencies in both men (range: 5-20 dB, P < 0.01) and women (range: 5-10 dB, P < 0.01). When investigating the effect of birth cohort on hearing in a linear regression, significant trends were found. Men's hearing improved more than women's. The prevalence of hearing loss declined in the study period (1971-2014) from 53 to 28% for men and 37 to 23% for women (P < 0.01). Conclusions: these results indicate that the hearing acuity in Swedish 70-year olds has improved significantly over more than four decades. The largest improvements were seen at 4-6 kHz in men, possibly reflecting a decrease in occupational noise exposure. Further studies are required to pinpoint the reasons for improved hearing-health among older people.