Modifiable determinants of hearing impairment in adults

ObjectiveTo identify factors contributing to the declining prevalence of hearing impairment in more recent generations.MethodsWe used data on hearing thresholds and potential risk factors of hearing impairment collected from studies in Beaver Dam, Wisconsin, the Epidemiology of Hearing Loss Study (1993-1995, n = 3753; 1998-2000, n = 2800 and 2003-2005, n = 2395), the concurrent Beaver Dam Eye Study on the same cohort, and a subgroup (n = 2173) of the Beaver Dam Offspring Study (2005-2008).ResultsEducational attainment significantly reduced the odds ratio (OR) of the birth cohort effect on hearing impairment from 0.90 to 0.93, while a history of ear infection had a reverse effect on the decreasing trend (significantly changing the OR from 0.93 to 0.94). Occupational noise exposure, smoking, and a history of cardiovascular disease, while associated with hearing impairment, did not attenuate the cohort effect. The cohort effect remained significant after known risk factors were adjusted (OR = 0.93; 95% confidence interval, 0.89-0.97).ConclusionThese data provide strong evidence that environmental, lifestyle, or other modifiable factors contribute to the etiology of hearing impairment and add support to the idea that hearing impairment in adults may be prevented or delayed.

► Educational attainment attenuated the birth cohort effect on hearing impairment. ► A history of ear infection partly countered the decreasing birth cohort effect. ► Noise exposure, smoking and a history of CVD did not change the cohort effect. ► The cohort effect remained significant after adjusting for known risk factors.