AN INCREASING PREVALENCE OF HEARING IMPAIRMENT AND ASSOCIATED RISK-FACTORS OVER 3 DECADES OF THE ALAMEDA COUNTY STUDY

Objectives. This study assessed changes in the prevalence of hearing i mpairment in persons aged 50 years and older over the past 30 years an d identified risk factors. Methods. Age-adjusted hearing impairment pr evalence rates at four time intervals were calculated from the Alameda County Study (n = 5108). Logistic regression models analyzed risk fac tors from 1974 for 1994 incident hearing impairment. Results. The prev alence of hearing impairment nearly doubled between 1965 and 1994. The increase was significantly greater for men. The higher incidence was associated with potentially high-noise-exposure occupations for men an d with symptoms and conditions associated with ototoxic drug use for b oth men and women. Exercise was protective. Conclusions. Given the ser ious health and social consequences of hearing impairment, its increas ing prevalence is cause for concern.