Purpose: This study describes the most common audiometric configurations and the prevalence of these configurations among adults (ages 20 to 69) in the noninstitutionalized population of the United States and in a sample of residents of a rural county in Iowa.
Research design: This was a cross-sectional population-based study.
Study sample: Estimates generalizing to the noninstitutionalized population of the United States were based on National Health and Nutrition Examination Survey (NHANES) data collected from 2819 women and 2525 men between 1999 and 2004. Estimates from the rural county were based on Keokuk County Rural Health Study (KCRHS) data collected from 892 women and 750 men between 1994 and 1998.
Data collection and analysis: Cluster analyses (kappa-means) were used to divide participants into groups including maximally similar bilateral air conduction audiograms. Separate cluster analyses were conducted for each gender. For NHANES data, prevalence and error estimates were obtained using sample weights intended to provide data generalizing to the noninstitutionalized population of the United States within this age range.
Results: The hierarchical structure of audiometric configurations revealed that approximately 25% of women and 50% of men aged 20 to 69 in the noninstitutionalized population of the United States were best described by a configuration consistent with a marked hearing impairment in at least one frequency. Hearing impairments were more common among participants in the KCRHS. Gently sloping configurations of hearing impairment were dominant among women, while configurations featuring a greater slope were dominant among men. There was a greater variety of audiometric configurations in men than women.
Conclusions: In addition to their descriptive value, these data can be used to inform future studies of risk factors and progression of hearing loss, and to improve the generalizability of studies involving rehabilitative options for people with hearing impairment.