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Americans Hear as Well or Better Today Compared With 40 Years Ago: Hearing Threshold Levels in the Unscreened Adult Population of the United States, 19591962 and 19992004

Hoffman, Howard J.1; Dobie, Robert A.2; Ko, Chia-Wen1; Themann, Christa L.3; Murphy, William J.3

Ear & Hearing:
doi: 10.1097/AUD.0b013e3181e9770e
Research Articles
Abstract

Objectives: (1) To present hearing threshold data from a recent nationally representative survey in the United States (National Health and Nutrition Examination Survey, 1999–2004) in a distributional format that might be appropriate to replace Annex B in international (ISO-1999) and national (ANSI S3.44) standards and (2) to compare these recent data with older survey data (National Health Examination Survey I, 1959–1962) on which the current Annex B is based.

Design: Better-ear threshold distributions (selected percentiles and their confidence intervals) were estimated using linear interpolation. The 95% confidence intervals for the medians for the two surveys were compared graphically for each of the four age groups and for both men and women. In addition, we calculated odds ratios comparing the prevalences of better-ear hearing impairment (thresholds > 25 dB HL) between the two surveys, for 500, 1000, 2000, and 4000 Hz, and for their four-frequency average.

Results: Across age and sex groups, median thresholds were lower (better) in the 1999–2004 survey at 500, 3000, 4000, and 6000 Hz (8000 Hz was not tested in the 1959–1962 survey). For both men and women, the prevalence of hearing impairment was significantly lower in 1999–2004 at 500, 2000, and 4000 Hz, but not at 1000 Hz.

Conclusions: For men and women of a specific age, high-frequency hearing thresholds were lower (better) in 1999–2004 than in 1959–1962. The prevalences of hearing impairment were also lower in the recent survey. Differences seen at 500 Hz may be attributable at least in part to changes in standards for ambient noise in audiometry. The National Health and Nutrition Examination Survey 1999–2004 distributions are offered as a possible replacement for Annex B in ISO-1999 and ANSI S3.44.

In Brief

Hearing threshold data are presented from a nationally representative survey in the United States (National Health and Nutrition Examination Survey, 1999–2004) in a format that could replace Annex B in international (ISO-1999) and national (ANSI S3.44) standards. The recent data are compared with older survey data (National Health Examination Survey I, 1959–1962) on which Annex B is based. For men and women, high-frequency hearing thresholds were lower (better) in 1999–2004 than that in 1959–1962. The prevalences of hearing impairment were also lower in the recent survey. Differences seen at 500 Hz are probably attributable in part to changes in standards for ambient noise in audiometry.

Author Information

1Epidemiology and Statistics Program, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, Maryland; 2Department of Otolaryngology-Head and Neck Surgery, The University of Texas Health Science Center at San Antonio, Texas; and 3Hearing Loss Prevention Team, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Cincinnati, Ohio.

The NHANES 1999–2004 audiometric data collection was funded with NIDCD research contract funds via an interagency agreement between NIDCD and NCHS. NIOSH provided funding for the audiometric testing equipment, training and monitoring of technicians, and editing of preliminary data files and had a separate interagency agreement with NCHS. Audiometric testing was conducted in the field by health technicians employed by WESTAT, Inc., under contract with NCHS.

The authors prepared this report in their roles as U.S. Federal employees, except for one (Dobie), who is a member of the faculties of The University of Texas Health Science Center at San Antonio and the University of California at Davis, and also has a private consulting practice in otology. The authors have no other financial or potential conflicts of interest to declare. The views expressed are solely those of the authors and do not necessarily represent the agencies or institutions for which they work.

The order of the authors is intended to reflect the relative contributions each author made to the article. Hoffman and Themann participated in the design and oversight of the NHANES audiometry and can vouch for the acquisition and quality control of the data. Hoffman, Dobie, and Ko participated in the conceptual design of the article and the statistical analysis. Dobie and Hoffman were the primary drafters. Each of the authors participated in the interpretation of the data and the preparation of the final manuscript.

Address for correspondence: Howard J. Hoffman, MA, Epidemiology and Statistics Program, National Institute on Deafness and Other Communication Disorders (NIDCD), National Institutes of Health (NIH), Suite 400A, Executive Plaza South (EPS) Building, 6120 Executive Boulevard, Bethesda, MD 20892. E-mail: hoffmanh@nidcd.nih.gov.

Received October 23, 2009; accepted May 2, 2010.

© 2010 Lippincott Williams & Wilkins, Inc.