TABLE III. (Cont'd.) Cases of specified notifiable diseases, United States, weeks ending March 12, 1988 and March 7, 1987 (10th Week)

*Mortality data in this table are voluntarily reported from 121 cities in the United states, most of which have populations of 100,000 or more. A death is reported by the place of its occurrence and by the week that the death certificate was filed. Fetal deaths are not included.

**Pneumonia and influenza.

*Because of changes in reporting methods in these 3 Pennsylvania cities, these numbers are partial counts for the current week. omplete counts will be available in 4 to 6 weeks.

otal includes unknown ages.

ta not available. Figures are estimates based on average of past 4 weeks.

Cause of mortality

(ICD, 9th Revision)

TABLE V. Estimated years of potential life lost (YPLL) before age 65* and causespecific mortality, by cause of death United States, 1986

*For details of calculation, see footnotes to Table V, MMWR 1988;37:45.

*Cause-specific mortality rates as reported in the National Center for Health Statistics' Monthly Vital Statistics Report are compiled from a 10% sample of all deaths. 'Equivalent to accidents and adverse effects.

'Category derived from disorders relating to short gestation and respiratory distress syndrome. **Reflects CDC surveillance data.

Hearing Loss - Continued probability sample of the civilian, noninstitutionalized U.S. population. Members of some 42,000 households, comprising approximately 120,000 persons, are interviewed each year to obtain information about health status. Thus, NHIS serves as a database for national estimates of prevalence of various health conditions in the U.S. population. The survey is also useful for following health trends in this population. For this study, the prevalence of self-reported hearing loss was obtained for all persons over 17 years of age who were in the labor force at the time of interview. The Gallaudet Scale, a well-validated, self-rating hearing scale consisting of seven questions, was used to evaluate the degree of hearing impairment (6). Unilateral hearing loss, which was involved in about half of the cases, was excluded.

Data from the 1972-1974 National Occupational Hazard Survey (NOHS) were used to classify worksites by noise level (7). NOHS was conducted by NIOSH from 1972 to 1974 on a probability sample of approximately 5,000 workplaces across the United States (7). The survey provides information on potential exposures of workers to chemical and physical agents. These data identified industries and occupations in which employees are exposed to continuous noise.*

Some degree of hearing loss was reported by 3.2% of all NHIS respondents. Self-reported hearing loss was higher among adults working in industries with potential exposure to industrial noise than among those working in industries without such potential exposures. NHIS data were then analyzed with the data collected independently during NOHS. Stratifying NHIS data on self-reported hearing loss by the noise levels reported in NOHS shows that self-reported hearing loss increases with age, and that, within age groups, it is consistently greater for noisy industries. The percentage and number of workers exposed to noise and the percentage of self-reported hearing loss in 31 broad industrial categories were estimated from the NOHS and the NHIS (Table 1). Industries in the manufacturing sector had the highest prevalence of noise exposure (overall exposure rate, 37%).

Results of the NHIS on self-reported hearing loss among workers 17 years of age or older were divided into three groups: 1) persons with light exposure, or those working in industries where <10% of the employees were estimated by NOHS to be exposed to noise at ≥85 dBA; 2) persons with moderate exposure, or those employed in industries where 10%-24% of the workers receive such exposure; and 3) persons with heavy exposure, or those employed in industries where >25% of the workers receive such exposure. These data were further stratified into three age groups: 17-44 years, 45-54 years, and 55 years. A comparison of these groups showed that the prevalence of self-reported hearing loss among white males increased with both age and increasing exposure to industrial noise (Figure 1).

Reported by: Surveillance Br, Div of Surveillance, Hazard Evaluations and Field Studies, National Institute for Occupational Safety and Health; Div of Health Interview Statistics, National Center for Health Statistics, CDC.

Editorial Note: Current findings indicate that occupational exposure to noise is a widespread problem that has a substantial impact on the prevalence of hearing loss *Occupational exposure to noise was assessed by an industrial hygienist who determined the effect of noise on employees in the workplaces surveyed by NOHS. Workers were considered to be exposed if the noise level was measured or estimated to be 85 dBA, irrespective of the number of hours of daily exposure.

*Results for other races are not shown because there were too few nonwhite males in the NHIS samples to provide reliable estimates after stratification of the data. No effect was seen for women, possibly because of the small number of women employed in industries with high noise levels.

among the working population. Exposure to intense noise causes hearing loss that may be temporary or permanent. Temporary hearing loss, also called auditory fatigue, may occur after only a few minutes of exposure to intense noise and is reversible after a period of time away from the noise. However, when exposure to excessive noise occurs over a period of months or years, only partial recovery of hearing may be possible.

TABLE 1. Estimated percentage of workers exposed to noise and prevalence of self-reported hearing loss, by industry United States, 1970s

*Estimated using data from the National Occupational Hazard Survey, 1972-1974. *Estimated using data from the National Health Interview Survey, 1971 and 1977. 'Derived by multiplying column 1 by column 2.