U.S. Occupational Historical Perspective on Race and Lung Function

To the Editor:

Several articles (1–4) have recently been published in the Journal on the topic of race and lung function. However, an important part of the history of this issue has not been addressed in these or other articles published to date. There is an extensive public record of the “Informal Public Hearing on Proposed Standard for Exposure to Cotton Dust” held in 1977 before the U.S. Occupational Safety and Health Administration (OSHA) Cotton Dust Standard was finalized in 1978, and these comments are relevant to the current general discussion as well as to the purposes of occupational spirometry testing in the United States (5, 6). As Lapp stated in 1974, “…differences [between Blacks’ and Whites’ lung volumes] are of more than academic and anthropological interest [because of] the recently introduced practice of performing preemployment spirometry in workers…” (7). The OSHA public comments, as Lapp anticipated, give insight into the origins of the use of a scaling factor for testing African Americans and its purpose in occupational and clinical settings, as well as the problem that false positives cause.

Comments in the OSHA Cotton Dust Docket recognized that reference values used in the 1970s (derived almost exclusively from White males) were preventing Black job applicants from being hired when pre-employment spirometry tests were required. As the Docket indicates, with those reference values in place, cotton processing mills attempted to expand the definition of “normality” to allow more job applicants to be hired. Dr. Harold Imbus evaluated job applicants being turned away by Burlington Industries and documented that 80% of them were Black, though Black individuals comprised only 35% of the applicant pool. It was not until the 1990s that the NHANES III provided race-specific reference equations based on thousands of self-identified African Americans, Whites, and Mexican Americans in the United States (8). Because the spirometry reference values used in 1977 were drawn from studies of primarily White individuals, OSHA determined that a scaling factor must be applied to the available White predicted values when assessing Black workers to avoid discriminatory hiring in the workplace. The Cotton Dust Standard was updated in 2019 and now requires workers to be evaluated using race-specific equations developed by the NHANES III, with a scaling factor applied for Asian- Americans (9).

Clearly the causes of the difference between self-reported Blacks and Whites are of great importance, particularly to determine whether another variable can be used to group individuals instead of self-identified race. NHANES III White predicteds and LLNs exceed Blacks’ by about 0.6 L when working-age men of the same ages and heights are compared (10). While poor living conditions and other socioeconomic factors most likely affect non-White individuals’ lung function, consideration must also be paid to possible differences in body build, which is likely ancestry-related, in addition to “modifiable social risk factors.” We surely need to investigate all possible explanations for observed differences before deciding that “modifiable social risk factors” fully explain differences that have been observed in current times since the 1970s, and for 100 years prior to that.

Our greatest concern is that practitioners, as they read papers questioning the value of race-specific reference values, will abandon use of self-identified race when evaluating individuals in occupational and clinical settings before a valid and practical substitute has been identified. Simply omitting self-identified race in interpretation practice would be premature before causes of differences have been carefully studied and clearly identified. Otherwise, we run the risk of returning to the era preceding the cotton dust standard, when non-White workers could be unfairly excluded from qualifying to wear a respirator or be denied hire in occupations for which personal respiratory protection is required.