Relationship of mortality, occupation, and pulmonary diffusing capacity to pleural thickening in the First National Health and Nutrition Examination Survey

Our plain-English summary of Relationship of mortality, occupation, and pulmonary diffusing capacity to pleural thickening in the First National Health and Nutrition Examination Survey, by D.P. Loomis, G.W. Collman, W.J. Rogan (American Journal of Industrial Medicine, 1989).

The study

• Authors: D.P. Loomis, G.W. Collman, W.J. Rogan
• Journal: American Journal of Industrial Medicine
• Published: 1989;16(5):477-84
• Cited by: 10 articles, as counted by NIH iCite
• Read it: PubMed · Publisher
• In J-M's library: Johns-Manville's company medical library held a copy (J-M no. 000119).

Abstract

We studied the relationship of pleural thickening consistent with asbestos exposure to mortality, career employment in asbestos-related jobs, and pulmonary diffusing capacity among participants in the first National Health and Nutrition Examination Survey. Three "B" readers examined chest X-rays to identify 59 individuals with such pleural abnormalities. From 1975 to 1984, the all-cause mortality rate ratio (RR) comparing males with and without occupational pleural thickening was 1.3 (95% C.I. 0.8-2.2). For lung cancer, the mortality RR for males was 3.0 (95% C.I. 1.0-9.1). Career asbestos work was not associated with occupational pleural thickening among men, probably because some with the condition had only short-term exposure to asbestos. Pulmonary diffusing capacity was lower in those with occupational pleural thickening, taking smoking into account. These results suggest that individuals in the general population who have occupational pleural thickening are at risk for some of the health consequences of asbestos work, including lung cancer, even if they were not career asbestos workers.

In plain English

This study used the First National Health and Nutrition Examination Survey (NHANES I), a 1971 to 1975 U.S. population sample. Three certified "B" readers re-read chest X-rays. Of 1,099 people classified, 59 had pleural changes consistent with asbestos exposure (the authors' "pleuroconiosis"; all had pleural thickening) and 1,040 did not. Deaths were followed to 1984. Among males, all-cause mortality was slightly higher in those with the changes (rate ratio 1.3, 95% CI 0.8-2.2). Four of the 17 deaths in that group were from lung cancer, all in men. The lung cancer rate ratio was 3.0 (95% CI 1.0-9.1) for males in the abstract and 2.9 (1.0-8.7) for male smokers in the results. There were no mesothelioma deaths in that group. An expert panel rated likely asbestos exposure in sampled participants' longest-held jobs. Using those ratings, the authors found no strong association between the changes and career asbestos work among men. Men with the changes had lower carbon monoxide diffusing capacity. The authors concluded this was consistent with the changes marking biologically significant asbestos exposure in men without career asbestos work. They cautioned that the numbers were small and the estimates unstable.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Analysis of a national health survey with mortality follow-up (comparing death rates in people with and without pleural changes), plus a case-control comparison of longest-held occupation and a comparison of lung diffusing capacity
• Who was studied: Participants in NHANES I, a cluster sample of the non-institutionalized, non-military U.S. population examined 1971 to 1975. Chest X-rays of 1,099 adults were classified: 59 with pleuroconiosis (pleural abnormality consistent with pneumoconiosis; all had pleural thickening) and 1,040 without. Mortality was followed to 1984. The occupation analysis used 51 people with pleuroconiosis and 135 sampled controls.
• Exposure: Pleural changes on chest X-ray read by ILO criteria were treated as a possible marker of asbestos exposure. Career asbestos exposure was judged by a panel of five experts from the census occupation and industry codes for each person's longest-held job. The probability of exposure was rated as none, possible, probable or definite, and the degree as mild, moderate or severe. No fiber types are specified.
• Main results:
  • By 1984 there were 17 deaths in 457 person-years among the 59 people with pleuroconiosis, and 212 deaths in 9,505 person-years among the 1,040 without it. The crude mortality rate was 1.7 (95% CI 1.0-2.8) times higher in the group with pleuroconiosis.
  • Age-adjusted all-cause mortality was slightly elevated among all males with pleuroconiosis (RR 1.3, 95% CI 0.8-2.2) and among smoking males (RR 1.4, 95% CI 0.8-2.5). Data for females and nonsmoking males were too sparse to interpret.
  • Four of the 17 deaths in the pleuroconiosis group were from lung cancer, all in men, giving 24% proportionate lung cancer mortality among males.
  • The lung cancer mortality rate ratio for male smokers with versus without pleuroconiosis was 2.9 (1.0-8.7). There were no lung cancer deaths among nonsmokers.
  • The abstract printed with the article gives a lung cancer mortality rate ratio of 3.0 (95% CI 1.0-9.1) for males.
  • In the pleuroconiosis group there were no deaths from other asbestos-related diseases.
  • The panel rated jobs for both men and women, but only five women were classified as potentially exposed and none had pleuroconiosis, so results were presented only for men.
  • Using the panel's exposure classifications, the investigators found that among smoking men the odds ratio for pleuroconiosis with employment in any asbestos-related occupation was 1.3 (95% CI 0.5-3.2). It fell below 1.0 for jobs with higher exposure levels. For nonsmoking men the odds ratio was 0.4 (95% CI 0.0-3.1).
  • Men with pleuroconiosis had lower pulmonary diffusing capacity than men without it. The mean differences were 3.6 to 7.4 ml/min/mm Hg across smoking strata, with an overall mean difference of 5.07 ml/min/mm Hg. There was no significant smoking effect. Adjusting for age, height, race and occupational asbestos exposure made no difference.
• The authors' conclusion: The authors concluded that the findings were consistent with the hypothesis that these pleural changes are a valid marker of biologically significant asbestos exposure in men without a career of asbestos exposure. They said the findings should encourage further study of the pleural changes as a marker of short-term exposure.
• Limitations the authors state:
  • The number of individuals was small and the effect estimates were unstable.
  • NHANES I lacked detailed occupational histories, so the authors could not check directly whether short-term exposure produced the changes. Only the longest-held occupation was available.
  • There is no consensus that these pleural changes mark asbestos exposure, especially without a clear occupational history.
  • Data for females and nonsmoking males were too sparse to interpret.
  • Occupational exposure was evaluated only for a random sample of the people without pleuroconiosis, not for all of them.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Pleural plaques and thickening.

Medical terms in this study, explained in our Lexicon: Diffusing Capacity (DLCO), Pleural Thickening, Asbestos Exposure, Chest X-Ray, rate ratio, Lung Cancer, Short-Term Exposure.

Related studies

• US prevalence of occupational pleural thickening. A look at chest X-rays from the first National Health and Nutrition Examination Survey — W.J. Rogan, B.C. Gladen, et al. (1987)
• Re: "US prevalence of occupational pleural thickening: a look at chest x-rays from the first National Health and Nutrition Examination Survey" — W.C. Cooper (1989)
• Diffusing capacity and forced vital capacity in 5,003 asbestos-exposed workers: relationships to interstitial fibrosis (ILO profusion score) and pleural thickening — A. Miller, R. Warshaw, et al. (2013)
• X-ray evidence of increased asbestos exposure in the US population from NHANES I and NHANES II, 1973-1978. National Health Examination Survey — W.J. Rogan, N.B. Ragan, et al. (2000)
• Pulmonary elastic recoil and diffusing capacity in subjects with intermediate concentrations of alpha-1 antitrypsin — A.W. Musk, P.W. Robertson (1976)
• Single breath diffusing capacity in the industrial setting — B. Make, A. Miller, et al. (1982)

Browse more research in American Journal of Industrial Medicine, or return to medical research.