Comment on spirometry

Our plain-English summary of Comment on spirometry, by P. Enright (Journal of Occupational Medicine., 1987).

The study

• Author: P. Enright
• Journal: Journal of Occupational Medicine.
• Published: 1987;29(10):842
• Type of article: Letter
• Cited by: 2 articles, as counted by NIH iCite
• Read it: PubMed
• In J-M's library: Johns-Manville's company medical library held a copy (J-M no. 000963).

In plain English

This was a letter to the editor, not a new study. The author, writing from the Mayo Clinic, commented on an earlier study by Mohsenifar and colleagues (J Occup Med 1986). The author agreed with an earlier letter by Dr Philip Edelman that the results of that study showed no evidence of an association between asbestos exposure and airflow limitation. The author pointed out that all 45 nonsmoking subjects in that study had normal lung function tests, including a normal FEV1/FVC ratio (mean of 80%). The subject with the lowest percent-predicted FEF25-75% (a mid-breath airflow measure) still had a normal FEV1/FVC of 72%. The author argued that in normal and near-normal subjects these two measures should not be treated as independent, and that they are redundant when trying to separate normal subjects from those with mild airflow limitation. The author also argued that using 75% of predicted as the lower limit of normal for FEF25-75% was invalid, and that the prediction equations used had been judged unreliable. The original authors had suggested that nine subjects with the lowest FEF25-75% values had evidence for small airways dysfunction because their FEV1/FVC ratios were lower than those of the other 36. The author called this reasoning "spurious logic." The letter reported no new data.

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: letter to the editor (commentary on a previously published study)
• Who was studied: No new population was studied; the letter discusses the 45 nonsmoking subjects of the earlier study by Mohsenifar et al (J Occup Med 1986;28:817-820)
• Exposure: asbestos exposure, as studied by Mohsenifar et al (no fiber type or job specified in the letter)
• Main results:
  • The author noted that all 45 nonsmoking subjects in the Mohsenifar et al study had normal pulmonary function tests, including a normal FEV1/FVC ratio (mean of 80%)
  • The author noted that the subject with the lowest percent predicted FEF25-75% had a normal FEV1/FVC of 72%
  • The author argued that in normal and near-normal subjects the FEV1/FVC ratio and the FEF25-75% are not independent measures, and are redundant for separating normal subjects from those with mild airflow limitation
  • The author argued that using 75% of predicted (or mean minus 1 SD) as the lower limit of normal for FEF25-75% is invalid
  • The author stated that Schmidt et al recommended limiting spirometry to the FVC, FEV1 and FEV1/FVC ratio, and that the Intermountain Thoracic Society recommends 95% confidence intervals to set the lower limit of normal
  • The original authors suggested that the nine subjects with the lowest FEF25-75% values had evidence for small airways dysfunction because their FEV1/FVC ratios were lower than those of the other 36 subjects; the author called this spurious logic
• The authors' conclusion: The author agreed with Dr Edelman that the Mohsenifar et al results show no evidence for an association between asbestos exposure and airflow limitation

Topics

Medical terms in this study, explained in our Lexicon: Spirometry.

Related studies

• Effects of spirometry standards in two occupational cohorts — E.A. Eisen, L.C. Oliver, et al. (1985)
• Associations between radiographic findings and spirometry in a community exposed to Libby amphibole — T.C. Larson, M. Lewin, et al. (2012)
• Spirometry: a predictor of lung cancer among asbestos workers — B. Świątkowska, N. Szeszenia-Dąbrowska (2017)
• Relation of airway responsiveness to duration of work in a dusty environment — P. Ernst, R.E. Dales, et al. (1989)
• The acute effects of chrysotile asbestos exposure on lung function — K.W. Harless, S. Watanabe, et al. (1978)
• Spirometry, rapid FEV1 decline, and lung cancer among asbestos exposed heavy smokers — J.W. Chien, D.H. Au, et al. (2007)

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