Lung health among plumbers and pipefitters in Edmonton, Alberta

Our plain-English summary of Lung health among plumbers and pipefitters in Edmonton, Alberta, by P.A. Hessel, L.S. Melenka, D. Michaelchuk, et al (Occupational and Environmental Medicine, 1998).

The study

• Authors: P.A. Hessel, L.S. Melenka, D. Michaelchuk, F.A. Herbert, R.L. Cowie
• Journal: Occupational and Environmental Medicine
• Published: 1998;55(10):678-83
• Cited by: 4 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Objectives: A cross sectional study was undertaken to assess lung health among plumbers and pipefitters. Respiratory symptoms, lung function, and radiographic changes among 99 actively employed plumbers and pipefitters with > or = 20 years of union membership were compared with 100 telephone workers.

Methods: A respiratory symptom questionnaire was administered, including smoking and occupational histories. Spirometry was conducted according to standard criteria. Posteroanterior chest radiographs were evaluated by two experienced chest physicians, with a third arbitrating disagreed films. Members of the union were categorised as pipefitters (n = 57), plumbers (n = 16), or welders (n = 26), based on longest service, and compared with the telephone workers and internally (between groups). Lung health was also compared with employment in several work sectors common to Alberta for time, and for time weighted by exposure to dust and fumes.

Results: Compared with the telephone workers, plumbers and pipefitters had more cough and phlegm, lower forced vital capacity, and more radiographic changes (20% with any change), including circumscribed (10%) and diffuse pleural thickening (9%). None of the plumbers and pipefitters had small radiographic opacities. Among the three subgroups of workers, plumbers had the highest prevalence of radiographic changes. Both plumbers and pipefitters showed higher odds ratios for cough and phlegm than the welders. No differences between groups were found for lung function. Indicators of lung health were not related to work in any sector.

Conclusions: Plumbers and pipefitters had increased prevalence of symptoms suggestive of an irritant effect with no evidence of bronchial responsiveness. The chest radiographs showed evidence of asbestos exposure, especially in the plumbers, but at lower levels than previously reported. Health screening programmes for these workers should be considered, although the logistical problems associated with screening in this group would be considerable.

In plain English

This cross-sectional study, done in Edmonton, Alberta, in 1995, compared 99 working union plumbers and pipefitters, each with at least 20 years of membership, with 100 telephone workers. Participants completed a respiratory symptom questionnaire, breathing tests and chest X-rays. After adjusting for age and smoking, the plumbers and pipefitters more often reported usual cough (20.2% versus 9.0%; odds ratio 2.60, 95% CI 1.05 to 6.40) and usual phlegm (25.3% versus 9.0%). Their forced vital capacity was lower, a difference limited to non-smokers and ex-smokers. Some X-ray abnormality appeared in 20.0% of the plumbers' and pipefitters' radiographs versus 2.1% of the telephone workers', including circumscribed and diffuse pleural thickening. None of the plumbers and pipefitters had small opacities. Among union members grouped by longest-held job, plumbers had the highest rate of any X-ray abnormality: 8 of 14 with X-rays (57.1%). The authors concluded that the X-rays showed evidence of asbestos exposure, especially in plumbers, but at lower levels than previously reported, and that screening should be considered. They noted that their sample was small and included only active workers.

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: cross-sectional study comparing union plumbers and pipefitters with telephone workers
• Who was studied: 99 actively employed members of plumbers' and pipefitters' union Local 488 in the greater Edmonton area, each with at least 20 years of union membership, compared with 100 workers at Edmonton Telephones. Only men younger than 65 were analysed. Testing ran from February to October 1995. Response rates were 77.9% for the plumbers and pipefitters and 72.7% for the telephone workers. By longest-held job, union members were grouped as pipefitters (57), plumbers (16) or welders (26).
• Exposure: Work as a plumber, pipefitter or welder, which involves welding fumes, insulation materials and solvents. Exposure was assessed from self-reported time in work sectors (industrial, commercial, residential, and specific industries), with dust and fumes graded none, slight, moderate or severe. No fiber types were named and no asbestos measurements were reported.
• Main results:
  • Usual cough was reported by 20 of 99 plumbers and pipefitters (20.2%) and 9 of 100 telephone workers (9.0%): odds ratio 2.60, 95% CI 1.05 to 6.40, adjusted for smoking and age.
  • Usual phlegm was reported by 25 plumbers and pipefitters (25.3%) and 9 telephone workers (9.0%): odds ratio 3.40, 95% CI 1.44 to 8.03.
  • Chronic phlegm was reported by 21 plumbers and pipefitters (21.2%) and 9 telephone workers (9.0%): odds ratio 2.58, 95% CI 1.09 to 6.13.
  • Forced vital capacity (FVC) differed significantly between the plumbers and pipefitters and the telephone workers (p=0.038). The deficit among the plumbers and pipefitters was limited to non-smokers and ex-smokers. The FEV1 difference was not significant (p=0.055).
  • Any radiographic abnormality was found in 18 plumbers and pipefitters (20.0%) and 2 telephone workers (2.1%): odds ratio 11.88, 95% CI 2.67 to 52.83.
  • Circumscribed pleural thickening was found in 9 plumbers and pipefitters (10.0%) and 1 telephone worker (1.0%): odds ratio 10.67, 95% CI 1.32 to 85.98.
  • Diffuse pleural thickening was found in 8 plumbers and pipefitters (8.9%) and 1 telephone worker (1.0%): odds ratio 9.37, 95% CI 1.15 to 76.46.
  • None of the plumbers and pipefitters had small radiographic opacities. One telephone worker did.
  • Grouped by longest-held job, any radiographic abnormality was found in 6 of 52 pipefitters (11.5%), 8 of 14 plumbers (57.1%) and 4 of 24 welders (16.7%), p=0.0023. These denominators are the men in each group with radiographic results.
  • Compared with the telephone workers, the odds ratio for usual cough was 3.08 for pipefitters (p=0.024), 4.93 for plumbers (p=0.034) and 0.80 for welders (p=0.797, not significant).
  • Each year of residential work was associated with any radiographic abnormality (odds ratio 1.41, 95% CI 1.11 to 1.80). However, across the many work-setting comparisons, the number of significant findings did not exceed what would be expected by chance.
• The authors' conclusion: The authors concluded that the plumbers and pipefitters had more symptoms suggestive of an irritant effect, with no evidence of bronchial responsiveness. They found that the chest radiographs showed evidence of asbestos exposure, especially in the plumbers, but at lower levels than previously reported. They said health screening programmes for these workers should be considered, although screening this group would pose considerable logistical problems.
• Limitations the authors state:
  • As a cross-sectional study, it may have missed the workers most affected by their work, who may have left the occupation before the study began.
  • The results apply only to active, long-term workers. Workers who retired because of disability or age were not included.
  • The sample size was set by the budget, not by a formal calculation, and was too small to assess subtle effects.
  • Very few abnormalities were found among the telephone workers, which made the radiographic risk estimates unstable.
  • None of the X-ray readers were NIOSH-certified B readers, although all had extensive experience.
  • The work-setting findings, such as those for residential work, could easily have arisen by chance given the many comparisons made.
  • The authors could not say with certainty that the excess cough and phlegm was due to worksite exposures.

Topics

Medical terms in this study, explained in our Lexicon: Pipefitter, Spirometry, Chest X-Ray, Diffuse Pleural Thickening, Odds Ratio, Asbestos Exposure.

Related studies

• Lung health among boilermakers in Edmonton, Alberta — P.A. Hessel, L.S. Melenka, et al. (1998)
• Patterns of mortality among plumbers and pipefitters — K.P. Cantor, J.M. Sontag, et al. (1986)
• Interspecies comparisons of lung responses to inhaled particles and gases — D.B. Warheit (1989)
• Under-reporting of compensable mesothelioma in Alberta — M.W. Cree, M. Lalji, et al. (2009)
• Non-Malignant Respiratory Illnesses in Association with Occupational Exposure to Asbestos and Other Insulating Materials: Findings from the Alberta Insulator Cohort — S. Moitra, A. Farshchi Tabrizi, et al. (2020)
• An epidemiological study of the respiratory health of workers in the European refractory ceramic fibre industry — H.A. Cowie, P. Wild, et al. (2001)

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