Lung health among boilermakers in Edmonton, Alberta

Our plain-English summary of Lung health among boilermakers in Edmonton, Alberta, by P.A. Hessel, L.S. Melenka, D. Michaelchuk, et al (American Journal of Industrial Medicine, 1998).

The study

• Authors: P.A. Hessel, L.S. Melenka, D. Michaelchuk, F.A. Herbert, R.L. Cowie
• Journal: American Journal of Industrial Medicine
• Published: 1998;34(4):381-6
• Cited by: 4 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Background: Construction boilermakers may be exposed to a variety of substances, including asbestos and welding fumes. Past studies of boilermakers have shown increases in mortality from lung cancer and asbestosis and radiographic changes consistent with asbestos exposure.

Methods: Respiratory symptoms, lung function, and radiographic changes were compared for 102 actively employed boilermakers with 20 or more years of union membership and 100 telephone workers. Posteroanterior chest radiographs were evaluated by two experienced chest physicians, with a third arbitrating disagreed films. Union members were further categorized as boilermakers (n = 50) or welders (n = 52), based on longest service. Lung health was also compared with employment in a number of work sectors for time, and time-weighted exposure to dust and fumes.

Results: Boilermakers had more respiratory symptoms than telephone workers, but lung function did not differ. Radiographic changes were more common among the boilermakers (20% with any change, 8% circumscribed, and 9% diffuse pleural thickening). None of the boilermakers had small radiographic opacities. Several symptoms suggestive of bronchial responsiveness were associated with fume exposures in the gas and oil industry. Workers whose longest service was as a boilermaker demonstrated more symptoms than did welders. FEV1, FEV1/FVC, FEF25-75, and FEF50 were significantly lower among boilermakers compared with welders.

Conclusion: Health screening programs for these workers are warranted.

In plain English

This cross-sectional study, done in Edmonton, Alberta, in 1995, compared 102 active boilermakers' union members with at least 20 years of membership and 100 telephone workers with 20 years of membership. All were men under 65. The authors described boilermakers as exposed to welding fumes and sometimes to asbestos from insulation. After adjustment for age and smoking, union members reported more respiratory symptoms. The odds ratios were 3.51 (confidence interval 1.43–8.61) for usual phlegm, 2.81 (1.36–5.80) for shortness of breath and 1.90 (1.01–3.56) for chest tightness. Lung function did not differ significantly between the two groups. Any chest X-ray abnormality, including pleural thickening, was found in 20 union members and 2 telephone workers. The table's percentages (20.6% and 2.1%) suggest not all films were counted, but the article does not give the number. No union member had small opacities. Union members whose longest job was boilermaker had significantly lower FEV1, FEV1/FVC, FEF25–75 and FEF50 than those whose longest job was welder. The authors concluded that health screening programs for these workers are warranted. They noted a limited sample size and reliance on self-reported exposures.

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 boilermakers with telephone workers (questionnaire, spirometry, chest X-rays read using the ILO 1980 classification)
• Who was studied: 102 actively employed male members of Local 146 of the International Brotherhood of Boilermakers with at least 20 years of union membership, and 100 male workers at Edmonton Telephones with 20 years of union membership. All were under 65 and lived in the greater Edmonton area. They were tested February to October 1995. Response rates were 77.4% (boilermakers) and 72.7% (telephone workers). Union members were later split by longest-held job into boilermakers (n = 50) and welders (n = 52).
• Exposure: Work as a construction boilermaker or welder. This included working near insulators and removing insulation, which in some situations involved asbestos (fiber type not specified), as well as welding fumes. Dust and fume exposures by work sector were self-reported and graded none, slight, moderate or severe.
• Main results:
  • Usual phlegm: 26 union members (25.5%) vs 9 telephone workers (9.0%). Odds ratio 3.51 (confidence interval 1.43–8.61), adjusted for smoking category and age.
  • Shortness of breath: 35 union members (34.3%) vs 15 telephone workers (15.0%). Adjusted odds ratio 2.81 (1.36–5.80).
  • Chest tightness: 40 union members (39.2%) vs 26 telephone workers (26.0%). Adjusted odds ratio 1.90 (1.01–3.56).
  • The odds ratio for chronic phlegm among union members compared with telephone workers was elevated but not statistically significant: 2.44 (0.99–6.04).
  • Lung function did not differ significantly between union members and telephone workers.
  • Any radiographic abnormality: 20 union members (20.6%) vs 2 telephone workers (2.1%). Odds ratio 12.34 (2.80–54.43). The percentages imply that fewer than 102 and 100 films were counted, but the article does not state the denominators.
  • Circumscribed pleural thickening: 8 union members (8.2%) vs 1 telephone worker (1.0%). Odds ratio 8.63 (1.06–70.38).
  • Diffuse pleural thickening: 9 union members (9.3%) vs 1 telephone worker (1.0%). Odds ratio 9.82 (1.22–79.07).
  • No union member had small radiographic opacities. Among union members, 5.2% had bilateral pleural change.
  • Among union members, fume exposure as a boilermaker in the gas and oil industry was significantly associated with usual cough, wheeze without a cold, chest tightness, attacks of wheeze, and pneumonia.
  • Union members whose longest service was as a boilermaker (n = 50) had lower percentage-of-predicted lung function than those whose longest service was as a welder (n = 52), adjusted for pack-years: FEV1 95.6 vs 103.0 (p = 0.022), FEV1/FVC 94.1 vs 98.3 (p = 0.030), FEF25–75 84.2 vs 99.2 (p = 0.006), FEF50 86.3 vs 100.6 (p = 0.021).
  • Compared with telephone workers, the odds ratio for phlegm was 5.10 (p = 0.002) for union members whose longest service was as a boilermaker and 2.37 (p = 0.105) for those whose longest service was as a welder.
• The authors' conclusion: The authors concluded that active boilermakers' union members with 20 or more years of membership appeared to be at increased risk of a variety of respiratory health effects compared with telephone workers. They noted that a small percentage showed evidence of asbestos exposure, and that health screening programs for these workers are warranted.
• Limitations the authors state:
  • Because of the cross-sectional design, the most affected workers may have already left. The results apply only to active, long-term workers, not those who left because of disability or retirement.
  • The sample size was limited, so subtle effects could not be assessed. Few radiographic changes were found, which made the X-ray risk estimates unstable, with very wide confidence intervals.
  • None of the X-ray readers was certified by NIOSH as a B reader.
  • Exposures to dust and fumes were self-reported.

Topics

Medical terms in this study, explained in our Lexicon: Lung Cancer, Asbestos Exposure, Chest X-Ray, Diffuse Pleural Thickening, FEV1, FEV1/FVC Ratio.

Related studies

• Lung health among plumbers and pipefitters in Edmonton, Alberta — P.A. Hessel, L.S. Melenka, et al. (1998)
• Asbestos-related disease among sheet-metal workers. Preliminary results of the National Sheet Metal Worker Asbestos Disease Screening Program — L.S. Welch, D. Michaels, et al. (1991)
• Under-reporting of compensable mesothelioma in Alberta — M.W. Cree, M. Lalji, et al. (2009)
• Asbestos-related disease among sheet metal workers 1986-2004: radiographic changes over time — L.S. Welch, E. Haile (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)
• Respiratory health of workers exposed to metal dusts and foundry fumes in a copper refinery — G. Ostiguy, C. Vaillancourt, et al. (1995)

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