Airways obstruction among older construction and trade workers at Department of Energy nuclear sites

Our plain-English summary of Airways obstruction among older construction and trade workers at Department of Energy nuclear sites, by J.M. Dement, L. Welch, K. Ringen, et al (American Journal of Industrial Medicine, 2010).

The study

• Authors: J.M. Dement, L. Welch, K. Ringen, E. Bingham, P. Quinn
• Journal: American Journal of Industrial Medicine
• Published: 2010;53(3):224-40
• Cited by: 36 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Background: A study of chronic obstructive pulmonary disease (COPD) among 7,579 current and former workers participating in medical screening programs at Department of Energy (DOE) nuclear weapons facilities through September 2008 was undertaken.

Methods: Participants provided a detailed work and exposure history and underwent a respiratory examination that included a respiratory history, respiratory symptoms, a posterior-anterior (P-A) chest radiograph classified by International Labour Office (ILO) criteria, and spirometry. Statistical models were developed to generate group-level exposure estimates that were used in multivariate logistic regression analyses to explore the risk of COPD in relation to exposures to asbestos, silica, cement dust, welding, paints, solvents, and dusts/fumes from paint removal. Risk for COPD in the study population was compared to risk for COPD in the general US population as determined in National Health and Nutrition Examination Survey (NHANES III).

Results: The age-standardized prevalence ratio of COPD among DOE workers compared to all NHANES III data was 1.3. Internal analyses found the odds ratio of COPD to range from 1.6 to 3.1 by trade after adjustment for age, race, sex, smoking, and duration of DOE employment. Statistically significant associations were observed for COPD and exposures to asbestos, silica, welding, cement dusts, and some tasks associated with exposures to paints, solvents, and removal of paints.

Conclusions: Our study of construction workers employed at DOE sites demonstrated increased COPD risk due to occupational exposures and was able to identify specific exposures increasing risk. This study provides additional support for prevention of both smoking and occupational exposures to reduce the burden of COPD among construction workers.

2009 Wiley-Liss, Inc.

In plain English

This cross-sectional study examined chronic obstructive pulmonary disease (COPD) in 7,579 construction and trade workers screened at Department of Energy (DOE) nuclear weapons sites through September 2008. Workers reported how often they did tasks involving asbestos, silica, welding, cement dust, solvents, paints and paint removal. Moderate to very severe COPD was found in 15.0% of workers. Their age-standardized prevalence was 1.3 times that in a US national survey (NHANES III). The researchers compared each trade with administrative, scientific and security workers, adjusting for age, race, sex, smoking and years of DOE work. In the results table, odds ratios ranged from 1.44 (boilermakers, not statistically significant) to 3.09; the authors' text gives 1.57 to 3.09. For asbestos workers/insulators the odds ratio was 2.66 (95% CI 1.42 to 4.97). Higher estimated asbestos task scores were associated with COPD, even after accounting for X-ray changes in the lung tissue. Silica, welding and cement dust tasks were also associated with COPD. Smoking was a strong risk factor, and a statistical test suggested a possible smoking-asbestos interaction. The authors concluded that occupational exposures increased COPD risk. They noted that exposures were self-reported and that asbestos-exposed trades often had other 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 analysis of medical screening data (questionnaires, work histories, chest X-rays, spirometry). It included internal comparisons by trade, comparison with published NHANES III data, and exploratory exposure-response analyses using group-level exposure estimates.
• Who was studied: 7,579 current and former construction and trade workers at DOE nuclear sites (including Hanford, Oak Ridge, Savannah River, Amchitka, Paducah, Rocky Flats and others). All had completed initial examinations with acceptable spirometry through September 2008. They were 93.4% male and 86.7% Caucasian, with a mean age of 58.0 years. The COPD exposure-response analyses used a sub-cohort of 4,935 workers (603 COPD cases) with five or fewer years of trade work outside DOE sites.
• Exposure: Self-reported frequency of tasks associated with seven exposures. For asbestos there were 8 tasks, including pipe insulation, asbestos-cement (Transite) products, gaskets, packings, floor tiles, spray fireproofing and drywall. The other exposures were silica, welding and cutting, cement dust, solvents, paints, and dusts/fumes from paint removal. Task frequencies were converted to estimated exposure days per month and modeled as group-level scores by trade, site, time period, sex and race. Fiber types were not specified.
• Main results:
  • Overall prevalence of moderate to very severe COPD (GOLD Stages II–IV) among all 7,579 workers was 15.0%. By site it ranged from 9.5% at Amchitka to 20.8% at Paducah.
  • Among 6,737 DOE workers aged 30–75, the age-standardized COPD prevalence was 9.3%, compared with 7.1% for all NHANES III participants. This gave a prevalence ratio of 1.3.
  • Trade groups were compared with administrative/scientific/security workers (COPD prevalence 6.69%), adjusting for age, race, sex, smoking and years of DOE work. In Table VII, adjusted COPD odds ratios ranged from 1.44 for boilermakers (95% CI 0.69–2.99, not statistically significant) to 3.09 for cement/brick masons and plasterers. The authors' text states the range as 1.57 to 3.09.
  • For asbestos workers/insulators, Table VII gives an adjusted COPD odds ratio of 2.66 (95% CI 1.42–4.97) compared with the administrative/scientific/security group. The narrative text prints the lower limit as 1.46.
  • COPD prevalence was 12.6% among workers with a normal chest X-ray by ILO criteria. It was 23.0% (247 of 1,075) with pleural changes only, 25.2% (34 of 135) with parenchymal changes only, and 32.5% (55 of 169) with both pleural and parenchymal changes.
  • In the exposure-response sub-cohort, the modeled sum of asbestos task scores was associated with COPD. The odds ratio was 1.115 (95% CI 1.010–1.230) per 1 standard deviation increase in the log score, adjusted for age, sex, race, smoking and years of DOE work.
  • The asbestos-COPD association remained statistically significant (OR 1.111, 95% CI 1.005–1.229) in a model that also included chest X-ray parenchymal changes of profusion 1/0 or greater.
  • Statistically significant positive associations with COPD were also found for welding, silica and cement dust task scores. Some specific solvent tasks (fueling trucks and equipment) and paint removal tasks were also associated with COPD.
  • A smoking-by-asbestos interaction term was statistically significant (P = 0.039). The authors described this as suggesting possible interactive effects.
  • Smoking was strongly related to COPD. Only 14.7% of workers with COPD had never smoked, compared with 39.3% of workers without COPD.
  • The validation analysis included 4,758 workers, 695 of whom had pleural or parenchymal X-ray changes. In it, the modeled asbestos task score was associated with asbestos-related chest X-ray changes, with an odds ratio of 1.348 (95% CI 1.218–1.492) per 1 standard deviation increase.
• The authors' conclusion: The authors concluded that their study demonstrated increased COPD risk due to occupational exposures among these construction workers. They identified asbestos, silica, welding, cement dust and some solvent, paint and paint-removal tasks as exposures associated with increased risk, and found smoking to be a powerful risk factor. They described their results as supporting an association between asbestos exposure and obstructive lung impairment, perhaps with an interaction with smoking.
• Limitations the authors state:
  • The exposure analyses were exploratory and based on workers' self-reported task frequencies.
  • Many trades with significant asbestos exposure also had exposure to other agents associated with COPD, such as silica and welding/cutting. The authors said their asbestos conclusion must be tempered for this reason.
  • Workers with significant cement dust exposure also had significant silica exposure, so the effect could not be attributed to either exposure alone.
  • The data were cross-sectional, with no repeated exposure assessments per worker.
  • Isocyanate-based paint exposures could not be evaluated separately because few workers reported them (0.8%).

Topics

Medical terms in this study, explained in our Lexicon: COPD, Exposure History, Chest X-Ray, Spirometry, Odds Ratio, Occupational Exposure.

Related studies

• Surveillance of respiratory diseases among construction and trade workers at Department of Energy nuclear sites — J.M. Dement, L. Welch, et al. (2003)
• Mortality of older construction and craft workers employed at department of energy (DOE) nuclear sites: follow-up through 2011 — K. Ringen, J. Dement, et al. (2015)
• Mortality of older construction and craft workers employed at department of energy nuclear sites: Follow-up through 2016 — K. Ringen, J. Dement, et al. (2019)
• Mortality of older construction and craft workers employed at Department of Energy (DOE) nuclear sites — J.M. Dement, K. Ringen, et al. (2009)
• Increased mortality in COPD among construction workers exposed to inorganic dust — I.A. Bergdahl, K. Torén, et al. (2004)
• High prevalence of reversible airway obstruction in asbestos-exposed workers — S. Delpierre, M.J. Delvolgo-Gori, et al. (2002)

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