Roentgenographic evidence of asbestos exposure in a select population of railroad workers

Our plain-English summary of Roentgenographic evidence of asbestos exposure in a select population of railroad workers, by M.J. Sepulveda, J.A. Merchant (American Journal of Industrial Medicine, 1983).

The study

• Authors: M.J. Sepulveda, J.A. Merchant
• Journal: American Journal of Industrial Medicine
• Published: 1983;4(5):631-9
• 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. 000642).

Abstract

A volunteer population of 266 current and former railroad workers was examined with posteroanterior and oblique chest roentgenograms, and a comprehensive occupational smoking history. Seventy-five percent of participants were over the age of 60, and 80% had fewer than 10 years of railroad-related asbestos exposure. Roentgenographic evidence of asbestosis was found in only six workers (2%), whereas 20% had one or more pleural changes. Radiological abnormalities were related to latency period, age, and occupation, but not to smoking habit. While selection factors qualify the results of this study, the findings support the exposure and suggest a past and future history of asbestos mortality and morbidity among steam era railway workers.

In plain English

This was a chest X-ray survey by the National Institute for Occupational Safety and Health of 266 volunteer current and former railroad shop workers in a Pennsylvania community. It was prompted by four cases of pleural mesothelioma among former workers of a local railway shop. Each participant had worked at least 2 years at the facility before 1950, in the steam-locomotive era. Most (79%) had 2 to 10 years of such work, and all were 30 or more years past first railroad work. Three certified readers independently read front and oblique chest films. Pleural abnormalities were found in 52 workers (20%). Eight (3%) had small lung opacities, and in six of them these were irregular opacities (asbestosis). Boilermakers (33%) and machinists (30%) had the highest proportions with pleural changes. Pleural changes were more common in older workers and with longer time since first railroad work, but these trends were not statistically significant. Smoking status made no difference after adjustment. The authors stressed that participants were self-selected survivors. They concluded that this occupational group may be at risk for other adverse health effects from asbestos.

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 radiographic (chest X-ray) survey with occupational and smoking questionnaire, conducted by NIOSH
• Who was studied: 266 volunteer current and former railroad shop workers in a Pennsylvania community, each with at least 2 years of tenure at the facility before 1950. 39 of 60 eligible active workers took part; the other 227 were recruited through the media, from a population of unknown size and composition. 75% were over age 60.
• Exposure: Asbestos exposure in steam-era railroad shop work before 1950. Dose was estimated only as years of pre-1950 shop tenure; 210 of 266 (79%) had 2 to 10 years. The background describes asbestos in 85% magnesia lagging for steam locomotive boilers and fireboxes and in other insulation products. The article does not name the fiber type for this population.
• Main results:
  • Pleural abnormalities (pleural thickening and/or calcification) were the most common finding, seen in 52 of 266 workers (20%).
  • Among workers with abnormal pleurae, localized pleural thickening alone (plaques) was present in 31%.
  • Eight persons (3%) had X-ray evidence of pneumoconiosis. Irregular small opacities predominated in six (asbestosis), and rounded opacities alone were seen in two. Three of the six with asbestosis also had pleural abnormalities. No large opacities were observed.
  • By pre-1950 occupation, pleural abnormalities were most frequent among boilermakers (9 of 27, 33%) and machinists (28 of 92, 30%).
  • Pleural abnormality prevalence rose with age group (12% at 50-59 years to 27% at 70-79 and 25% at 80 or older) and with years since onset of railroad work (14% at 30-39 years to 28% at 50 or more). In logistic regression, neither the age coefficient nor the years-from-onset coefficient was statistically significant; the authors said the trend was in the expected direction.
  • Of the 266 participants, 22% were current smokers, 44% ex-smokers and 34% never smokers. After adjusting for age and years since onset of employment, the prevalence of radiological findings did not differ between smoking categories.
  • 38 workers had also been exposed to other dusts, mostly coal and silica. Six of them had abnormal X-rays, and in each case the abnormality was pleural.
• The authors' conclusion: The authors concluded that, while selection factors limit interpretation, the asbestos-related radiological findings suggest this occupational group may be at risk for other adverse health effects from asbestos. They called for better assessment of the health experience of workers in this industry.
• Limitations the authors state:
  • Participants were not representative of the pre-1950 workforce. They were survivors whose exposure had ended 31 years earlier, expected to be the fittest and least likely to show ill effects.
  • Other selection factors in the volunteer group (ambulatory health, living in the community, retiree association membership, media recruitment) further limit the quantitative findings.
  • Most participants were media recruits from a population of unknown size and composition.
  • Using oblique films in addition to the front view increases sensitivity, which cautions against comparing the findings with other occupational groups.
  • There were no environmental exposure measurements; dose was estimated only from years of pre-1950 shop employment.
  • The lack of statistical significance for age and years from first exposure may reflect the relatively low number of abnormal X-rays available for the logistic regression analysis.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Asbestosis, Mesothelioma, Railroads.

Medical terms in this study, explained in our Lexicon: Asbestos Exposure, Latency, Habit.

Related studies

• Asbestos-related disease in railroad workers. A cross-sectional study — L.C. Oliver, E.A. Eisen, et al. (1985)
• A case-control study of lung cancer and diesel exhaust exposure in railroad workers — E. Garshick, M.B. Schenker, et al. (1987)
• Railroad workers with pleural plaques: I. Spirometric and nitrogen washout investigation on smoking and nonsmoking asbestos-exposed workers — U. Hjortsberg, P. Orbaek, et al. (1988)
• Asbestos-related mesothelioma risk among railroad workers — M. Huncharek (1987)
• Railroad workers with pleural plaques: II. Small airway dysfunction among asbestos-exposed workers — U. Hjortsberg, P. Orbaek, et al. (1988)
• A retrospective cohort study of lung cancer and diesel exhaust exposure in railroad workers — E. Garshick, M.B. Schenker, et al. (1988)

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