Asbestos exposure and cancer mortality among petroleum refinery workers: a Poisson regression analysis of updated data

Our plain-English summary of Asbestos exposure and cancer mortality among petroleum refinery workers: a Poisson regression analysis of updated data, by F. Montanaro, M. Ceppi, R. Puntoni, et al (Archives of Environmental Health, 2004).

The study

• Authors: F. Montanaro, M. Ceppi, R. Puntoni, S. Silvano, V. Gennaro
• Journal: Archives of Environmental Health
• Published: 2004;59(4):188-93
• Cited by: 6 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

The authors investigated the relationship between asbestos exposure and respiratory cancer mortality among maintenance workers and other blue-collar workers at an Italian oil refinery. The cohort contained 931 men, 29,511 person-years, and 489 deaths. Poisson regression analysis using white-collar workers as an internal referent group provided relative risk estimates (RRs) for main causes of death, adjusted for age, age at hiring, calendar period, length of exposure, and latency. Among maintenance workers, RRs for all tumors (RR = 1.50), digestive system cancers (RR = 1.41), lung cancers (RR = 1.53), and nonmalignant respiratory diseases (RR = 1.71) were significantly increased (p < 0.05); no significant excess was found for all causes and among maintenance (RR = 1.12) and other blue-collar workers (RR = 1.01). Results confirm the increased risk of death from respiratory diseases and cancer among maintenance workers exposed to asbestos, whereas other smoking-related diseases (circulatory system) were not statistically different among groups.

In plain English

This cohort mortality study followed 931 men from a La Spezia, Italy, oil refinery, closed in 1977, to June 30, 1999. Lacking asbestos measurements, the authors used job title as the exposure measure; asbestos materials were found at the plant's demolition. Poisson regression, adjusted for age, age at hiring, calendar period, length of employment and latency, compared 357 maintenance and 353 other blue-collar workers with 221 white-collar workers. Maintenance workers had significantly higher death risks from all cancers (RR 1.50, 95% CI 1.18–1.90), digestive cancers (1.41, 1.07–1.87), lung cancer (1.53, 1.11–2.10) and non-cancer respiratory diseases (1.71, 1.23–2.38). Their all-cause death risk (1.12, 0.95–1.33) was not significantly raised. Other blue-collar workers showed no significant differences in the estimated relative risks. Pleural mesothelioma killed eight maintenance workers, one other blue-collar worker and no white-collar workers, preventing an internal comparison. Circulatory disease deaths did not differ significantly, suggesting to the authors similar smoking habits. The authors concluded the analysis confirmed their earlier findings. They noted the comparison might underestimate asbestos effects because white-collar workers also worked on the plant grounds.

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: Retrospective cohort mortality study with an internal comparison (Poisson regression, white-collar workers as the reference group)
• Who was studied: 931 male workers employed at an oil refinery in La Spezia, Italy, that shut down in 1977. They were grouped as 221 white-collar workers (7,285 person-years), 357 maintenance workers (11,016 person-years) and 353 other blue-collar workers (11,210 person-years). Follow-up ran to June 30, 1999, giving 29,511 person-years in total, with 1.5% lost to follow-up.
• Exposure: Asbestos exposure was estimated from job title (maintenance, other blue-collar, white-collar) because no direct exposure data were available. Asbestos materials were found during demolition of the plant. No fiber type is named.
• Main results:
  • All malignant tumor deaths: 74 among maintenance workers, RR 1.50 (95% CI 1.18–1.90), and 51 among other blue-collar workers, RR 1.01 (0.78–1.30). The white-collar reference group had 34 deaths.
  • Lung cancer deaths: 24 among maintenance workers, RR 1.53 (95% CI 1.11–2.10), and 17 among other blue-collar workers, RR 1.04 (0.75–1.46). The white-collar reference group had 11 deaths.
  • Digestive system cancer deaths: 27 among maintenance workers, RR 1.41 (95% CI 1.07–1.87), and 17 among other blue-collar workers, RR 0.89 (0.66–1.22). The white-collar reference group had 13 deaths.
  • Non-cancer respiratory tract disease deaths: 23 among maintenance workers, RR 1.71 (95% CI 1.23–2.38), and 16 among other blue-collar workers, RR 1.22 (0.86–1.72). The white-collar reference group had 9 deaths.
  • The respiratory disease deaths included 8 from pneumoconiosis among maintenance workers and 2 among other blue-collar workers.
  • All-cause deaths: 196 among maintenance workers, RR 1.12 (95% CI 0.95–1.33), and 175 among other blue-collar workers, RR 1.01 (0.85–1.20). Neither was significantly increased. The white-collar reference group had 118 deaths.
  • Pleural mesothelioma: 8 deaths among maintenance workers, 1 among other blue-collar workers and none among white-collar workers, so no internal relative risk could be calculated.
  • Circulatory system disease deaths: 58 among maintenance workers, RR 0.82 (95% CI 0.66–1.02), and 74 among other blue-collar workers, RR 1.05 (0.86–1.29). Neither differed significantly from the white-collar reference group.
  • The authors interpreted the lack of a significant difference in circulatory disease deaths as suggesting that the three groups had similar smoking habits.
• The authors' conclusion: The authors concluded that, using updated data and a new statistical approach, the study confirmed their previous results obtained with SMR and attributable risk analyses. They also concluded that job title can serve as a simple surrogate for exposure when measurements are not available.
• Limitations the authors state:
  • The authors stated that the internal comparison could underestimate the effects of asbestos, because white-collar workers also worked on the plant grounds.

Topics

Medical terms in this study, explained in our Lexicon: Asbestos Exposure, Relative Risk, Latency, Lung Cancer.

Related studies

• An updated mortality study of workers at a petroleum refinery in Beaumont, Texas — G.K. Raabe, K.W. Collingwood, et al. (1998)
• Long-term follow-up mortality study of petroleum refinery and chemical plant employees — S.P. Tsai, E.L. Gilstrap, et al. (1996)
• An updated study of mortality among workers at a petroleum manufacturing plant — Y. Honda, E. Delzell, et al. (1995)
• Asbestos-related cancers in refinery workers in the Australian petroleum industry — R. Gun, N.L. Pratt, et al. (2006)
• Mortality and cancer morbidity in a cohort of Canadian petroleum workers — R.J. Lewis, A.R. Schnatter, et al. (2003)
• Mesothelioma and lung tumors attributable to asbestos among petroleum workers — V. Gennaro, M.M. Finkelstein, et al. (2000)

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