Cancer Incidence and Mortality among Petroleum Industry Workers and Residents Living in Oil Producing Communities: A Systematic Review and Meta-Analysis

Our plain-English summary of Cancer Incidence and Mortality among Petroleum Industry Workers and Residents Living in Oil Producing Communities: A Systematic Review and Meta-Analysis, by F.M. Onyije, B. Hosseini, K. Togawa, et al (International Journal of Environmental Research and Public Health, 2021).

The study

• Authors: F.M. Onyije, B. Hosseini, K. Togawa, J. Schüz, A. Olsson
• Journal: International Journal of Environmental Research and Public Health
• Published: 2021;18(8)
• Type of article: Meta-analysis, Systematic review
• Cited by: 54 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Petroleum extraction and refining are major sources of various occupational exposures and of air pollution and may therefore contribute to the global cancer burden. This systematic review and meta-analysis is aimed at evaluating the cancer risk in petroleum-exposed workers and in residents living near petroleum facilities. Relevant studies were identified and retrieved through PubMed and Web of Science databases. Summary effect size (ES) and 95% confidence intervals (CI) were analysed using random effect models, and heterogeneity across studies was assessed (I2). Overall, petroleum industry work was associated with an increased risk of mesothelioma (ES = 2.09, CI: 1.58-2.76), skin melanoma (ES = 1.34, CI: 1.06-1.70 multiple myeloma (ES =1.81, CI: 1.28-2.55), and cancers of the prostate (ES = 1.13, Cl: 1.05-1.22) and urinary bladder (ES = 1.25, CI: 1.09-1.43) and a decreased risk of cancers of the esophagus, stomach, colon, rectum, and pancreas. Offshore petroleum work was associated with an increased risk of lung cancer (ES = 1.20; 95% CI: 1.03-1.39) and leukemia (ES = 1.47; 95% CI: 1.12-1.92) in stratified analysis. Residential proximity to petroleum facilities was associated with childhood leukemia (ES = 1.90, CI: 1.34-2.70). Very few studies examined specific exposures among petroleum industry workers or residents living in oil producing communities. The present review warrants further studies on specific exposure levels and pathways among petroleum-exposed workers and residents living near petroleum facilities.

In plain English

This was a systematic review and meta-analysis. It reviewed 57 papers from 1990 to 2019, 43 on petroleum workers and 14 on residents near petroleum facilities; 41 cohort and 10 case-control studies were pooled in the meta-analysis. Among workers, mesothelioma risk was higher in mortality studies (effect size 1.98, 95% CI 1.46 to 2.67; nine studies, 280 deaths) and incidence studies (2.09, 95% CI 1.58 to 2.76; four studies, 52 cases). Incidence studies showed higher multiple myeloma, skin melanoma, prostate and urinary bladder cancer. Several digestive cancers showed lower risk. Pooled lung cancer mortality was lower (0.82, 95% CI 0.76 to 0.88). Offshore workers had a higher lung cancer risk (1.20, 95% CI 1.03 to 1.39) in an analysis that combined mortality and incidence studies. Two studies of residents showed higher childhood leukemia (1.90, 95% CI 1.34 to 2.70). The authors concluded that many associations appear due to factors other than petroleum production, such as asbestos for mesothelioma, and the evidence remains weak. They noted crude exposure assessment in some studies and no data on asbestos fiber concentrations in petroleum facilities.

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: Systematic review and meta-analysis (random effects) of cohort, case-control and cross-sectional studies published 1990 to 2019
• Who was studied: 57 eligible papers (41 cohort, 14 case-control, two cross-sectional). 43 papers studied petroleum workers and 14 studied residents living near petroleum facilities. Most came from North America and none from Africa. The 41 cohort and 10 of the case-control studies were pooled in the meta-analysis; four case-control and two cross-sectional studies were described separately.
• Exposure: Work in the petroleum industry, from exploration and production through refining and distribution, analysed by category (refinery, petroleum, petrochemical, refinery and petrochemical, offshore). The review also covered residence near petroleum facilities. A few included studies looked at specific exposures such as benzene, hydrocarbons and asbestos.
• Main results:
  • Petroleum workers, mesothelioma mortality: pooled effect size 1.98 (95% CI 1.46, 2.67) from nine mortality studies, based on 280 mesothelioma deaths
  • Petroleum workers, mesothelioma incidence: pooled effect size 2.09 (95% CI 1.58, 2.76) from four incidence studies with 52 incident cases
  • Mesothelioma by industry category, with mortality and incidence combined: refinery OR 1.94 (95% CI 1.00, 3.76); petroleum OR 1.58 (1.30 to 1.93); refinery and petrochemical OR 2.86 (2.16, 3.77); offshore OR 2.47 (1.66, 3.67)
  • One included death-certificate-based case-control study (Finkelstein; 17 mesothelioma cases) looked at maintenance work in the refinery and petrochemical company in Canada. That work was associated with an OR of 24.5 (90% CI 3.1, 102) for mesothelioma.
  • Petroleum workers: elevated risks of multiple myeloma, skin melanoma, prostate cancer and urinary bladder cancer were seen in incidence studies but not in mortality studies
  • Petroleum workers, multiple myeloma incidence: pooled effect size 1.80 (95% CI 1.28, 2.55) from five incidence studies with 32 incident cases
  • Petroleum workers, lung cancer mortality: pooled effect size 0.82 (95% CI 0.76, 0.88) from 18 mortality studies, based on 7231 lung cancer deaths
  • Offshore workers, stratified analysis combining mortality and incidence: lung cancer OR 1.20 (95% CI 1.03, 1.39); leukemia (combined) OR 1.47 (95% CI 1.12, 1.92)
  • Petroleum workers: inverse associations for cancers of the liver, esophagus, colon, pancreas, stomach and rectum, which were stronger in mortality studies than in incidence studies
  • Residents near petroleum facilities, childhood leukemia: pooled effect size 1.90 (95% CI 1.34, 2.70) from two case-control studies
• The authors' conclusion: The authors concluded that petroleum work was associated with increased risks of mesothelioma and other cancers. They added that many associations appear to be due to factors other than those directly emerging from petroleum production, including asbestos for mesothelioma.
• Limitations the authors state:
  • Some studies used crude exposure assessment, such as ever employment in the industry.
  • Some studies did not analyse duration or level of exposure.
  • Some analyses were severely under-powered.
  • Lower mortality in occupational cohorts may reflect the exclusion of unhealthy people from employment.
  • No data were available on asbestos fiber concentrations in petroleum facilities.
  • Residential studies were not excluded for low methodological quality because so few papers were eligible.
  • The overall evidence was weak, especially for the residential studies.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Mesothelioma, Refineries and petrochemical plants.

Medical terms in this study, explained in our Lexicon: Systematic Review, Meta-Analysis, Occupational Exposure, confidence interval, Mesothelioma, Myeloma, Lung Cancer.

Related studies

• Update of mortality and cancer incidence in the Australian petroleum industry cohort — R.T. Gun, N. Pratt, et al. (2006)
• Update of a prospective study of mortality and cancer incidence in the Australian petroleum industry — R.T. Gun, N.L. Pratt, et al. (2004)
• Mortality and cancer morbidity in a cohort of Canadian petroleum workers — R.J. Lewis, A.R. Schnatter, et al. (2003)
• Select mortality and cancer incidence among residents in various U.S. communities that received asbestos-contaminated vermiculite ore from Libby, Montana — D.K. Horton, F. Bove, et al. (2008)
• Systematic Review and Meta-Analysis of Selected Cancers in Petroleum Refinery Workers — A.R. Schnatter, M. Chen, et al. (2018)
• Asbestos exposure and cancer mortality among petroleum refinery workers: a Poisson regression analysis of updated data — F. Montanaro, M. Ceppi, et al. (2004)

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