Asbestos and lung cancer in Glasgow and the west of Scotland

Our plain-English summary of Asbestos and lung cancer in Glasgow and the west of Scotland, by H. De Vos Irvine, D.W. Lamont, D.J. Hole, et al (BMJ, 1993).

The study

• Authors: H. De Vos Irvine, D.W. Lamont, D.J. Hole, C.R. Gillis
• Journal: BMJ
• Published: 1993;306(6891):1503-6
• Cited by: 36 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Objective: To quantify the relation between lung cancer and exposure to asbestos in men in west Scotland and to estimate the proportion of lung cancer which may be attributed to exposure to asbestos.

Design: An ecological correlation study of the incidence of lung cancer in men and past asbestos exposure. The unit of analysis was the postcode sector. Correction was made for past cigarette smoking, air pollution, and deprivation.

Setting: The region covered by the west of Scotland cancer registry, containing 2.72 million people and including Glasgow and the lower reaches of the River Clyde, where shipbuilding was once a major industry.

Subjects: All men diagnosed with lung cancer between 1975 and 1984 whose residence at the time of registration was within the west of Scotland.

Main Outcome Measure: The population attributable risk for asbestos related lung cancer.

Results: An estimated 5.7% (95% confidence interval 2.3 to 9.1%) of all lung cancers in men registered in the west of Scotland during the period 1975-84 were asbestos related, amounting to 1081 cases.

Conclusions: A considerable proportion of cases of lung cancer in men in Glasgow and the west of Scotland from 1975 to 1984 were asbestos related. Most of these may not have been considered for compensation by the Department of Social Security. Given the very small annual number of recorded cases of asbestosis this condition is probably not a prerequisite for the development of asbestos related lung cancer. A heightened awareness of the increasing incidence of asbestos related neoplasms and their more thorough investigation are recommended.

In plain English

This was an ecological correlation study, meaning it compared geographic areas rather than individual people. The authors used west of Scotland cancer registry data on all men diagnosed with lung cancer from 1975 to 1984, grouped by postcode sector. There was no direct measure of who had been exposed to asbestos, so each area's mesothelioma rate for 1980-9 was used as a stand-in for past asbestos exposure of all fibre types. The analysis corrected for past cigarette smoking, air pollution and deprivation. After these corrections, areas with higher mesothelioma rates had higher lung cancer rates (p less than 0.01). The smoking measure explained the largest share of the differences between areas. The authors estimated that 5.7% of lung cancers in men registered in the region over 1975-84, or 1081 cases, were asbestos related, with a 95% confidence interval of 2.3% to 9.1% (436 to 1725 cases). They concluded that at least 5% were asbestos related. They noted that mesothelioma was probably underdiagnosed and said further study would be needed to confirm the estimate.

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: Ecological correlation study using postcode sectors as the unit of analysis, with correction for past cigarette smoking, air pollution and deprivation
• Who was studied: All men living in the west of Scotland who were diagnosed with lung cancer between 1975 and 1984, analysed by postcode sector
• Exposure: Past asbestos exposure of all fibre types, measured indirectly: the age standardised mesothelioma incidence in men for 1980-9 in each postcode sector was used as a proxy
• Main results:
  • Among the postcode sectors studied, 148 sectors (42%) recorded no cases of mesothelioma, while 25 sectors (7%) had mesothelioma rates greater than 10 per 100 000 per year
  • The four variables (smoking proxy, air pollution, deprivation, mesothelioma) together accounted for over 70% of the variation in lung cancer rates between postcode sectors. The proxy for cigarette smoking accounted for 54%
  • The regression coefficient for log-transformed mesothelioma incidence was 11.545 (p less than 0.01; 95% confidence interval 4.628 to 18.462 in table III). This means an increase of 11.545 in lung cancer incidence per 100 000 men for each unit change in the log-transformed mesothelioma rate
  • The population attributable risk for asbestos related lung cancer among men in the west of Scotland for 1975-84 was 5.7%, amounting to 1081 cases
  • The 95% confidence interval for the population attributable risk was 2.3% to 9.1%, equivalent to between 436 and 1725 cases
• The authors' conclusion: The authors concluded that at least 5% of all lung cancers registered in men in the west of Scotland between 1975 and 1984 were asbestos related
• Limitations the authors state:
  • There was no direct estimate of how common asbestos exposure was in the population, so exposure was estimated indirectly
  • Mesothelioma was likely underdiagnosed to a varying degree; the authors said their estimate may therefore be conservative
  • Histological verification was much higher for mesothelioma (80%) than for lung cancer (46%). The authors argued that misdiagnosis would weaken rather than create a correlation
  • The authors considered whether the area-level correlation could reflect an 'ecological fallacy', and judged this risk minimal
  • The authors said further retrospective or prospective study would be needed to confirm the estimate

Topics

The National Library of Medicine indexes this study under subjects our site covers: Lung cancer.

Medical terms in this study, explained in our Lexicon: Lung Cancer, Asbestos Exposure, Cancer Registry, Population Attributable Fraction (PAF), confidence interval, Neoplasm.

Related studies

• Clinical features and epidemiology of malignant pleural mesothelioma in west Glasgow 1987-1992 — A.N. McLean, K.R. Patel (1997)
• Malignant pleural mesothelioma in western Glasgow 1980-6 — G. Hulks, J.S. Thomas, et al. (1989)
• Mesothelioma in Scotland — J. McEwen, A. Finlayson, et al. (1970)
• Asbestos in Scotland — T. Gorman, R. Johnston, et al. (2004)
• Malignant pleural mesothelioma from nonoccupational asbestos exposure in Metsovo (north-west Greece): slow end of an epidemic? — K. Sakellariou, V. Malamou-Mitsi, et al. (1996)
• Incidence of interstitial lung disease in patients with mesothelioma in the west part of Japan — S. Nojiri, K. Gemba, et al. (2011)

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