Mortality from lung cancer in asbestos workers

Our plain-English summary of Mortality from lung cancer in asbestos workers, by R. Doll (British Journal of Industrial Medicine, 1955).

The study

• Author: R. Doll
• Journal: British Journal of Industrial Medicine
• Published: 1955;12(2):81-6
• Cited by: 584 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text
• In J-M's library: Johns-Manville's company medical library held a copy (J-M no. 001858).

Abstract

The cause of death, as determined at necropsy, is reported for 105 persons who had been employed at one asbestos works. Lung cancer was found in 18 instances, 15 times in association with asbestosis. All the subjects in whom both conditions were found had started employment in the industry before 1923 and had worked in the industry at least nine years before the regulations for the control of dust had become effective. One hundred and thirteen men who had worked for at least 20 years in places where they were liable to be exposed to asbestos dust were followed up and the mortality among them compared with that which would have been expected on the basis of the mortality experience of the whole male population. Thirty-nine deaths occurred in the group whereas 15.4 were expected. The excess was entirely due to excess deaths from lung cancer (11 against 0.8 expected) and from other respiratory and cardiovascular diseases (22 against 7.6 expected). All the cases of lung cancer were confirmed histologically and all were associated with the presence of asbestosis. From the data it can be concluded that lung cancer was a specific industrial hazard of certain asbestos workers and that the average risk among men employed for 20 or more years has been of the order of 10 times that experienced by the general population. The risk has become progressively less as the duration of employment under the old dusty conditions has decreased.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.

In plain English

This study looked at workers at one large asbestos works. Neither the works, the town, nor any fiber type is named. First, the author reviewed coroners' necropsies (post-mortem examinations) on 105 people who had worked there. Lung cancer was found in 18 of them, 15 times together with asbestosis. All 15 had started work before 1923 and had worked at least nine years before the works' dust-control precautions became effective by the end of 1932. Second, the author followed 113 men who had worked at least 20 years in dusty areas. Their deaths were compared with numbers expected from national male death rates for England and Wales. There were 39 deaths against 15.4 expected. These included 11 lung cancer deaths against 0.8 expected, all with asbestosis. Lung cancer with asbestosis was less frequent among men with fewer years under pre-1933 conditions. The author concluded that lung cancer was a specific industrial hazard of certain asbestos workers, and that for men employed 20 or more years the average risk had been of the order of 10 times the general population's.

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: Review of necropsy records at one asbestos works, plus a mortality follow-up of long-serving male employees comparing observed deaths with deaths expected from national (England and Wales) male death rates
• Who was studied: 105 consecutive coroners' necropsies on people who had worked at one large asbestos works (Table 1 covers 1933-52). Separately, 113 men who had worked at least 20 years in the works' dusty 'scheduled areas', followed for the years 1922 to 1953 (1042.25 man-years).
• Exposure: Asbestos dust in 'scheduled areas' of an asbestos works, meaning areas whose processes were classed as dusty under the Asbestos Industry Regulations of 1931. Precautions under those regulations had become effective at the works by the end of 1932. Fiber types are not stated. Jobs among the necropsy lung cancer cases included weaver, fiberizer, spinner, disintegrater, bag carrier and maintenance man.
• Main results:
  • Necropsy series: lung cancer was found in 18 of the 105 people, 15 times in association with asbestosis.
  • Necropsy series: everyone in whom both lung cancer and asbestosis were found had started work before 1923. Each had also worked at least nine years before the dust-control regulations became effective, which at the works was by the end of 1932.
  • Necropsy series: one of the tumours listed among the primary lung cancers was recorded in the pathology report as 'Endothelioma of pleura'. This was a fiberizer who died in 1936, aged 65.
  • Cohort of 113 men: there were 39 deaths from all causes against 15.4 expected from England and Wales rates (P less than 0.000001).
  • Cohort of 113 men: there were 11 lung cancer deaths against 0.8 expected. All 11 were confirmed histologically, and all were associated with asbestosis.
  • Cohort of 113 men: mortality from other respiratory diseases and cardiovascular diseases was increased in association with asbestosis. Mortality from other diseases was close to that expected: neoplasms other than lung cancer, 4 observed against 2.3 expected; all other diseases, 4 against 4.7.
  • Men with asbestosis and lung cancer, grouped by years worked before January 1, 1933: 1 observed with under 10 years; 3 observed (2.4 expected) with 10 to 14 years; 7 observed (3.1 expected) with 15 years or more. Men with asbestosis: 13, 14 and 16 observed, against 21.9, 10.3 and 10.8 expected. The author reported these differences as statistically significant (asbestosis P = 0.025; asbestosis and lung cancer P = 0.01).
• The authors' conclusion: The author concluded that lung cancer was a specific industrial hazard of certain asbestos workers. For men employed 20 or more years, the average risk was of the order of 10 times that of the general population, and the risk before 1933 was perhaps 20 times the general risk. The risk became progressively less as the time worked under the old dusty conditions decreased. Whether the risk had been completely eliminated could not be determined with certainty.
• Limitations the authors state:
  • Expected deaths were based on England and Wales rates rather than on rates for the town where the men lived and died, because the town's rates were not known in sufficient detail.
  • Expected deaths from all causes were likely somewhat underestimated, because the town's all-cause death rate was about 25% higher than the England and Wales rate.
  • The firm's personnel records could not be guaranteed complete.
  • Some of the excess may reflect underestimated expected deaths, since part of the national rise in lung cancer was due to improvements in diagnosis.
  • Too few men had been exposed only under the post-1933 conditions, and for long enough, to judge whether the risk had been eliminated.
  • The expected numbers of lung cancers were small, so the chance probabilities were somewhat underestimated.

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, Autopsy.

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