Occupational differences in rates of lung cancer

Our plain-English summary of Occupational differences in rates of lung cancer, by H.R. Menck, B.E. Henderson (Journal of Occupational Medicine., 1976).

The study

• Authors: H.R. Menck, B.E. Henderson
• Journal: Journal of Occupational Medicine.
• Published: 1976;18(12):797-801
• Cited by: 149 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. 002300).

Abstract

Lung cancer rates in Los Angeles County were reviewed for different occupations and industries. Employment groups found to be at excess risk who have not been previously implicated included roofers, dental lab technicians, decorators, nonautomotive mechanics, photoengravers, clothing ironers, electricians, bar and restaurant managers, janitors: and workers in the radio-TV brooad-casting, dairy, leather, food and drink, bakery, and auto repair industries. Mo lung cancer in Los Angeles County had exposure to asbestos, polycyclic aromatic hydrocarbon compounds (PAH), or both.

In plain English

This study looked at lung cancer by occupation and industry among white men aged 20 to 64 in Los Angeles County. The authors pooled 2,161 death certificates mentioning lung cancer from 1968-1970 with 1,777 new cases reported to the county cancer registry in 1972-1973. They compared the cases in each job with the number expected from 1970 census figures, as a ratio where 100 is the average for all occupations. Occupations with significantly raised ratios, a list that included asbestos and insulation workers, together had 942 cases against 537 expected, a ratio of 175. These workers made up 15% of the age group but had 29% of the lung cancers among men who reported an occupation. Thirteen industries had significantly raised ratios, from 127 to 279. The authors had no smoking information. They said they could not determine whether the differences came from workplace carcinogens, smoking or other factors such as air pollution. Exposures were not measured, but the authors concluded that most higher-risk groups had exposure to asbestos, polycyclic aromatic hydrocarbons (PAH), or both.

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: Population-based analysis of lung cancer deaths and registry-reported cases by last occupation and industry, comparing observed with expected cases (ratios the authors called Standard Mortality Ratios) using census population estimates
• Who was studied: White males aged 20-64 in Los Angeles County: 2,161 death certificates mentioning lung cancer (trachea, bronchus and lung) for 1968-1970, plus 1,777 incident cases reported to the County Cancer Surveillance Program for 1972-1973 (3,938 subjects; 689 had no reported occupation and 1,222 no reported industry)
• Exposure: Last reported occupation and industry of employment, coded with the 1970 U.S. Census classification. No asbestos or other exposure was measured.
• Main results:
  • Occupations with significantly increased ratios combined: 942 observed lung cancers versus 537 expected, a ratio of 175
  • Workers in these high-risk occupations made up 15% of white males aged 20-64 but accounted for 29% of the lung cancer among men who reported an occupation
  • Asbestos and insulation workers were listed among the occupations with significantly increased ratios (Table 1). Their individual figures cannot be reliably read in this copy.
  • Occupational groups at excess risk that the authors said had not been previously implicated included roofers, dental lab technicians, decorators, nonautomotive mechanics and photoengravers, among others
  • 16 occupations had a ratio below 70, including physicians, teachers, dentists and judges
  • Workers in 13 industries had significantly increased ratios ranging from 127 to 279
  • Workers in the high-risk industries, who made up 27% of the age group, accounted for 42% of the lung cancer among men reporting an industry
  • No significant lung cancer risk was detected among chemical and rubber workers
  • The authors suggested that clothing ironers, plasterers, dry wall workers, electricians and plumbers may have been exposed to asbestos. This was their interpretation, not a measurement.
• The authors' conclusion: The authors concluded that most of the occupational and industrial groups at greater lung cancer risk in Los Angeles County had exposure to asbestos, PAH compounds, or both. In the discussion they wrote that most of the risk 'may be related' to these exposures.
• Limitations the authors state:
  • No information on smoking, which limited the authors' ability to separate occupational risk from other causes
  • Whether the risk differences came from occupational carcinogens or from smoking habits and other factors such as general air pollution could not be determined
  • Some risk estimates, such as those for bookbinders and blasters (greater than fourfold), rested on so few cases that inferences would be speculative
  • Excesses among bartenders and janitors may reflect smoking rather than occupation
  • The lack of a finding in chemical and rubber workers may be due to small numbers of such workers in the county

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.

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• Non-occupational exposure to asbestos and malignant mesothelioma in females — N.J. Vianna, A.K. Polan (1978)
• Occupational risk factors for laryngeal carcinoma: Connecticut, 1975-1980 — R.T. Zagraniski, J.L. Kelsey, et al. (1986)
• Defining asbestos: differences between the built and natural environments — M.E. Gunter (2010)
• Occupational associations with lung cancer in two Ontario cities — M.M. Finkelstein (1995)

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