Feasibility of identifying high-risk occupations through tumor registries

Our plain-English summary of Feasibility of identifying high-risk occupations through tumor registries, by M.D. Whorton, J. Schulman, S.R. Larson, et al (Journal of Occupational Medicine., 1983).

The study

• Authors: M.D. Whorton, J. Schulman, S.R. Larson, H.A. Stubbs, D. Austin
• Journal: Journal of Occupational Medicine.
• Published: 1983;25(9):657-60
• Cited by: 16 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. 001731).

Abstract

The primary objective of this study was to assess the feasibility of using a population-based tumor registry to identify occupational groups at high risk of developing cancer. The study group comprised 6,424 union members residing in the San Francisco/Oakland Standard Metropolitan Statistical Area (SMSA) who represent six occupations: asbestos workers, bakers, painters, plasterers, plumbers and roofers. Computer linkage of union rosters to the California Tumor Registry (CTR) file identified incident cases of cancer. The CTR's age-sex-year-specific incidence rates were used to calculate the expected number of cancer cases, and estimated standardized incidence ratios (SIRs). The results demonstrate, as expected, increased cancer incidence (SIR = 498) for trachea, bronchus, lung and pleura among asbestos workers, a group widely recognized as having high risk for respiratory cancers, and among painters (SIR = 199). Strengths and weaknesses of such an approach are discussed.

In plain English

This study tested whether matching union membership lists against a population-based cancer registry could identify occupations at high risk of cancer. By computer, the authors linked the rosters of 6,424 union members (6,238 men and 186 women) living in the San Francisco/Oakland area with the California Tumor Registry for 1976 and 1977. Six occupations were included: asbestos workers (235 men), bakers, painters, plasterers, plumbers and roofers. The number of cancers observed was compared with the number expected from registry rates. Cancer of the trachea, bronchus, lung and pleura was statistically significantly increased among asbestos workers (SIR 498, based on three cases) and among painters (SIR 199). The all-site SIRs for asbestos workers (220), painters, plumbers and roofers were not statistically significant. One peritoneal mesothelioma was observed among the asbestos insulation workers. The authors concluded that the method found a known high-risk group. They noted that the small cohort and very short observation period meant a disease would have to be rampant to be detected, and that non-significant findings carried little weight. They said the painters' result needs further investigation.

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: Record-linkage cohort study: union rosters linked to a population-based tumor registry, comparing observed with expected cancer cases (standardized incidence ratios). The aim was to test the feasibility of the method.
• Who was studied: 6,424 union members (6,238 male, 186 female) living in the San Francisco/Oakland Standard Metropolitan Statistical Area, who were members in July 1976 and 1977. Cohorts ranged from 235 asbestos insulation workers (all male) to 2,200 painters; the others were bakers, plasterers, plumbers and roofers.
• Exposure: Occupation (union membership) in six trades: roofers, painters, plasterers, asbestos workers, plumbers and bakers. Bakers were included as a group with no known carcinogenic exposure. No fiber types or doses were measured.
• Main results:
  • Asbestos workers: SIR 498 for cancer of the trachea, bronchus, lung and pleura, statistically significant.
  • Painters: statistically significant increase in cancer of the trachea, bronchus, lung and pleura (SIR 199).
  • Three asbestos insulation workers had cancer of the lung or pleura.
  • All-site SIRs were 220 for asbestos workers, 119 for painters, 108 for plumbers and 142 for roofers. None was statistically significant.
  • Some site-specific SIRs were elevated but not statistically significant: painters (leukemia; cancer of rectum and anus), plumbers (larynx and bladder) and roofers (cancer of rectum and anus).
  • One peritoneal mesothelioma was observed among the asbestos insulation workers.
• The authors' conclusion: The authors concluded that the record-linkage approach found a known high-risk population. They said the increase in respiratory cancer among painters needs further investigation.
• Limitations the authors state:
  • The cohort was small and the observation period very short, so a disease would have to be rampant to be detected.
  • Because of the short observation time and sample size, negative or non-significant findings are weak.
  • About 950 subjects (14.8%) had unknown vital status. The authors said person-years may have been overestimated, so the SIRs could be underestimated to a minor degree.
  • The way the cohort was defined (membership status on July 1 of each year) could cause errors in apparent incidence for 1976 and 1977.
  • The registry misses cases not reported to it and cases among residents diagnosed outside the area.
  • There were no race data, so incidence rates for all races combined were used.
  • Determining vital status was time-consuming and costly, which works against the aim of an inexpensive study.

Topics

Medical terms in this study, explained in our Lexicon: Cancer Registry, Incidence, Standardized Incidence Ratio (SIR), Bronchus, Pleura.

Related studies

• Mesothelioma registries in identifying asbestos hazards — A.D. McDonald (1979)
• Women's occupation and cancer: preliminary analysis of cancer registrations in England and Wales, 1971-1990 — J. Simpson, E. Roman, et al. (1999)
• Occupation and cancer in Britain — L. Rushton, S. Bagga, et al. (2010)
• Occupation and risk of cancer of the renal pelvis in Nordic countries — I.M. Michalek, J.I. Martinsen, et al. (2019)
• Incidence of mesothelioma and asbestosis by occupation in a diverse workforce — N.L. DeBono, H. Warden, et al. (2021)
• International renal-cell cancer study. IV. Occupation — J.S. Mandel, J.K. McLaughlin, et al. (1995)

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