Proportionate mortality among US shoeworkers, 1966-1977

Our plain-English summary of Proportionate mortality among US shoeworkers, 1966-1977, by P. Decouflé, J. Walrath (American Journal of Industrial Medicine, 1983).

The study

• Authors: P. Decouflé, J. Walrath
• Journal: American Journal of Industrial Medicine
• Published: 1983;4(4):523-32
• Cited by: 24 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Proportionate mortality for various causes was examined among 3,754 decedents (2,144 men, 1,610 women) who had worked in shoe manufacturing plants represented by either of two labor unions in the US. None of the shoeworker deaths were attributed to nasal cancer, whereas 2.2 were expected on the basis of general population data. Mortality from leukemia and cancer of the urinary bladder was not unusual in either sex or either union. However, deaths from cancers of the liver and gallbladder combined were significantly increased among male and female members of one union. Three deaths from mesothelioma were seen among members of this same union. Rectal cancer mortality was higher than expected among men and women in both unions. The findings are at variance with previous reports of high risks of certain cancer sites among shoeworkers. However, results for liver and gallbladder cancer and mesothelioma suggest the possibility that other previously unsuspected hazards may have been present in certain areas of the US shoe industry.

In plain English

This proportionate mortality study examined death certificates of 3,754 white members of two US shoe workers' unions who died from 1966 to 1977. The authors compared each cause's share of deaths with the share expected in the US white population. No death had nasal cancer as its underlying cause, against 2.2 expected; one man's certificate listed nasal sinus carcinoma as a contributing cause. Bladder cancer was not unusual, and leukemia was only slightly increased, with no statistically significant differences. Cancer overall caused significantly more deaths than expected in both sexes. Cancers of the liver, gallbladder and bile ducts, grouped together, were significantly increased among men and women of the Boot and Shoe Workers Union. Rectal cancer was higher than expected in both sexes. That union had three mesothelioma deaths (one man, two women): one pleural, one abdominal and one of unstated site. The study had no data on individual jobs or exposures. The authors did not know whether asbestos-related practices reported in UK shoemaking occurred in the US. The authors concluded that the liver, gallbladder and mesothelioma findings raised the possibility of other hazards in parts of the industry.

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: Proportionate mortality study based on union death listings and death certificates. The share of deaths from each cause was compared with the US white population, taking sex, age at death and year of death into account.
• Who was studied: 3,754 white decedents (2,229 men and 1,525 women) who had been members of the United Shoe Workers of America (2,144) or the Boot and Shoe Workers Union (1,610). They belonged to union locals in Illinois, Massachusetts, Missouri, New Hampshire, Ohio, Pennsylvania and Wisconsin and died from 1966 to 1977.
• Exposure: Work in shoe manufacturing plants represented by the two unions. There were no individual data on dates of employment, length of employment, jobs held or specific exposures.
• Main results:
  • No deaths with nasal cancer as the coded cause occurred in the study group, whereas 2.2 were expected for men and women combined.
  • One man's death certificate mentioned nasal sinus carcinoma as a contributing cause of death.
  • Cancer as a whole caused significantly more deaths than expected in men (PMR 1.10) and in women (PMR 1.12).
  • Bladder cancer was not unusual in either sex. Leukemia deaths were slightly increased: men 20 observed vs 16.7 expected, women 16 vs 12.9. By age group, none of the leukemia differences were statistically significant.
  • The combined category of cancers of the liver, gallbladder and bile ducts was significantly increased among Boot and Shoe Workers Union members: men 9 observed vs 3.4 expected, women 9 vs 3.5. Five of the nine male deaths were gallbladder or extrahepatic bile duct cancer. Six of the nine female deaths were liver cancer, five of them primary.
  • Three deaths from mesothelioma (one man and two women) occurred in three different midwestern locals of the Boot and Shoe Workers Union.
  • Of the three mesothelioma deaths, one was pleural, one abdominal, and one was not specified as to site on the death certificate.
  • Rectal cancer was higher than expected in both sexes: men 22 observed vs 14.0 expected, women 19 vs 10.5, both p less than 0.05. The excess was largest among women in the United Shoe Workers Union (12 observed vs 6.0 expected).
• The authors' conclusion: The authors were hesitant to conclude that the US shoe industry had been free of unusual risks for leukemia and nasal cancer. They said their findings for liver and gallbladder cancer and mesothelioma raised the possibility that other hazards may have been present in certain areas of the US shoe industry.
• Limitations the authors state:
  • Deaths were missing for workers in non-union plants, former members not eligible for death benefits, and eligible members whose benefit was not claimed.
  • Death certificates could not be found for 14% of the obituary notices.
  • There was no information on dates of hire and termination, length of employment or jobs held, so risk could not be examined by length of employment or by work area.
  • The authors could not gather information on the jobs and exposures of the people who died of liver and gallbladder cancer or mesothelioma.
  • The authors described reported asbestos-related practices in UK and English shoemaking (an asbestos filler for shoe soles, and heating molds insulated with asbestos board). They did not know whether these practices occurred in the US shoe industry and posed a significant exposure.
  • Part of the excess in ischemic heart disease may reflect methodological limitations of a proportionate mortality study.

Topics

Medical terms in this study, explained in our Lexicon: Mesothelioma.

Related studies

• Proportionate mortality among unionized roofers and waterproofers — F.B. Stern, A.M. Ruder, et al. (2000)
• Proportionate mortality among construction laborers — F. Stern, P. Schulte, et al. (1995)
• A proportionate mortality study of bricklayers and allied craftworkers — J. Salg, T. Alterman (2005)
• Lung cancer risk of workers in shoe manufacture and repair — K.H. Jöckel, H. Pohlabeln, et al. (2000)
• Bias in the proportionate mortality ratio analysis of small study populations: a case on analyses of radiation and mesothelioma — J.Y. Zhou (2014)
• Proportionate mortality study of the United Association of Journeymen and Apprentices of the Plumbing and Pipe Fitting Industry — E.J. Lehman, M.J. Hein, et al. (2008)

Browse more research in American Journal of Industrial Medicine, or return to medical research.