Cancer risks among iron and steel workers in Anshan, China, Part I: Proportional mortality ratio analysis

Our plain-English summary of Cancer risks among iron and steel workers in Anshan, China, Part I: Proportional mortality ratio analysis, by Z. Xu, G.W. Pan, L.M. Liu, et al (American Journal of Industrial Medicine, 1996).

The study

• Authors: Z. Xu, G.W. Pan, L.M. Liu, L.M. Brown, D.X. Guan, Q. Xiu, J.H. Sheng, B.J. Stone, M. Dosemeci, J.F. Fraumeni, W.J. Blot
• Journal: American Journal of Industrial Medicine
• Published: 1996;30(1):1-6
• Cited by: 34 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

A standardized proportional mortality ratio (SPMR) study of 8,887 deaths during 1980-1989 among male workers in a large integrated iron-steel complex in Anshan, China, was conducted to provide clues to occupational risk factors. Accidents and cancer accounted for a higher proportion of deaths among the iron-steel workers than among the general male population (SPMR = 1.21; 95% CI = 1.12-1.31 and 1.14; 95% CI = 1.10-1.18, respectively). Among all workers, SPMRs were significantly elevated for stomach, lung, and colorectal cancers (SPMR = 1.37, 1.37, 1.38, respectively), but not other cancers. Risks of stomach cancer appeared to be highest among workers employed in jobs with exposure to iron and coal dust, whereas significant increases in colorectal cancer were seen for loading and other dusty jobs and for administrative and sedentary jobs without dust exposure. Risks of lung cancer appeared increased for a variety of jobs throughout the complex, especially those with probable high levels of exposure to polycyclic hydrocarbons and asbestos. Risk of esophageal cancer was significantly elevated for fire-resistant brick makers, and risk of nonmalignant respiratory disease was significantly elevated for those employed as furnace workers, foundry workers, and fire-resistant brick makers.

In plain English

This study looked at causes of death among male workers at the Anshan iron-steel complex in China. The authors compared the share of deaths from each cause among 8,887 male workers who died during 1980-1989 with the share among 22,005 deaths of other men in Anshan city, adjusting for age. This method, a standardized proportional mortality ratio analysis, compares proportions of deaths, not death rates. Cancer and accidents made up a higher share of the workers' deaths than expected (ratios of 1.14 and 1.21). Stomach, lung and colorectal cancers were significantly elevated (1.37, 1.37 and 1.38). Lung cancer was raised across the complex. It was highest among furnace workers and coke oven workers (each 1.5) and pipefitters (1.9), groups the authors described as potentially exposed to polycyclic aromatic hydrocarbons and asbestos. Esophageal cancer was elevated among fireproof brick makers (2.4), whom the authors described as exposed to asbestos and dust. The study had no information on exposure to specific dusts, smoking or diet, and jobs were classed by the longest-held job. The authors called the analysis exploratory and said it provided leads for follow-up case-control studies.

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: Standardized proportional mortality ratio (SPMR) study comparing the proportion of deaths from each cause among workers with the proportion expected from the city population, standardized by age
• Who was studied: 8,887 deaths during 1980-1989 among active and retired male employees of the Anshan iron-steel complex, Anshan, China. The comparison group was 22,005 deaths among male Anshan city residents not employed at the complex. Females were excluded because few were employed.
• Exposure: Employment in the iron-steel complex, classified by factory system and by the job held longest. Asbestos is mentioned only as a probable or possible exposure for some jobs. No fiber type is named and asbestos exposure was not measured.
• Main results:
  • Among all male workers, accidents (SPMR 1.21) and total cancer (SPMR 1.14) made up a higher proportion of deaths than in the general male population.
  • Among all male workers, SPMRs were significantly elevated for stomach cancer (1.37), colorectal cancer (1.38) and lung cancer (1.37), but not for other cancers.
  • Lung cancer SPMRs were highest for furnace workers (1.5), coke oven workers (1.5) and pipefitters (1.9). The 1.5 values are confirmed in Table V; the text's figures are OCR-damaged. The authors described these groups as potentially exposed to polycyclic aromatic hydrocarbons and asbestos.
  • Lung cancer was elevated throughout the complex, with the authors linking the highest groups to possible PAH and asbestos exposure.
  • Esophageal cancer was significantly elevated among fireproof brick makers (SPMR 2.4). The authors described workers in the fire-resistant brick plant as exposed to asbestos and dust.
  • Colon cancer was significantly elevated for loading and dusty jobs (SPMR 1.4) and highest for administrative and nondusty jobs (SPMR 1.7). The authors said the loading workers were possibly exposed to asbestos and other dusts.
  • Nonmalignant respiratory disease mortality was significantly elevated for furnace workers (SPMR 1.7), fireproof brick makers (SPMR 3.6) and foundry workers (SPMR 1.6).
• The authors' conclusion: The authors concluded that this exploratory analysis provided leads about causes of stomach and lung cancers. They said these leads could be evaluated in nested case-control studies, reported in the following paper.
• Limitations the authors state:
  • The analysis was based on the longest-held job. It lacked information on exposure to specific types of dust and on confounding factors such as smoking and diet.
  • The authors acknowledged limitations of the proportional mortality method itself.

Topics

Medical terms in this study, explained in our Lexicon: Proportional mortality, Colorectal Cancer, Stomach Cancer, Lung Cancer, Esophageal Cancer.

Related studies

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• Asbestos disease in sheet metal workers: proportional mortality update — D. Michaels, S. Zoloth (1988)
• Cancer morbidity and quartz exposure in Swedish iron foundries — H. Westberg, L. Andersson, et al. (2013)
• Lung and bladder cancer in a Norwegian municipality with iron and steel producing industry: population based case-control studies — T.K. Grimsrud, H. Langseth, et al. (1998)
• Proportionate mortality among unionized construction ironworkers — F.B. Stern, M.H. Sweeney, et al. (1997)

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