Risk of stomach cancer associated with 12 workplace hazards: analysis of death certificates from 24 states of the United States with the aid of job exposure matrices

Our plain-English summary of Risk of stomach cancer associated with 12 workplace hazards: analysis of death certificates from 24 states of the United States with the aid of job exposure matrices, by P. Cocco, M.H. Ward, M. Dosemeci (Occupational and Environmental Medicine, 1999).

The study

• Authors: P. Cocco, M.H. Ward, M. Dosemeci
• Journal: Occupational and Environmental Medicine
• Published: 1999;56(11):781-7
• Cited by: 15 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Objective: To investigate the risk of gastric cancer associated with 12 workplace exposures suspected or discussed as aetiological agents in previous reports.

Methods: A case-control study was conducted based on the death certificates of several million deaths in 24 states of the United States in 1984-96. Overall, the data base included 41,957 deaths from stomach cancer among subjects aged > or = 25 years. These were 20,878 white men, 14,125 white women, 4215 African American men, and 2739 African American women. Two controls for each case were selected from among subjects who died from non-malignant diseases, frequency matched to cases by geographic region, race, sex and 5 year age group. Each three digit occupation and industry code listed in the 1980 United States census was classified for probability and intensity of exposure to asbestos, inorganic dust, metals, lead, polycyclic aromatic hydrocarbons (PAHs), nitrogen oxides, nitrosamines, sulphuric acid, fertilisers, herbicides, other pesticides (including insecticides and fungicides), and wood dust. These job exposure matrices were subsequently applied to the occupation-industry combinations in the death certificates of study subjects, separately by sex and race.

Results: Risk of stomach cancer showed a modest association with occupational exposure to inorganic dust (odds ratio (OR) = 1.06; 95% confidence interval (95% CI) 1.03 to 1.11) with significant increasing trends by probability and intensity of exposure overall and by cross classification of the two exposure matrices. Workplace exposure to nitrosamines also showed a modest association (OR = 1.06; 95% CI 1.01 to 1.11), but the excess risk was even smaller after adjusting for inorganic dust exposure. Risk of gastric cancer was not associated with any of the other workplace exposures considered in this study.

Conclusions: Non-differential misclassification of exposure may have caused negative findings in this study, and inorganic dust may be a partial surrogate for exposure to other unknown risk factors. Alternatively, our results suggest that occupational factors contribute little to the aetiology of gastric cancer. Inorganic dust might act through non-specific mechanisms, similar to those proposed for salt, aspirin, and heat by other authors.

In plain English

This was a case-control study of death certificates from 24 US states, 1984 to 1996. The authors compared 41 957 people who died of stomach cancer (20 878 white men, 14 125 white women, 4215 African American men and 2739 African American women) with two controls per case who died from non-malignant diseases. Using job exposure matrices, the one occupation and industry on each certificate was scored for probability and intensity of exposure to 12 workplace hazards. These included asbestos (fiber type unspecified), inorganic dust, metals and nitrosamines. Among white men, any inorganic dust exposure had an odds ratio of 1.07 (95% CI 1.03 to 1.11), with significant trends of rising risk. For nitrosamines it was 1.06 (1.01 to 1.11) among white men, and this weakened after adjustment for inorganic dust. The authors reported no association with the other exposures, including asbestos. The authors noted that job information on death certificates is poor. They wrote that exposure misclassification may have caused the negative findings and that inorganic dust may partly stand in for unknown risk factors, or alternatively that occupational factors contribute little to stomach cancer.

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: Case-control study based on death certificates, with exposure assigned by job exposure matrices
• Who was studied: 41 957 deaths from stomach cancer in 24 US states, 1984 to 1996 (20 878 white men, 14 125 white women, 4215 African American men, 2739 African American women). There were two controls per case, chosen from people who died from non-malignant diseases and frequency matched by geographic region, race, sex and 5 year age group.
• Exposure: Probability and intensity, each scored none, low, medium or high, of exposure to 12 hazards: asbestos (fiber type not specified), inorganic dust, metals, lead, polycyclic aromatic hydrocarbons (PAHs), nitrogen oxides, nitrosamines, sulphuric acid, fertilisers, herbicides, other pesticides, and wood dust. Exposure was assigned from the one occupation and industry recorded on the death certificate.
• Main results:
  • Among white men, any exposure to inorganic dust was associated with an odds ratio of 1.07 (95% CI 1.03 to 1.11) in 8904 exposed cases, with a significant trend by probability of exposure (p less than 0.01).
  • Among white men, any exposure to nitrosamines was associated with an odds ratio of 1.06 (95% CI 1.01 to 1.11) in 4400 exposed cases. The authors reported that adjustment for inorganic dust exposure weakened this association.
  • When inorganic dust, metals, nitrosamines and sulphuric acid were adjusted for each other, the odds ratios were 1.05 (1.0 to 1.10) for inorganic dust, 1.04 (0.99 to 1.09) for nitrosamines, 1.01 (0.96 to 1.07) for metals and 0.99 (0.95 to 1.03) for sulphuric acid.
  • The authors reported no association between stomach cancer and the other workplace exposures, which included asbestos. Among white men, the asbestos odds ratios by probability of exposure were 0.97 (0.93 to 1.02) in 4007 cases and 1.09 (0.54 to 2.20) in 22 cases. For asbestos, the reference group included people with low exposure.
• The authors' conclusion: The authors wrote that non-differential misclassification of exposure may have caused negative findings and that inorganic dust may be a partial surrogate for other unknown risk factors. Alternatively, in their view, the results suggest that occupational factors contribute little to stomach cancer. In their discussion they concluded that their results confirm previous reports of an association between occupational inorganic dust exposure and stomach cancer.
• Limitations the authors state:
  • Occupational information from death certificates is poor, and the coding system is not specific enough.
  • Only one occupation and industry is recorded, so exposures in other jobs, especially short-term ones, were lost. Non-differential misclassification could have lowered the observed associations.
  • Diet could not be controlled, so residual confounding is possible. Rural residence was not available, and metropolitan residence was used as a substitute.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Stomach cancer.

Medical terms in this study, explained in our Lexicon: Stomach Cancer, Death Certificate, Case-Control Study, Occupational Exposure, Odds Ratio, confidence interval.

Related studies

• Occupation and risk of stomach cancer in Poland — S. Krstev, M. Dosemeci, et al. (2005)
• Occupational exposures and risk of stomach cancer by histological type — M. Santibañez, J. Alguacil, et al. (2012)
• Use of death certificates in epidemiological studies, including occupational hazards: variations in discordance of different asbestos-associated diseases on best evidence ascertainment — I.J. Selikoff, H. Seidman (1992)
• Death certificates in epidemiological studies, including occupational hazards: inaccuracies in occupational categories — I.J. Selikoff (1992)
• Occupational risk factors for mortality from stomach and lung cancer among rubber workers: an analysis using internal controls and refined exposure assessment — K. Straif, L. Chambless, et al. (1999)
• Assessment of mortality in the construction industry in the United States, 1984-1986 — C. Robinson, F. Stern, et al. (1995)

Browse more research in Occupational and Environmental Medicine, or return to medical research.