Additional notes on the case-control study in western Washington on the cancer risk from asbestos in drinking water

Our plain-English summary of Additional notes on the case-control study in western Washington on the cancer risk from asbestos in drinking water, by L. Polissar, R.K. Severson, E.S. Boatman (Environmental Health Perspectives, 1983).

The study

• Authors: L. Polissar, R.K. Severson, E.S. Boatman
• Journal: Environmental Health Perspectives
• Published: 1983;53:189-90
• Cited by: 1 article, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

In plain English

This is a short commentary in which the authors answered questions raised after a presentation of their case-control study of cancer and asbestos in drinking water in western Washington, in the Sultan River water area. It was not the full report, which the authors said would appear in another journal. Each subject's exposure was assigned from detailed residence and work histories, water habits and water-system records. Twenty-two samples were taken from the Sultan River distribution system from June 1978 to April 1979, and 73 from other sources. No estimated exposure to asbestos in drinking water was found in 1% of the cases and 0.6% of the controls. For male pharynx and stomach cancers, the risks were statistically significant, but the confidence intervals approached 1.0. The authors concluded these results were not strong enough to suggest a causal relationship with imbibed asbestos. Female pancreas relative risks ranged from 1.4 to 1.7, with a smallest significance level of 0.07. The authors stated they had low power for several cancer sites and that unknown risk factors could give spurious results.

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: Commentary answering questions about the authors' population-based case-control study of asbestos in drinking water and cancer; the full report is a companion paper published elsewhere
• Who was studied: Cancer cases and randomly chosen, living, unmatched general population controls in western Washington (Sultan River distribution area and other water areas). 53% of cases were alive at interview; next of kin answered for deceased cases. Total numbers of cases and controls are not given in this commentary.
• Exposure: Asbestos in community drinking water from the Sultan River, accumulated over each subject's lifetime from residence and work histories and water-use habits. 22 samples came from the Sultan River system (June 1978 to April 1979) and 73 from other water sources. The fiber type is not named in this commentary.
• Main results:
  • No estimated exposure to asbestos in drinking water was found in 1% of cases and 0.6% of controls
  • 86% of the fibers measured in the water were less than 1 in length; the unit is garbled in the scan (printed as 'gm')
  • Among males, risks for pharynx and stomach cancers were statistically significant, but their 95% confidence intervals approached 1.0
  • Among females, relative risks for pancreas cancer ranged from 1.4 to 1.7 depending on the analysis; the smallest significance level was 0.07
  • Among males, relative risks for pancreas cancer were less than 1.0
  • Accuracy of responses to key questions was similar for living cases, next of kin of deceased cases, and controls
• The authors' conclusion: The authors concluded that the results for male pharyngeal and stomach cancers were not strong enough to suggest a causal relationship with imbibed asbestos. They said they did not know the reason for the elevated risks and suggested these sites be included in further studies.
• Limitations the authors state:
  • Low statistical power to detect risks of interest for several cancer sites, so nothing firm can be said about the negative results for those sites
  • Many significance tests were performed, so multiple comparisons must be considered
  • A case-control study cannot include every risk factor, and unknown, uncontrolled risk factors could give spurious results

Topics

Medical terms in this study, explained in our Lexicon: Case-Control Study.

Related studies

• Cancer risk from asbestos in drinking water: summary of a case-control study in western Washington — L. Polissar, R.K. Severson, et al. (1983)
• A case-control study of asbestos in drinking water and cancer risk — L. Polissar, R.K. Severson, et al. (1984)
• Cancer incidence in relation to asbestos in drinking water in the Puget Sound region — L. Polissar, R.K. Severson, et al. (1982)
• Assessment of studies on cancer risks from asbestos in Connecticut drinking water — J.W. Meigs (1983)
• The control of potential health risks related to drinking water in the UK — T.A. Dick (1981)
• Use of quantitative analysis of urine to assess exposure to asbestos fibers in drinking water in the Puget Sound region — E.S. Boatman, T. Merrill, et al. (1983)

Browse more research in Environmental Health Perspectives, or return to medical research.