"Asbestos in drinking water and cancer incidence in the San Francisco Bay area"

Our plain-English summary of "Asbestos in drinking water and cancer incidence in the San Francisco Bay area", by K. Browne (American Journal of Epidemiology, 1982).

The study

• Author: K. Browne
• Journal: American Journal of Epidemiology
• Published: 1982;115(1):142-4
• Type of article: Letter
• Cited by: 2 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

In plain English

This item was a letter to the editor, not a research study. Its author, Kevin Browne of Cape Industries Limited in London, called a 1980 paper by Kanarek and colleagues seriously flawed. That paper had reported an association between asbestos in drinking water and cancer incidence in the San Francisco Bay area. The author argued that the paper did not mention studies with opposite conclusions. The author also said it omitted nonwhites, although significance levels were often lower when the total population was used, and that it excluded census tracts with fiber levels between 4,100,000 and 5,400,000 from several tables. The author's main objection concerned social class. By the author's count from one of the paper's tables, low-asbestos areas had higher cancer incidence than medium-asbestos areas in eight of 21 comparisons within income levels, lower incidence in 12, and no difference in one. The author also argued that the peritoneal cancer finding probably included peritoneal mesothelioma cases, most of them expected to be occupational, which should have been excluded. The original authors' reply, which is cut off, said no census tracts had fiber counts in that range.

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: Letter to the editor criticizing a published study, followed by the start of the original study authors' reply
• Who was studied: No population of its own. The letter discusses the study by Kanarek et al. (Am J Epidemiol 1980;112:54-72) of cancer incidence and asbestos in drinking water in the San Francisco Bay area, analysed by census tract.
• Exposure: Asbestos fibers in drinking water, with census tracts grouped by fiber level per liter
• Main results:
  • The letter writer stated that the Kanarek et al. paper omitted any mention of papers with opposite conclusions. The writer gave as an example a Connecticut study of asbestos cement pipe and gastrointestinal cancer (Harrington et al.).
  • The letter writer stated that nonwhites were omitted from the analysis. The writer added that significance levels in the paper's table 4 were in many cases lower when the total population was used.
  • The letter writer stated that census tracts with fiber levels between 4,100,000 and 5,400,000 were excluded, without explanation, from the analyses in tables 5 to 8.
  • The letter writer noted that in the paper the proportion in the lower social class, measured by education, increased as asbestos level increased. The writer said this could produce a spurious link between asbestos and cancer rates.
  • For low income groups in the paper's table 5, the letter writer said low-asbestos areas had higher cancer incidence than medium-asbestos areas in six groups and nearly the same incidence in the remaining one. For male lung cancer, the writer said low asbestos went with higher incidence in three groups, about the same in one, and lower in two.
  • Using the paper's table 7 (income levels), the letter writer counted 21 paired comparisons between low and medium asbestos levels. Low asbestos went with higher cancer incidence in eight, lower in 12, and no difference in one.
  • The paper's strongest finding was for the peritoneum (p less than 0.01). The letter writer argued that many of these cancers would be expected to be peritoneal mesothelioma, that most of those cases, probably 80-90 per cent, would have been occupationally caused, and that they should be excluded.
  • In their reply, the original authors said that results for the nonwhite group were essentially negative. They attributed this to small population and case numbers in that group.
  • In their reply, the original authors said no census tracts were selectively omitted. They stated that no tracts had fiber counts of 4,100,000-5,400,000 per liter.
• The authors' conclusion: The letter writer concluded that the Kanarek et al. paper, which reported an association between asbestos in drinking water and cancer incidence in the San Francisco Bay area, was seriously flawed.

Related studies

• Asbestos in drinking water and cancer incidence in the San Francisco Bay area — M.S. Kanarek, P.M. Conforti, et al. (1980)
• "Asbestos in drinking water and cancer incidence in the San Francisco Bay area" — I.T. Higgins (1981)
• The San Francisco Bay epidemiology studies on asbestos in drinking water and cancer incidence: relationship to studies in other locations and pointers for further research — M.S. Kanarek (1983)
• Cancer incidence in relation to asbestos in drinking water in the Puget Sound region — L. Polissar, R.K. Severson, et al. (1982)
• A case-control study of asbestos in drinking water and cancer risk — L. Polissar, R.K. Severson, et al. (1984)
• Asbestos in drinking water and cancer — K.D. MacRae (1988)

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