Cancer incidence and asbestos in drinking water, Town of Woodstock, New York, 1980-1998

Our plain-English summary of Cancer incidence and asbestos in drinking water, Town of Woodstock, New York, 1980-1998, by M.L. Browne, D. Varadarajulu, E.L. Lewis-Michl, et al (Environmental Research, 2005).

The study

• Authors: M.L. Browne, D. Varadarajulu, E.L. Lewis-Michl, E.F. Fitzgerald
• Journal: Environmental Research
• Published: 2005;98(2):224-32
• Cited by: 17 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Late in 1985, asbestos contamination was discovered in the public water supply of the Town of Woodstock, Ulster County, New York. Contamination resulted from asbestos-cement pipes installed in the town water system in the mid to late 1950s and the corrosiveness of the local water. The New York State (NYS) Department of Health established the Woodstock Asbestos Exposure Registry (WAER) in 1986 to monitor rates of cancer among individuals who lived on the water supply between 1960 and 1985. Demographic, health, and residential information were collected on 2936 registrants. The follow-up period for observation of cancer was 1980-1998, consistent with the expected lag of 20-30+ years for development of asbestos-related cancers. The NYS Cancer Registry was used to ascertain cancer diagnoses. Standardized incidence ratios (SIRs) for gastrointestinal, respiratory, and total cancers were all approximately 1.00 or less and all 95% confidence intervals (CIs) included 1.00. For individual types of the gastrointestinal cancers, only the SIR for pancreatic cancer was marginally statistically significant at 2.19 (95% CI=1.00-4.16), based on a total of nine observed cases. The excess in pancreatic cancer occurred primarily among men (SIR=3.08; 95% CI=1.13-6.70) and was only slightly elevated among women (SIR=1.39; 95% CI=0.29-4.06). This association may be related to factors other than asbestos exposure such as occupation and lifestyle or to chance. No cases of mesothelioma were observed among WAER participants. There was no increase in incidence by latency or duration of residence on the water supply, but the ability to detect these trends is limited by small numbers and unknown dates of initial exposure. The general pattern of results did not demonstrate a likely link between exposure to asbestos in drinking water and cancer occurrence among participants in the WAER.

In plain English

This New York State Department of Health cohort study followed the Woodstock Asbestos Exposure Registry. The registry was set up in 1986 after asbestos was found in the Woodstock, New York, public water supply in 1985. It came from deteriorating asbestos-cement pipes laid in the 1950s. Over 90% was chrysotile, the rest crocidolite. Of 2936 registrants, the main analysis covered 1852 who stayed in New York State. Their cancers from 1980 to 1998 were compared with rates for whites in New York State outside New York City. Total, gastrointestinal and respiratory cancers were at or slightly below expected (total: 144 observed, SIR 0.94, 95% CI 0.79 to 1.10). No mesothelioma was found. Pancreatic cancer was marginally significantly raised (9 cases, SIR 2.19, 95% CI 1.00 to 4.16), mainly among men (6 cases, SIR 3.08, 95% CI 1.13 to 6.70). The authors said this may relate to occupation, lifestyle or chance rather than asbestos. Gastrointestinal and respiratory cancers did not rise significantly with longer residence; men's respiratory cancer ratios rose with duration but stayed below 1.00. The authors noted historical exposure data were lacking.

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: Prospective cohort study (with a retrospective component for 1980 to 1985) comparing observed cancers with expected numbers (standardized incidence ratios)
• Who was studied: 2936 current or former residents who, between 1960 and 1985, lived 6 months or more in a home served by the Woodstock, New York, water supply. 2623 were alive and available for follow-up in 1980. The main analysis included the 1852 who remained New York State residents, followed for cancer from 1980 through 1998. The comparison group was the white population of New York State excluding New York City.
• Exposure: Asbestos in public drinking water leached from asbestos-cement pipes installed in the mid to late 1950s. Over 90% of the asbestos was chrysotile and the remainder crocidolite. Four of five samples taken in 1985 exceeded 10 million fibers per liter, with a maximum of 304.5. Duration and timing of residence on the water supply were used as indirect measures of exposure.
• Main results:
  • Among the 1852 New York State residents, SIRs were at or slightly below 1.00 and all confidence intervals included 1.00 for each cancer grouping. Total cancers: 144 observed, SIR 0.94, 95% CI 0.79 to 1.10. Gastrointestinal cancers: 29 observed, SIR 0.87, 95% CI 0.58 to 1.25. Respiratory cancers: 21 observed, SIR 0.82, 95% CI 0.50 to 1.25.
  • Pancreatic cancer, the only gastrointestinal subsite reaching marginal statistical significance: 9 cases, SIR 2.19 (95% CI 1.00 to 4.16).
  • The pancreatic cancer excess was mainly among men: 6 cases, SIR 3.08 (95% CI 1.13 to 6.70). Among women it was 3 cases, SIR 1.39 (95% CI 0.29 to 4.06).
  • No cases of mesothelioma were observed among registry participants.
  • By duration of residence, there was no discernible pattern for gastrointestinal cancers. Among men, respiratory cancer SIRs increased with duration but stayed below 1.00 even in the longest-duration category. Confidence intervals for all duration categories overlapped and none excluded 1.00.
  • In lagged analyses, the only interval excluding 1.00 showed a reduced risk of gastrointestinal cancer among women with a minimum 10-year lag: SIR 0.44 (95% CI 0.16 to 0.96).
  • Smoking history was available for 8 of the 9 pancreatic cancer cases, and 7 of these 8 were current or former smokers.
  • Results were generally similar when exposure was assumed to begin in 1976 and when the whole cohort, including those who moved out of state, was analyzed.
• The authors' conclusion: The authors concluded that the increased pancreatic cancer risk seen among males (but not females) may be related to factors other than asbestos exposure, such as occupation and lifestyle, or to chance.
• Limitations the authors state:
  • There were no historical exposure data showing when leaching of asbestos into the water first produced measurable exposure.
  • The 1985 water samples were taken soon after the mains were flushed, so measured asbestos levels may not reflect usual concentrations.
  • Statistical power was low for some individual gastrointestinal sites, for example only 43% for stomach cancer.
  • Uncertainty about the timing of first exposure and small numbers limited the analysis of duration of residence.
  • Because actual exposure levels were not well known, the findings cannot be generalized to other exposure situations.
  • The authors could not directly control for confounding by smoking, alcohol use and socioeconomic status in the SIR estimates.

Topics

Medical terms in this study, explained in our Lexicon: Asbestos-Cement Pipe, Asbestos Exposure, Cancer Registry, Standardized Incidence Ratio (SIR), confidence interval, Mesothelioma, Latency.

Related studies

• Drinking water and cancer — R.D. Morris (1995)
• Cancer incidence following exposure to drinking water with asbestos leachate — H.L. Howe, P.E. Wolfgang, et al. (1989)
• Asbestos in drinking water and cancer incidence in the San Francisco Bay area — M.S. Kanarek, P.M. Conforti, et al. (1980)
• Cancer incidence in relation to asbestos in drinking water in the Puget Sound region — L. Polissar, R.K. Severson, et al. (1982)
• Asbestos-contaminated drinking water: its impact on household air — J.S. Webber, S. Syrotynski, et al. (1988)
• Cancer of the gastrointestinal tract and exposure to asbestos in drinking water among lighthouse keepers (Norway) — K. Kjaerheim, B. Ulvestad, et al. (2005)

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