Neil Osterweil

May 25, 2005

May 25, 2005 (San Antonio) — People who live near leaking underground storage tanks or incineration sites are at significantly higher risk for bladder cancer, report University of Michigan researchers in a poster presentation here at the annual meeting of the American Urological Association 2005 Annual Meeting.

The findings suggest that chemicals seeping into ground water or otherwise present in the local environment put residents of these areas at risk for bladder cancer or other cancers of the urinary tract.

Although exposure to chemicals is known to increase the risk of bladder cancer, whether the exposure comes from pollution or from other environmental sources is less clear. To identify possible sources of exposure, lead author Rabii Madi, MD, a urology fellow at the University of Michigan in Ann Arbor, and colleagues looked at records of new cancer cases in various age groups from different regions in Michigan.

They obtained records of new cancer cases from the state department of community health for five years: 1987, 1990, 1993, 1995, and 2000. They then grouped these into six age cohorts spanning the range from younger than 15 years to 75 years and older. The records were also sorted according to zip code of the patients, and these records were then combined with information from University of Michigan databases on natural resources and on lawsuits involving environmental issues.

Using data on the total number of cancers, Dr. Madi and colleagues then determined rates per thousand population for each age group and classified the zip codes (N = 455) by cancer incidence. They also examined whether household income, minority status, and major pollution source could be predictive of cancer incidence.

In all, close to 178,000 cancer records were reviewed; bladder and urinary tract cancers represented 4.7% of all cancers during each of the study years.

The pollution sources included leaking underground storage tanks for gasoline, diesel, and oil, incineration sites, landfills, and other sources of possible chemical hazards as determined by the state health department.

"We found that two of the pollution sources we looked at were closely associated with risk for bladder cancer," said Dr. Madi.

The odds ratio for living in proximity to leaky storage tanks was 1.2 ( P = .05). Living near an incineration site carried an odds ratio of 1.5 ( P = .01).

The authors also found that for every age group except children younger than 15 years, the increasing incidence of bladder cancer directly correlated with increasing pollution density.

Race and income were also significant predictors of bladder cancer, with minorities and people with lower incomes being at greater risk, Dr. Madi and colleagues report.

"Specific pollution sources and aggregate pollution density can increase the risk of bladder cancer incidence, particularly in older individuals. Regions with large numbers of [leaking underground storage tanks] and incineration sites, as well as high pollution density, should be studied to determine whether disproportionate minority or low-income populations reside in these communities and whether more aggressive tumors develop under prolonged pollutant exposure," the investigators write.

"This is a great poster," commented one of the moderators at the poster discussion session. "These data show that there appears to be a significant correlation between these pollution sources and cancer risk, and this is a problem with public health and social implications."

AUA 2005 Annual Meeting: Abstract 182. Presented May 22, 2005.

Reviewed by Gary D. Vogin, MD


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