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Show Was There an Epidemic of Environmentally Caused Brain Cancer in Davis County? Answers from an Epidemiological Investigation Jeremy J. Biggs, M.S.P.H., Aaron M. Wendelboe, M.S.P.H., George L. White Jr., Ph.D., M.S.P.H. Lewis Garrett, A.P.R.N., M.P.H., and Joseph L. Lyon, M.D., M.P.H. Abstract Media reports of a nine-fold excess of brain cancer among citizens in Layton, Davis County, Utah prompted concerns over a local municipal solid waste incinerator known to have emitted dioxin (2,3,7,8-tetrachlorodibenzo-p-dioxin). Environmental activists believed the excess cases of brain cancer were caused by the dioxin from the incinerator. Many citizens also believed that other types of cancer were more common in Davis County compared to the rest of the state of Utah. We investigated the putative link between dioxin exposure from the incinerator emissions and development of brain cancer, and found no exposure-disease response in the area around the incinerator. We calculated age adjusted rate ratios (RR) for brain and other cancers. The nine-fold excess of brain cancer was caused by an error in estimating the denominator for a single zip code. All other cancers were at or below the rate for Utah. In addition to analyzing the burden of the most eight common re-portable cancers in Utah, we chose to analyze soft tissue sarcoma, and non-Hodgkin's lym-phoma as a measure of possible dioxin exposure, and brain cancer due to public concern about dioxin exposure. Although dioxin is a known carcinogen in rodents, there is inconclusive evidence concerning its carcinogenicity in humans. This study and others have found no relationship between dioxin exposure and the development of brain cancer in humans. The Environmental Protection Agency (EPA) and Agency for Toxic Substances and Disease Registry (ATSDR) have not identified any specific cancers associated with dioxin exposure, only an overall cancer increase. However, there are some studies that have reported a weak association between dioxin and soft tissue sarcoma and non-Hodgkin's lymphoma. Thus, if the elevated cases of brain cancer were linked to dioxin exposure, it is reasonable to assume there would be elevated levels of soft tissue sarcoma and non-Hodgkin's lymphoma in the exposed population. Cancer incidence rates are of great interest to the public as well as professional health care workers. Most recently, citizens in Davis County have been concerned over a perceived elevation of brain cancer rates. This concern was due to a combination of factors. First, a citizen, whose father was diagnosed with a brain tumor, began compiling a list of patients with brain cancer after being informed by a doctor that several new cases of brain cancer had been diagnosed in her neighborhood. Second, a group composed of local citizens and health professionals was also looking into the possible cancer burden in the Layton area. Many citizens believed that the polluter causing these excess cases of brain cancer was Wasatch Energy Systems (WES) located at 650 East Highway 193, Layton, Utah 84041, east of Hill Air Force Base [HAFB]. WES began a municipal waste disposal operation in 1988, burning solid waste from Davis County and the surrounding areas. Dioxin (2,3,7,8-tetrachlorodibenzo-p-dioxin) from WES' stack emissions was of greatest concern to the citizens as the cause of the alleged increase in brain cancer cases. In previous scientific studies no link between dioxin exposure and human brain cancer has been found (Bertazzi, et al., 2001, Kogevinas, M., 2001, Smith, A. and Lopipero, P., 2001, Steenland, et al., 2001, Viel, et al., 2000). However, in January of 2001 the National Toxicology Program announced its decision to place dioxin on the list of substances "known to be a human carcinogen." (National Toxicology Program, January 19, 2001. NIEHS PR #01-04). This 40 Utah's Health: An Annual Review Volume VIII |
