Discontinuity in the cancer slope factor as it passes from high to low exposure levels – arsenic in the BFD-endemic area
| Autor: | Jun Lu, Brian Goodrich, Manning Feinleib, Rusan Chen, Shayhan A. Robbins, Steven H. Lamm |
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| Rok vydání: | 2014 |
| Předmět: |
Male
Lung Neoplasms Endemic Diseases Taiwan chemistry.chemical_element Rural Health Biology Toxicology Risk Assessment Arsenic symbols.namesake Discontinuity (geotechnical engineering) Risk Factors Water Supply Arsenic Poisoning Low exposure Humans Poisson regression ARSENIC EXPOSURE Dose-Response Relationship Drug Endemic area Carcinogens Environmental Urinary Bladder Neoplasms chemistry symbols Female Cancer risk Water Pollutants Chemical Cancer slope factor Demography |
| Zdroj: | Toxicology. 326:25-35 |
| ISSN: | 0300-483X |
| DOI: | 10.1016/j.tox.2014.08.014 |
| Popis: | Background The ingestion of inorganic arsenic causes bladder and lung cancers demonstrably at >400–500 ug/L but questionably below 100–200 ug/L. Using the standard 42-village cancer mortality dataset from the Blackfoot-disease (BFD) endemic area of southwest Taiwan ( Wu et al., 1989 ), we examined the risk from low exposures by excluding the high exposures. Method Poisson regression analyses with the sequential removal of the highest exposure village have been performed using the median, mean, or maximum village well water arsenic level and demonstrated graphically. Results Risk estimates are positive when villages with exposures of 200–400 ug/L are included and significantly so when villages with >400 ug/L are included. Risk estimates for exposures below 100 ug/L are negative but rarely significantly so. The inflection point where the slope is no longer positive occurs in the range of 100–200 ug/L, depending upon whether the exposure metric used is the median, the mean or the maximum. Conclusion There is a discontinuity in the cancer slope factor or risk from arsenic exposure that occurs in the range of 100–200 ug/L. Above these levels, there are significantly positive risks, while below these levels there are not. The analysis reveals within this dataset an intrinsic non-linearity in the cancer risk. The literature speaks to this discontinuity, but this is the first demonstration within a single dataset that shows the discontinuity across the full exposure range and where the low-dose data are not compromised with high-dose data. |
| Databáze: | OpenAIRE |
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