Is colon cancer mortality related to arsenic exposure?
Arsenic has been well documented as the major risk factor for blackfoot disease (BFD), a unique peripheral vascular disease that was endemic to the southwestern coast of Taiwan, where residents consumed high-arsenic artesian well water for more than 50 yr. Chronic arsenic exposure was also reported to be associated with increased mortality attributed to colon cancer. A tap-water supply system was implemented in the early 1960s in the BFD-endemic areas. Artesian well water was no longer used for drinking and cooking after the mid-1970s. The objective of this study was to determine whether colon cancer mortality decreased after the improvement of the drinking-water supply system through elimination of arsenic ingestion from artesian well water. Standardized mortality ratios (SMRs) for colon cancer were calculated for the BFD-endemic area for the years 1971-2006. Results showed that mortality due to colon cancer declined in males, but not in females, gradually after the improvement of drinking-water supply system. Based on the reversibility criterion, the association between arsenic exposure and colon cancer incidence is likely to be causal for males but not females. The possibility that our results may be due to chance should be considered; however, gender-specific differences in arsenic metabolism may be a critical factor.
Yang
Chun-Yuh
CY
Faculty of Public Health, College of Health Sciences, Kaohsiung Medical University, Kaohsiung, Taiwan 80708. chunyuh@kmu.edu.tw
Chang
Chih-Ching
CC
Ho
Shu-Chen
SC
Chiu
Hui-Fen
HF
D001151:Arsenic / Q000009:adverse effects*; D003110:Colonic Neoplasms / Q000401:mortality*; D004781:Environmental Exposure; D005260:Female; D006801:Humans; D008297:Male; D009026:Mortality; D012737:Sex Factors; D013624:Taiwan / Q000453:epidemiology; D014874:Water Pollutants, Chemical / Q000009:adverse effects* / Q000032:analysis; D018508:Water Purification; D014881:Water Supply
D014874:Water Pollutants, Chemical; D001151:Arsenic