Decreasing trend in renal disease mortality after cessation from arsenic exposure in a previous arseniasis-endemic area in southwestern Taiwan.

Arsenic has been well documented as a major risk factor for blackfoot disease (BFD), a unique peripheral vascular disease that was endemic in the southwestern coast of Taiwan, where residents imbibed artesian well water containing excessive amounts of arsenic for more than 50 yr. Long-term arsenic exposure has also been reported to be associated with mortality attributed to renal disease. 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 examine whether mortality attributed to arsenic-induced renal diseases decreased after the improvement of the drinking-water supply system through elimination of arsenic exposure from artesian well water. Standardized mortality ratios (SMRs) for renal diseases were calculated for the BFD endemic area for the years 1971-2000. Results show that mortality from renal disease declined gradually after improvement of the drinking-water supply system to eliminate arsenic from artesian well water. Based on the reversibility criterion, the association between arsenic exposure and mortality attributed to renal disease is likely to be positively correlated.