The incidence of bladder cancer in the black foot disease endemic area in Taiwan.

A high incidence of bladder cancer (23.53/100,000 population per annum from 1981-1985) was found in an endemic area of peripheral vascular disease known as black foot disease (BFD) on the southwest coast of Taiwan. The average incidence of bladder cancer in the whole of the Taiwan area was 2.29/100,000 during the same period. The incidence of female bladder cancer (21.10/100,000) in this area was also high. The ratio of male to female bladder cancer in the BFD endemic area and the neighbouring area was 1.24 and 1.09, lower than that in the whole Taiwan area (2.75) and elsewhere around the world. The high content of arsenic and the high concentration of a "fluorescent substance" in artesian well water in this area are the only 2 related factors identified so far. Determination of the actual carcinogen requires further investigation.