Effects and dose-response relationships of skin cancer and blackfoot disease with arsenic

Abstract

In a limited area on the southwest coast of Taiwan, where artesian well water with a high concentration of arsenic has been used for more than 60 years, a high prevalence of chronic arsenicism has been observed in recent years. The total population of this “endemic” area is approximately 100,000. A general survey of 40,421 inhabitants and follow-up of 1,108 patients with blackfoot disease were made. Blackfoot disease, so-termed locally, is a peripheral vascular disorder resulting in gangrene of the extremities, especially the feet. The overall prevalence rates for skin cancer was 10.6 per 1000, and for blackfoot disease 8.9 per 1000. Generally speaking, the prevalence increased steadily with age in both diseases. The prevalence rates for skin cancer and blackfoot disease increased with the arsenic content of well water, i.e., the higher the arsenic content, the more patients with skin cancer and blackfoot disease. A dose–response relationship between blackfoot disease and the duration of water intake was also noted. Furthermore, the degree of permanent impairment of function in the patient was directly related to duration of intake of arsenical water and to duration of such intake at the time of onset. The most common cause of death in the patients with skin cancer and blackfoot disease was carcinoma of various sites. The 5-year survival rate after the onset of blackfoot disease was 76.3%; the 10-year survival rate was 63.3% and 15-year survival rate, 52.2%. The 50% survival point was 16 years after onset of the disease. Images FIGURE 1. FIGURE 2.

Clinicopathological features of bladder cancer associated with chronic exposure to arsenic

“…The history of As exposure was established by interviewing the patients or their families about the wells they had drunk from during their daily lives (Tseng, 1968 deep-well water in the township where As levels in the well water exceed 0.05 mg 1-' were designated as As exposed (Smith et al, 1992). Those who had resided in these townships for 50 years or longer were also included in this category, irrespective of their water-drinking history.…”

“…The commonest route of exposure is through ingestion of water containing inorganic As. In an endemic area of chronic arsenicism from drinking high-As artesian well water in south-western Taiwan, residents have been suffering from the so-called blackfoot disease (BFD), a peripheral vascular disease (Tseng, 1968). Significantly high incidence and mortality rates of transitional cell carcinoma of the urinary bladder, up to 30 times greater than those in other regions, have been reported from the BFD-endemic area (Su et al, 1985;Chen et al, 1990;Chiang et al, 1993).…”

Cardiovascular effects of arsenic: clinical and epidemiological findings

“…The relationship is particularly evident for peripheral arterial disease ("blackfoot disease" is a form of PAD endemic to areas of Taiwan with extremely high levels of As in drinking water (Tseng 1977)) and coronary heart disease, while the association with stroke is less strong and of borderline significance (Lisabeth et al 2010;Moon et al 2012). The studies globally show a temporal sequence between time of exposure and onset of disease, have yielded consistent results in different countries and populations, show a dose-response relation, and show decreased incidence of disease where reduced exposure has been implemented (Chang et al 2004;Yuan et al 2007).…”

A silent epidemic of environmental metal poisoning?

“…In the most detailed of the epidemiological studies done in Taiwan, Tseng (1977) found a very strong positive correlation between As intake from drinking contaminated water, and both skin cancer and the peripheral vascular disorder known as 'blackfoot' disease. The prevalence rates for skin cancer, hyperpigmentation and keratosis were about 11, 184 and 71 per 1000 in the survey of 40 000 people, out of the total exposed population of 100 000 persons.…”