A new study in the Journal of Urology finds that people with moderately elevated levels of arsenic in their urine may have an increased risk of kidney cancer, especially if they have high blood pressure and kidney disease. This does not necessarily mean that arsenic leads to kidney cancers. Researchers report that one possibility is that kidney cancer leads to higher levels of arsenic in the urine.
While high levels of arsenic have been linked to many forms of cancer and some studies have linked moderately elevated levels of arsenic to high blood pressure and type 2 diabetes, the effects of low-level arsenic exposure are not yet fully known.
This new study was conducted in Taipei, Taiwan, where researchers looked at the arsenic levels in the urine of people who live in an area with low arsenic concentrations in the drinking water. In Taipei, arsenic levels in tap water ranges from undetectable to 4 micrograms per liter, which is below the 10 micrograms per liter allowed by the U.S. Environmental Protection Agency (EPA). Researchers compared 132 patients with kidney cancer to 260 cancer-free adults of the same age and sex.
In general, there was a relationship between higher arsenic levels in the urine and higher chances of kidney cancer. This relationship was strongest for people who had high blood pressure or impaired kidney function, which have been established as risk factors for kidney cancer. Study participants with both of these conditions and relatively high levels of arsenic in their urine were six times more likely than people with none of these risk factors to contract kidney cancer. Participants with two of these risk factors had a quadruple rate of increase in risk of kidney cancer.
One possibility proposed by both researchers involved with the study and researcher who were not was that arsenic exposure led to high blood pressure or kidney disease in some people, which, in turn, contributed to their kidney cancer.
An estimated 13 million Americans live in areas where the public water supply exceeds the EPA’s limit of 10 micrograms per liter, and water from unregulated private wells may contain too much arsenic.