Arsenic exposure through drinking water increases kidney cancer risk, finds study

A new study published in the journal of Environmental Pollution found an elevated risk of kidney cancer may be linked to exposure to low levels of drinking water arsenic. Kidney cancer is the 7th most frequent cancer in the United States, with an age-adjusted incidence rate of 17.2 per 100,000 from 2017 to 2021.

Male gender, family history, African American race or ethnicity, obesity, smoking, alcohol use, diabetes mellitus, high blood pressure, severe kidney disease, and chemical exposures like trichloroethylene are risk factors for kidney cancer. One naturally occurring element that is commonly found in groundwater is arsenic. About 2.1 million individuals in over 25 states in the US are exposed to high amounts of arsenic in their drinking water, with levels above the current 10 ppb legal limit. 

The increase of kidney cancer is thought to be caused by arsenic which is a recognized human carcinogen, especially in places where groundwater is high in arsenic. However, nothing is known about the link between kidney cancer and low levels of arsenic in drinking water. In this ecological analysis, this study used data from 240 Texas counties to evaluate the relationship between kidney cancer occurrences and county-level drinking water arsenic levels.

The analysis covered 101,776,294 person-years from 2016 to 2020 and 28,896 cancer diagnoses among people aged ≥20. In addition to geographical determinants spatial Poisson regression models calculated the risk ratio (RR) for incident kidney cancer based on drinking water arsenic levels by controlling for demographic, socioeconomic, and other risk variables. The data from water testing for both private wells and public water systems were used to determine population-weighted drinking water arsenic levels, which were then corrected for the populations supplied by each source.

This study found a dose-response connection (p-trend <0.001) between the medium (1 to 5 ppb) and high (>5 ppb) group counties and the low arsenic level counties (<1 ppb), with the incidence of cancer being 6% and 22% higher, respectively, after controlling for geographical variables and covariates. Furthermore, when drinking water arsenic level was viewed as a continuous variable, the incidence rose by 4% for every doubling of the level.

Overall, in line with other studies showing a link between drinking water exposure and skin, bladder, and lung cancers, this study indicates that even low levels of arsenic exposure may be linked to an increased risk of kidney cancer.

Source:

Hasan, N. T., Han, D., Xu, X., Sansom, G., & Roh, T. (2024). Relationship between low-level arsenic exposure in drinking water and kidney cancer risk in Texas. In Environmental Pollution (Vol. 363, p. 125097). Elsevier BV. https://doi.org/10.1016/j.envpol.2024.125097