New evidence further supports link between high urinary arsenic levels and kidney damage

In a recent study, epidemiologists at the Texas A&M University School of Public Health examined a link between high urinary arsenic levels and kidney damage in humans using U.S. population-level data.

Specifically, the study identified an association between higher urinary arsenic levels and elevated odds of albuminuria (the presence of a protein normally found in the blood) and hyperuricemia (elevated levels of serum uric acid in the blood), which are indicators of kidney disease.

“Previous studies have observed a positive association between arsenic exposure and kidney damage or reduced kidney function. Our study further supports this link by examining urinary arsenic levels and chronic kidney disease using large U.S. population data,” said Taehyun Roh, PhD, who supervised the study.

He added that this is important given that about 37 million people in the United States—about one out of seven—has chronic kidney disease, and the number is growing here and around the world.

Arsenic occurs naturally in the earth’s crust and the environment, and most people’s exposure is through contaminated water. Chronic arsenic exposure is also associated with several cancers, skin diseases and cardiovascular diseases.

“Our study was important because kidneys are particularly vulnerable, experiencing cellular damage, inflammation and lipid peroxidation after long-term arsenic exposure,” said Nishat Tasnim Hasan, DrPH, who led the study. “Despite this, a strong connection between arsenic exposure and kidney diseases has not been clearly established.”

To identify any association between urinary arsenic levels and kidney damage, the team used a multi-marker approach with data from the National Health and Nutrition Examination Survey (NHANES) on 9,057 adults from 2007 to 2018. The most recent data cycle (2019–2020) was excluded because the COVID-19 pandemic disrupted the survey’s complex sample collection processes, compromising the data’s national representativeness.

The researchers applied multivariate logistic regression models to estimate the odds ratios for kidney damage based on total urinary arsenic levels and multiple kidney biomarkers while adjusting for various sociodemographic and risk factors. The biomarkers for kidney damage included albuminuria, hyperuricemia, high blood urea nitrogen, and low estimated glomerular filtration rate.

The study found a 29 percent higher odds of overall kidney damage in individuals in the highest quartile of urinary arsenic compared to those in the lowest quartile. Among specific components, albuminuria and hyperuricemia were associated with 49 percent and 38 percent higher odds, respectively. Additionally, when arsenic levels in drinking water were analyzed as a continuous variable, each one-unit increase in the natural log of arsenic levels was significantly associated with these markers.

“Populations facing socioeconomic challenges often experience a higher burden of kidney disease due to factors such as limited health care access, food insecurity, and other social determinants of health,” Hasan said. “Therefore, it is crucial to consider these factors as covariates in a study of large, nationally representative data, and our approach allowed us to generalize our findings to the entire United States population.”

Hasan said this study had several additional strengths: it minimized the influence of the arsenic in seafood, adopted a multi-marker approach to assess kidney damage and identified potential risk factors that have further implications for both chronic kidney disease and kidney cancer.

The study’s cross-sectional design, which measured participants’ exposures and outcomes at the same time, however, means that the researchers could not identify cause-and-effect relationships.

“From a public health standpoint, our findings show that arsenic in drinking water threatens vulnerable populations—especially those who rely on groundwater,” Roh said. “From a policy standpoint, they indicate a need for stricter monitoring and policies aimed at reducing arsenic exposure and increased public awareness about the risks of arsenic exposure on kidney health.”

This research was supported by the Houston Methodist Cancer Center, the Robert and Janice McNair Foundation, and the National Institute of Environmental Health Sciences. Along with Hasan and Roh,  the research team included Garett Sansom, DrPH, Xiaohui Xu, PhD, and Daikwon Han, PhD.