No amount of lead in drinking water is safe for people with kidney disease, study shows

BOSTON – Despite advances in reducing the amount of lead in drinking water, low levels of contamination remain widespread throughout the United States. This may be especially dangerous for the 30-40 million Americans living with chronic kidney disease, who have heightened susceptibility to the toxic effects of lead.

In a new study led by John Danziger, MD, MPhil, a nephrologist at Beth Israel Deaconess Medical Center (BIDMC), investigators examined the effects of lead contamination in drinking water on individuals with advanced kidney disease. The findings, published in Journal of the American Society of Nephrology, reveal that even the low lead levels in drinking water that are permissible by the Environmental Protection Agency (EPA) have detrimental health effects in individuals with kidney disease. In addition, higher levels of lead exposure were observed among Black patients compared to white patients.

“Even in water with lead levels below the EPA’s safety threshold, low levels of lead contamination found in the majority of drinking water systems in the United States may have toxic effects for those with chronic kidney disease,” said Danziger, who is also assistant professor of medicine at Harvard Medical School. “Combined with the increased susceptibility to kidney disease among Black individuals, this represents a significant environmental injustice.”

Researchers analyzed health information for 600,000 patients initiating dialysis in the United States between 2005 and 2017. The team also assessed lead concentrations in community water systems in the five-year period prior to dialysis initiation, relying on city-level data from the EPA’s Safe Drinking Water Information System and focusing on the potential effects of lead on levels of hemoglobin, the oxygen carrying protein in red blood cells known to be effected by lead poisoning.

Individuals living in cities with detectable levels of lead in their community’s water had significantly lower hemoglobin concentrations before starting dialysis and during the first month of dialysis therapy. These patients were also prescribed higher doses of medications to treat anemia, which occurs when red blood cell counts or hemoglobin levels are lower than normal. These associations were observed at lead levels below the EPA’s threshold (0.015 mg/L) that mandates regulatory action. The findings also revealed significant differences in the community water lead levels for Black compared to white patients.  Across the period of study, community water levels decreased by 0.0002 mg/L per year among white patients, compared to 0.0001 mg/L per year among Black patients.

“These findings suggest that for patients with poor kidney function, there is no safe amount of lead in drinking water,” said Danziger. “This is particularly poignant for Black communities, as we know circulating lead levels and rates of lead toxicity are known to be higher among Black individuals. More rigorous efforts to improve the water system infrastructure are needed to protect individuals from unrecognized hazard, in addition to further research to examine the role of contaminated water to this disparity.”

Study co-authors include study senior author Eric Weinhandl of the Hennepin Healthcare Research Institute and Kenneth J. Mukamal of BIDMC.

The authors reported no financial disclosures.

This article was repurposed from a Journal of the American Society of Nephrology press release.