Research shows that even low lead levels in U.S. water are linked to lead poisoning among susceptible people

In a first-of-its-kind study, physician-researchers at Beth Israel Deaconess Medical Center (BIDMC) report that even lead levels below the EPA threshold in household water can negatively impact individuals with chronic kidney disease.

In a nationwide, cross-sectional analysis of lead concentrations in household water and blood characteristics in patients starting dialysis therapy, the team’s findings are:published in JAMA Internal Medicine– suggested that the lead levels commonly found in US drinking water may be associated with lead poisoning in susceptible individuals.

“Low lead levels are commonly found in drinking water in the United States, and to date there is little information about their potential health effects,” says corresponding author John Danziger, MD, MPhil, a nephrologist at BIDMC and an assistant professor at Harvard Medical School.

“Our study provides a large-scale analysis of how measured levels of lead contamination commonly found in the U.S. water supply can negatively impact people with chronic kidney disease.”

Experts agree that any exposure to lead – a known neurotoxin – in drinking water is unsafe, but the lack of systematic monitoring means that the extent and risk of lead contamination in American domestic water remains largely undocumented. The United States’ aging infrastructure and plumbing expose millions of Americans to household tap water with lead levels of 15 micrograms per liter (μ/L) or less – the allowable limit set by the U.S. Environmental Protection Agency (EPA) in 1991.

Because household water is routinely tested as part of clinical care for patients with kidney failure considering home hemodialysis, Danziger partnered with a major dialysis organization to synchronize individual household water lead levels and comprehensive health information for more than 6,400 patients treated with household water between 2017 and 2021. dialysis started.

The team looked at patient data during each of the three 30-day periods after starting dialysis, and divided the patients into five levels of lead exposure; above the EPA’s allowable limit of 15 micrograms per liter (μ/l) of water; 7.5-15 µ/l; 5-7.5 µ/l; 2-5 µ/l; or less than 2 µ/l. Analysis found that 12% of study participants, or 742 people, had measurable levels of lead in their household water.

Danziger and colleagues examined patients’ use of erythropoiesis-stimulating agent (ESA) – a cornerstone therapy for anemia in patients with chronic kidney disease and other diseases that stimulate the body’s production of red blood cells – during the first 90 days of dialysis treatment. The proportion of patients with maximum ESA dose, monthly ESA dose, and ESA resistance were all higher in increasing categories of household lead concentrations.

To investigate whether exposure to lead from household water could impact people with chronic kidney disease before starting dialysis, the researchers used Medicare data describing patient characteristics in the 45 days before the onset of kidney failure. The team’s analysis found that higher levels of lead in household water were associated with lower levels of hemoglobin – the protein in red blood cells responsible for delivering oxygen to tissues – prior to the onset of kidney failure among 2,648 patients with this data available.

“Our study demonstrates the negative health impacts of lead contamination levels well below the Environmental Protection Agency’s allowable threshold,” Danziger said. “At a time of ongoing debate about the safety of the water supply in the United States, these results warn that the extent and impact of lead contamination may be underappreciated.”

Co-authors included Kenneth J. Mukamal, MD, MPH of BIDMC; Joanna Willetts, MS, John Larkin, Ph.D., Sheetal Chaudhuri, Ph.D., Len A. Usvyat, Ph.D., and Robert Kossmann, MD of Fresnius Medical Care.