Tom Neltner, J.D., is Chemicals Policy Director
Two recent articles add to the already strong evidence that adult exposure to relatively low levels of lead is associated with heart disease, the leading cause of death in the United States, after COVID-19. These studies reinforce the urgent need to reduce not only children’s exposure to lead but also adult exposure through regulatory action.
A February 2021 Environmental Health Perspectives article found that blood lead levels were positively associated with prevalence of moderate to severe coronary artery stenosis (CAS), the narrowing of at least 25% of these vital arteries to the heart. The researchers studied a cohort of 2,000 Korean adults studied with no history of CAS, cardiovascular disease (CVD), or occupational exposure to lead. The vast majority of their blood lead levels were below the U.S. Center of Disease Control’s (CDC) reference level.[1] The researchers found that he severity of CAS is an important predictor for life threatening cardiovascular disease, even after adjusting for factors such as age, sex, hypertension, body mass index, regular exercise, smoking, and alcohol drinking.[2]
This study is important because it quantifiably links an early indicator of heart disease to lead exposure and reinforces recent studies that did the same for cardiovascular disease deaths. They conclude that the “evidence is strong that the time to recognize metal contaminants in the evaluation, treatment, and prevention, of CVD is in the here and now.”
The second study was a May 2021 review in the Journal of American Health Association that concluded that the burden of proof has been met for lead and cadmium as cardiovascular risk factors based on an integration of clinical, toxicological, epidemiological, and experimental evidence a. The review goes on to recommend that “as metal exposure remains widespread, additional efforts are needed. Funding for public health efforts is urgently needed to develop infrastructure, in particular for handling wastewater and producing metal-free drinking water, as ≈18 million people in the United States currently receive water through aged lead pipes, and to decrease urban lead exposure in neighborhoods affected by lead contamination in homes and residential soil.”
The socioeconomic benefits of prevention were made clear in a September 2020 study by Brown et al. (that we blogged about previously), which estimated that reduced adult blood lead levels from 1999 to 2014 avoided 34,000 to 99,000 CVD deaths in 2014. The model underpinning the study was developed by the Environmental Protection Agency (EPA), which completed its peer review in June 2019. This type of review is essential to adoption of a model that can be used in regulatory decision-making.
We encourage the federal government to use the model and these studies in assessing options to improve federal rules designed to reduce lead exposure including the Lead and Copper Rule, Lead-based Paint Hazard Standard, and the Occupational Safety and Health Administration’s worker protection rules. The model allow a more complete understanding of the societal benefits of strengthening these rules and why they should be a high priority. Further, these latest studies reinforce the need for Congress to provide funding to initiatives that will reduce everyone’s exposure to lead – from water, paint, and other sources.
[1] 94% were below 5 micrograms per deciliter of blood (µg/dL), the reference level established by the U.S. National Institute for Occupational Safety and Health, with a median of 2.03 µg/dL.
[2] A 1 µg/dL increase in blood lead had a statistically significant increased odds ratio of moderate-to-severe CAS by 1.22. It dropped to 1.13 after considering other risk factors.