Although lead has been removed from gasoline and paint, it still remains in our bodies, particularly in our hearts.
Many might believe lead poisoning is a thing of the past, save for incidents like water contamination in Flint, Michigan, or Milwaukee. Yet, a recent study analyzing lead levels in bones reveals that lead persists in the body indefinitely. It accumulates in critical areas like the heart’s arteries, potentially raising blood pressure, damaging blood vessel linings, and increasing the risk of fatal heart attacks.
A new study elevates lead from the 18th to the 8th spot on the global list of risk factors for coronary artery disease deaths. Published in JAMA on Monday, the report maintains that high blood pressure, bad cholesterol, obesity, and other known heart attack and stroke predictors remain significant threats, making cardiovascular disease the leading cause of death in the U.S. and worldwide. However, alongside these factors, lead exposure continues to affect those who encountered it through contaminated water, air, or other sources. It remains present in areas near lead-acid battery factories, soil-grown food, and common products like certain cosmetics, medicines, e-cigarettes, and electronic waste.
“Yes, cardiovascular disease is an environmental disease. For so many decades, the environmental contributions were completely overlooked, completely ignored,” said Ana Navas-Acien, a physician-epidemiologist, while discussing the new study with STAT. A professor and chair of environmental health sciences at Columbia University, she was not involved in the JAMA study. “It has been such a lifestyle-oriented disease, there has been so much blame on the individual level factors, that it feels very satisfying to me to see the recognition for the environmental contributions to the cardiovascular disease epidemic. And especially lead, because it’s such an important factor.”
The JAMA study tracked over 42,000 individuals aged 18 to 90 from 1988 to 2013, using blood tests to measure bone lead levels and exposure history from the U.S. National Health and Nutrition Examination Survey, or NHANES. By 2015, there were more than 1,700 cardiovascular deaths. Globally, the authors linked 3.5 million deaths in 2023 to lead exposure.
Bruce Lanphear, a professor of health sciences at Simon Fraser University and author of a related editorial, commented via email to STAT, “This study reframes coronary heart disease. This and other research show that a large share of heart disease bears the imprint of industrialization. Lead, air pollution, and secondhand smoke aren’t side notes — they’re central to the story.”
Lead poisoning in history
While contemporary research on cardiovascular disease grows, lead’s harmful effects have been recognized since ancient times, dating back to the Roman Empire. A review published in 2024 in the New England Journal of Medicine described lead poisoning as an ancient malady. Navas-Acien, a co-author of that review, noted that early scientists realized drinking water from clay pipes was preferable to lead pipes after observing illnesses linked to lead pipes.
The Industrial Revolution brought vast amounts of lead into the air and water, impacting people born in the 1930s and 1940s the most. Lead levels in the U.S. rose sharply with industrialization but began to decline dramatically 50 years ago when lead was removed from gasoline and paint, and stricter pollution controls were enacted. During this time, heart attack deaths also began to fall, although not everyone benefited equally.
“Part of what’s going on here is that while lead exposure levels are going down, you have a cohort of people now who are older and in the age groups that are at highest risk for cardiovascular disease mortality, who also grew up during a period when lead exposure was the highest,” explained study co-author Jeffrey Stanaway, associate professor of health metrics sciences and global health at the Institute for Health Metrics and Evaluation, in an interview with STAT.
Navas-Acien recalled realizing the parallel between the rise and fall of lead exposure and heart attack deaths. As a Ph.D. student, she noticed the correlation between increased lead exposure, subsequent decrease, and the similar trend in cardiovascular disease rates in the U.S.
She pondered whether these two peaks were mere coincidence, reflecting on the critical realization of a deeper connection.
Although the JAMA study is not the first to link lead with cardiovascular disease and mortality, the authors acknowledge the long-standing awareness of lead’s neurodevelopmental toxicity in children. A statement from the American Heart Association in 2023 identifies lead as an additional cardiovascular disease risk factor, alongside hypertension, high cholesterol, diabetes, obesity, smoking, and a sedentary lifestyle. The authors introduced the term “environmental cardiology,” emphasizing the role of exposure to toxic metals and pollutants as significant, modifiable cardiovascular risk components.
The recent paper increases the perceived risk by posing a different question than previous studies. Earlier analyses focused on lead’s effect on blood pressure, an indirect heart disease indicator. The new study directly examines lead’s impact on cardiovascular disease, considering blood pressure numbers.
The researchers accounted for overlapping risk factors, such as individuals with high lead exposure who were also smokers before developing coronary heart disease, Stanaway noted.
How lead does its damage
Lead is hazardous because it weakens blood vessels internally, causing oxidative stress and disrupting nitric oxide, which is vital for maintaining flexible blood vessel linings and regulating blood pressure. This process can lead to the hardened arteries responsible for heart attacks and strokes.
Lead enters cells through the same pathways as essential minerals like calcium, iron, and zinc. Once inside, lead can displace these minerals, accumulating in bones. Breathing lead particles is the fastest way for this displacement, Navas-Acien elaborated, though ingestion through the stomach is also possible but slower. A diet high in beneficial minerals like calcium, iron, and zinc can help block lead absorption, she said.
Lead stored in bones gradually leaches out, circulating in red blood cells, particularly with aging, osteoporosis, and menopause, directly raising blood pressure.
“Lead doesn’t disappear. It lingers in our bones and in our environment — paint, dust, soil, and water systems,” Lanphear shared in his message to STAT. “Blood lead levels have dropped dramatically, but our body burden remains far above preindustrial levels. And as wealthy countries reduced use, industry shifted to lower-income countries. The exposure didn’t end — it moved.”
Stanaway stressed the importance of global equity in reducing lead exposure, advocating for bringing lower-income countries to the same lead reduction standards achieved by high-income nations. This challenge extends beyond regulation. He cited an example where people, lacking alternative income opportunities, work in lead-battery recycling for the U.S. auto industry despite high lead exposure. While regulations prohibit such work in wealthier nations, this is not the case in Africa, where workers and nearby residents endure high exposure levels.
Ensuring sustained efforts to eliminate lead exposure is crucial, Stanaway emphasized. “We really do need lead exposures not only to decline, but to stay low to get the long-term benefits in cardiovascular disease, since the cardiovascular damage is a long-term cumulative risk.”
Lanphear pointed out that lead is still prevalent, and eliminating it is possible. “What’s missing,” he remarked, “isn’t knowledge — it’s urgency.”
STAT’s coverage of chronic health issues is supported by a grant from Bloomberg Philanthropies. Our financial supporters are not involved in any decisions about our journalism.
