Lead may be out of gasoline and paint but it’s not out of our hearts.
Physicians and patients alike may assume that lead poisoning is a relic of the past, with the notable exceptions of contaminated water plaguing people in Flint, Mich., or Milwaukee in recent years. A new study analyzing lead levels in bones reminds us that lead lingers in the body for a lifetime, including in the heart’s vital arteries, where it can elevate blood pressure, injure the lining of blood vessels, and raise risk of death from heart attacks.
A new analysis moves lead up from 18th on the global list of leading risk factors for death by coronary artery disease to eighth. In the paper, published Monday in JAMA, high blood pressure, “bad” cholesterol, obesity, and other familiar predictors of heart attack and stroke are still up there as dangers, contributing to the No. 1 cause of death in the United States and the world. But the new report makes the case that alongside those contributors, lead continues to harm people who were exposed to it in the past, in water or the air or in some other way. Its presence is still felt in and around factories that make lead-acid batteries, food grown from contaminated soil, and other everyday products like some 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,” Ana Navas-Acien, a physician-epidemiologist, told STAT about the new study. 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 followed more than 42,000 people who were 18 to 90 years old from 1988 through 2013, relying on lead in bones as measured by blood tests and exposure history recorded in the U.S. National Health and Nutrition Examination Survey, or NHANES. Following up through 2015, there were more than 1,700 cardiovascular deaths. Globally, based on their data review, authors attributed 3.5 million deaths in 2023 to lead exposure.
“This study reframes coronary heart disease,” Bruce Lanphear, a professor of health sciences at Simon Fraser University and author of a companion editorial, told STAT in an email interview. “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 the current scientific evidence for cardiovascular disease has been building, lead’s ill effects have long been known, dating back to the Roman Empire. A review published in 2024 in the New England Journal of Medicine called lead poisoning an ancient disease. Navas-Acien, a co-author of that review, said last week that scientists from the time knew it was better to drink water from clay pipes than lead pipes after seeing people get sick after drinking from the lead pipes.
Centuries later the dawn of the industrial age brought massive amounts of lead mined from deep in the earth into the air and water. Lead’s effects are cumulative, so people born in the 1930s and 1940s had the most lead exposure and the worst outcomes. In the 20th century, lead levels rose steeply in the U.S., in sync with industrialization, but they began a precipitous fall 50 years ago. That’s when lead was removed from gasoline and paint while stricter measures focused attention on air and water pollution. That’s also when deaths from heart attacks began to plunge, the new JAMA paper notes. But not all people are spared.
“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,” study co-author Jeffrey Stanaway, associate professor of health metrics sciences and global health at the Institute for Health Metrics and Evaluation, told STAT in an interview.
Navas-Acien remembers when she first realized the climbing then falling trajectory of lead in the environment looked very much like the rise and fall of heart attack deaths. As a Ph.D. student, she saw a parallel between the rise of lead exposure, the decline in lead exposure, the rise of cardiovascular disease in the U.S., and the sudden drop in cardiovascular disease in the same years that lead exposure also dropped.
Could these two mountain peaks be a coincidence, she asked herself then. “That was a really critical moment for me, to have that sense that there was something more important,” she said.
The JAMA study isn’t the first to link lead to cardiovascular disease and death, and its authors acknowledge how long neurodevelopmental toxicity to children has been known. A statement issued by the American Heart Association in 2023 calls lead an added risk factor for cardiovascular disease, along with hypertension, high cholesterol, diabetes, obesity, smoking, and a sedentary lifestyle. The authors invoked the term “environmental cardiology,” recognizing that exposure to toxic metals and other pollutants represents an important, modifiable component of cardiovascular risk.
The new paper raises the level of risk because the researchers asked a different question than has been posed in past studies. Previous analyses have looked at how much lead increased blood pressure, an indirect predictor of heart disease. The new work looks at the direct effects of lead on cardiovascular disease, including blood pressure numbers.
The researchers took into account overlapping risk factors such as when someone who had high lead exposure was also a smoker before developing coronary heart disease, Stanaway said.
How lead does its damage
Lead is dangerous because it weakens blood vessels from the inside, exerting oxidative stress and interfering with nitric oxide, whose role is to keep blood vessel linings flexible and blood pressure under control. That’s how lead can set people up for the hardened arteries that bring on heart attacks and strokes.
Wherever people are exposed to the metal, it follows the same route into cells taken by minerals that are mainstays of a healthy diet: calcium, iron, and zinc. After sneaking into cells, lead can displace those minerals and become deposited in the bones. Breathing in lead particles is the quickest route to displacement, Navas-Acien explained, but the stomach can also be an entry point, if a slower one. Eating a diet rich in good minerals like calcium, iron, and zinc can block some lead, she said.
While lead is deposited in bone, it also leaches out from the bone to circulate in red blood cells, especially with age, osteoporosis, and menopause, directly increasing blood pressure.
“Lead doesn’t disappear. It lingers in our bones and in our environment — paint, dust, soil, and water systems,” Lanphear said 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 called global equity in lead exposure reductions important, which means bringing lower-income countries up to the same level that high-income countries have achieved in terms of lead reductions. That’s a challenge beyond regulation. He gave one example of how it plays out on the individual level. People who don’t have many ways to earn money might work in lead-battery recycling for the U.S. auto industry despite the high exposure to lead. Regulations prohibit this work in wealthier countries, but that’s not true in Africa, where workers and people living near these factories suffer from high lead exposure.
Sustaining existing efforts to eliminate lead into the future is vital, Stanaway said. “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 said lead is still everywhere, and we know how to eliminate it. “What’s missing,” he said, “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.
