Lead may be gone from our gasoline and paint, but that doesn’t mean it’s gone from our hearts.
Doctors and patients alike may think that lead poisoning is a thing of the past, with the notable exception of contaminated water that has afflicted people in Flint and Milwaukee in recent years. A new study analyzing lead levels in bones is a reminder that lead remains in the body throughout life, including in the heart’s vital arteries, where it can raise blood pressure, damage the lining of blood vessels and increase the risk of death from a heart attack.
The new analysis has moved the country up from 18th to 8th on the global list of major risk factors for death from coronary artery disease. High blood pressure, “bad” cholesterol, obesity and other well-known predictors of heart attacks and strokes remain dangerous and contribute to the No. 1 cause of death in the United States and the world, according to a paper published Monday in JAMA. But a new report argues that alongside these contributors, lead continues to harm people who have been exposed to it in the water, in the air, or in other ways. Its presence is still felt in and around factories that produce lead-acid batteries, food grown from contaminated soil, and other everyday products such as some cosmetics, medicines, e-cigarettes, and e-waste.
“Yes, cardiovascular disease is an environmental disease. For decades, environmental effects have been completely overlooked and completely ignored,” physician epidemiologist Ana Navas Asien told STAT about the new study. A professor and professor of environmental health sciences at Columbia University, she was not involved in the JAMA study. “This is very much a lifestyle disease, and a lot of the blame has been placed on individual-level factors. So it’s very gratifying to see the environmental contribution to the prevalence of cardiovascular disease recognized, especially since lead is such an important factor.”
The JAMA study followed more than 42,000 people ages 18 to 90 from 1988 to 2013 who were dependent on lead in their bones, as measured by blood tests and exposure histories recorded in the U.S. National Health and Nutrition Examination Survey (NHANES). Follow-up through 2015 resulted in more than 1,700 cardiovascular disease deaths. Based on a data review, globally the authors believe that 3.5 million deaths in 2023 will be due to lead exposure.
Early menopause is associated with a 40% increased risk of heart disease
“This study reframes coronary heart disease,” Bruce Lanphear, professor of health sciences at Simon Fraser University and author of an accompanying editorial, told STAT in an email interview. “This study and others show that heart disease is largely influenced by industrialization. Lead, air pollution, and second-hand smoke are at the center of the story, not supporting players.”
Historical lead poisoning
Although scientific evidence regarding cardiovascular disease is currently accumulating, the harmful effects of lead have been known for a long time, dating back to the Roman Empire. A paper published in the New England Journal of Medicine in 2024 describes lead poisoning as an ancient disease. Navas Assien, a co-author of the review, said last week that scientists at the time knew it was better to drink water from clay pipes than from lead pipes because they saw people getting sick from drinking water from lead pipes.
Centuries later, the dawn of the industrial age brought large quantities of lead, mined from deep underground, into the air and water. The effects of lead are cumulative, so people born in the 1930s and 1940s had the most lead exposure and had the worst outcomes. Lead levels in the United States rose sharply in the 20th century, coinciding with industrialization, but began to decline rapidly 50 years ago. It was at this time that strict measures were taken to focus attention on air and water pollution, while lead was removed from gasoline and paint. According to a new JAMA paper, it was also around this time that the number of deaths from heart attacks began to decline sharply. However, not everyone will be saved.
“Part of what’s happening here is that while lead exposure levels are decreasing, there is now a cohort of people who are older and in the age group at highest risk of dying from cardiovascular disease, and who grew up when lead exposure was highest,” study co-author Jeffrey Stanaway, associate professor of health metrics science and global health at the Institute for Health Metrics and Evaluation, told STAT in an interview.
Navas Assien remembers the first time he noticed that the trajectory of the rise and fall of lead in the environment was very similar to the rise and fall of deaths from heart attacks. As a doctoral student, she saw similarities between increased lead exposure in the United States, decreased lead exposure, increased cardiovascular disease, and a sudden decrease in cardiovascular disease in the same year that lead exposure decreased.
Could these two mountain peaks be a coincidence, she asked herself? “That was a really important moment for me. I felt like there was something more important,” she said..
The JAMA study is not the first to show an association between cardiovascular disease and death, and its authors acknowledge how long neurodevelopmental toxicity in children has been known. A 2023 statement from the American Heart Association says that this is an additional risk factor for cardiovascular disease, on top of high blood pressure, high cholesterol, diabetes, obesity, smoking, and a sedentary lifestyle. The authors cited the term “environmental cardiology” in recognition that exposure to toxic metals and other pollutants is an important and modifiable component of cardiovascular risk.
The new paper raises the level of risk because the researchers asked different questions than those posed in previous studies. Previous analyzes looked at how much lead, an indirect predictor of heart disease, increases blood pressure. New research looks at the direct effects of lead on cardiovascular disease, including blood pressure levels.
The researchers took into account overlapping risk factors, such as if people with high lead exposure were also smokers before developing coronary heart disease, Stanaway said.
How Lead Causes Damage
Lead is dangerous because it weakens blood vessels from the inside out, causing oxidative stress and interfering with nitric oxide, which is responsible for keeping blood vessel linings flexible and controlling blood pressure. Thus, lead causes arteriosclerosis in people, which can lead to heart attacks and strokes.
Wherever people are exposed to this metal, it enters cells by following the same route that minerals such as calcium, iron, and zinc, which are key components of a healthy diet, take up. Once lead enters cells, it can displace those minerals and be deposited in bones. Navas Assien explained that inhaling lead particles is the quickest route to evacuation, but if it’s slow, the stomach can also be an entry point. Eating a diet rich in good minerals like calcium, iron and zinc can block some of the lead, she said.
Lead is deposited in the bones, but especially with aging, osteoporosis, and menopause, lead leaches from the bones and circulates in red blood cells, directly increasing blood pressure.
“Lead doesn’t go away. It lingers in our bones and in our environment: in paint, dust, soil, and water systems,” Lanphear said in a message to STAT. “Blood lead levels have fallen dramatically, but the burden on our bodies remains far above pre-industrial levels. And as rich countries have reduced use, industry has shifted to lower-income countries. Exposure has not ended, it has shifted.”
Stanaway said global equity in reducing lead exposure is important, and this means bringing low-income countries to the same level achieved by high-income countries in reducing lead. It is a challenge that goes beyond regulation. He gave an example of how it happens on an individual level. People with fewer means of making money may work in the U.S. auto industry recycling lead batteries, despite the high exposure to lead. While regulations prohibit this work in wealthy countries, this is not the case in Africa, where workers and people living near factories suffer from massive lead exposure.
Mr Stanaway said it was critical to continue existing efforts to eliminate lead into the future. “Cardiovascular damage is a long-term cumulative risk, so we really need to not only reduce lead exposure, but keep it low to get long-term benefits from cardiovascular disease.”
Llanfair said lead is still everywhere and we know how to remove it. “What’s missing is not knowledge, it’s urgency,” he says.
STAT’s chronic health coverage is supported by a grant from. bloomberg philanthropy. our financial supporter It has no role in any of our journalism decisions.
