Highlights of the statement:
- According to a new statement from the American Heart Association, most people worldwide are exposed to low to moderate environmental levels of lead, cadmium, and arsenic on a regular basis, increasing the risk of coronary artery disease, stroke, and peripheral artery disease.
- These metals, considered pollutants, have no function in the human body. They are found in groundwater, water pipes, paint, tobacco products, fertilizers, plastics, electronics, gasoline, batteries, some foods, and other common items.
- Lead, cadmium, and arsenic are absorbed through the respiratory and/or gastrointestinal tract. People living in lower-income areas often have high exposure to these metals.
- A multipronged approach to reducing cardiovascular risk from pollutant metals may include public health measures such as environmental monitoring and mitigation, individual testing, further evaluation of the consequences of metal exposure and the development of treatments.
DALLAS, 2023 June 12, 2018 Chronic exposure to low levels of lead, cadmium, and arsenic in commonly used household items, air, water, soil, and food is linked to an increased risk of cardiovascular disease, according to a new scientific statement from the American Heart Association. published today in the Journal of the American Heart Association, an open access, peer-reviewed journal.
This scientific statement reviews the evidence linking chronic low-to-moderate exposure to three pollutant metals—lead, cadmium, and arsenic—with cardiovascular disease, including coronary artery disease, stroke, and peripheral artery disease. It emphasizes the clinical and public health implications. Traditional risk factors for cardiovascular disease are not currently environmentally toxic. In the field of environmental cardiology, exposure to pollutants, including pollutant metals, is a modifiable risk factor for cardiovascular disease.
“Large population studies show that even low levels of exposure to pollutant metals are nearly universal and contribute to the burden of cardiovascular disease, particularly heart attacks, stroke, leg artery disease, and premature death from heart disease,” Gervasio said. A. Lam, MD, FAHA, chair of the statement writing group and medical chair and chief of the Division of Cardiology at Columbia University Mount Sinai Medical Center in Miami Beach, Florida.
“These metals interfere with basic biological functions and affect most populations globally,” said Ana Navas-Acien, MD, Ph.D., a professor of environmental health sciences at Columbia University and co-chair of the statement. Postman School of Public Health and director of the Northern Plains Superfund Research Program at Columbia University in New York. “After exposure, lead and cadmium accumulate in the body and remain in bones and organs for decades. In the US alone, one large study found that more than 450,000 deaths each year can be attributed to lead exposure.
Where are people exposed to pollutant metals?
Exposure to pollutant metals is mostly accidental in the course of daily activities. Lead can be found in many things, such as paint in old houses (lead paint was banned in the US in 1978), tobacco products, secondhand smoke, contaminated food (groundwater and some ceramics, pottery, and cookware are sources of lead contamination in food), water pipes, spices, cosmetics, electronics, and industrial pollutants. Cigarette smoking is a source of lead and cadmium.
Cadmium is found in nickel-cadmium batteries, pigments, plastics, ceramics, glass, and construction products. Industrially produced fertilizers use phosphate rock, which is naturally rich in cadmium, which then contaminates root crops and leafy greens (including tobacco).
Arsenic first enters groundwater, which affects drinking water, soil, and food grown in contaminated soil. It should be noted that arsenic accumulates in rice more than in other food crops.
While exposure and risk occur across populations, regardless of socioeconomic level, some people experience greater exposure to toxic metals, the statement said. The risk of exposure is greater for people living closer to major roads, industrial sources, and hazardous waste sites; living in older homes; or in areas where environmental regulations are poorly enforced and responses to community complaints are inadequate.
“It’s a global problem where lower-income communities are disproportionately exposed to toxic metals through polluted air, water, and soil,” Navas-Acien said. “Addressing metal exposure in these populations may provide a strategy to reduce disparities in cardiovascular disease and promote environmental equity.”
What are the cardiovascular risks of contaminated metals?
The scientific statement cites global epidemiologic studies confirming that lead, cadmium, and arsenic are associated with premature death, mainly through an increased risk of cardiovascular disease. Global research includes:
- in 2021 A scientific statement from the American Heart Association identified exposure to toxic metals as a non-traditional risk factor for peripheral artery disease.
- in 2018 The review, published in the British Medical Journal, evaluated 37 studies involving nearly 350,000 people from more than a dozen countries. Higher levels of arsenic in urine and blood levels of lead and cadmium were associated with a 15% to 85% higher risk of stroke and heart disease, the review said.
- One study in China found that higher blood lead levels were associated with carotid artery plaque in people with type 2 diabetes. Another study found that cadmium and arsenic were associated with higher rates of heart disease and ischemic stroke.
- A general population study in Spain found that urinary cadmium was associated with an increased incidence of newly diagnosed cardiovascular disease.
What can be done about metals in the environment?
Monitoring environmental metal levels and testing individuals for metals are key steps in implementing appropriate public health initiatives, the writing group suggests. Lead levels in children with symptoms of exposure are monitored by healthcare professionals through blood tests. However, there are no established monitoring guidelines or exposure limits for pollutant metals for adults other than those required for certain occupations. Further research is needed to determine whether such tests can be an effective strategy to identify and protect people at risk of cardiovascular disease.
Reducing exposure to metals in tobacco, protecting community water systems and wells, and reducing metal contamination in air, food, and soil are examples of public health measures that can reduce exposure to metals, the statement’s authors note.
“Cardiovascular health can be improved through a multifaceted approach that recognizes environmental cardiology and includes environmental monitoring and biomonitoring of pollutant metals; control of exposure sources; and the development of clinical interventions that remove metals or reduce their effects on the body,” said Lam, who is also a professor of medicine at Columbia University Irving Medical Center in New York.
Although there is currently no standard medical therapy to counteract the effects of pollutant metals on the blood vessels, research is underway to see if it is possible to treat exposure in humans. Some studies are evaluating the effects of chelating agents, which are drugs that can remove polluting metals, especially lead and cadmium, from the body. The component bonds with metals, so they can be removed. In addition, the statement says research is needed to investigate dietary supplements that can reduce exposure to and accelerate the release of pollutant metals. Supplements that have shown potential based on small studies include folic acid and N-acetylcysteine.
This scientific statement was prepared by a volunteer writing group on behalf of the American Heart Association Council on Epidemiology and Prevention, the Cardiovascular and Stroke Nursing Council, the Council on Lifestyle and Cardiometabolic Health, the Peripheral Vascular Disease Council, and the Renal Cardiovascular Council. Scientific statements from the American Heart Association promote greater awareness of cardiovascular disease and stroke and help make informed health care decisions. Scientific statements indicate what is currently known about a topic and what areas require additional research. Although scientific statements inform guideline development, they do not provide treatment recommendations. The American Heart Association guidelines provide the association’s official clinical practice guidelines.
Additional members of the Statement Writing Committee include Aruni Bhatnagar, Ph.D., FAHA; Miranda R. Jones, MHS, PhD; Koren K. Mann, PhD; Khurram Nasir, MD, MPH, FAHA; Maria Tellez-Plaza, MD; and Francisco Ujueta, MD, MS Author disclosures are listed in the manuscript.