Chronic exposure to lead, cadmium and arsenic increases risk of cardiovascular disease

The American Heart Association has recently published a scientific statement in the Journal of the American Heart Association, indicating that chronic exposure to low levels of lead, cadmium, and arsenic from common household items, air, water, soil, and food can lead to a higher risk of cardiovascular disease. This study highlights the negative effects of exposure to these toxic substances and the need to take precautionary measures to avoid their harmful impact on health.

This scientific statement examines the connection between chronic exposure to low or moderate levels of lead, cadmium, and arsenic and cardiovascular diseases like coronary artery disease, stroke, and peripheral artery disease. It emphasizes the importance of this evidence for clinical and public health practices. Currently, traditional risk factors for cardiovascular disease don't account for environmental toxicants. However, the field of environmental cardiology recognizes exposure to pollutants, such as contaminant metals, as factors that can be modified to reduce the risk of cardiovascular disease.

According to Gervasio A. Lamas, M.D., FAHA, who is the chair of the statement writing group and also the chairman of medicine and chief of the Columbia University Division of Cardiology at Mount Sinai Medical Center in Miami Beach, Florida, large population studies have shown that exposure to contaminant metals, even in low levels, is almost universal and contributes to the burden of cardiovascular disease. This includes heart attacks, stroke, disease of the arteries to the legs, and premature death from cardiac causes.

According to Ana Navas-Acien, the vice chair of the statement writing group, these metals can disrupt crucial biological functions and affect a large portion of the global population. Lead and cadmium, in particular, can build up in the body after exposure and remain in bones and organs for many years. Shockingly, a study conducted in the U.S. estimated that over 450,000 deaths each year could be linked to lead exposure alone.

Where are people exposed to contaminant metals?

Exposure to harmful metals typically happens unintentionally during our daily routine. Lead, for instance, can be present in various things like old paint in homes (which was banned in the U.S. in 1978), tobacco products, second-hand smoke, contaminated foods (ground water and some pottery, ceramics and kitchenware are sources of lead contamination in food), water pipes, spices, cosmetics, electronics, and industrial emissions. Smoking cigarettes can expose you to both lead and cadmium.

Cadmium can be found in various products such as nickel-cadmium batteries, pigments, plastic, ceramics, and glassware, as well as construction products. The use of industrially produced fertilizers that contain phosphate rock can also lead to cadmium contamination in root vegetables and leafy green plants, including tobacco. Arsenic exposure primarily occurs through groundwater, which can affect drinking water, soil, and food grown in contaminated soil. Rice tends to accumulate more arsenic than other food crops. Although exposure to toxic metals occurs across diverse populations, some people may experience greater exposure due to factors such as living near major roadways, industrial sources, or hazardous waste sites; residing in older houses; or living in areas where environmental regulations are poorly enforced. According to a statement, lower-income communities are disproportionately exposed to toxic metals through contaminated air, water, and soil, which is a global issue. Addressing metal exposure in these populations may help reduce cardiovascular disease disparities and promote environmental justice.

What are the cardiovascular risks of contaminant metals?

The scientific statement outlines global epidemiologic research confirming that lead, cadmium and arsenic are associated with premature death, due in large part to increased cardiovascular disease risk. The global research includes:

- A 2021 American Heart Association scientific statement recognized exposure to toxic metals as a non-conventional risk factor for peripheral artery disease.

- A 2018 review published in the British Medical Journal assessed 37 studies representing nearly 350,000 people from more than a dozen countries. The review reported that higher urine levels of arsenic and blood levels of lead and cadmium were associated with 15%-85% higher risk for stroke and heart disease.

- One study in China found that higher levels of lead in the blood were associated with carotid plaque in people with Type 2 diabetes. Another found that cadmium and arsenic were associated with a higher rate of heart disease and ischemic stroke.

- In Spain, a general population study found that cadmium in urine was associated with increased rates of newly diagnosed cardiovascular disease.

What can be done about metals in the environment?

The group of writers suggests that it is important to monitor the levels of metals in the environment and test individuals for metal exposure in order to implement appropriate public health initiatives. Health professionals use blood tests to monitor lead levels in children with symptoms of exposure. However, there are currently no established monitoring guidelines or exposure limits for contaminant metals in adults, except for those required for specific types of work. Further research is necessary to determine if testing for metal exposure in adults may be an effective strategy to protect those at risk of cardiovascular disease. The authors recommend implementing public health measures such as reducing metal exposure in tobacco, protecting community water systems and wells, and minimizing metal contamination in air, food, and soil. They believe that a multi-pronged approach that includes environmental and biomonitoring, controlling sources of exposure, and developing clinical interventions may improve cardiovascular health. that remove metals or weaken their effects on the body,” said Lamas, who is also a professor of medicine at Columbia University Irving Medical Center in New York City.

The medical field currently lacks a standard therapy to counteract the negative effects of contaminant metals on our vascular system. However, there are various ongoing researches to tackle the potential of treating those who are exposed to these metals. One such research is exploring the effect of chelating agents, which are medications that can remove contaminant metals from the body, specifically lead and cadmium. The chelating agent binds the metals, making it easier to excrete them. Moreover, there is a need for further research to examine the efficacy of nutritional supplements in reducing the impact of contaminant metals and hastening the excretion process. Nutritional supplements such as folate and N-acetyl cysteine have displayed potential based on small trials.

This statement was prepared by the volunteer writing group representing the American Heart Association's Council on Epidemiology and Prevention, the Council on Cardiovascular and Stroke Nursing, the Council on Lifestyle and Cardiometabolic Health, the Council on Peripheral Vascular Disease, and the Council on Kidney in Cardiovascular Disease. The American Heart Association's scientific statements aim to raise awareness about cardiovascular diseases and stroke issues and assist in making informed health care decisions. They outline the current knowledge on a topic and areas that require further research. However, they do not make treatment recommendations.

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