Exposure To Lead, Cadmium, And Arsenic Increases Risk Of Cardiovascular Disease

The AHA scientific statement reviews the evidence linking chronic exposure to low to moderate levels of the three contaminant metals to cardiovascular diseases (CVD) and highlights the clinical and public health implications as currently traditional risk factors for CVD do not include environmental toxicants rather they identify exposure to pollutants which includes contaminant metals as being modifiable risks. 

"Large population studies indicate that even low-level exposure to contaminant metals is near-universal and contributes to the burden of cardiovascular disease, especially heart attacks, stroke, disease of the arteries to the legs and premature death from cardiac causes," said Gervasio A. Lamas, M.D., FAHA, chair of the statement writing group and chairman of medicine and chief of the Columbia University Division of Cardiology at Mount Sinai Medical Center in Miami Beach, Florida.

"These metals interfere with essential biological functions and affect most populations on a global scale," said vice chair of the statement writing group Ana Navas-Acien, M.D., Ph.D., a professor of environmental health sciences at Columbia University's Mailman School of Public Health and the director of the Columbia University Northern Plains Superfund Research Program in New York City. "After exposure, lead and cadmium accumulate in the body and remain in bones and organs for decades. In the U.S. alone, one large study suggested that more than 450,000 deaths annually could be attributed to lead exposure."

Exposure to contaminant metals happens more often than one would think, most often occurring involuntarily through regular activities of daily living. For instance, lead paint can still be found in a variety of items like paint in older homes, tobacco products, secondhand smoke, contaminated foods or water, pottery, ceramics, plumbing, spices, cosmetics, electronics, and industrial emissions. 

Cadmium can be found in cigarettes, batteries, pigments, plastics, ceramics, glassware, construction products, and fertilizers which can then contaminate root vegetables, leafy green plants, and tobacco.

Arsenic most notably build-ups in food crops but in rice more than other crops, exposure is primarily through groundwater which affects drinking water, soil, and food grown in contaminated soil or watered with contaminated water.

Regardless of socioeconomic level exposure and risk occurs across diverse populations, but some people experience greater exposure to toxic metals, including those that live closer to major roadways, industrial sources and hazardous waste sites, those that live in older homes, or in areas where environmental regulations are poorly enforced and responses to complaints are inadequate.

"This is a global issue in which lower-income communities are disproportionately exposed to toxic metals through contaminated air, water and soil," said Navas-Acien. "Addressing metal exposure in these populations may provide a strategy to reduce cardiovascular disease disparities and advance environmental justice."

This statement draws to attention global epidemiologic research that confirms lead, cadmium, and arsenic are associated with premature death which is in large part due to cardiovascular disease risk. One 2021 study recognized exposure to toxic metals as a non-conventional risk factor for peripheral artery diseases. In 2018 a study reported that higher levels of these contaminant metals in urine and blood were associated with a 15%-85% increased risk for stroke and heart disease. Another study found that higher levels of lead in blood was associated with carotid plaque in those with type 2 diabetes. Cadmium and arsenic were associated with a higher rate of heart disease and ischemic stroke in a study from China. A general population study in Spain found that cadmium in urine was associated with higher rates of new cases of CVD.

Currently, there are no monitoring guidelines or exposure limits for contaminant metal in adults outside of those required for certain types of jobs. The researchers note that decreasing meal exposure in tobacco, protecting water systems and wells, and minimizing metal contamination in air, food, and soil are a few examples of public health measures that could help to reduce exposure to metal and help to reduce the risk of cardiovascular disease. 

"Cardiovascular health may be improved with a multi-pronged approach that recognizes environmental cardiology and includes environmental monitoring and biomonitoring of contaminant metals; controlling for sources of exposure; and developing clinical interventions 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.

Unfortunately, there currently are no standard medical therapies to counteract the vascular impacts of contaminant metals, but there is some progress in research investigating ways to address the potential of treating exposure using chelating agents that bind to metals so that they can be excreted from the body, and supplementing folate and N-acetyl cysteine have shown some potential in reducing the effects of contaminant metals by accelerating excretion in small trials.