Contaminant Metals as Cardiovascular Risk Factors: A Scientific Statement From the American Heart Association

Abstract

Exposure to environmental pollutants is linked to increased risk of cardiovascular disease. Beyond the extensive evidence for particulate air pollution, accumulating evidence supports that exposure to nonessential metals such as lead, cadmium, and arsenic is a significant contributor to cardiovascular disease worldwide. Humans are exposed to metals through air, water, soil, and food and extensive industrial and public use. Contaminant metals interfere with critical intracellular reactions and functions leading to oxidative stress and chronic inflammation that result in endothelial dysfunction, hypertension, epigenetic dysregulation, dyslipidemia, and changes in myocardial excitation and contractile function. Lead, cadmium, and arsenic have been linked to subclinical atherosclerosis, coronary artery stenosis, and calcification as well as to increased risk of ischemic heart disease and stroke, left ventricular hypertrophy and heart failure, and peripheral artery disease. Epidemiological studies show that exposure to lead, cadmium, or arsenic is associated with cardiovascular death mostly attributable to ischemic heart disease. Public health measures reducing metal exposure are associated with reductions in cardiovascular disease death. Populations of color and low socioeconomic means are more commonly exposed to metals and therefore at greater risk of metal-induced cardiovascular disease. Together with strengthening public health measures to prevent metal exposures, development of more sensitive and selective measurement modalities, clinical monitoring of metal exposures, and the development of metal chelation therapies could further diminish the burden of cardiovascular disease attributable to metal exposure.

Keywords: AHA Scientific Statements; arsenic; cadmium; cardiac risk factors; coronary disease; heavy metals; lead; myocardial infarction.

Figure 1. Sources of exposure, pharmacokinetics, and cardiovascular outcomes of environmental metals lead (Pb), cadmium (Cd), and arsenic (As).

Figure created with Biorender.com.

Figure 2. Pharmacokinetics and relevant mechanisms for the subclinical and clinical effects of lead (Pb), cadmium (Cd), and arsenic (As). Figure created with Biorender.com.

This is not a complete figure on mechanisms. For example, evidence on metals and hyperglycemia and thrombosis also exists. Ca indicates calcium; ROS, reactive oxygen species; and Zn, zinc.

Figure 3. Pooled relative risks of lead, cadmium, and arsenic exposure and incident cardiovascular outcomes in a systematic review.

Adapted with permission from Chowdhury et al. © Copyright 2018 BMJ Publishing Group Ltd.