You’re likely to associate atherosclerosis – or ‘hardening of the arteries’ as it’s commonly called – with cholesterol and triglycerides.

These fatty substances are given much of the blame for the plaque that builds up in the arteries, causing the artery walls to stiffen and thicken.

But they’re not the whole story.

Cellular waste products, salt and a clot-making substance called fibrin also contribute to coronary artery disease.

You can now add another to that list: Exposure to metals in environmental pollution.

Last year, the Journal of the American Heart Association published a research statement that profoundly expands and heightens the role of pollution as a modifiable risk factor for heart disease.

“Chronic exposure to low levels of lead, cadmium and arsenic through commonly used household items, air, water, soil and food is associated with an increased risk of cardiovascular disease,” it read.

According to scientists from Columbia University, whose research led to the review, traditional risk factors for cardiovascular disease do not currently include environmental toxins.

What the researchers say

Dr Gervasio A. Lamas was chair of the statement writing group and chairman of medicine and chief of the Columbia University Division of Cardiology at Mount Sinai Medical Centre in Miami Beach, Florida.

He said: “Large population studies indicate that even low-level exposure to contaminant metals is near-universal.”

He said this contributes to the burden of cardiovascular disease.

Especially heart attacks, stroke, disease of the arteries to the legs and premature death from cardiac causes, he said.

Professor Ana Navas-Acien was chair of the statement writing group, and professor of environmental health sciences at Columbia University Mailman School of Public Health.

“These metals interfere with essential biological functions and affect most populations on a global scale,’’ she said.

“After exposure, lead and cadmium accumulate in the body and remain in bones and organs for decades. In the US alone, one large study suggested that more than 450,000 deaths annually could be attributed to lead exposure.”

Cadmium, for example, exerts toxic effects on the kidneys as well as the skeletal and respiratory systems.

It is classified as a human carcinogen. It’s found in batteries and cigarettes.

How this affects the arteries

A new study by Columbia University Mailman School of Public Health has found that exposure to these metals is linked to an increased buildup of calcium in the coronary arteries.

This occurs at a level that is comparable to traditional risk factors like smoking and diabetes.

The study findings were published by American College of Cardiology.

The editor-in-chief of that journal, Yale professor Harlan M. Krumholz, was moved to write in a statement: “This groundbreaking study underscores the critical associations of metal exposure from environmental pollution to cardiovascular health.

“It challenges us to broaden our approach to CVD prevention beyond traditional risk factors and to advocate for stronger environmental regulations, and it underscores the need for continued research in this critical area.”

How the study was done

The researchers analysed data from about 6400 adults aged 45 to 84 from 2000 to 2002.

Study participants came from different ethnic backgrounds and all were free from clinical cardiovascular disease.

Participants received testing to establish levels of metals in their urine. These included non-essential metals – cadmium, tungsten, and uranium. Also tested were and essential metals, such as cobalt,  copper and zinc.

Dr Katlyn E. McGraw, a postdoctoral research scientist in the Department of Environmental Health Sciences at Columbia Mailman School was lead author of the study.

She told Medical News Today: “Based on previous research on cadmium and copper and heart disease, and zinc and diabetes, we were not surprised by these findings.”

However, she said they were surprised to find tungsten, uranium and cobalt associated with atherosclerosis.

“Because there is less existing research on these metals. Therefore, these are somewhat new findings,” she said.