People who are environmentally exposed to low levels of arsenic, cadmium, and titanium may be more likely to have plaque buildup in their arteries in the neck, heart, and legs, according to new research in the journal Arteriosclerosis, Thrombosis, and Vascular Biology (ATVB).
Metal traces can enter the body via polluted soil that seeps into food, contaminated drinking water, air pollution, or tobacco smoke. There is compelling evidence that toxic metals such as arsenic and cadmium are risk factors for cardiovascular disease.
Arsenic and cadmium are frequently found in cigarettes and food, and arsenic is also present in drinking water.
The primary source of titanium exposure includes dental and orthopedic implants, screws, pacemaker encasings, cosmetic goods, and certain foods such as chewing gum, candies, pastries, chocolates, coffee creamers, and cake decorations.
“Metals are ubiquitous in the environment, and people are chronically exposed to low levels of metal,” says lead investigator of the study Maria Grau-Perez.
“According to the World Health Organization, 31% of the cardiovascular disease burden in the world could be avoided if we could eliminate environmental pollutants.”
Atherosclerosis occurs when fatty deposits, or plaque, accumulate in the arteries, narrowing, weakening, and stiffening them. It can result in a heart attack, stroke, angina, peripheral artery disease, or renal disease, depending on the arteries affected.
Historically, research on the effect of metal exposure on atherosclerosis has focused on the carotid arteries, the neck’s primary arteries. This study assessed subclinical atherosclerosis – the development of the disease prior to the onset of symptoms – and the effect of metal exposure on the carotid, femoral, and coronary arteries. Previous research indicates that imaging the femoral artery, the primary artery delivering blood to the lower body, may help diagnose atherosclerosis early.
The Aragon Workers Health Study assessed 1,873 participants (97 percent of whom were men). The study’s participants were between the ages of 40 and 55 and worked in an auto assembly plant in Spain. The researchers assessed participants’ environmental exposure to nine toxic metals—arsenic, barium, uranium, cadmium, chromium, antimony, titanium, vanadium, and tungsten—as well as the association between the exposure and the presence of subclinical atherosclerosis in the carotid, femoral, and coronary arteries. The study investigated the potential impact of specific metals and metal combinations in atherosclerosis development.
Between 2011 and 2014, socioeconomic and health information on each participant were collected during their yearly occupational health checkups, including their education level, smoking status, and medication use. Each participant underwent a medical checkup that included measurements of their body mass index, blood pressure, blood glucose levels, cholesterol levels, and triglyceride levels, among other things. Urine samples were taken to determine metal contamination in the air, water, and food. Carotid and femoral ultrasounds, as well as coronary calcium scoring tests, were done.
The analysis revealed:
- Older study participants had higher levels of most of the metals measured in the urine
- The few female participants in the study had higher metal levels compared to men, when levels were measured in the urine.
- Adults who had smoked at any time showed higher levels of arsenic, cadmium, chromium and titanium than the people who had never smoked.
- Higher levels of arsenic, cadmium, titanium, and potentially antimony were associated with a higher probability of having subclinical atherosclerosis.
- Arsenic and cadmium appear to be most closely associated with increased plaque levels in the carotid arteries; cadmium and titanium are of greater concern for the femoral arteries; and titanium, and possibly cadmium and antimony, are of more concern for the coronary arteries.
- Arsenic may be more toxic for the arteries when found in combination with cadmium and titanium.
“This study supports that exposure to toxic metals in the environment, even at low-levels of exposure, is toxic for cardiovascular health,” adds study co-author Dr. Maria Tellez-Plaza.
“The levels of metals in our study population were generally lower compared to other published studies. Metals, and in particular arsenic, cadmium, and titanium, likely are relevant risk factors for atherosclerosis, even at the lowest exposure levels and among middle-aged working individuals.”
Since the study focused on a fairly specific demographic of predominantly men in a particular region of Spain, the findings may not be totally generalizable to women or other populations worldwide. Additional research is required to decipher the mechanisms underlying the development of atherosclerosis in the presence of metals.
“Current global environmental, occupational and food safety standards for cadmium, arsenic and other metals may be insufficient to protect the population from metal-related adverse health effects,” says Tellez-Plaza.
“Metal exposure prevention and mitigation has the potential to substantially improve the way we prevent and treat cardiovascular disease.”
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