By Linda Carroll
(Reuters Health) – Drinking water that is contaminated with even moderate levels of arsenic may lead to harmful thickening of the heart’s main chamber walls, a new U.S. study suggests.
Researchers who analyzed arsenic levels from more than 1,000 adults under the age of 50 found the risk of heart thickening over the next roughly five years was significantly higher in those with the highest exposure to the toxin, according to the report published in Circulation.
“It’s important for the general public to be aware that arsenic can be a risk factor for cardiovascular disease,” said the study’s lead author, Dr. Gernot Pichler, a medical specialist in internal medicine in the department of cardiology at Hospital Hietzing/Heart Center Clinic Floridsdorf in Vienna. “Potential sources of exposure need to be considered, in particular for people drinking water from private wells. Private wells are currently not regulated and people using private wells, including children and young adults, are not protected.”
“Testing of those wells is a critical first step in order to take action and prevent arsenic exposure,” Pichler said in an email.
To take a closer look at the impact of arsenic on the heart, Pichler and his colleagues turned to data from the Strong Heart Family Study, a long-term study of cardiovascular risk factors among Native Americans. The new report included 1,337 adults in Arizona, Oklahoma, North Dakota and South Dakota whose average age was just under 31 when their arsenic levels were measured. At the outset, none of the study participants had diabetes or heart disease.
The researchers evaluated the shape, size and function of the study participants’ hearts using echocardiography, a type of ultrasound imaging. Arsenic exposure was evaluated in urine samples. Arsenic exposure in the participants overall was found to be higher than in the general U.S. population, but lower than what is found in Mexico and Bangladesh, the study authors note.
After following participants for up to about seven years, the researchers found that those with higher levels of arsenic were more likely to have thickening of the left ventricle. Indeed, a two-fold higher level of arsenic was associated with a 47 percent increased risk of a participant having left ventricular thickening, known as hypertrophy.
Among participants with higher blood pressure levels – above 120/80 – or those using blood-pressure lowering drugs, the impact of arsenic appeared to be stronger: higher levels of arsenic were linked to a 58 percent greater chance of developing left ventricular hypertrophy in this group.
Pichler suspects that individuals with high blood pressure might be more susceptible to the deleterious effects of arsenic.
For those with arsenic-contaminated drinking water, Pichler suggests water treatment. “The best treatment systems are at the point of entry,” he said. “Some states, such as New Jersey, help families to treat their water. Simple water filters, heating or boiling water do not remove arsenic. The use of bottled water is an option but treatment will be cheaper in the long run.”
The first thing, for people whose water comes from wells, “is to have water tested,” said Jessica Wilson, a clinical dietician affiliated with Magee-Womens Hospital in Pittsburgh, Pennsylvania, who wasn’t involved in the study. “You want to see if it’s safe and OK to drink.”
The new study highlights a big problem, said Dr. Omar Ali, director of the cardiac catheterization lab at Detroit Medical Center’s Heart Hospital in Michigan, who also wasn’t involved in the study.
“The World Health Organization estimates that more than 800 million people worldwide are being exposed to high concentrations of arsenic,” Ali said. “And in the U.S., statistics from the (Centers for Disease Control and Prevention) and the (U.S. Geological Survey) show that 45 million Americans are drinking well water and 2.1 million are drinking water from wells with high concentrations of arsenic.”
This isn’t the first paper to show that arsenic can lead to cardiovascular disease, Ali said. Others have linked the toxin to stroke and to accelerated atherosclerosis.
The new findings should spur doctors to find out where patients get their drinking water from, Ali said. “We need to increase awareness of this potential problem and to investigate it more,” he added. “In communities where people rely solely on well water, we need to be extra vigilant.”