Environmental phenols are found in a wide range of common consumer products. They include preservatives in packaged foods, parabens in shampoos, and bisphenol A (BPA) in plastic tableware, so humans are widely exposed to them, day after day.
Some of these environmental phenols are known to have cardiac toxicities. Now, an interdisciplinary study involving four professors at the University of Cincinnati College of Medicine is revealing its adverse impact on the electrical properties of the heart, and the research was published in the journal Environmental Health.
“This is the first study to examine the impact of phenol exposure on cardiac electrical activity in humans,” said Hong-Sheng Wang, PhD, professor in the Department of Pharmacology, Physiology and Neurobiology and senior author of the study.
The researchers used data from the Fernald Community Cohort, which includes nearly 10,000 people who lived near the former U.S. Department of Energy uranium processing site in Fernald, outside Cincinnati, and participated in the Program of Fernald Medical Monitoring between 1990 and 2008.
Much of the cohort did not experience exposure to uranium beyond the radiation received by the general population. Wang and his team used their data, including biological samples and medical records, in the study so that uranium exposure was not a factor in the findings, making them relevant to the general population. Because urine samples and electrocardiograms (ECGs) were collected on the same day, the results were significant for analyzing exposure to environmental phenols.
The electrocardiographs, which measure cardiac electrical activity, were read by certified physicians and the urine samples were sent to the Centers for Disease Control and Prevention for exposure analysis.
One of the objectives of the study was to identify any changes in ECG parameters associated with environmental phenol exposure.
The heart is driven by electrical activity, so anything that affects its electrical properties can have a detrimental impact and possibly lead to arrhythmias.
The research concluded that increased exposure to some environmental phenols is associated with altered cardiac electrical activity.
The researchers found that greater exposure to BPA, BPF and BPA+F in women is associated with a longer PR interval, a delay in the time it takes for electrical signals to pass from the atria at the top of the heart to the ventricles.
“Our findings were very sex-specific,” Wang said. In women, the researchers identified an association with longer QRS duration, or contraction of the ventricles, and dysfunction of the heart’s electrical impulses.
“It was particularly pronounced in women with higher body mass indexes,” Wang said.
In men, researchers found that greater exposure to triclocarban (TCC), an antimicrobial agent, led to longer QT intervals in the heart, meaning that the heart’s electrical system takes too long to recharge, a situation that may contribute to heart rhythm dysfunction. CBT has since been banned in the United States.
Wang also noted that typical exposure levels alone are unlikely to cause clinically significant heart disease in healthy people.
“These were not dramatic changes that we observed, but rather moderate changes in cardiac electrical activity,” he said. “However, they were especially pronounced in certain subpopulations.”
He said altered cardiac activity could exacerbate a patient’s existing heart disease or arrhythmias, especially in older adults or those with other risk factors.
“There are new chemicals now, so the next step would be to examine these new environmental chemicals and focus on their impact at the individual level on those who are predisposed to heart disease,” Wang said.
Other contributors to this study were Susan Pinney, PhD, FACE, professor of epidemiology in the Department of Public Health and Environmental Sciences; Jack Rubinstein, MD, FACC, professor of clinical cardiology in the Department of Internal Medicine; and Changchun Xie, PhD, professor in the Department of Biostatistics, Health Informatics and Data Sciences.
This study was funded by grants from the National Institute of Environmental Health and the Center for Environmental Genetics at the University of Cincinnati.