Liver disease has long been recognized as one of the world’s most serious health concerns, affecting millions of people globally. Traditionally, its major causes have been attributed to three key factors: chronic alcohol consumption, metabolic disorders such as obesity and diabetes leading to fatty liver, and viral infections like hepatitis B and C. However, in recent years, scientists have begun to explore another crucial and often overlooked dimension—environmental toxins. Among these, one chemical in particular has drawn increasing attention: tetrachloroethylene (PCE), a solvent commonly used in dry cleaning and found in various household products. A groundbreaking study from Keck Medicine of USC, published in Liver International, has revealed compelling evidence linking PCE exposure to serious liver damage, particularly liver fibrosis, a potentially fatal condition that can lead to liver cancer or liver failure.
Understanding PCE: A Common but Dangerous Chemical
Tetrachloroethylene (also known as perchloroethylene or PCE) is a man-made, colorless liquid with a mild, sweet odor. Since its introduction in the early 20th century, it has been widely used as a solvent for degreasing metals, dry cleaning fabrics, and producing adhesives, polishes, and spot removers. Its chemical stability and ability to dissolve oils made it a staple in both industrial and household products.
However, the same chemical properties that make PCE useful also make it hazardous. PCE is volatile—it evaporates easily into the air—and it can persist in the environment for long periods. When released into the atmosphere, it can contaminate soil and groundwater, posing long-term health risks to communities. People can be exposed to PCE through inhalation of vapors from recently dry-cleaned clothes, ingestion of contaminated drinking water, or occupational contact in industries where the solvent is used.
The International Agency for Research on Cancer (IARC) has classified PCE as a probable carcinogen. Previous studies have linked exposure to cancers such as bladder cancer, multiple myeloma, and non-Hodgkin lymphoma. Until now, however, limited research had explored its effects on liver health in human populations.
The Keck Medicine Study: A Groundbreaking Discovery
In the recent study led by Dr. Brian P. Lee, hepatologist and liver transplant specialist at Keck Medicine of USC, researchers analyzed data from the National Health and Nutrition Examination Survey (NHANES), a large and nationally representative sample of U.S. adults collected between 2017 and 2020. Their analysis focused on participants aged 20 and older, examining blood samples for detectable levels of PCE and assessing liver health indicators.
The results were striking. Approximately 7% of participants had measurable levels of PCE in their bloodstream. Among them, those exposed to PCE were found to be three times more likely to suffer from significant liver fibrosis compared to those without exposure. Liver fibrosis is a condition characterized by the buildup of scar tissue in the liver due to chronic injury or inflammation. Over time, this scarring interferes with the liver’s ability to function properly, progressing to cirrhosis, liver cancer, or even liver failure.
Moreover, the study identified a dose-response relationship, meaning that the risk of liver fibrosis increased in proportion to the level of PCE in the bloodstream. Specifically, for every one nanogram per milliliter increase in PCE concentration, the likelihood of developing significant liver fibrosis rose fivefold.
Unmasking Environmental Causes of Liver Damage
Traditionally, physicians have attributed liver disease primarily to well-known risk factors—alcohol abuse, obesity, diabetes, and hepatitis infection. However, Dr. Lee and his colleagues emphasize that environmental exposures like PCE may represent a hidden cause of liver damage, especially in individuals who do not fit the typical profile for liver disease.
“Patients often ask how they can have liver disease if they don’t drink or have any of the usual conditions,” said Dr. Lee. “The answer may be environmental exposure—specifically, exposure to chemicals like PCE.”
The findings underscore the need to broaden the medical and public health perspective on liver disease. Environmental pollutants, previously overlooked in this context, could account for a significant portion of unexplained liver conditions.
Who Is Most at Risk?
The study revealed an intriguing pattern: higher-income individuals were more likely to have detectable PCE levels in their blood, possibly due to greater use of dry-cleaning services, where PCE is still commonly used. While this finding might appear counterintuitive, it highlights how lifestyle factors related to convenience and hygiene can inadvertently increase chemical exposure.
However, the greatest risk lies among workers in dry-cleaning facilities and industrial sectors who experience chronic, direct contact with PCE. Prolonged inhalation or skin exposure over months or years can lead to high levels of accumulation in the body, causing both liver and neurological damage.
Regulatory and Health Implications
Due to mounting evidence of its toxicity, the U.S. Environmental Protection Agency (EPA) has initiated a 10-year phaseout of PCE in dry cleaning, along with restrictions in other industries. Yet, despite these regulatory steps, PCE continues to persist in certain products and remains unregulated in many parts of the world.
The persistence of PCE in the environment poses a continuing threat. Spills or improper disposal can contaminate groundwater, while evaporating vapors from dry-cleaned clothing or industrial exhaust can expose nearby residents. These pathways make it difficult for individuals to completely avoid contact with the chemical.
Dr. Lee emphasized that PCE is likely just one of many environmental toxins contributing to liver disease. Other pollutants, solvents, and heavy metals may have similar effects but remain under-researched. He calls for greater scientific attention, environmental regulation, and public awareness to identify and mitigate such risks.
Public Health Awareness and Preventive Measures
The implications of this research extend beyond scientific curiosity—they directly affect public health policy and personal lifestyle choices. Greater awareness about chemical exposure in everyday environments could lead to preventive interventions, such as using non-toxic alternatives to dry-cleaning solvents, improving workplace safety standards, and enhancing monitoring of environmental pollutants.
Moreover, physicians should consider environmental exposure histories when diagnosing and managing liver diseases. As Dr. Lee noted, screening individuals with known PCE exposure for liver fibrosis could enable earlier detection and treatment, improving outcomes and potentially saving lives.
The general public can also take steps to reduce exposure. Choosing wet cleaning or CO₂-based cleaning methods, ensuring proper ventilation after dry cleaning, and avoiding products containing PCE are practical steps to minimize risk.
Conclusion: A Call for Environmental Vigilance in Liver Health
The discovery of the link between PCE exposure and liver fibrosis marks a pivotal moment in understanding the environmental dimensions of liver disease. It challenges the traditional view that alcohol and metabolic disorders are the only significant contributors, highlighting instead the silent role of industrial and household chemicals.
This study from Keck Medicine of USC serves as a powerful reminder that environmental health and human health are deeply intertwined. Chemicals like PCE, which pervade our daily lives, can have long-term and devastating effects on vital organs. Recognizing these risks and taking proactive steps—through regulation, medical screening, and personal choices—can pave the way toward a healthier, more sustainable future.
As Dr. Lee aptly summarized, “We hope our research will help both the public and physicians understand the connection between PCE exposure and liver fibrosis. If more people with PCE exposure are screened early, we can intervene sooner and offer a better chance at recovery.”
In essence, the fight against liver disease must now expand beyond personal habits to include the environmental context in which we live. Only by acknowledging and addressing these hidden dangers can we hope to truly protect liver health for future generations.
Story Source: University of Southern California - Health Sciences.
Tags:
Comments
Post a Comment