Common Solvent Linked to Tripled Risk of Severe Liver Fibrosis

Exposure to tetrachloroethylene (PCE), a chemical prevalent in dry cleaning and various industrial processes, has been linked to a substantial increase in the likelihood of developing serious liver fibrosis. Researchers at Keck Medicine of USC discovered that individuals with detectable PCE levels in their bloodstream faced more than triple the risk of dangerous liver scarring compared to those without exposure.

The study, published in Liver International, analyzed data from the National Health and Nutrition Examination Survey (NHANES) involving 1,614 adults aged 20 and above between 2017 and 2020. Approximately 7.4% of participants showed measurable PCE in their blood, with concentrations ranging from 0.034 to 57.5 nanograms per milliliter.

Industrial Chemical’s Widespread Presence and Health Risks

Tetrachloroethylene, also known as perchloroethylene, is a colorless organic solvent primarily used for stain removal in dry cleaning. Beyond this, it serves in metal degreasing, manufacturing, adhesives, and household cleaning products. The chemical often enters the body through inhalation, as PCE can off-gas from freshly dry-cleaned clothing and contaminate indoor air for days.

Environmental contamination has also been documented, with PCE seeping into groundwater and drinking water supplies following industrial spills or improper disposal. Due to its volatility, the chemical can disperse through buildings and neighborhoods as vapor.

Classified as a probable carcinogen by the International Agency for Research on Cancer, PCE has been linked to multiple cancers including bladder and liver cancer. Animal studies have demonstrated its capacity to induce liver inflammation, oxidative stress, and cellular damage.

Strong Correlation Between PCE and Liver Fibrosis

After adjusting for demographic and health variables such as age, sex, race, ethnicity, and education, the association between PCE exposure and liver fibrosis remained significant. The odds of having significant liver fibrosis were more than three times higher among those with detectable PCE levels.

The research revealed a dose-response relationship: each one nanogram per milliliter increase in blood PCE concentration corresponded to more than a fivefold rise in the odds of liver fibrosis. Overall, detectable PCE exposure was linked to an absolute fibrosis risk increase of nearly 28%.

Notably, this association appeared independent of common liver disease risk factors such as alcohol consumption and obesity-related fatty liver disease, suggesting environmental toxins like PCE may explain liver disease cases without traditional causes.

“Patients will ask, how can I have liver disease if I don’t drink and I don’t have any of the health conditions typically associated with liver disease, and the answer may be PCE exposure,” said Brian P. Lee, MD, MAS, lead author and hepatologist at Keck Medicine.

Exposure Patterns and Public Health Implications

The study found that individuals from higher-income households were more likely to have detectable PCE, possibly due to greater use of dry-cleaning services. However, workers in dry-cleaning and industrial environments may experience higher exposure levels through prolonged direct contact.

Researchers conducted a “negative control” analysis using a biomarker for mixed volatile organic compounds (VOCs), which indicated the liver fibrosis connection was specific to PCE rather than general VOC exposure, reinforcing the study’s conclusions.

Liver disease prevalence is rising globally, and scientists are increasingly investigating environmental pollutants as contributing factors alongside diet and alcohol. Unlike lifestyle risks, chemical exposures are often invisible and accumulate slowly, complicating early detection and prevention.

Lee emphasized the need for further research into environmental toxins’ impact on liver health and advocated for screening programs to identify liver damage early in exposed populations.