A recent study from the University of Southern California (USC) indicates that teenagers with higher levels of per- and polyfluoroalkyl substances (PFAS) in their blood before undergoing bariatric surgery experienced less improvement in blood sugar control over five years. The research, published in Environmental Endocrinology, highlights that these differences were significant enough to potentially reduce the long-term metabolic benefits of the surgery.
PFAS are industrial chemicals commonly found in consumer products and tend to accumulate in the body. They have been detected in almost all U.S. adults and have been associated with health issues such as kidney and liver problems, as well as certain cancers. Recent evidence also suggests a possible link between PFAS exposure and metabolic conditions like type 2 diabetes.
The study was conducted by researchers at the Keck School of Medicine’s Southern California Superfund Research and Training Program for PFAS Assessment, Remediation and Prevention (ShARP) Center. This center is funded by the National Institute of Environmental Health Sciences to investigate hazardous chemicals’ health effects and inform prevention strategies.
Earlier findings from the same USC team revealed that teens with higher PFAS levels were more likely to regain weight after bariatric surgery. The ongoing research aims to identify factors influencing patient outcomes, including environmental toxins like PFAS. Screening for PFAS prior to surgery could help pinpoint patients who may require additional monitoring or interventions to maintain healthy blood sugar levels over time.
The data used for this study came from the Teen Longitudinal Assessment of Bariatric Surgery (Teen-LABS), which follows adolescents who have undergone weight loss procedures. Researchers measured eight types of PFAS in 186 teens aged 19 or younger before their surgeries.
Participants’ metabolic health was tracked at intervals up to five years post-surgery, focusing on fasting glucose and hemoglobin A1c (HbA1c), which reflects average blood sugar over two to three months. Insulin levels and insulin resistance were also assessed.
While most participants showed significant improvements after surgery, those with higher combined exposure to all eight PFAS saw smaller gains in long-term blood sugar control. Their HbA1c increased by an average of 0.27 percentage points three years after surgery—a notable change given that normal HbA1c is below 5.7%.
One specific chemical, perfluorohexanesulfonic acid (PFHxS), had a pronounced effect. Teens with higher pre-surgery PFHxS exposure had annual increases of 0.15 percentage points in HbA1c, raising concerns about progression from normal blood sugar levels to prediabetes or type 2 diabetes within a few years.
PFHxS was also associated with an annual rise of about one milligram per deciliter in fasting glucose, suggesting that initial improvements could be lost within a decade if trends continue. No clear link was found between pre-surgery PFAS levels and post-surgery insulin measures; further research is needed on this aspect.
The Teen-LABS dataset enabled exploration of diabetes-related outcomes even though it was not its primary focus. Researchers noted that future studies should include more detailed diabetes testing, dietary information, and larger groups for broader insights.
"This is another step toward understanding the relationship between PFAS and type 2 diabetes, including differences between types of PFAS and the role of patient age, sex and lifestyle. But many questions remain unanswered," said joint first author Elizabeth Costello, PhD, now at Brown University School of Public Health but formerly a postdoctoral researcher at Keck School during the study.
Researcher Baumert is leading follow-up work using metabolomics and proteomics—techniques measuring small molecules and proteins—to better understand how PFAS might affect metabolism after bariatric surgery.
"This study adds to growing evidence that PFAS can interfere with the body's ability to regulate glucose, even after substantial weight loss," said last author Vaia Lida Chatzi, MD, PhD, professor at Keck School of Medicine and director of ShARP Center. "The findings underscore that metabolic recovery is shaped not only by clinical treatment but also by environmental factors." She added that ShARP Center's mission includes identifying hidden barriers like these environmental exposures during adolescence.
