Environmental Health

PFAS Found in 100% of Blood Samples Among Group of Recreational Skiers 

Among these skiers, a new study detected the highest amount of serum PFAS concentrations in ski coaches and more experienced skiers.

Previous research has indicated that skiers face high risk of exposure to per- and polyfluoroalkyl substances (PFAS), hazardous chemicals found in the fluorinated waxes that skiers apply to their skis to ensure maximum speed and efficiency. As ski resorts begin to reopen and skiers glide into another winter season with newly waxed equipment, new research by the School of Public Health is shedding light on actual PFAS levels present in skiers who use fluorinated wax—as well as the health conditions associated with this exposure.

Published in the journal Environmental Research, the study found nine different types of PFAS in all of the study participants, who were recreational and amateur skiers. PFAS concentrations were particularly high among ski coaches, as well as people who spent time as a winter athlete for more than 10 years, and skiers who waxed their skis more than 100 times each year.

Higher PFAS levels were also associated with high cholesterol—a risk factor for cardiovascular disease, and a concerning finding among a group of healthy, physically active adults.

The study is the first to document internal levels of PFAS in skiers and snowboarders, which had previously only been studied in wax technicians. Known as “forever chemicals” because they are difficult to break down, PFAS are hazardous to human health and to the environment, and are linked to a number of diseases and other health conditions, including multiple cancers, liver damage, thyroid disease, decreased vaccine response, and developmental and reproductive complications. In response to mounting data around this health threat, the International Ski and Snowboard Federation (FIS) banned the use of fluorine wax in all FIS competitions—a rule that took effect in the 2023-2024 ski season—but many recreational and amateur skiers continue to use this wax on their equipment and remain at high risk of exposure to these chemicals. 

Compared to the general population, skiers are also at greater risk of adverse health effects from these chemicals than the general population because of the multiple pathways in which they are exposed. In addition to ingestion through drinking water and dermal contact through consumer products, they likely inhale PFAS that are released into the air during the process of waxing or cleaning skis, particularly in enclosed spaces. 

“Ski wax is one of many consumer products that contain PFAS, however, the levels of PFAS in ski wax are—or at least have been—extremely high,” says study lead and corresponding author Birgit Claus Henn, associate professor of environmental health. “Our current and previous work shows that individuals who apply ski wax typically do so regularly and frequently, placing them at higher risk of PFAS-associated health effects, including higher LDL cholesterol.”  

This research was supported by an Established Investigator Innovation Award provided by SPH’s idea hub.

For the study, Claus Henn and colleagues utilized survey data and blood samples from 30 adult skiers (18 and older) participating in a summer training group for skiers and snowboarders in New England in 2023. The participants, who were all physically active and healthy, provided information about their health status, skiing and snowboarding history, ski wax usage, other PFAS exposures, and family health history. The researchers analyzed this data to examine potential connections between serum PFAS levels, various indicators of high wax use, and health biomarkers, including cholesterol, thyroid hormones, and antibodies, compared to similar data among the general population (non-winter sport athletes participating in the 2017-2018 National Health and Nutrition Examination Survey).

Almost all of the skiers (97 percent) had applied fluorinated waxes to their skis, and 27 percent—nearly all of whom were ski coaches—said that they had waxed more than 100 pairs of skis each year.

After accounting for age and gender, the researchers observed associations of higher serum PFAS concentrations with higher levels of total cholesterol, low-density lipoprotein (LDL) cholesterol, and small dense low-density lipoprotein (sdLDL) cholesterol among the skiers, the latter of which is rarely studied among this population. Scientists believe sdLDL cholesterol is a more accurate marker of cardiovascular disease than LDL cholesterol because it can predict this risk even among individuals with low-risk LDL levels and, thus, could serve as a valuable indicator of adverse health in skiers. The team didn’t observe any PFAS associations with thyroid hormones and antibody levels.

“We were surprised to find positive associations between serum PFAS levels and total, LDL, and sdLDL cholesterol among our small cohort of healthy, fit skiers,” says study senior author Kate Crawford (SPH’18), assistant professor of environmental studies at Middlebury College and a graduate of SPH’s PhD program in environmental health. “This study contributes important knowledge to the growing body of evidence linking PFAS exposure and dyslipidemia.” 

Future studies should consider how evolving regulations will affect formulations in a variety of consumer products including ski wax, the researchers say. 

“What are the replacement chemicals and how do they affect human health and the environment? Follow-up in a larger, longitudinal study is needed to assess changes in PFAS body burden over time, given the changing formulations, as well as to fully characterize the health risk in this population that has a higher exposure risk,” Claus Henn says.