Exposure to chemicals commonly found in everyday household items may be linked to a higher risk of developing multiple sclerosis (MS), according to new research from Sweden that is adding to growing concerns about the long-term health effects of environmental contaminants.
The study, conducted by researchers at Uppsala University and published in the scientific journal Environmental International, found a significant association between MS diagnoses and exposure to two categories of chemicals: PFAS often referred to as “forever chemicals” and PCBs, a group of industrial compounds banned decades ago but still present in the environment.
Multiple sclerosis is a chronic neurological disease in which the immune system mistakenly attacks the protective covering surrounding nerve fibers, disrupting communication between the brain and the rest of the body. Over time, the condition can cause persistent symptoms such as numbness, muscle weakness, coordination problems, vision changes, and cognitive impairment. While genetics play a role, scientists have long believed that environmental triggers are critical in determining who ultimately develops the disease.
What the Study Found
The Swedish research analyzed blood samples from approximately 1,800 individuals, about half of whom had recently been diagnosed with MS. By measuring levels of specific chemical compounds in participants’ blood, researchers were able to compare exposure patterns between those with MS and those without the disease.
In the first phase of the study, scientists examined 14 different PFAS compounds along with three chemical byproducts formed when PCBs are broken down in the body. Several of these substances were found at higher levels in people diagnosed with MS.
Notably, individuals with the highest concentrations of PFOS a well-known PFAS compound as well as certain PCB breakdown products had roughly double the likelihood of receiving an MS diagnosis compared to those with the lowest measured levels.
Lead author Kim Kultima emphasized that the findings point to correlation rather than proof of direct causation. Still, the consistency of the association across multiple chemicals suggests that environmental exposure may meaningfully contribute to MS risk.
“We observed that several individual substances were linked to increased odds of MS,” Kultima said. “People with the highest levels showed significantly higher risk compared to those with lower exposure.”
Why PFAS and PCBs Matter
PFAS, or per- and polyfluoroalkyl substances, are synthetic chemicals widely used for their resistance to heat, water, and stains. They are found in non-stick cookware, food packaging, stain-resistant fabrics, cleaning products, firefighting foam, and even some cosmetics. Because these chemicals do not easily break down, they persist in the environment and accumulate in the human body over time.
PCBs, or polychlorinated biphenyls, were once used extensively in electrical equipment, hydraulic systems, and industrial materials. Although banned in many countries decades ago, PCBs remain in soil, water, and food chains, meaning exposure continues long after production stopped.
Researchers believe both PFAS and PCBs may interfere with immune and hormonal systems. These chemicals are classified as endocrine disruptors, meaning they can mimic or block hormones and alter normal biological signaling.
Chemical Mixtures Pose a Bigger Threat
One of the most important findings from the study was that chemical mixtures appeared to pose a greater risk than individual substances alone. Since people are typically exposed to many chemicals simultaneously through water, food, air, and consumer products, researchers argue that health assessments should reflect real-world exposure scenarios.
Co-author Aina Vaivade explained that evaluating chemicals one at a time may underestimate their combined impact on human health.
“Our results indicate that risk assessments should consider chemical mixtures, not just single compounds,” she said. “The combined exposure seems to play a meaningful role.”
Genetics and Environmental Interaction
In the final phase of the study, researchers explored how genetic factors interact with chemical exposure. They found that individuals carrying a specific gene variant actually had a reduced baseline risk of MS. However, among those same individuals, higher exposure to PFOS was linked to an unexpected increase in MS risk.
This suggests that genetic protection may be overridden or altered by environmental exposure under certain conditions.
“These findings highlight the complex interaction between heredity and environmental contaminants,” Kultima said. “Understanding these interactions may help explain why some individuals develop MS while others do not.”
Expert Reactions: Caution but Concern
Dr. Marc Siegel, a senior medical analyst, said the study supports long-standing theories about environmental triggers in MS but urged caution in interpretation.
“MS is a complex disease with both autoimmune and inflammatory components,” Siegel explained. “We already know that infection with the Epstein-Barr virus dramatically increases MS risk. Environmental factors like microplastics and industrial chemicals are plausible contributors, but this study shows correlation, not causation.”
Dr. Richard Ransohoff, a leader in MS research and a board member of the American Brain Foundation, noted that the chemicals identified in the study could influence immune function in subtle but important ways.
“These substances can interact with receptors involved in both hormone regulation and immune response,” Ransohoff said. “Disrupting these pathways could increase susceptibility to autoimmune diseases like MS.”
Limitations of the Research
The researchers acknowledged several limitations. Chemical exposure was measured only once, at the time blood samples were taken, which may not fully represent long-term exposure during the years when MS develops. Additionally, blood samples were collected around the time of diagnosis, making it difficult to determine whether exposure preceded disease onset.
Ransohoff also noted that the average age of participants—around 40—means exposure earlier in life may not have been captured accurately.
“To strengthen the conclusions, future studies should follow individuals with a family history of MS over many years,” he said. “Tracking chemical exposure long before diagnosis would help clarify whether these substances truly predict disease development.”
Reducing Risk and Exposure
While no single action can prevent MS, experts recommend minimizing known risk factors where possible. Avoiding smoking is one of the most effective steps, as tobacco use is strongly linked to MS progression. Reducing exposure to PFAS and PCBs may also be beneficial.
Practical steps include using stainless steel or cast-iron cookware instead of non-stick pans, filtering drinking water, avoiding plastic bottles when possible, and staying informed about product ingredients.
In April 2024, the U.S. Environmental Protection Agency implemented new federal limits on certain PFAS chemicals in drinking water and announced funding for expanded testing and treatment initiatives aimed at reducing exposure nationwide.
The Bigger Picture
Multiple sclerosis currently has no cure, but treatments can slow disease progression and manage symptoms. As researchers continue to uncover how environmental factors influence autoimmune diseases, studies like this underscore the importance of environmental health policies and individual awareness.
The findings do not suggest that household chemicals directly cause MS, but they add to mounting evidence that long-term exposure to persistent pollutants may shape disease risk in vulnerable individuals. As science continues to untangle the interplay between genetics and environment, reducing unnecessary chemical exposure may prove to be an important step toward protecting neurological health.