Cancer-causing ‘forever chemicals’ that have been linked to chronic disease and infertility are now being associated with a debilitating neurological disease.
Having high blood concentrations of PFAS, called forever chemicals because they lodge in the body’s tissues and the environment and can take decades, sometimes centuries, to degrade, has been linked to up to four times the risk of developing multiple sclerosis (MS) in genetically vulnerable individuals.
MS is a chronic autoimmune disorder that affects nearly one million Americans. The immune system mistakenly targets the protective myelin sheath around nerves in the central nervous system, disrupting communication between the brain and body.
This results in symptoms like severe fatigue, numbness, vision loss, and walking difficulties, often leading to progressive disability.
Not only were high blood concentrations of two specific forever chemicals, PFOS and PCBs, linked to a higher risk of MS, but researchers also found that PFOS exposure can completely overwhelm a gene that is known to be protective against MS.
Even among people with this protective gene, those with high PFOS exposure saw their risk of MS increase more than fourfold.
Forever chemicals are synthetic ingredients engineered to be extremely stable and resistant to heat, water, oil and stains. They have been used for decades in nonstick cookware, forming the coating on pans to prevent food from sticking.
They are also used in some grease-resistant plastic food containers, as well as in waterproof, water-resistant, and stain-resistant fabrics.
Forever chemicals are human-made compounds designed to resist heat, water, oil, and stains. For decades, they have been used to create the nonstick coating in common household cookware (stock)
These harmful forever chemicals, including MS-linked PFOS and PCBs, leach into the food and enter the body, resulting in a direct route of significant exposure to the hazardous chemicals, which have been linked to several health issues, including cancers of the prostate, kidney and testicles, low birth weight, liver damage, developmental delays in children and thyroid disease.
Swedish researchers analyzed data from a major Swedish health study conducted between 2005 and 2015.
They recruited 907 people in their 30s and 40s who had recently been diagnosed with MS. For each MS patient, they found 907 matching individuals identical to the cases in key ways: same age, sex and geographic area in Sweden.
All of them gave blood samples and completed detailed surveys on their lifestyle and environment. Scientists then tested their blood for 31 industrial chemical pollutants, including PFAS and similar compounds such as OH-PCBs.
Researchers calculated participants’ past sun exposure, as sunlight triggers the synthesis of vitamin D when it hits the skin, which modulates the immune system in a way that reduces the risk of MS.
They also identified key genetic markers, specifically variants in the immune system’s HLA genes known to influence MS risk.
The researchers divided chemical exposure levels into four groups: Quartile 1 was the lowest, Q4 was the highest.
Elevated blood levels of three specific pollutants, PFOS (a common PFAS) and two OH-PCBs (4-OH-CB187 & 3-OH-CB153), were each independently linked to an eight to 10 percent higher odds of having MS.
Each graph shows odds of having MS with greater exposure to PFOS, 4-OH-CB187 and 3-OH-CB153. They show that MS risk does not increase in a straight line with exposure. Instead, the odds rise more sharply at higher exposure levels. The shading represents the statistical uncertainty in the estimate. A wider band means less certainty; a narrow band means high certainty. The true effect likely lies within this shaded zone
For PFOS and one OH-PCB, only people in the top 25 percent exposure group, Q4, had roughly double the risk of having MS of the lowest-exposure group.
The researchers tested how chemical exposure interacted with key HLA immune system genes and found a significant gene-chemical interaction. HLA-B*44:02 protein is a known protective gene that reduces a person’s baseline risk of MS.
PFOS exposure promotes a state of chronic, low-grade inflammation. This inflammatory chaos drowns out the calming signals normally sent by the protective HLA-B*44:02 protein.
As a result, the immune system becomes imbalanced, producing an overabundance of attack cells and a shortage of regulatory cells, which cripples the gene’s ability to protect against MS.
People with this protective gene but also with high PFOS levels had a more than four-fold higher risk of MS. In people without the protective gene, only the very highest PFOS exposure increased risk, by about 60 percent.
When the researchers analyzed the combined effect of all the PFAS and OH-PCBs together, they found a strong and significant link to higher MS odds.
This biological mechanism, chronic inflammation, immune dysregulation and disruption of immune tolerance, is a general pathway that can make someone vulnerable to multiple autoimmune conditions, not just MS, including lupus and rheumatoid arthritis.
Aina Vaivade, a PhD student at Uppsala University in Sweden and first author of the study, said: ‘The results show that when attempting to understand the effects of PFAS and other chemicals on human beings, we need to take mixtures of chemicals into account, not just individual substances, as people are generally exposed to several substances at the same time.’
The study was published in the journal Environment International.
