Potent industrial pollutants known as 'forever chemicals' have been connected to a heightened risk of developing the debilitating neurological condition multiple sclerosis (MS). A major new study indicates that individuals with a genetic predisposition to MS face up to a fourfold greater risk if they also have high concentrations of these persistent substances in their blood.
The Alarming Link Between PFAS and Autoimmune Disease
Scientists from Sweden have uncovered a disturbing interaction between per- and polyfluoroalkyl substances (PFAS) and the human immune system. Their research, published in the journal Environment International, analysed data from a significant Swedish health study conducted between 2005 and 2015.
The team examined 907 people in their 30s and 40s who had recently been diagnosed with MS, comparing them to an equal number of matched individuals of the same age, sex, and location. All participants provided blood samples and detailed lifestyle surveys.
The analysis revealed that elevated blood levels of specific pollutants—PFOS (a common PFAS) and two OH-PCBs (4-OH-CB187 & 3-OH-CB153)—were each independently linked to an 8-10% higher odds of having MS. Crucially, the risk did not increase linearly but rose sharply at the highest exposure levels.
How Chemicals Overwhelm the Body's Defences
The study's most striking finding concerns a protective gene known as HLA-B*44:02, which normally reduces a person's baseline risk of MS. Researchers discovered that high exposure to PFOS promotes a state of chronic, low-grade inflammation. This inflammatory chaos effectively drowns out the calming signals sent by the protective gene.
As a result, the immune system becomes severely imbalanced, producing too many attack cells and too few regulatory cells. This cripples the gene's ability to defend against MS, meaning people with this protective gene but high PFOS levels had a more than fourfold higher risk of the disease. In those without the gene, only the very highest PFOS exposure increased risk, by about 60%.
Widespread Exposure and Broader Health Implications
Forever chemicals are synthetic compounds engineered for stability and resistance to heat, water, and stains. For decades, they have been used in:
- Non-stick cookware coatings.
- Grease-resistant food packaging.
- Waterproof and stain-resistant fabrics.
These chemicals leach into food and the environment, entering the human body and accumulating over time. They have previously been linked to cancers, liver damage, thyroid disease, and developmental issues.
First author Aina Vaivade, a PhD student at Uppsala University, emphasised the importance of studying chemical mixtures: "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 concluded that the biological mechanism disrupted by PFAS—chronic inflammation and immune dysregulation—is a general pathway that could increase vulnerability to other autoimmune conditions like lupus and rheumatoid arthritis, not just MS.
