Scientists have long known about some factors linked to a higher risk of developing multiple sclerosis (MS).These include low levels of sunlight exposure, low vitamin D blood levels, smoking, and being infected with the Epstein Barr virus in adolescence and adulthood (infectious mononucleosis). Recent research has identified another risk factor - exposure to mixtures of PFAS and PCBs.
Multiple sclerosis (MS) is an autoimmune disorder in which the immune system attacks myelin in the central nervous system, including the brain.
Researchers in Sweden found that people exposed to both PFAS and PCBs, resulting in higher levels of these chemicals in the blood, are at higher risk for MS. And the higher the levels of both in the blood, the higher the risk. The research was important in that it showed the need to look at mixtures of chemicals people are exposed to (real life!), not just chemicals in isolation.
PFAS (per- and polyfluorinated substances) are commonly known as "forever chemicals" due to their buildup and persistence in people and the environment. They are of great concern because they are endocrine disruptors, have harmful health effects (e.g., cancer, kidney disease, fertility problems), and unfortunately are found in many products that people use daily (e.g., nonstick pots, nonstick finishes). In the study, PCB exposure was primarily from foods, especially Baltic Sea fish, and water.
Bottom line: We can't avoid all exposures to environmental toxins, but we can lower our exposures, for example, by avoiding nonstick cookware. [More tips on avoiding harmful chemicals.]
From Medical Xpress: Exposure to PFAS and PCBs linked to higher odds of multiple sclerosis
People who have been exposed to both PFAS and PCBs are more likely to be diagnosed with multiple sclerosis (MS). These new research findings are based on analyses of blood samples from more than 1,800 individuals in Sweden, one of the most comprehensive studies to date on the influence of chemical environmental exposure on the development of MS.
Multiple sclerosis (MS) is an autoimmune disease in which both genetic and environmental factors can contribute to the risk of the disease. In the current study, researchers analyzed blood from individuals who had recently been diagnosed with MS to investigate concentrations of the common environmental contaminants PFAS and PCBs.
PFAS and PCBs are collective names for a range of subsidiary groups of environmental toxins. In a first phase, the researchers studied the incidence of 14 different PFAS contaminants and three different substances that arise when PCBs are broken down in the body, called hydroxylated PCB metabolites. For each substance, the link between concentration and the odds of being diagnosed with MS was investigated.
"We saw that several individual substances, such as PFOS and two hydroxylated PCBs, were linked to increased odds for MS. People with the highest concentrations of PFOS and PCBs had approximately twice as high odds of being diagnosed with MS, compared with those with the lowest concentrations," says Kim Kultima, who led the study.
The study included approximately 900 individuals who had recently been diagnosed with MS. They were compared with a control group consisting of an equal number of people without MS.
The individuals with and without MS were drawn from the EIMS cohort, a nationwide collection of samples and data designed to investigate the reasons why people are affected by MS. The researchers then measured the concentrations of environmental toxins in the blood and used statistical methods to study the link between them and the odds of being diagnosed with MS.
To better reflect the actual exposure that people experience, the researchers also investigated how the odds were affected when the substances occurred together as a mixture of chemicals.
"We could then see that an increase in total exposure was linked to higher odds of MS, even after adjusting for previously known lifestyle and genetic risk factors. 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," says Aina Vaivade, the first author of the study.
In a final phase, the researchers also studied the relationship between inheritance, chemical exposure and the odds of being diagnosed with MS. Individuals who carry a certain gene variant have a reduced risk of MS. In individuals in the study who carried this gene variant, unexpected increased odds of getting MS were observed in the case of higher PFOS exposure.