Khaberni - A recent scientific study revealed a worrying relationship between exposure to certain types of chemicals known as "persistent substances" and an increased risk of developing multiple sclerosis (MS), which is an autoimmune disease that affects the central nervous system and still has no definitive cure or known single cause.
The study was conducted in Sweden, where researchers analyzed health data and blood samples from more than 1,800 people, half of whom were newly diagnosed with multiple sclerosis, and the other half were healthy individuals for comparison. The research team focused on measuring levels of 24 compounds of "per- and polyfluoroalkyl substances" (PFAS), in addition to byproducts of other chemical compounds known as "polychlorinated biphenyls" (PCBs).
The results showed that individuals whose blood samples contained high concentrations of these chemicals were more susceptible to developing multiple sclerosis compared to others. The researchers noted that the risk was not linked to a single substance but increased more clearly when exposed to a combination of several chemical compounds at the same time, a phenomenon described by scientists as "toxic synergy".
The lead researcher of the study, Åsa Fåvad from Uppsala University, stated that these findings underscore the necessity of studying the impact of combined chemical exposure, not each substance individually, since humans are often exposed to multiple compounds in their daily lives.
Persistent substances have been used since the mid-20th century in various industries including non-stick cookware, stain-resistant fabrics, firefighting foams, and cosmetics. Due to their extreme resistance to degradation, these substances are found in water, food, air, and even in human brain and blood.
Although more than 12,000 types of PFAS compounds have been produced, only a limited number are known to be associated with serious diseases such as cancer and congenital disorders, leading many countries to gradually ban them. However, their continuous presence in the environment makes their effects persistent even today.
The study showed that some of these substances, such as PFOS and hydrogenated PCB compounds, are capable of crossing the blood-brain barrier, potentially allowing for a direct impact on the cells of the nervous and immune systems. The researchers believe that these compounds might cause oxidative stress that weakens the natural defense mechanisms of the brain, potentially contributing to the development of multiple sclerosis symptoms, such as muscle weakness, numbness, and vision disorders.
Interactions with genetic factors
The notable findings of the study revealed that high exposure to these substances doubled the risk of developing multiple sclerosis even in individuals carrying genetic variants supposed to reduce the disease risk. In some cases, the risk increased to more than four times, indicating a complex interaction between genetic and environmental factors.
Researcher Kim Kolsetema, one of the study’s contributors, explained that understanding this interplay could open new avenues for understanding the origins of the disease and possibly other autoimmune diseases.
These results come at a time when statistics indicate a 26% global rise in the prevalence of multiple sclerosis over the past three decades, with cases doubling in some countries since 1990, heightening concerns about the role of modern environmental factors in this increase.
The study was published in the journal Environment International, amid calls for further research on the long-term effects of chemicals on the nervous system's health and the need for stricter regulation of their use and spread.
