The Multiple Sclerosis was first diagnosed in 1868, but its cause is still unknown today. This disease of the brain and spinal cord causes the immune system to attack its own tissues. Specifically, it attacks myelin , the protective sheath that covers nerve fibers, leading to communication problems between the brain and the body. It can cause disability over time, it has no cure and no confirmed cause, as we already discussed, although two recent investigations have shed light on this last aspect.
The first study, led by British epidemiologist Scott Montgomery and other international doctors, looked at the relationship between infections diagnosed in young people before their 20s, and the risk of future multiple sclerosis as a consequence.
To do this, they analyzed in detail the medical histories of 2.5 million people born in Sweden between the years 1970 and 1994. About 4,000 were diagnosed with multiple sclerosis after their 20th birthday. Within this group, 19% had been diagnosed with a previous infection in a hospital between birth and 10 years of life, and 14% between 11 and 19 years.
The study published in the ‘ Brain Journal ‘ concluded that the majority of infections before the age of 11 were not associated with a future diagnosis of multiple sclerosis. In contrast, those who had infections between the ages of 11 and 19 were associated with an increased risk of sclerosis . The infections with the highest risk are those related to the central nervous system, as well as respiratory infections such as pneumonia .
The relationship between mononucleosis and multiple sclerosis
The same team of doctors went into even more detail on the subject in new research published on October 11 in the ‘ JAMA Network Open’ . The finding of it can be revolutionary, since it identifies for the first time a possible cause associated with multiple sclerosis.
According to this scientific study, infectious mononucleosis (also known as glandular fever), can trigger the appearance of multiple sclerosis in the future.
The publication also shed light on the assumption that families with more infections differ in terms of risk of later developing the disease from those with fewer infections. Therefore, in order to confirm that infections are a real risk for developing sclerosis, the work compared siblings from the same family.
Thus, if one brother contracted mononucleosis and later had sclerosis, while the other did not have either of the two, it is concluded that mononucleosis is a determining factor prior to a diagnosis of sclerosis, and not the genetic predisposition of which it is usually speak habitually. If, on the contrary, one had mononucleosis and both later suffered sclerosis, it is concluded that the cause is genetic predisposition.
The results of the study
The sample of participants again included 2.5 million inhabitants of Sweden. Around 6,000 had a diagnosis of sclerosis beyond the age of 20.
Having had mononucleosis between the ages of 11 and 19 was associated with a significantly increased risk of having sclerosis , confirming this infection as a possible trigger. It should also be noted that those who had mononucleosis between the ages of 11 and 15 are at higher risk of sclerosis later in life.
Of course, the development of the disease is slow. Many of the study patients were not diagnosed until after age 30. This is because the damage to the brain caused by sclerosis develops slowly until it makes someone sick enough to receive the diagnosis.
Mononucleosis in adolescence can trigger sclerosis because sclerosis can affect the brain. The damage it causes to nerve cells prompts the immune system to attack a part of the myelin nerves.