A new study has found a link between multiple sclerosis (MS) and infection in adolescence. The researchers had previously found that pneumonia in adolescence is linked to a raised risk of MS, so they undertook a new study to find out if other kinds of infection could be linked.
Because infections can be the result of MS rather than the cause, and the fact it can take five or ten years for MS to begin causing symptoms, extra steps had to be taken to ensure the infections were present before the disease was.
Researchers used health records 2.5 million people in Sweden born between 1970 and 1994. Slightly more than 4,000 were diagnosed with MS after 20, and in this group, 19% had been diagnosed with an infection in a hospital in the first ten years of life, and 14% from the ages of 11 to 19.
The study found that while most infections before the age of 11 were not associated with a future diagnoses of MS, hospital-diagnosed infection between 11 and 19 were consistently associated with a risk of developing MS.
The infections most associated with MS risk were those of the brain and spinal cord. The researchers said this makes sense, as they believe inflammation in the central nervous system may kick off autoimmunity that causes MS.
Adolescent respiratory infections were also associated with a higher risk. The researchers said that sometimes inflammation in the lungs can trigger immune activity in other areas of the body, such as the brain and spinal cord. Or it could be that the infection itself has a direct influence on the brain.
Researchers concluded that with this further evidence that adolescence is a time of susceptibility to possible triggers for MS. It also helps further understand which kinds of exposures might increase the risk, and that it may be worth considering whether someone displaying neurological symptoms has MS if they had a serious infection between the ages of 11 and 19.
Source: MS-UK 07 September 2021