The number of individuals diagnosed with multiple sclerosis (MS) has doubled in the UK between 2000 and 2020, with approximately 190,000 patients now living with the condition. This increase, averaging about 6% annually, is noticeable even in individual clinics, where doctors report seeing a rising number of new cases, disproportionately affecting young women.
MS is an autoimmune disease where the immune system attacks myelin, the protective coating around nerves in the brain and spinal cord. Damage to myelin disrupts nerve signals, leading to a range of symptoms from fatigue and numbness to vision problems and mobility issues. While once considered mysterious, research has identified several risk factors.
One significant factor is vitamin D deficiency, suggested by a north-south divide in MS rates within the UK, with Scotland having the highest incidence. Lower sunlight exposure in northern regions correlates with lower vitamin D production, and vitamin D receptors are present on immune cells, linking low levels to autoimmune diseases. While the exact mechanism is still under investigation, the correlation is considered significant.
Viral infections are also implicated in the development of MS. Research points to the Epstein-Barr virus, commonly known for causing glandular fever, as a potential trigger for many MS cases. Although nine in ten people contract Epstein-Barr virus, it confuses the immune system in a small fraction of individuals, leading it to attack the body. A large Swedish study indicated that individuals hospitalized with COVID-19 had approximately two and a half times the risk of a subsequent MS diagnosis. However, experts caution that due to the long development time of MS, it is too early to definitively link these COVID-19 cases directly, suggesting the virus might have accelerated an existing condition.
The higher rate of MS among women, who are three times more likely than men to be diagnosed, is attributed to their more reactive immune systems. This heightened reactivity, while offering better defense against infections and vaccines, also makes the immune system more prone to turning against the body, particularly when triggered by viruses like Epstein-Barr or COVID-19.
Lifestyle choices present modifiable risk factors for MS. Obesity is a significant concern, with children who are obese being twice as likely to develop MS, a risk further amplified when combined with glandular fever. Approximately 22% of children in the UK are obese, a rate that has been increasing for decades. Weight loss through diet and exercise is considered one of the most effective ways to reduce MS risk.
Smoking has long been established as a risk factor for MS, and while smoking rates are declining, vaping has seen a surge in popularity. Around 5.4 million Britons now vape, with usage extending to a significant portion of adolescents. While vaping is considered a safer alternative for existing smokers, there is emerging evidence that vaping may prime the immune system similarly to cigarettes. This raises concerns, especially for non-smokers considering starting vaping.
While there is no cure for MS, treatments have advanced considerably. High-dose steroids can manage flare-ups, disease-modifying drugs can reduce relapses and slow progression, and other therapies can alleviate specific symptoms. Early intervention significantly improves long-term outcomes. Looking ahead, scientific research into vaccines and antiviral drugs targeting Epstein-Barr virus offers hope for preventing MS before its onset.