MS is a complex disease due to an interaction between genetic factors and the environment. The interaction between genetic and environmental factors probably occurs in childhood and adolescence, and possibly even earlier inside the womb when the immune system is developing.
The main environmental factors identified that increase your risk of getting MS are:
1. Vitamin D (vD) and sunlight: low vitamin D levels and/or reduced sunlight exposure increases your chances of getting MS. This is why we recommend to all MSers that their siblings, children and family members should keep themselves vitamin D replete. To do this you probably have to take vD supplements. Our current vD supplementation guidelines are based on the advice of the Vitamin D Council's guidelines.
2. Epstein-Barr virus (EBV): EBV infection, in particular symptomatic EBV infection that is typically referred to as infectious mononucleosis (IM) or glandular fever. If you have had IM your risk is about 2x to 2.5x higher than the people who have not had IM. People who have never been infected with EBV have a very low chance of getting MS. Unfortunately, at present we have no vaccination for EBV and hence can't prevent you becoming infected with the virus.
3. Smoking: people who smoke have about twice the risk of getting MS than non-smokers. Even passive smoking from being exposed to second-hand smoke may increase your risk of getting MS. Will stopping smoking decrease your risk of getting MS? We don't know, but with other autoimmune diseases the risk falls in people who have stopped smoking and gets smaller the longer you have stopped smoking.
4. Obesity: how obesity increases your chances of getting MS is unknown. It may be that the fat alters the hormonal balance, which increases your chances of getting MS. It is therefore important to try and maintain a normal body weight to reduce your chances of getting MS.
Blog posts of interest:
Vitamin D: What dose of vD?; vD and MS disease activity, vD levels in pregnancy
Smoking: Educating yourself about smoking and MS
Obesity: childhood obesity and risk of MS; childhood obesity and risk of paediatric-onset MS
This is part of the so called 'pre-diagnostic stage' when people have no symptoms of MS or mild, non-specific, symptoms not attributable to MS. The latter stage is often referred to as 'prodromal' MS.
People at this stage often get diagnosed when they have an MRI for another reason, for example due to headaches, after a head injury, as part of routine medical assessment, for example in the military, or not uncommonly when they volunteer for a research study that includes MRI.
The important thing to know is that from a biological perspective RIS is really MS. Given time a significant number of people diagnosed with RIS develop MS, i.e. they have attacks and develop RRMS or develop progressive neurological disability and are diagnosed as having PPMS.
Blog posts of interest: