Where your DNA places you among other people, and the studies behind it.
Not tailored to your result, and not medical advice
Quit or Avoid Smoking: Tobacco is the best-established modifiable risk factor for MS. In a Frontiers in Immunology analysis, ever-smokers had about 41% higher MS risk than never-smokers (95% CI 1.33 to 1.50), and 13.1% of cases in that population were attributable to smoking, rising to 19.1% in men. The attributable fraction was under 1% in ex-smokers, which the authors read as a benefit of quitting. The same analysis reported an odds ratio of 4.9 for people who both smoked and carried the HLA-DRB1*15:01 variant, and it discusses smoking as being associated with faster disability progression as well. Frontiers in Immunology (PMC)
Get Everyday Sun Exposure: MS becomes more common with distance from the equator, and sunlight is one of the leading explanations. In the Nurses' Health Study cohorts, women living in high ambient UV-B areas before onset had 45% lower MS risk than those in low UV-B areas (adjusted RR 0.55, 95% CI 0.42 to 0.73), and having both high UV-B and high summer sun exposure between ages 5 and 15 was associated with 55% lower risk (RR 0.45, 95% CI 0.21 to 0.96). This is observational, and sunlight, vitamin D status, and time spent active outdoors are hard to separate from one another. Sun protection still matters for skin cancer risk, so this is not an argument for burning, and oily fish, eggs, and fortified foods are the usual dietary sources of vitamin D. Neurology (PMC)
Keep Adolescent Weight Healthy: Body weight in childhood and the teenage years, rather than later adult weight, is the exposure that shows up in MS research. Observational data summarised in the American Journal of Epidemiology show a more than two-fold higher MS risk in people whose BMI was 30 or above at around age 18. A Mendelian randomisation analysis using a 97-variant BMI score found that higher genetically predicted BMI also predicted MS susceptibility (meta-analyzed OR 1.10, 95% CI 1.05 to 1.15), which argues the link is causal rather than only a correlation. The proposed mechanism runs through the chronic low-grade inflammation and altered vitamin D handling that accompany excess adiposity. American Journal of Epidemiology (PMC)
Build Exercise Into The Week: Exercise was once discouraged in MS because heat raises body temperature and can temporarily worsen symptoms, but trial evidence now points the other way. A 2024 meta-analysis of 40 randomised trials (1,300 people exercising, 827 controls) found exercise improved balance on the Berg Balance Scale by 3.77 points and six-minute walk distance by 25.56 meters, reduced fatigue, and improved quality of life on the MSQOL-54 by 11.80 points. Resistance training was the most effective type for fatigue and aerobic training the most effective for quality of life. General adult activity guidance is around 150 minutes of moderate activity a week, and how that is adapted for symptoms and mobility is worth working through with a clinician or physiotherapist. Frontiers in Public Health (PMC)
Know What Is Not Preventable: The strongest known trigger for MS is not a lifestyle factor. In a longitudinal study of more than 10 million US military personnel, of whom 955 developed MS, risk rose 32-fold after Epstein-Barr virus infection and was not raised after other viral infections, and the nerve-damage marker neurofilament light chain increased only after EBV seroconversion. EBV infects most of the world's adult population, usually in childhood or adolescence, and there is no reliable way to avoid it. Smoking, adolescent obesity, and low sun exposure shift risk at the margins, but no combination of behaviors prevents MS, and new or unexplained neurological symptoms such as vision loss, numbness, or weakness are worth getting looked at rather than managed at home. Science (PubMed)
How much of this is genetic?
Genetics explains 30% of why people differ in this trait. The rest is environment, daily habits and chance.
Heritability estimate: Twin and family studies (heritability ~30-50%); IMSGC, Science 2019
Background and further reading
Multiple sclerosis (MS) is a chronic autoimmune disease in which the immune system attacks the myelin sheath that insulates nerve fibers in the brain, spinal cord, and optic nerves. This demyelination disrupts nerve signaling and, over time, can damage the nerves themselves. An estimated 2.8 million people live with MS worldwide, and it is roughly two to three times more common in women than in men. Onset is typically between ages 20 and 40. Symptoms are highly variable and can include vision problems, numbness or tingling, muscle weakness, fatigue, balance and coordination difficulties, and cognitive changes. Most people begin with a relapsing-remitting course, and while there is no cure, modern disease-modifying therapies can substantially reduce relapses and slow progression.
Genetic Basis: MS is a polygenic disease with a substantial but not deterministic genetic component; twin and family studies place heritability at roughly 30-50%, with much of the remaining variation attributed to environmental exposures. By far the strongest genetic association is the HLA-DRB1*15:01 allele within the major histocompatibility complex on chromosome 6, which points to the central role of adaptive immunity and antigen presentation. Large genome-wide studies by the International Multiple Sclerosis Genetics Consortium have mapped more than 200 additional non-MHC risk variants, most of low individual effect and concentrated in genes expressed by immune cells such as T cells, B cells, and microglia. A polygenic score aggregates the small contributions of many such common variants into a single estimate of inherited predisposition.
Environmental Factors: Environment and lifestyle interact strongly with genetic susceptibility in MS. Infection with Epstein-Barr virus (EBV) is now considered a leading environmental factor: a large longitudinal study found that MS risk rose sharply only after EBV infection, supporting a causal role. Other well-supported associations include low vitamin D levels and limited sun exposure (MS is more common at higher latitudes), cigarette smoking, and obesity during adolescence. Because these factors are modifiable, they are of particular interest for reducing risk and, in people already diagnosed, supporting overall health. A genetic predisposition does not mean MS is inevitable, and most people carrying common risk variants never develop the disease.
The published research behind your score, and the variants it draws on.
1 published score from 1 study
The multiple sclerosis score combines 1 polygenic score drawn from 1 published study.
These traits are influenced by some of the same genes and variants as this one
Content updated August 2026.
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