15 Causes And Risk Factors Linked To Multiple Sclerosis

7. Smoking and Tobacco Exposure

Smoking doesn’t just damage your lungs—it heightens your risk for developing MS and may accelerate disease progression. Tobacco use triggers chronic inflammation, alters immune cell behavior, and may promote breakdown of the blood-brain barrier, allowing harmful cells to access the nervous system. Studies show that smokers are significantly more likely to develop MS than non-smokers, and that quitting may slow the disease course. Even secondhand smoke exposure during childhood has been linked to increased MS risk later in life. In MS, every inflammatory hit counts—and cigarettes are one of the most preventable ones.

8. Low Vitamin D Levels

Beyond its bone-building benefits, vitamin D plays a crucial role in immune modulation. Low levels of this "sunshine vitamin" have been strongly associated with an increased risk of developing MS, especially in individuals living in northern latitudes. Vitamin D helps regulate T-cell activity, reducing the chances of an autoimmune attack on the nervous system. Deficiency in childhood or adolescence may be particularly critical. While supplements alone can’t prevent MS, maintaining optimal vitamin D levels through safe sun exposure and diet may offer a layer of protection. It's a simple factor with outsized influence on immune resilience.