Waterpipe Tobacco Smoking and Multiple Sclerosis: A Systematic Review and Meta-Analysis.

Background: Multiple sclerosis (MS), as an autoimmune disease of the central nervous system, has a significant burden among people worldwide. Tobacco smoking is one of the most prevalent habits of patients with different diseases including those with MS, and among the methods of use, waterpipe tobacco smoking is gaining popularity. Herein, we aimed to systematically evaluate the association between waterpipe smoking and MS.