How does this work?
How do cigarettes have this effect? Well, when you look at the brain, both MS and cigarettes alter chemicals in the brain. Nicotine, along with a myriad of other chemicals in cigarettes, all have damaging effects on the brains, its nerves, and its cells. MS also has a negative effect on the brain by attacking and damaging the myelin sheath, causing the brain to heal and create scar tissue. Because the progression of MS is due to damage to the myelin cells, the damage from the cigarettes is almost like MS doing double the damage. The chemicals introduced to your body also affect your body’s healing process, making it more difficult to heal the damage that the cigarettes and MS have done. This, in turn, leads to deeper, more destructive scarring.
To date, there are only a handful of known correlations that have a definitive causal effect on the development of multiple sclerosis. As far as second-hand smoke is concerned, the research pulled was not able to either confirm or deny the effect second-hand smoke has on individuals and multiple sclerosis, so more research is needed before results can be reported.