Smoking as a risk factor of onset and relapse of Multiple Sclerosis - a review

Multiple Sclerosis (MS) is a chronic demyelinating disease caused by damage to myelin in the brain and spinal cord. The cause of the disease is unclear, but it is probably correlated with dysregulation of the immunological system, as well as non-modifiable and modifiable risk factors. Unfortunately, there is no cure for MS. However, the course of the condition has been shown to be modifiable by treatment and various environmental factors. Cigarette smoking is one of the most common addictions around the world, and may be a key modifiable risk factor in MS. Here, we review data available on Pubmed and Scopus from the last 10 years. The following consecutive key words were used in our search: "multiple sclerosis", "smoking", "cigarette", "impact", "progression", and "tobacco". This search yielded 248 initial articles, 43 of which were included in our review. In our review, we have examined the impact of smoking on the immunology, course, treatment, relapse, recurrence, quality of life, and changes visualised on MRI among patients with MS in general. We have also explored these patterns in MS subtypes. In general, smoking is reported to have negative effects on MS, including a decrease in quality of life, as well as cognitive and mental state, and an increase in disability, as well as in the frequency of relapses and recurrences. Smoking has a widespread negative impact on patients with MS. Thus, it is important to educate patients and to help them to give up smoking to improve their health and quality of life. Further research about the impact of smoking and nicotine on MS and other neurodegenerative diseases is needed; in particular, research on e-cigarettes.