Systematic Review of Multiple Sclerosis Progression and Mental Health Among Smokers

Background: Multiple sclerosis (MS)is a debilitating disease of the central nervous system, with little understanding of progressive course. Smoking has been shown to increase physical progression of the disease, however, there is not consensus on how smoking effects the mental health of an individual with MS. The aim of this systematic review was to evaluate the relationship between tobacco smoke and mental health disability among individuals with MS. Methods: The literature search was conducted by using PubMed and Web of Science in Sept 2018. Five English-language studies met inclusion criteria. All studies were conducted in distinct human populations, had an observational study design, and were of high methodological quality. All studies used unique measurement tools for depression, anxiety and/or self-report health. Results: Current smoking was associated with higher depression and anxiety scores in three of five studies. One study found as high as a 2.3 fold increase in depression among current smokers after adjusting for age, gender, marital status, education, disease duration, number of comorbidities, level of physical disability, and clinically significant fatigue. Additionally, ever smoking was significantly associated with depression and anxiety in this study. Two studies found no difference in mental health outcomes among MS smokers, however, depression and anxiety were both higher among MS cases than healthy controls. Discussion: These results suggest that current smoking may confer risk for poor mental health outcomes in individuals with MS. However, smoking cessation remains critical for improving mental health and has prompt clinical implications. The lack of comparable quantitative data remains a limitation, and further research is needed.