Cigarette smoking worsens shortness of breath and fatigue, increases the rate of hospital admissions, and fosters a sedentary lifestyle in patients with multiple sclerosis (MS), according to a new study.
The research, “Effects of cigarette smoking on respiratory problems and functional levels in multiple sclerosis patients,” was published in the journal Multiple Sclerosis and Related Disorders.
Environmental factors such as smoking, ultraviolet radiation, and lack of vitamin D have been associated with the development of MS. Smoking reportedly affects the development and progression of other neurological disorders — such as stroke — but its precise harmful mechanisms in brain blood vessels remain unclear.
Cigarette smoke includes a still unknown number of highly reactive oxidative molecules, which can cause inflammatory damage. Oxidative species and inflammation have been proposed to play a role as part of the central mechanisms triggering and favoring the progression of MS, Alzheimer’s disease, and stroke.
Studies have shown that smokers have a higher incidence of MS, as well as faster disease progression. Also, smokers have decreased levels of an anti-inflammatory enzyme called indolamine 2,3-dioxygenase, and higher amounts of certain pro-inflammatory molecules, which could increase the risk of MS.
Now, a research team from Dokuz Eylul University, in Turkey, assessed the effects of smoking on MS patients, focusing on respiratory symptoms such as dyspnea (shortness of breath), cough, sputum, fatigue, and aspects such as distance walked daily, average sitting time (watching TV, reading a book, or using a computer), and total time with no activity.
A total of 135 MS patients received a questionnaire on cigarette use. All participants had to be self-sufficient and able to walk without help for about 12 hours per day.
Disability was determined with the Expanded Disability Status Scale (EDSS) score (0-10), and dyspnea was measured with the Modified Medical Research Council (mMRC) Dyspnea Scale. Severity of dyspnea and fatigue perceived during rest and effort was assessed by the mBORG scale. Respiratory symptoms were assessed in patients requiring hospitalization in the six months preceding the study.
Mean age was approximately 39 years among the 68 smokers, and 37 years among the 67 non-smokers.
Smokers had higher rates of cough (67%), sputum (69%), and hospital admission due to respiratory complaints (29%), as well as increased severity of dyspnea and fatigue during effort, and of perceived dyspnea, compared with non-smokers.
Data also showed that smokers had lower mean daily walked distance than non-smokers — 384.71 meters (420 yards) versus 993.28 meters (1,086 yards) — and higher levels of sedentary life.
Also, the higher the more cigarettes smoked, the lower the distance walked and the greater the fatigue, effort and resting dyspnea, cough, sputum, hospitalization, and sedentary levels.
The mean EDSS score was 2.85 in smokers and 2.96 in non-smokers (representing mild-to-moderate disability), which is not statistically different. Weight, body mass index, gender proportions, and incidence of respiratory and cardiac diseases also were no different between these two groups.
Overall, the team concluded: “it has been proven that smoking increases respiratory problems even in MS patients with a good EDSS score. Moreover, these problems lead to a further reduction in the functional levels of the patients, in addition to the disease progression,” they wrote.
The team recommends MS patients quit smoking, that both patients and families receive education about the effects of cigarette smoking, and that healthcare services support this lifestyle change.
The researchers added that further studies with more patients are warranted to assess the effects of cigarette smoking on MS progression.