Is There Really a Connection Between Smoking and MS?
Editor’s Note: This article is a part of an Op-Ed series, “Second Opinion,” where patient experts share their take on current research, news, and trends in health and medicine. The views expressed in this article do not reflect the opinions or views of HealthCentral.com.
Does smoking play a role in multiple sclerosis (MS)? Several studies have investigated possible connections between tobacco smoke and MS. A 2015 brochure written by Tiffani Stroup and published by the National MS Society (NMSS), presents a summary of information gathered from many of these research studies. Here’s an excerpt:
“Together, these findings demonstrate the many negative effects of cigarette smoking in people with MS. Not only are smokers at higher risk of developing multiple sclerosis, but they are also more likely to: 1) be diagnosed with the progressive form of the disease; 2) have higher disability scores, increased disease activity on MRI and more significant symptoms; 3) develop antibodies that make some of the multiple sclerosis medicines ineffective; and 4) transition to the secondary progressive form of the disease faster than ex-smokers or never smokers.
The brochure continues: “Passive (second-hand) smoke exposure has also been associated with an increased risk of developing multiple sclerosis in adults and children. The good news is that stopping smoking can help to reduce these negative effects.”
Study in neurology journal
I’ve never smoked. I have no strong, emotion-based opinion on the matter. But I’ve seen how difficult quitting smoking can be for others who have fought hard to do so. Yet as a person interested in what research studies can reveal about different aspects of living with MS, I feel an obligation to point out when information presented as definitive fact seems to have potential weaknesses that contradict the primary position that something (in this case, smoking) has negative effects on people with MS.
I refer to a July 2016 study published in the journal Neurology Neuroimmunology & Neuroinflammation, which suggests no association between tobacco use and MRI activity or relapse rate in MS. Researchers examined data from a group of 87 patients with RRMS who were followed for two years as part of the randomized placebo-controlled trial of omega-3 fatty acids in MS (the OFAMS study). Within this group of patients, 61 percent had higher blood serum levels of cotinine that indicated regular use of tobacco products.
As part of the original study, participants underwent multiple MRI scans that revealed non-significant reductions in new T1 Gd+ lesions and/or new or enlarging T2 lesions among tobacco users. Researchers found no difference in number of relapses between the tobacco users and non-tobacco users, with mean number of relapses of 0.42 and 0.59, respectively. During the study, 37 percent of the tobacco users experienced disease progression compared to 21 percent of the non-tobacco users, but the difference was not significant.
A potential weakness of this study involves the use of cotinine levels as a biomarker for tobacco use because cotinine levels will also be high among people who use snuff or nicotine gum. A previous study suggested possible neuro-protective effects of nicotine while exposure to non-nicotine components of cigarette smoke accelerated and increased clinical symptoms and disease severity during early stages of the disease.
In an international internet-based study of 2,469 people with MS, approximately 12 percent of participants were current smokers and just over 40 percent had smoked previously. Researchers found no association between smoking and relapse rate or disease activity. However, they did find that smokers had significantly lower health-related quality of life than never smokers and former smokers, and heavy smoking was associated with greater disability.
I don’t think that anybody would argue that smoking isn’t bad for you. But I do think that it’s important to provide unbiased information about contradictory results from clinical trials when discussing modifiable factors that may influence your experience with MS. Until researchers can provide clear answers regarding what it is, exactly, about smoking that is detrimental for people with MS, it’s advisable that we each try to do what we can to improve quality of life.
Eat well, exercise, get plenty of rest, engage in enjoyable activities, take advantage of medical advances (e.g., medications) that address your personals needs, and reduce behaviors, such as smoking, that are known to reduce quality of life.