Smoking and Multiple Sclerosis

Cigarettes may worsen or even increase the risk of MS

cigarette smoking and multiple sclerosis
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When it comes to the hazards of smoking, we tend to think almost exclusively about lung cancer and nothing else. But the simple truth is that there are few organ symptoms that cigarette smoking doesn't hurt.

While it may come as no surprise that smoking can aggravate the symptoms of multiple sclerosis (MS) simply by damaging a person's heart and lungs, research now suggests that lighting up may, in fact, increase the risk of developing MS in the first place.

Smoking and MS Risk

It was in 2003 that Norwegian researchers first demonstrated a clear association between smoking and the risk of MS. According to the study, which assessed the medical history of 22,312 people in Hordaland, Norway, the risk of MS among smokers was nearly double that of people who had never smoked.

While the Norwegian researchers were unable to pinpoint a specific cause, scientists at the Harvard School of Public Health believe that the blame may lie in the combination of smoking, genetics, and exposure to the Epstein Barr virus (the virus closely liked to MS).

In pooling data from 1,465 people with MS who either smoked, used to smoke, or never smoked, the researchers were able to conclude that:

  • The presence of the HLA-DR15 gene increased the risk of MS by 300 percent.
  • A history of infectious mononucleosis, caused by the Epstein Barr virus, increased the risk by an additional 250 percent.
  • Smoking further increased the risk by 150 percent.

Smoking and Disease Progression

Beyond the risk of developing MS, there can be little doubt that smoking is directly linked to progression of the disease. Not only were smokers more likely to advance from relapsing-remitting MS (RRMS) to primary progressive MS (PPMS) to secondary progressive MS (SPMS), they typically had a far more extensive damage in the brain.

Among the various research findings:

  • A 2009 study conducted by the Partners Multiple Sclerosis Center at Brigham and Women's Hospital found that current smokers were 250 percent more likely to have PPMS than persons who had never smoked, smokers with RRMS progressed to SPMS 2.5 times faster than nonsmokers.
  • A similar study from the Menzies Research Institute in Australia showed that persons who started smoking early in life (before the age of 15) were more likely to have PPMS as their first diagnosis, entirely skipping RRMS altogether.
  • Another study, this time from the State University of New York at Buffalo, showed that smokers with MS had greater evidence of cerebral damage on an MRI, a greater volume of brain lesions, and more brain atrophy and shrinkage.

While it is still not entirely clear which substance in cigarettes speeds up MS in smokers, research suggests that it may not be nicotine.

In 2009, scientists from the Institute of Environmental Medicine in Stockholm compared the impact of smoking and Swedish snuff (a moist tobacco powder placed under the lip) on MS disease progression. After assessing 902 people with MS and 1,855 people without, they concluded that snuff had absolutely no association with MS.

As such, the chemicals in cigarette smoke appear to the sole culprit.

Why Quitting Smoking Is Important

People in the more advanced stages of MS may not see the point in quitting given that there is no evidence that stopping will reverse the course of the disease.

There is, however, evidence that quitting may slow the process and help preserve key cognitive functions (including memory, abstract reasoning, and verbal skills). The evidence is supported by research the links the amount a person smokes to the severity of the disease.

Among them, the Buffalo study showed the degree of brain atrophy (characterized by the loss of neurons and intracellular nerve communication) was directly associated with the number of packs smoked.

The Australian study further concluded that persons who smoked the equivalent of two packs per day accumulated three times as much disability as those who smoked less than a pack per day.

A Word From Verywell

Quitting cigarettes is never an easy thing, particularly if you believe that they help you cope with the stress of living with MS. But you cannot ignore the fact the benefits of quitting far outweigh any perceived benefit cigarettes may offer

If you don't how to stop, there are people who can help. Start by calling 1-800-QUIT-NOW (1-800-784-8669) to connect directly with a staffed hotline in your state. The National Cancer Institute also offers an instant messaging LiveHelp hotline (in English only) from 8:00 a.m. to 8:00 p.m. EST.

Sources:

Healy, B.; Ali, E.; Guttmann, C. et al. "Smoking and disease progression in multiple sclerosis." Arch Neurol. 2009; 66(7):858-64.

Hedström, A. Baanhielm, M.; Olsson, T.; and Alfredsson, L. "Tobacco smoking, but not Swedish snuff use, increases the risk of multiple sclerosis." Neurology. 2009; 73(9):696-701.

Pittas, F.; Ponsonby, A.; van der Mei, I. et al. "Smoking is associated with progressive disease course and increased progression in clinical disability in a prospective cohort of people with multiple sclerosis." J Neurol. 2009; 256(4):577-85.

Sundström, P. and Nyström, L. "Smoking worsens the prognosis in multiple sclerosis." Mult Scler. 2008; 14(8):1031-5.

Zivadinov, R; Weinstock Guttman, B.; Hashmi, K. et al. "Smoking is associated with increased lesion volumes and brain atrophy in multiple sclerosis." Neurology. 2009, 73:7 504-510.

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