To smoke or not to smoke that is the question

T

Barts-MS rose-tinted-odometer  ★ ★ ★ ★ ★

Yawn! I am getting tired of the saying the same-old things on this blog. Is it time to retire and do something new? 

We have done some modelling work and predict that ~20% of new or incident cases of MS could be prevented if we stop the population from smoking. The question is how do we achieve this? Taxation has worked to some extent in that we are seeing a fall in the number of current smokers, but the numbers of teenagers smoking looks as if it is quite resistant to change. The solution must be education, education, education and a war against the tobacco industry. 

If social media is such a powerful tool to hack the brains of voters, why don’t public health departments use this technology to promote their agenda? What we need are companies like Cambridge Analytica to do some good in the world and to promote a ‘Don’t Start Smoking’ campaign. 

We did try and get some insights into why teenage girls start smoking when Amy Sankey, a work experience student, did a survey in her school for us. Despite the almost universal awareness of the harms of smoking in terms of lung cancer, most girls, however, did not know that there is a link between smoking and autoimmunity. I suspect even if they knew about the link it would be unlikely to prevent them from starting to smoke. 

We are interested in smoking as a risk factor for MS as it is telling us something about the cause of the disease. It appears that smoking must be acting via the lungs and is due to tobacco itself. Use of oral, non-smoked, tobacco is in fact associated with a reduced risk of getting MS, hence it is not tobacco exposure. Solvent exposure is also associated with an increased risk of getting MS, which supports the lung hypothesis of developing MS. 

Lung hypothesis #1 argues that damage to the lung from smoking or solvents creates a pro-inflammatory environment that is sufficient to activate pre-existing autoreactive T-cells. In comparison, lung hypothesis #2 argues that smoking damages proteins by a process called post-translational modification and that these proteins stimulate an immune response that then cross-reacts with normal antigens to set-up autoimmunity. The argument for the latter in triggering rheumatoid arthritis, an autoimmune disease of joints, is quite compelling but is less compelling when it comes to MS. We hope to study whether post-translational modification of CNS antigens is relevant in MS via an ECTRIMS fellowship we have supported.  

What is interesting is that smoking interacts with genetic risk factors for developing MS and with EBV infection suggesting that there is a critical gene-environment interaction that causes MS. Wouldn’t it be interesting to study and find out what these interactions are? We have an exceptionally bright and able young researcher, Ben Jacobs, who wants to do a PhD on this exact topic; gene-environment interactions. At the moment we are ruminating about the best approach he should take to address this question. It is not an easy experiment so if you have suggestions please feel free to contact us.

I would also like to remind you that smokers who have MS have a much poorer prognosis, which is why we recommend that you stop smoking if you can.

If you are interested in smoking and MS there is a new review that has just come out. 

Rosso &  Chitnis. Association Between Cigarette Smoking and Multiple Sclerosis: A Review. JAMA Neurol. 2019 Dec 16. doi: 10.1001/jamaneurol.2019.4271

IMPORTANCE: Cigarette smoking is a common environmental exposure and addiction, which has severe health consequences. Smoking is a risk factor for multiple sclerosis (MS); also, smoking has been associated with disease activity and overall prognosis for patients with MS.

OBSERVATIONS: Cigarette smoking is an irritative agent on the lungs, in which a proinflammatory cascade starts that culminates in autoimmunity. Inflammation may increase the risk of MS in some individuals, in a process driven by antigen cross-reactivity between lung antigens and myelin antigens. Genetics plays a central role in the individual predisposition to mounting an autoimmune reaction. Also, free radicals, cyanates, and carbon monoxide in cigarette smoke may be directly toxic to neurons. Patients with MS who smoke have higher rates of disease activity, faster rates of brain atrophy, and a greater disability burden. Some of the outcomes of smoking were found to be reversible, which makes counselling key.

CONCLUSIONS AND RELEVANCE: The pathways involved in cigarette smoking should be further analyzed to understand the mechanisms whereby smoking worsens MS prognosis. The proinflammatory and neurotoxic outcomes of cigarette smoking may be shared by other environmental exposures, such as pollution and organic solvents. From a global perspective, efforts should be made to diminish the prevalence of cigarette smoking in patients with MS.

CoI: multiple

About the author

Prof G

Professor of Neurology, Barts & The London. MS & Preventive Neurology thinker, blogger, runner, vegetable gardener, husband, father, cook and wine & food lover.

10 comments

  • “Tobacco industry figures in the 1940s showed well over half the over-16s in the UK were smokers, with the proportion rising to nearly two-thirds of men. The proportion of women smokers did not peak until the late 1960s. When the ONS started collating figures in 1974, 45% of Britons smoked, 52% of men and 41% of women.”

    Please can you explain why MS wasn’t an endemic when smoking peaked in the 1930s to 1960s.

    I’m also sceptical about Vit D. If Vit D was a big factor nuns and prisoners would have higher rates of MS.

    EBV, EBV, EBV. You must see it everyday when diagnosing in clinic. I suspect the vast majority of patients recall a bad case of glandular fever.

    • Please can you explain why MS wasn’t an endemic when smoking peaked in the 1930s to 1960s.

      Well smoking is only one of a number of risk factors “Bob”

      I’m also sceptical about Vit D. If Vit D was a big factor nuns and prisoners would have higher rates of MS.

      I suspect there’s much you are sceptical about “Bob” but Saint Lidwina of Schiedam (1380-1433), a Dutch nun, may be one of the first clearly identifiable multiple sclerosis (MS) patients. From the age of 16 until her death at 53, she suffered intermittent pain, weakness of the legs, and vision loss indicating symptoms typical of MS. I haven’t come across any figures for increase of MS in nuns or prisoners but it’s a moot point as it is likely the influence of vitamin D is much earlier in life, particularly during pregnancy and the link with MS and latitude is robust, so argue that away “Bob”.

    • I wonder if the formulations for cigarettes changed over the years, though, as tobacco companies got better at manipulating the smoking experience. The American Lung Association says there are 600 ingredients in a cigarette. Would be interesting to compare that ingredients list to the tobacco in my grandfather’s pipe pouch in the 1940s.

      • Yes, much has changed. The dirty little secret was the addition of maple syrup and then sugar to create the American blend. Added sugars reduce the harshness of smoke, making it easier to inhale. This led to an increase in the addictive potential of smoking and drove the massive rise in smoking after WW2. Sugar has plenty to answer for!

  • I don’t know about you but when I was a teenager/young adult I had a bad case of ‘Captain Scarlet’ syndrome.

    Freestyle Skiing
    Parachuting
    Smoking
    Drinking
    Recreational drug taking
    Very loud music
    Unprotected…you know what I mean
    Driving like a lunatic

    An inflated optimism bias allowed me to live comfortably through this risk-taking. Do I regret it? No. I can’t change it and that would just become a mental health issue if I agonised over what might have been.

    It was all cool. Adults do not understand what it is to be cool. That is part of the certainty of knowledge about being young. Adults are boring.

    I know this because I am the father of a teenager. She frequently reminds me that I am not cool, am not woke, am unsafe to be in public with her, am boring, have boring friends, make boring suggestions and so forth. She used to hold my hand and want me to walk her to school. How the worm has turned.

    Beating a teen around the head with logic and common sense is a fools errand.

    Just MHO.

    Dom

  • I never smoked a day in my life but I do have asthma so my lungs are unhappy. But no smoking and otherwise super healthy. Lots of sun even took vitamin d supplements to prevent ms. no family history of anything other than a mother with aggressive deadly ms. The genes are a big part of this.

  • I have felt all along that cigarettes caused my MS. I was born in the early 60s to a smoking mother, took it up myself when I was 9(!), and switched to “ultralights” that had god know what in them when I was 18 or so. Quit at 29. But it didn’t matter. I was showing overt signs of MS at 43.

    I was an outdoorsy kid, raised in Southern California, born in November, thin, active. No family history of autoimmunity of any kind. Absolutely not a candidate for MS, right? But the cigarettes were everywhere.

    Recently, I was watching videos of my favorite entertainers from the 70s/80s. Everybody had a cigarette hanging from their mouths/guitars. How could you NOT become a smoker in that world? It seemed to me that smoking was the price of admission if you wanted to be truly adult in those days.

    Of course many of those people died earlier than expected from cancers and lifestyle illnesses. They seemed so glamorous at the time. Now they just look naive to me. How could we guess at 25 that we’d still cherish our lives and health at 65?

    • I thought it was well known how to stop girls (and nowadays boys) from smoking – show them pictures of smokers faces, not their lungs. Wrinkles and bad skin are not cool. I was going to say show them an old smokers face but was surprised to see from your graph that there are very few of us left over 65. Is this because they are all dead? That might have some resonance as well!

      Prof, is there a difference in risk of MS in current smokers vs ex smokers? Most health risks from smoking are cumulative depending on your pack-year count but reduce after stopping, some more quickly than others. Is this also true of MS?

      Writing as an ex smoker I assume it raised my risk of getting MS. Having been suspected of having COPD I know well how stupid smoking is. Fortunately I didn’t have that but instead a version of ‘farmers lung’ an immune related lung condition called hypersensitivity pneumonitis. That was ten years before I developed MS. Have somtimes wondered if there was any connection but have found none in the literature.

  • Hi pro G

    One of your slide decks the other day, had a prognosis checklist…

    One of the items was smoking… is that at diagnosis? I.e. even if you quit does your prognosis still remain worse than if you had never smoked?

    Thanks

  • What a waste of research time by looking into smoking. Reasearch time could beter be spent on looking into Progressive ms. And solving it. 🙂
    Smoking is not going to be benficial to any disease. Please stop wasting time en money

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