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Comment by sporedro | Hacker News Reader

This reminds me of what I read about Nicotine and how it was thought to prevent Alzheimer's, but I believe it was just the fact those smoking tobacco had a lower chance to live to the age to be diagnosed or develop it.

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Fun fact: strangely enough, there are two conditions for which smoking is known to be a protective factor. Parkinson's disease, and Ulcerative Colitis (UC).

Interestingly, though Crohn's Disease (CD) and UC are strikingly similar forms of IBD, nicotine has the opposite effect on both. Nicotine will increase inflammation in CD and reduce it in UC, through the a7 receptor and up/down-regulation of Treg cells: https://www.jimmunol.org/content/187/5/2677

Smoking is also ridiculously prevalent among schizophrenics, and nicotine seems to help with the negative symptoms.

I smoked just long enough to get addicted, but successfully weaned myself onto nicotine lozenges some years back. From what I've read, nicotine itself is fairly safe, but I wonder what it's helping/hurting (I have several rare diseases.)

Tobacco contains monoamine oxidase inhibitors which might act as anti-depressants, also this is very anecdotal but I have a sensory processing disorder (visual snow syndrome) and my concentration has gone to shit ever since I stopped smoking.

MAOI

What do you mean?

https://en.m.wikipedia.org/wiki/Monoamine_oxidase_inhibitor

Smoking also makes you less likely to contract covid but more likely to have serious outcomes from it if you do.

Something about the immune reaction to the smoke being beneficial to avoid infection and the long term lung damage making it worse when infected.

My suspicion is it’s a byproduct of coating the lungs with tar. You sacrifice lung function for a slightly more robust physical barrier. The obvious test for immune system response would be if chewing tobacco users would see similar resistance to infection.

Hopefully this will eventually clear things up: https://clinicaltrials.gov/ct2/show/NCT04896918

I thought it was lowered expression of the receptors covid-19 binds to (known condition among smokers) ace-2... Because smokers have suppressed ace-2 while smoking but a higher baseline; they are protected from getting it because when they are in public they are likely smoking and protected but once they get it they get very severe COVID...

I mean it's all kind of a just-so story. Iirc Omeprazole which also depresses ace-2 failed as a prophylactic treatment

Cigarette smoking definitely does not provide with a better physical barrier, and does not "coat" the surface of your lungs with tar. There could be some effect from reduced surface area (see: emphysema, although typically patients with this condition, or even smokers generally, will have an increased risk of infection), but my bet is on some nicotine receptor effect. These are quite immunomodulatory.

Everything in a relative of mine who smokes house is coated with tar. They regularly burn out computers because they get so impacted with tar covered lint. I find it very likely their lungs are covered in tar as well - moreso I don’t understand how they could possibly not be.

This same relative has Crohn’s which is why I am here reading this.

That’s why I was so interested in the study of smokeless tobacco users.

Anyway, I don’t mean the tar is the physical barrier, inflammation response plus common changes to the extracellular matrix should both result in a physical barrier. The compensative increased respiratory rate seems like it would offset reduced surface area, but these changes are more complicated than that.

Also, it’s increased risk of detected infection, but patients without symptoms are rarely tested for viral disease at this scale. That makes comparisons very tricky.

Is that true when adjusted for close human connection? My understanding of smoker culture is they are less likely to be in close quarters with other people, unless those others are also smoking. And then they tend to be outside.

For colitis, it doesn't seem to simply be the nicotine as studies using nicotine patches saw little or no effect. This suggests the smoke itself may have some effect.

There is a summary at https://www.crohnsandcolitis.org.uk/about-crohns-and-colitis....

Many years ago on a discussion list for a really deadly condition, someone talked about a child in the family dying really young and no one knew why and everyone was so heartbroken and felt so guilty. And I guess later someone else was diagnosed with this very deadly condition and eventually someone suggested to the mother of the child "Maybe the child also had this deadly genetic disorder and they were just not diagnosed. Maybe you didn't do anything wrong." And the mother was finally able to make her peace with the mysterious death of this child, who had been maybe five years old.

I think the person who told the story was a lot older than me. Children dying young tends to be a thing in less developed countries and people don't necessarily know why.

My family tree from a mere two generations ago is filled with kids who died under the age of 5 - some are mundane but most are undiagnosed. They just know the symptoms that were fatal not the cause. 1960s and earlier. That’s not at all that long ago.

I haven’t seen nicotine as being protective for alzheimers, but it is protective for Parkinson’s and Ulcerative colitis. In fact during medical school I saw a young patient who was trying to get healthy to help deal with her autoimmune issues, and had stopped smoking, inadvertently likely triggering a massive flare of UC

I can personally attest this is true. Nicotine does help with ulcerative colitis. I buy Swedish snus which is far less toxic that American tobacco.

Why not just vape?

Vaping is certainly an option.

I think you are confusing with Parkinsons, and there is a co-relation with dopamine receptors, and it's proven. Also, this being a Crohn's post, smoking also has benefits in curtailing Inflammatory Bowel Disease, but not Crohn's

edit: more specifically smoking decreases the incidence of ulceraive colitis (an IBS)

UC is not an IBS (irritable bowel syndrome), it is an IBD (inflammatory bowel disease) of which I believe crohns is as well.

Survivorship bias

https://en.wikipedia.org/wiki/Survivorship_bias

That's relatively easy to correct for.

This is an animal study, which doesn't have that bias: https://www.sciencedaily.com/releases/2016/09/160920160635.h...

Basically, this is why I vape. Early onset dementia represents much higher existential risk than vaping does.

I wonder too if it has to do with the eating. People who eat less and intermittently fast have lower rates of Alzheimer’s.

The thought is when you fast your body recycles excess proteins that build up on your brain, reducing brain plaque buildup over time.

Nicotine is a known appetite suppressant.

I am going to add this to my list of examples for survivorship bias. https://en.wikipedia.org/wiki/Survivorship_bias

Motorcycles prevent old age.

Old age prevents older age.

Birth is the leading cause of death.

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