Naked Science Forum
General Science => Question of the Week => Topic started by: katieHaylor on 01/10/2018 12:11:21
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Bethany asks:
Is second hand smoke more likely to give you cancer than smoking a cigarette?
What do you think?
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It matters how much. If you occasionally meet with smokers, you have betterr health than who meets them daily. Also distance matters, too (diffusion of particles).
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And some of it is a result of genetics. Some people are just more susceptible to developing lung cancer than others.
Person A can be a heavy smoker for most their life and never develop it, while person B just lived them and developed it.
It isn't that second hand smoke was more dangerous in general, just that cigarette smoke presented a much greater risk for person A than person B.
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For many carcinogens and poisons (including cigarette smoke), risk increases with exposure.
- The biggest exposure is for the person inhaling the smoke directly into their lungs.
- The next biggest exposure is for the person who spends a lot of time near, them, breathing their exhaled smoke (which is less concentrated than the smoke inhaled directly from the cigarette).
- Lower risks for people who spend less time near the smoker, and more time further away
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It's possible that there are some interesting "survivor population" type effects here.
If you parents didn't smoke it's less likely that you will.
If they smoked, and were badly affected then it's less likely that you will smoke.
So, if you smoke, one possible factor is that your parents "got away with it".
And, if they did, it's possible that (at least part of) the reason is genetic.
So, it's entirely possible that smokers are genetically less susceptible to the harm from smoke.
Similarly, non-smokers may be more susceptible.
Now, if we assume that passive smoke is likely that smokers are exposed to "primary" smoke and that passive smokers are exposed to secondary smoke, it's possible that the latter does proportionately more harm- because it is inhaled by people who are more readily affected.
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I can tell you that a doctor once showed me a lung X-ray and said: "You have emphysema." I said, "Really?" He said, "Yes."
At that time (age early 40s), the number of cigarettes I had "smoked" could be counted on one hand. How did this happen?
I will tell you.
When I was in my early 20s (early 80s) I used to drink and dance in the bars (Southeastern, NY State, USA) that hired a very popular dance-band called "The Dates."
I did this repeatedly, spending hours inhaling and exhaling the bleeping cigarette smoke in fits of exertion.
End of story.
[I did forget to mention that I had a very good time.]
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For many carcinogens and poisons (including cigarette smoke), risk increases with exposure.
Interesting choice of words, @evan_au , begging me to enquire what carcinogens and poisons do not follow a dosage-dependent relationship?
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Although most cancers caused by carcinogens are dose dependent those that are caused by viruses such as HPV and HIV that can hide away and multiply wily nilly I would think a small dose could have much the same effect as a large one
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Although most cancers caused by carcinogens are dose dependent those that are caused by viruses such as HPV and HIV that can hide away and multiply wily nilly I would think a small dose could have much the same effect as a large one
The definition of a carcinogen is any "substance" that causes cancer. Viruses are not strictly substances; they are biological entities; that said, they probably do fit a dose-dependent relationship because the viral replication is what triggers malignant transformation within cells by disabling various anti-proliferative processes and forcing the cells to grow...
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Lots of side-tracking...
NO, second hand smoke cannot be more dangerous that first hand exposure...
First hand exposure requires a direct draw into your mouth and lungs
Your mouth and lungs are designed to take things from what you put in them
What is left after you blow the smoke has to be inhaled by "the victim" of the second hand smoke
The Victim doesn't draw it in, which means they get less smoke in their mouth and lungs, and what they are taking in has already been filtered by the smoker, which means the net affect of the second hand smoke has to be much less than the firsthand smoke..
That Said... the sidetrack about health of the second hand smoked people does make a difference in the affect on them, BUT, If those people where smokers the net affect of the first hand would still far outweigh the net affect of second hand on those individuals...
Second hand smoke danger is simply a form of anti-smoking propaganda put together by the huge-ego'd-maniacs... And like most things they come up with, a few minutes of actual thinking time, rips them to shreds...