20

My friend is a smoker. His dad is a doctor. Both claim there is no firm proof that cigarettes cause lung cancer. This article makes a similar claim -- in particular that smoking cigarettes is not proven to cause cancer, but that it is linked to an increased risk of dying from lung cancer:

Yes, a US white male (USWM) cigarette smoker has an 8% lifetime chance of dying from lung cancer but the USWM nonsmoker also has a 1% chance of dying from lung cancer.

Is there any firm science behind the argument that smoking does or does not cause lung cancer?

David Hammen
  • 14,500
  • 9
  • 57
  • 51
samthebrand
  • 4,730
  • 4
  • 32
  • 56
  • 34
    Here it is again! Someone insisting that the word "causes" only means 100% every time, ignoring how everyone else uses the word. Worse: this is being used to justify smoking? – Oddthinking Feb 06 '12 at 00:16
  • 4
    Ugh. I couldn't read a single sentence of that article without some kind of "skeptic alarm" going off in my head. That thing could be the coursework for an entire class on critical thinking. – John Rhoades Feb 06 '12 at 14:37
  • @JohnRhoades - clearly, it's not a reputable journal. But it's the 4th result when Googling: "does smoking cigarettes cause lung cancer". And the 3 above that don't seem to succinctly answer the question, and certainly don't ask it in the title. – samthebrand Feb 06 '12 at 14:46
  • As explained [here](http://meta.skeptics.stackexchange.com/questions/1432/is-this-answer-up-to-the-skeptics-standards), I decided to close the older question as a duplicate of this one. – Borror0 Feb 09 '12 at 18:23
  • Hey Sam, can you help me in scoping your question better. The article is making the claim that, while smoking increases the risk of lung cancer, it does not cause it. Is that the belief you want us to look into or does your friend and his dad believe something else? – Borror0 Feb 09 '12 at 18:28
  • @Borror0 - I expanded upon the claim. I suppose this question may be one of semantics, ie: can somebody ever prove that X 'causes' Y? – samthebrand Feb 09 '12 at 18:57
  • That was what I thought immediately: your friend and his dad are making a semantic argument about the definition of "cause" or "firm proof". – JaseMachine Feb 09 '12 at 19:42
  • 4
    let alone about whether the smoking itself causes something or the chemicals deposited in the lungs as a side effect of that smoking :) Falling out of a 100m crane doesn't cause you to break your neck after all, it's the falling on the ground afterwards that does that :) – jwenting Feb 10 '12 at 07:35
  • 7
    The article seems to argue for a distinction between *smoking makes lung cancer about 10 times more likely* and *smoking causes lung cancer*. That's not really a big distinction. – matt_black Feb 10 '12 at 13:53
  • 1
    @matt_black, especially if you use it to justify not quitting. – Oddthinking Feb 10 '12 at 16:28
  • @SamTheBrand: I know Google gives different people different results. Would you like to try your search experiment again and see if the situation has improved? I get good references well down the list. – Oddthinking May 01 '13 at 08:58
  • @Oddthinking Can you elaborate on "Someone insisting that the word "causes" only means 100% every time, ignoring how everyone else uses the word." please? I didn't understand it – Honinbo Shusaku Jul 18 '16 at 13:19
  • 4
    @Abdul: Most people use the term "A causes B" to mean that the intervention of A greatly increases the chance of B. HIV causes AIDS. Smoking causes lung cancer. I have noticed some people seem to define it differently (at least when having arguments) to be something like "implies" - the intervention of A means B must necessarily proceed from it. Under this definition, a single counter-example is sufficient to disprove the claim: Smoking does not cause cancer if there is at least one smoker who doesn't get it. Being shot in the head doesn't *cause* death. It is a perverse definition. – Oddthinking Jul 18 '16 at 17:17
  • 2
    I would say that the statement "smoking causes lung cancer" is imprecise, but not inaccurate. "Smoking greatly increases the risk of lung cancer" is more precise. Whether that precision is necessary depends on context and aim. If the aim is to say "you're not 100% guaranteed to die from it, so you should do it," then, well... I guess that's a thing you could say... – Chris Berger Aug 02 '18 at 20:05
  • 1
    Smoking does not always cause lung cancer but in most patients who have it, it was due to smoking. It's that simple. Also, the majority of premature deaths among smokers is not due to lung cancer but heart disease which often kills them before lung cancer can develop. – netrox Feb 18 '19 at 04:32
  • 1
    This question could be turned into a good lesson about what causation is, how it is established experimentally, and what sort of criteria are generally used to evaluate such claims. – Nate Eldredge Feb 22 '19 at 04:33
  • 1
    The linked article no longer works. It currently points to a rant against relativity. Fortunately, the internet wayback machine (archive.org) has grabbed the linked article multiple times. I'm replacing the link with a link to the archived version. – David Hammen Jun 01 '22 at 07:28
  • I think it's fair to say the statement "Smoking causes lung cancer," while accurate, is misleading. Smoking *can* cause lung cancer, but usually doesn't. Maybe it's true that lung cancer is usually caused by smoking, but that's not a strong argument against smoking. Probably the strongest arguments are that the added risk of premature death is not worth the enjoyment gained, and that there are other risks besides lung cancer to consider. – Patrick87 Jun 01 '22 at 11:15
  • @Patrick87 I think the first part of your comment has been covered by previous comments about what exactly is meant by the word "causes". A discussion about what makes for a strong argument for stopping doesn't belong in the comments here (though since I'm commenting anyway, I'd say it's important to also remember that it is nearly impossible to smoke without causing any risk to other people as well as yourself). – Rob Watts Jun 01 '22 at 18:35

2 Answers2

64

I don't have much to say here, because Cancer Research UK have already written a winning answer. (Sometimes the giants are tall enough that there's no need to stand on their shoulders.)

If you visit Tobacco, smoking and cancer: the evidence you will find explanations of all these facts:

  • Smoking is the single biggest cause of cancer in the world
  • Smoking greatly increases the risk of lung cancer
  • The people with the highest lung cancer risks are those who:
    • smoke the most cigarettes per day
    • smoke over long periods of time, and
    • start smoking young
  • Smoking is a major cause of several types of cancer
  • Stopping smoking can reduce your risk
  • Tobacco smoke contains many dangerous chemicals
  • Tobacco smoke contains significant amounts of dangerous chemicals
  • Chemicals in tobacco smoke can build up to harmful amounts
  • The chemicals in smoke are more dangerous in combination than individually
  • The poisons in cigarettes can affect almost every organ in the body
  • Nicotine is a very addictive drug
  • Smokers are still exposed to dangerous chemicals if they smoke filtered or ‘low-tar’ cigarettes
  • Alcohol and other substances worsen the effect of smoking
  • Second-hand smoking also causes cancer and kills thousands of people every year
  • Children are especially at risk from second-hand smoking.
  • Smoking while pregnant can harm your baby
  • Smokeless tobacco can also cause cancer

They explain it all clearer than I could hope to, and include references to 93 different journal articles. You've got to admit they've certainly done their research on cancer, those guys at err.. Cancer Research UK.

Oh look, a donate button. Maybe you can persuade your mistaken friend and his father to donate to make up for all the people they have misled with their ignorance and semantic word games?

Furlevent
  • 103
  • 2
Oddthinking
  • 140,378
  • 46
  • 548
  • 638
5

We know that smoking causes cancer due to research carried out a long time ago. In the original, and famous, paper Smoking and Carcinoma of the Lung by Doll and Hill, the authors attempt to answer the question of why there has been such a large increase in lung cancer. They consider different possibilities, but the data shows that smokers are more likely to get lung cancer than non-smokers (the paper contains figures by age and sex) and that heavy smokers are more likely to get lung cancer than light smokers. Other cancers are considered, to ensure that it is specifically lung cancer that is being caused. Overall, this paper is quite good evidence by itself (especially as it comes from a time when smoking was not seen as dangerous, so patients had no incentive to conceal the extent of their smoking), but of course there have been many more published since then.

DevSolar
  • 19,034
  • 8
  • 77
  • 74
ch.
  • 143
  • 2
  • 2