So where’s the evidence?

Hundreds of thousands of children are traveling in smoke-filled cars every week.
In England alone, more than 430,000 children aged 11 to 15 are exposed to second hand smoke in cars each week, according to estimates by the British Lung Foundation.
185,000 children of the same age are exposed to smoke while in the family car on “most days”, if not every day.
“Given these data only cover children aged between 11 and 15, it is possible that the total number of children affected on a weekly basis could be in excess of half a million.”

Lots of up to and possibly as many as and estimates in there. So it might all be a load of blown smoke anyway.
But I ask the readership this.
IF the medical evidence is correct …..

If that evidence is indeed correct then the question is: well, where are all the sick children?

If passive smoking is a bad idea then, if 500,000 children are exposed to it on a weekly basis, then we should have some evidence of the bodies piling up. If we don’t then one of two things must be true: either that the exposure isn’t happening or the exposure doesn’t cause the bodies to pile up.

So where are the sick kiddies?

65 thoughts on “So where’s the evidence?”

  1. As I said regarding another issue (the lost tribe of gypsy harlots); they are lying, we know they’re lying, and they know we know they’re lying. But still the bandwagon rolls on, because in a society, the received wisdom is that which the powerful choose to believe, however detached from reality it actually is.

  2. OK, not being a smoker, and actually preferring pubs since they banned smoking (though I wouldn’t have banned it, obviously), I have never taken any interest in the science on smoking/second hand smoke etc.

    It seems pretty well accepted that smoking is a major causative factor in lung cancer and heart disease etc.

    It also seems logical that sitting next to someone who is smoking in a non-ventilated space would have *some* similar effect.

    We know that attractive appearance of logic are not the way forward, so…

    Can anyone explain to me, ideally with sources, why it *isn’t* bad for kids to sit in the car with smokers (or why second hand smoke generally isn’t bad for you)?

    I’m not in favour of the ban – like most of us here, I am generally against banning, plus they don’t seem to want to ban heroin-addict burglars and fat unemployed sub 100 IQ women from forming loose and highly soluble associations to breed in the first place, which is probably far worse for children anyway. So I highly doubt their motive. I’m just interested in the facts.

  3. Surely any illnesses they have will be caused solely by the fact that every child in Britain is morbidly obese. We know this because Science tells us so.

  4. Interested-

    It’s a matter of dosage. There is some point below which concentrations of a toxin cease to have a proportionate effect, because the human body has a certain threshold for dealing with it. Chlorine is an horrific poison at high dosages. At low concentrations you can stick it in a swimming pool as a disinfectant, and it doesn’t have a proportionately lesser effect; it has no effect (on humans) at all.

    All the evidence is that “passive” smoke is simply a smell that some people don’t like. It can act as a trigger for people who are hypersensitive- like the athsmatics the campaigners always wheel out- but they can also be triggered by other harmless stimuli (e.g. perfume or cat dander) so are not instructive in the general case.

  5. You should never smoke in a car with kids, or even in the same room as them. I never did when I smoked.

    But it shouldn’t be banned. It isn’t a police matter; the effects of second-hand smoke are controversial.

  6. Most people who smoke in cars tend to do so with the window open. It’s somewhat counter-intuitive, but your own second-hand smoke is just as unpleasant as other people’s. Particularly so in a confined space such as a car.

  7. but your own second-hand smoke is just as unpleasant as other people’s

    Dunno about that; it’s a matter of taste. I actually like smoky environments, in some situations. It’s like how a spit’n’sawdust pub can be a more salubrious environment than some smart, clinically clean one. A bit of grime implies an ease and looseness in an environment. Too much hygeine is alienating. Which is why I think in general, back in the old days the best rock’n’roll venues were shit-holes. All part of the charm.

  8. None of the alleged evidence against passive smoking has ever been above the random limits of the study. Sometimes, for the same random reasons “studies” have found a marginal negative correlation but such “studies” tend not to get published.

    Logically when you compare the volume of a smoker’s mouth with the volume of air 5 feet around the smoker (900,000 cubic inches) it is obvious we are dealing with homeopathic levels of “pollution” and homeopathic levels of “science” too.

  9. Part of the problem also is that people are unaware of how sensitive human noses are, and how low a concentration can trigger awareness of a smell. One fart can fill a room to eyewatering levels.

  10. @Ian B

    ‘It’s a matter of dosage. There is some point below which concentrations of a toxin cease to have a proportionate effect, because the human body has a certain threshold for dealing with it. Chlorine is an horrific poison at high dosages. At low concentrations you can stick it in a swimming pool as a disinfectant, and it doesn’t have a proportionately lesser effect; it has no effect (on humans) at all.

    All the evidence is that “passive” smoke is simply a smell that some people don’t like. It can act as a trigger for people who are hypersensitive- like the athsmatics the campaigners always wheel out- but they can also be triggered by other harmless stimuli (e.g. perfume or cat dander) so are not instructive in the general case.’

    OK, not saying you’re wrong, I don’t know, but that’s not evidence, that’s just a comment on the internet (which is fair enough as far as it goes).

    Is there any actual evidence, a study knocking back the evidence that gets wheeled out?

  11. Interested-

    The evidence is absence of evidence; it’s the prove a negative problem and all that. If you’ve dilligently searched for an effect, and none has been found, you can say there isn’t one.

    The studies that have been done cluster around zero. Some show a positive effect, some don’t, some show even a negative correlation. The campaigners solve this by cherry picking. But overall, there is simply no science showing any effect. If there is one, it is so small as to be lost in the noise. In particular, the most comprehensive study ever done (Enstrom and Kabat) showed no correlation at all; so it was immediately denounced for being partially funded by tobacco (only because the cancer charities funding it pulled funding when they realised it wasn’t going to get the “right” answer).

    If the quality of evidence for passive smoking were produced in support of something “politically incorrect”, nobody would give them any credibility at all.

    This is the best for evidence we can ever hope to do; you cannot prove the negative “PS does not cause cancer”. You can only say there is no evidence that it does.

  12. Interested,

    Can anyone explain to me, ideally with sources, why it *isn’t* bad for kids to sit in the car with smokers (or why second hand smoke generally isn’t bad for you)?

    There was a Stamford study done that researched 76000 women and found no clear link between passive smoking and lung cancer.

    You’d have to be a moron to say that breathing in second hand smoke doesn’t increase your risk of death. But so does your neighbour lighting a bonfire. Or driving your kids to school in a classic car rather than a modern car.

    The fact that no-one is trying to outlaw people driving their kids to school in MG Midgets and 1960s Minis, which can be demonstrated in crash tests to pose a high risk of fatality to passengers shows that this is just a moral crusade against smoking. They’re slowly turning the ratchet, moving from pubs to cars. When they’ve done with cars, they’ll start putting it into tenancy agreements on local authority and eventually all homes.

  13. Further to Ian B’s comment.
    The studies that revealed that smoking was correlated with cancer compared smokers and non-smokers in the same, or what was deemed to be sufficiently similar, environments. So the “control group” who didn’t get cancer were all “passive smokers”.
    If “passive smoking” caused a significant risk of cancer then the difference between smokers and non-smokers would never have been spotted in the first place.

  14. Do people still smoke in cars? People I know who smoke don’t even smoke in their own homes.
    Smoking has become like the water cooler. A way to think, get gossip or get away from bores.
    Scientific paper you’re unlikely to read this year: “Smoking is good for you because it gets you out in the fresh air”.

  15. @ IanB

    It’s not (according to wiki) quite the whole story to say that:

    ‘Enstrom and Kabat) showed no correlation at all; so it was immediately denounced for being partially funded by tobacco (only because the cancer charities funding it pulled funding when they realised it wasn’t going to get the “right” answer).’

    Wiki: ‘A 2003 study by Enstrom and Kabat, published in the British Medical Journal, argued that the harms of passive smoking had been overstated.[113] Their analysis reported no statistically significant relationship between passive smoking and lung cancer…

    The American Cancer Society (ACS), whose database Enstrom and Kabat used to compile their data, criticized the paper as “neither reliable nor independent”, stating that scientists at the ACS had repeatedly pointed out serious flaws in Enstrom and Kabat’s methodology prior to publication.[117] Notably, the study had failed to identify a comparison group of “unexposed” persons.[118]’

    There is some stuff then about their links to the tobacco industry, but I can’t see much difference between that and your (effective) complaint that the cancer charities are also motivated by funding.

    In a related court case, the tobacco firms were prosecuted under RICO for (wiki again):

    conspiring to minimize, distort and confuse the public about the health hazards of smoking;
    publicly denying, while internally acknowledging, that second-hand tobacco smoke is harmful to nonsmokers
    and
    destroying documents relevant to litigation.

    Without reading the whole trial, and accepting I’ve only gone on wiki, the bits I have bolded do seem to have been accepted in court (nobbled by the cancer charities?) and would, if applied to anything the government does, draw justified howls of outrage.

    I still wouldn’t ban it, and I still don’t know beyond wiki what the truth is, but if the tobacco firms ‘internally acknowledge’ the harm where does that leave the argument?

  16. @The Stigler

    ‘You’d have to be a moron to say that breathing in second hand smoke doesn’t increase your risk of death. But so does your neighbour lighting a bonfire. Or driving your kids to school in a classic car rather than a modern car.

    The fact that no-one is trying to outlaw people driving their kids to school in MG Midgets and 1960s Minis, which can be demonstrated in crash tests to pose a high risk of fatality to passengers shows that this is just a moral crusade…’

    Oh, absolutely. A point I basically made in my original question.

  17. Interested-

    It depends then on more of social factors. The Enstrom/Kabat study was passed by peer review, published in the BMJ, and then the hounds of hell from the activist groups descended on the BMJ and declared the study (in their opinion) to be flawed. Bear in mind there was also a study by the UN which showed no correlation- and the WHO themselves first buried it then when pressured, declared that their own study was flawed. This is the same sort of thing as the ACS suddenly withdrawing funding from Enstrom and Kabat when they found that they weren’t getting the answers they wanted.

    Most of this is politics, not science. I do however repeat my assertion that any effect for which there is this kind of evidence- if not a PC hobby horse- would be considered risible.

    As to the tobacco companies, we’re constantly told that they are liars. They aren’t scientific institutions. Why is their supposed internal opinion suddenly valid when it agrees with the activists?

  18. @Interested… “Wiki” is about as unbiassed a source on smoking as it is on “climate change” (or any other politically-contentious subject. NB “politically-” not “scientifically-“).

    One major study, done originally under the auspices of the W.H.O. was “Boffetta et al: Multicenter case-control study of exposure to environmental tobacco smoke and lung cancer in Europe”. It’s getting a bit old now (1998) but was the largest cohort study ever performed on the subject. They came to the conclusion that “Our results indicate no association between childhood exposure to ETS and lung cancer risk“. This was a “wrong” result and was buried quite quickly! It still however exists in the outer reaches of the interwebs:-

    http://www.ncbi.nlm.nih.gov/pubmed?cmd=Retrieve&list_uids=9776409&dopt=AbstractPlus

    Concerning the canard of childhood asthma… 50 years ago 80% of the adult population smoked, everywhere!, and childhood asthma was quite rare. Nowadays 25% (if that) smoke, and often quite “considerately”, and childhood asthma is very common. The only correllation is inverse, so if anything fag smoke has a protective effect.. 🙂 (I know, bad stats, “correllation does not imply causation”, etc..)

  19. @ Pogo

    @Interested… “Wiki” is about as unbiassed a source on smoking as it is on “climate change” (or any other politically-contentious subject. NB “politically-” not “scientifically-”).

    Yes, I know that, or suspect it, but it’s an assertion which you can eventually make to damage any case you don’t agree with.

    One major study, done originally under the auspices of the W.H.O. was “Boffetta et al: Multicenter case-control study of exposure to environmental tobacco smoke and lung cancer in Europe”. It’s getting a bit old now (1998) but was the largest cohort study ever performed on the subject. They came to the conclusion that “Our results indicate no association between childhood exposure to ETS and lung cancer risk“. This was a “wrong” result and was buried quite quickly! It still however exists in the outer reaches of the interwebs:-

    I googled it and it was the first hit!

    That does seem to deal with lung cancer, which isn’t the only posited risk.

  20. Ian>

    You’re missing the part of the story, the nubbin of truth, that makes the lie work. Obviously, being in a room absolutely filled with smoke is going to be harmful – although maybe not quite as harmful as smoking yourself. I’ve seen people get stoned from passive smoking, so clearly it can have an effect if the concentration of passive smoke is high enough.

  21. @Ian B

    As to the tobacco companies, we’re constantly told that they are liars. They aren’t scientific institutions. Why is their supposed internal opinion suddenly valid when it agrees with the activists?

    It’s partly because the lie (allegedly) is about the content of their internal opinion, where the motive for falsely accepting evidence they believed (or knew) to be false that their products are bad for their customers is not quite as obvious* as for lying about it, and partly because everyone understands that companies (and govts and individuals) are less honest externally than internally.

    *ie it’s completely hatstand.

    I dunno. If I were convinced that it was bad for children I still wouldn’t ban it because thin end of wedges, and worse and more proximate evils etc. But still not convinced it’s not bad for you.

  22. To be fair to Wikipedia, it is an encyclopedia, so its job is to report the consensus view, which it generally does. If we posit a situation in which the consensus view is in some way in error, so will Wiki be. Not because of a conspiracy, just because that is inevitable for any encyclopaedia.

    I once lived with a professional encyclopaedia editor, btw. She was always getting emails from outsiders seeking to get their view into the encyclopaedia; but that’s not an encylopaedia’s job. It reports the consensus.

  23. @Dave

    You’re missing the part of the story, the nubbin of truth, that makes the lie work. Obviously, being in a room absolutely filled with smoke is going to be harmful – although maybe not quite as harmful as smoking yourself. I’ve seen people get stoned from passive smoking, so clearly it can have an effect if the concentration of passive smoke is high enough.

    It’s not a lie if there’s a ‘nubbin of truth’, is it? It’s just a question of degrees of concentration?

    I must admit, as I said at the start, I haven’t followed the whole thing, but presumably the concentration – small space, potentially unventilated, potentially cooped up for quite a while – is why they are looking at cars?

    (I quite believe they will go for fields, eventually, mind you, but that’s a different argument.)

    It being hard to frame a law, or expensive to provide the police with meters to measure a ‘safe’ level, even if they know what that is, it does seem reasonable (in that light only) for them to propose an across-the-board ban.

  24. Interested-

    I take the point re tobacco companies, but it’s not scientifically helpful. If a porn producer himself believes that porn causes rape (but carries on producing porn, and denying the correlation publicly) it’s no help to us as to whether it actually is true or not. He is going by the same evidence as everyone else. Creating porn does not confer expertise in its social effects, just as manufacturing cigarettes does not confer expertise in their health effects.

  25. I’ve seen people get stoned from passive smoking, so clearly it can have an effect if the concentration of passive smoke is high enough.

    I’ve seen people get drunk on alcohol-free wine. The brain’s capacity for conforming to its own expectations is vastly underrated 🙂

  26. Pogo
    January 31, 2014 at 2:38 pm
    …. 50 years ago 80% of the adult population smoked, everywhere!
    ==============================================
    I grew up in the 40s & 50s when non-smokers were the odd-man-out. How on earth did us kids survive?

  27. @VftS

    ‘I grew up in the 40s & 50s when non-smokers were the odd-man-out. How on earth did us kids survive?’

    Yeh, but life expectancy.

  28. @Ian B

    I take the point re tobacco companies, but it’s not scientifically helpful. If a porn producer himself believes that porn causes rape (but carries on producing porn, and denying the correlation publicly) it’s no help to us as to whether it actually is true or not. He is going by the same evidence as everyone else. Creating porn does not confer expertise in its social effects, just as manufacturing cigarettes does not confer expertise in their health effects.

    Yes, but it’s not really analagous to a porn producer ‘personally believing’ anything.

    If this was about the head man at BAT personally believing X, the porn analogy might work (and it may indeed have worked vis a vis smoking a few decades ago, when I’m willing to believe that the head man at BAT probably even thought smoking was good for you).

    But I think the difference is pretty obvious – the tobacco firms have been engaged for 40 years or more in enormous legal battles over this, with budgets of billions involved, and vast epidemiological studies involved.

    I am willing to believe (though I don’t know) that some of the evidence is by, or paid for by, authoritarian shills, but if that were the case I can’t quite work out why the tobacco firms would want to hide it?

    Sunlight, etc.

    Contra the porn guy, I think we can take it that they will have interrogated the evidence very clearly – and, having done so, the US courts appear to think they have then suppressed their own belief in the evidence.

    I think it’s pretty obvious that if a random man tells you Panda Pops will kill you, you’ll shrug and keep on drinking Panda Pops.

    If the man who owns Panda Pops says Panda Pops will kill you, you’d sit up and take notice.

    (Which is, by analogy, maybe why Mr Panda Pops says they won’t kill you, even though he appears to believe evidence that they will.)

  29. @ Interested
    The life expectancy of us kids who grew up in the 40s & 50s when non-smokers were the odd-man-out is so much greater than those who grew up in the 1920s that people are regularly panicking about the cost of our pensions.

  30. Interested>

    “It’s not a lie if there’s a ‘nubbin of truth’, is it? It’s just a question of degrees of concentration?”

    In general it depends on what precisely is being said, but in this case it’s a lie.

    To give another example of the technique in action, look at the way anti-Semitic nutters use one or two Jewish bankers to ‘prove’ that the Jhooz run the world.

    Here, we can say with a fair degree of certainty that passive smoke inhalation levels similar to those consistent with active smoking are likely to be about as bad for you as actually smoking. That’s not an extraordinary claim, and doesn’t require any extraordinary evidence; I’d go as far as to say it ought to be the null hypothesis.

    To go on from that to say that therefore a single dilute whiff of smoke is significantly harmful is a lie, based on the state of current scientific evidence.

    Ian>

    “I’ve seen people get drunk on alcohol-free wine. The brain’s capacity for conforming to its own expectations is vastly underrated :)”

    True, but in this case there was no doubt – in large part because the rather socially and culturally backwards chap in question didn’t have any idea what weed is supposed to do to you. It doesn’t take a lot to get a non-smoker stoned, and the passive smoke levels in the room were high (no pun intended) – and he was sitting with his head right in the cloud.

    John>

    It wasn’t an analogy, just an anecdote intended to demonstrate that at extremes ‘passive’ smoke can be concentrated enough to have similar effects to active. This is well known to teenage weed smokers who ‘hotbox’ enclosed spaces in order to increase the effects.

  31. Interested-

    I think my point about the tobacco companies’ internal opinions stands. Even so, I haven’t read this stuff (and am too busy and lazy to find it now) but from past documentation I have read, the anti-smokers have a tendency to exaggerate these internal document revelations and put the worst spin on them. The actual “smoking gun”, when you see it, is often a rather faint wisp indeed.

  32. There exists empirical evidence from medical experimentation on animals and evidence from autopsies of tissue damage at cellular level from primary exposure to nicotine and other by-products of tobacco smoking.

    None such evidence exists for secondary smoking.

    Much of what passes for scientific evidence these days particularly in matters of health, is assertion which suggest, links and relates (not causes) this with that, might and could, adds to ‘growing’ evidence, and which ignores any confounding factors and uncertainty.

    Such evidence is derived from epidemiological studies, notoriously prone to confirmation bias, which cannot be conducted blind or randomised and are very often designed to give the conclusion that confirms the question they are conducted to answer.

    It is also derived from the need to do popular and fashionable research to get grants so not very clever scientists can earn a living.

    If there was clear, empirical evidence of disease caused by passive smoking such as there is from active smoking, the question surely is why have Governments not acted before now?

    The answer is: like climate change, it’s all fooey, and interested parties shouting loudly to drown out dissent and distract from the lack of even a shred of evidence.

    The louder they shout, the weaker their case.

  33. PS

    Secondary tobacco smoke has most of the nicotine, tars and other gubbins filtered out by the upper respiratory tract of the smoker, if not smoking would not be so harmful.

    In order to get a similar effect from secondary smoke, the passive smoker would have to be in a relatively small, unventilated space (like a car) with a very dense concentration of exhaled smoke from perhaps hundreds of chain smokers for a very long time.

  34. It would be very pleasant to commission a study on the dangers to road users of the carrying of children in cars. For we can certainly all assert the distracting affect on drivers.
    Ban it!
    Then we don’t need to worry about the hazards of their passive smoking.
    You know this makes sense.

  35. I once lived with a professional encyclopaedia editor, btw. She was always getting emails from outsiders seeking to get their view into the encyclopaedia; but that’s not an encylopaedia’s job. It reports the consensus.

    That’s the major flaw with Wikipedia, it reports the consensus of random people rather than those who know what they’re on about.

  36. It’s a matter of dosage. There is some point below which concentrations of a toxin cease to have a proportionate effect, because the human body has a certain threshold for dealing with it…

    All the evidence is that “passive” smoke is simply a smell that some people don’t like.

    On the contrary, the evidence from meta-analysis of many studies is that passive smoking carries a risk of lung cancer, coronary heart disease, and asthma, among other things.

    There may be a threshold effect for some carcinogens, but it’s difficult to tell what the threshold level is. Or the dose-response relationship could be quadratic, which would make low doses less important. But we do know that passive smoking at a sufficient dose is bad for you.

  37. “Here, we can say with a fair degree of certainty that passive smoke inhalation levels similar to those consistent with active smoking are likely to be about as bad for you as actually smoking. That’s not an extraordinary claim, and doesn’t require any extraordinary evidence; I’d go as far as to say it ought to be the null hypothesis.”
    I should say that if you travelled to the centre of the Sun in a wooden chariot you would get burnt. That’s not an extraordinary claim, and doesn’t require any extraordinary evidence: I’d go as far as to say it ought to be the null hypothesis.
    Compare and contrast.
    “Tar”- partially combusted particulate ,matter – is widely reckoned to be the major cause of lung cancer and cannot be absorbed by passive smokers because it is neither gaseous nor light enough to be carried in exhaled smoke. Likewise, as it is not possible to reach the surface of the Sun in a wooden chariot, it is impossible to reach the centre of the Sun in one.

  38. Paul B-

    And there’s the problem, because many of us have sound statistical arguments that the people doing those studies are doing pathological science (or worse, simply advocacy science); that is, the methodology is not valid and the conclusions are useless.

    The particular problem is that the levels of effects being sought are of the same magnitude as the noise, and this is where pathological science tends to specialise (e.g. Blondot’s N-Rays). By cherry-picking studies by criteria influenced by the researcher’s subconscious bias for meta-analysis, a selection of low level positives whcih are merely noise are combined into another, equally valueless weakly positive correlation.

    One good indication of this situation is that large studies show smaller and non-existent effects than smaller ones.

    It is worth noting that medicine’s gold standard for clinical trials is double blinding, precisely because we know that experimenter bias and influence can be extremely powerful, even with utterly honest, diligent, experimenters. Sadly, statistical public health studies- particularly these meta-analyses- are not blinded at all. The researcher knows what result he is looking for- which he very much wants to get, for ideological reasons. And that highly desired result, quelle surprise, is what he finds.

  39. I love these “sidestream” smoke arguments. The smoker him or herself is exposed to that more that any other. Yet I remember textbooks from my childhood implying dishonestly that only bystanders are, and yet somehow the smoker manages to avoid it.

  40. @PaulB: January 31, 2014 at 6:56 pm

    On the contrary, the evidence from meta-analysis of many studies is that passive smoking carries a risk of lung cancer, coronary heart disease, and asthma, among other things.

    Strewth Paul, are they the best you could come up with?

    “lung cancer” – Taylor et al…
    Results The pooled RR for never-smoking women exposed to passive smoking from spouses is 1.27 (95% CI 1.17–1.37). The RR for North America is 1.15 (95% CI 1.03–1.28), Asia, 1.31 (95% CI 1.16–1.48) and Europe, 1.31 (1.24–1.52)…

    Conclusions The abundance of evidence, consistency of finding across continent and study type, dose–response relationship and biological plausibility, overwhelmingly support the existence of a causal relationship between passive smoking and lung cancer.

    “Overwhelmingly support”?? RRs of 1.15 to 1.31 at a 95% CI from a metastudy?? These would probably be statistically insignificant in a double-blind trial, let alone a data dredge!

    A former editor of the NEJM, supported by the National Cancer Institute in 1994 stated that RRs of less than 3 should be treated with caution and less than 2 should be treated as insignificant – the above study didn’t come within a country mile of significance and yet its authors claim “overwhelming support”… Pull the other one.

    “coronary heart disease” – Jiang He et al…
    nonsmokers who were exposed to 1 to 19 cigarettes per day and to 20 or more cigarettes per day had relative risks of coronary heart disease of 1.23 (95 percent confidence interval, 1.13 to 1.34) and 1.31 (95 percent confidence interval, 1.21 to 1.42), respectively

    RRs all insignificant…

    “asthma” – Burke et al…
    We identified 79 prospective studies. Exposure to pre- or postnatal passive smoke exposure was associated with a 30% to 70% increased risk of incident wheezing (strongest effect from postnatal maternal smoking on wheeze in children aged #2 years, OR = 1.70, 95% CI = 1.24–2.35, 4 studies) and a 21% to 85% increase in incident asthma (strongest effect from prenatal maternal smoking on asthma in children aged #2 years, OR = 1.85, 95% CI = 1.35–2.53, 5 studies).

    So, from 79 studies they found a total of 9 that had even vaguely significant results. What, one is tempted to enquire, were the results of the 70 studies they ignorred?

    Sorry Paul, these three seem to be typical of much of the “research” on ETS – basically very poor, inept “science”, generally serving to confirm the results that the “researchers” intended to produce.

  41. Pogo: you don’t actually know what “significant” means in statistics, do you?

    If the true relative risk is 1.25 then a very large study with a very low p-value will give a relative risk very close to 1.25 .

  42. @ PaulB
    Meta-analysis is only valid if every single experiment is included. The first study finds no “strong evidence of publication bias” – implying that it found evidence which it was convenient to discount. It posits that …”suggest that an association between passive smoking and lung cancer is biologically plausible.” i.e. it cannot find any logical or scientific justification. Since my elder son is a better mathematician than I am it is plausible that he is a mathematical genius.
    The methodology used to *pretend* that the second reference avoided publication bias is laughable unsound.
    There used to be a famous example in elementary statistics courses where a professor of statistics in Berlin proved that his baker was deliberately cheating customers by giving short weight although every loaf that the baker gave him after he first complained that they were short weight was above the required size. The asthma meta-analysis claims to prove that passive smoking causes wheeze and asthma but finds no correlation between fathers smoking and asthma – which put its authors in the same camp as the Berlin baker. If passive smoking causes asthma it should do so if the father smokes.
    As for “sidestream smoke” being more toxic than “mainstream smoke” that is complete bullshit. The study deduced that it is more toxic to rats *per 100gm of particulates*. They found this by analysing the effect on rats subjected to a massively higher dose of smoke in order to get an equal weight of particulates so a massively greater dose of carbon monoxide. They even admit, in the small print that “Exposure to sidestream smoke results in higher concentrations of carboxyhaemoglobin, nicotine, and
    cotinine in blood of research animals than exposure to equal
    quantities of mainstream smoke.” The CO killed the rats.
    The report was published by two people employed by the “Centre for Tobacco Control …” Some years ago researchers proved that di-hydrogen monoxide was a carcinogen if applied to rats in massive doses. Carbon monoxide is lethal in quite small doses and it was supplied in relatively high dosages in “sidestream smoke”.
    Back to square one: if “passive smoking” was a significant risk, the dangers of active smoking would not have been discovered in the first place.

  43. Paul>

    Sidestream smoke theory is an excellent example of the kind of junk that confuses the issue. It is, of course, a prima-facie ludicrous hypothesis to suggest that the vast majority of a cigarette’s smoke comes from the burning end without being inhaled. There is no evidence in support of the nonsensical claim that the whole field relies on, and in fact reputable scientists in the field of passive smoking research are condemnatory of a sub-field they feel discredits the genuine research being carried out.

    I’m surprised you’re unaware of this, given your pretence of a good knowledge of the work. Ah, but wait…

    “But we do know that passive smoking at a sufficient dose is bad for you.”

    Yes, the dose equivalent to active smoking. Are you now going to pretend to be unaware that you’ve redefined the question when you couldn’t prove the real thing?

    John77>

    What the damn hell are you on about? Of course the null hypothesis is that if you travel to the sun in a wooden chariot, you’ll burn.

  44. @ Pogo
    “Statistically significant” is jargon and means something that is very unlikely to have occurred just from random fluctuations in the humans or other subjects for study. If a coin turned up heads 51% of the time in a million throws that would be statistically significant.
    What you would call a “significant difference” might not be statistically significant if it was a random variation in a small study
    Anyhow, these results would be significant – a 23% or 31% higher risk of dying of heart disease when heart disease is the biggest cause of death in the USA is quite enough to scare people who are unable to spot the unsound method of selecting the data.
    I disagree with PaulB on this but he is sensibly trying to quote stuff that looks impressive (except to guys like me with some training in statistics and loads of cynicism).

  45. To be less flip…

    I’m perfectly aware of the meaning of statistical significance and also agree that under certain circumstances If the true relative risk is 1.25 then a very large study with a very low p-value will give a relative risk very close to 1.25… However, the studies that you cite are not of that class, they are all meta-analyses.

    To quote Prof Brignell on the topic: Meta-analysis (meta-study) is a technique for trying to get a convincing result by combining the results of a lot of unconvincing studies. . . It might perhaps be valid in some applications, such as well-controlled randomised studies on animals, but for ill-controlled observational studies on human populations it is, to say the least, dubious.

    @John77: If a coin turned up heads 51% of the time in a million throws that would be statistically significant – indeed.

    enough to scare people who are unable to spot the unsound method of selecting the data. – my point exactly, it’s poor science dressed up with a bit of statistical mumbo-jumbo.

  46. We have at least dispensed with Ian B’s claim of “no evidence”.

    it is a prima-facie ludicrous hypothesis to suggest that the vast majority of a cigarette’s smoke comes from the burning end without being inhaled

    who said that? I said, because it’s true, that most of the smoke reaching passive smokers is sidestream smoke. Which renders irrelevant claims above that exhaled smoke is safe.

    if “passive smoking” was a significant risk, the dangers of active smoking would not have been discovered in the first place

    Active smoking is much more dangerous than passive smoking. That doesn’t make passive smoking safe.

    The first study finds no “strong evidence of publication bias” – implying that it found evidence which it was convenient to discount.

    It implies no such thing. It means that their test for publication bias might not have been strong enough to detect weak bias.

  47. @ Paul B
    If they had not found any evidence (whether or not their test was too weak to find weak evidence of bias), they could have said they found “no evidence of publication bias”. You will have to put up with my cynicism – their wording implies that they found evidence of weak bias, it is not only myself who will infer that.

  48. I have to own up. During the seventies, myself and my wife smoked around our two daughters, we didn’t have a car at the time. Both were born a very healthy weight. Growing up they never saw the inside of a hospital. no respiratory problems or health problems of any sort.

    Where’s the kiddie who has been rushed to hospital because the parent smoked whilst driving. If there was one, we would surely have heard about it.

  49. The tobacco companies (actually I think its only Philip Morris) who agree that se ond hand smoke poses risks to healthy individuals did it for two reasons:

    The first was to stabilize the price of their shares which was shrinking in the face of the controversy public health had created.

    The second was as a precautionary tactic to avoid law suits from alleged victims of SHS who may have jumped on the flawed studies to win their case.

    i havent looked lately but the tobacco companies (except for Philip Morris), phrase their warning in such a way that they dont ne cessarily agree with it but “public health believes that SHS could be hazardous” . This way they are protected without necessarily agreeing. Its all politics. lifetime experience and observations should be enough to convince the biggest of skeptics that SHS does not harm healthy children and adults. it takes a minimum of 20 years (if ever) for a disease suspected to have been caused by heavy smoking to develop. SHS even in the most smoky environments gets diluted by hundreds of times once it hits ambient air. One would have to live hundreds of years for SHS to cause one any serious harm except for irritation to the eyes and throat. one exception would be asthmatiics who are triggered by SHS and very severely ill patients who shouldnt be anywhere but completely sterilized places on the first place.

  50. Let’s try an opposite point of view.
    I am a non-smoker and I have always hated smoking. This is because of my parents smoking. I believe it caused my asthma – which made much of my childhood a misery. Since I moved away from my parents, my asthma no longer causes any problems.
    Ok, so this is an uncontrolled experiment of 1, but during my time at uni, I was fine whilst away and suffered during the holidays whilst at home. I have no doubt whatsoever that second hand smoking causes my asthma.

    If people want to smoke where they don’t pollute the air of those who don’t smoke – then I agree, that up to them it is fine. However, IMHO, smoking does have significant negative externalities on surrounding people – something which I do not believe most smokers acknowledge.

    Frankly, the smoking ban has made my life considerably better. Smokers can smoke in private or outside – which, to me, simply recognises that doing otherwise imposes their habit on others. This why I am in favour of the ban – including stopping people from smoking in cars with their kids (opening the car window did not stop the smoke affecting me).

  51. Frankly, the smoking ban has made my life considerably better.

    As a non-smoker, I am reasonably happy to say that the smoking ban has made my life marginally more pleasant. However, I’m fairly sure that that is a wholly inadequate justification, even en masse rather than merely personally, for the authoritarian restrictions on those people who actually enjoy smoking.

  52. What we know beyond any serious doubt is that active smoking carries a high relative risk of lung cancer (especially) and some other cancers. We know that active smoking carries a high risk of cardiovascular disease (the relative risk is not so high, but the danger is important because it’s a common disease).

    We know that for these effects, the risk is roughly proportional to how much you smoke.

    We know that passive smoking exposes one to much the same mixture of toxic substances, albeit at a much lower dose.

    The natural and obvious conclusion from this is that passive smoking also carries a risk of the same diseases, albeit a smaller risk than active smoking.

    Statistical studies (looking at the non-smoking spouses of smokers) strongly suggest that passive smoking carries a risk of the same diseases.

    Now, it’s true that the results of these studies are not as strong as the results of studies on active smoking: that is to be expected since they are looking for a weaker effect. But they fit well with what one might expect.

    On the other side of the argument, we have Ian B’s hypothesis that there’s a threshold effect, at a high enough dose that the expected consequences of passive smoking do not in fact occur. That is just a hopeful guess, there really is no supporting evidence.

  53. Fascinating discussion of passive smoking here, but, to my mind, all quite irrelevant, because Richard Peto — a scientist who refuses to accept tobacco industry funding on the grounds that they wouldn’t give him the funding if they didn’t think they’d get a return on it, implying that to accept it would lead to increased cigarette sales and therefore increased deaths — hardly a Big Tobacco patsy, is what I’m saying — says that the good news for smokers is that if you can give up by the time you’re thirty, your risk levels return to the population norm. And that’s for active smoking. So, even if passive smoking were every bit as dangerous as active smoking, the epidemiology says it’s completely irrelevant in any discussion of children.

  54. Interested,

    “Can anyone explain to me, ideally with sources, why it *isn’t* bad for kids to sit in the car with smokers (or why second hand smoke generally isn’t bad for you)?”

    Your logic is wrong. It does not follow that “sitting next to someone who is smoking in a non-ventilated space would have *some* similar effect” to smoking.

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