Cannabis bigger cancer risk than cigarettes: study

By mouthwater · Jan 30, 2008 · ·
  1. mouthwater
    Cannabis bigger cancer risk than cigarettes: study;_ylt=ArCpTbSNMjNPf55Sl2WZ4Kus0NUE

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  1. Bajeda
    Interesting, but I don't think the sample size is big enough to be able to generalize to the entire population.

    Also, I don't know why they are referring to a "new carcinogen." The article doesn't even mention specific carcinogens! Maybe they just meant cannabis, but that wouldn't make sense either. There is either information from the study not included in the article (such as a new carcinogen in cannabis smoke they discovered?) or the article is just misleading. Judging from some of the overly forceful and/or misleading statements in the article, I'm leaning towards the latter.

    Anyone know the name of the study being referenced?
  2. enquirewithin
    The source of this report is the "Medical Research Institute of New Zealand"-- "an independent medical research organisation." This report is part of their Alcohol and Drug Abuse programme. All their reports are negative and may well be aimed at getting funding for anti-drug research.

    For example,

    If it was actually proved that "one cannabis joint had similar adverse effects on the lung as between 2.5 and 5 tobacco cigarettes" (I assume they mean a marijuana 'joint' the same size as a cigarette, which themselves are very varied in their levels of carcinogens anyway), not many smokers smoke anything like the number of joints as cigarette smokers smoke cigarettes. You can't help feeling that this group is not very objective.

    It's all scary stuff!
  3. Mr. Giraffe
  4. TDIDriver
    SWIM would like to say the following:
    Like any study you have to ask what was the researcher's agenda and what is the point they are tring to make? But above all you have to know who paid for the research.

    Even though this study came from the Medical Research Institute of New Zealand [MRINZ]
    which is "supposed" and proported to be an independent medical research organisation.

    As far an their agenda or their intent in doing this research again you have to ask what is their (the research organization) motivation.

    This information that I've quoted comes from MRINZ own web site.
    What this "study" really is just more govermental propaganda and a waste of tax payer $

  5. enquirewithin
    The ever sensational Daily Mail reports the story-- now it's 20 times!

    PDF here
  6. realitybias
    I posted this in another forum and will cross-post it here...

    1) Out of 79 individuals with cancer, 70 of those individuals were tobacco smokers. Here's some rough news guys, tobacco causes lung cancer!

    2) Out of 79 individuals with cancer, 9 of them were not tobacco smokers at all. The study does not say whether these 9 smoked marijuana or not, only that they had lung cancer. That corresponds to 11-12% of lung cancer cases being not related to tobacco smoke. Anyone care to take a guess what the population rate of cancer in complete nonsmokers is? 10-15% Radon gas, secondhand smoke, asbestos, estrogen, genetics, etc. are all other causes of lung cancer. See source 1.

    3) Here's where it gets better. All of the tobacco smoking participants had smoked a 5 pack-years or more (they use a weird system called joint-years and pack-years. For those who spent as long as me trying to decode it, take the number of joints/day you smoke and multiply by the number of years you've been smoking to get your "joint - year." Pack years work the same way, number of packs per day * years you've been smoking. In this case, 5 pack-years equates to 5 packs of cigarettes a day for a year or 1 pack for 5 years). This shows pretty much straight-up, smoking lots of tobacco will give you cancer.

    4) Those with 10 joints/day for a year (or 5 for 2 years, or 1 for 10 years) or less showed a DECREASE in the chances that you'll get lung cancer from their OWN study! 8.9% of the lung cancer cases had smoked 10 joint-years, while 11.1% of the NORMAL population had smoked 10 joint-years.

    5) This study only had 21 cannabis smokers out of its 79 cancer patients. Population size is so small, and the study once again does not point out how many of those cannabis smokers also smoked tobacco. at least 12 of those cannabis smokers smoke tobacco assuming ALL non-tobacco smokers with lung cancer smoked cannabis, which is extremely unlikely (given that the natural non-smoker's lung cancer makes up 10%-15% of lung cancer cases). What seems more likely to me is that most of the cannabis smokers with lung cancer smoked tobacco as well.

    6) This study did not test anyone that they identify as "Marijuana smoker-non-tobacco smoker." which says to me that they did not find a significant number (read greater than 10% to correct for environmental causes of lung cancer) of pure marijuana no-tobacco smokers with lung cancer. Hell, for all we know, there might not be a SINGLE pure marijuana smoker in their study, as those details are not released.

    7) The only thing this study proves is that smoking more than 10 joint-years (10 joints/day for a year or 1 joint a day for 10 years) or more while smoking heavy amounts of tobacco (a pack a day for 5 years) as well will screw your world over.

    8) There is still not a SINGLE study, this one included, that shows causation between marijuana and cancer. Some only hint to the mixing of tobacco with marijuana as being dangerous, but even this seems vague.

    So there you have it, guys. The study is horribly flawed. It takes a population of 79 cancer patients, 70 of which are tobacco smokers, and says that marijuana is more dangerous than tobacco. They take their facts, twist them to say something else, and present it as you see it here. Suddenly a single joint becomes as devastating as 20 cigarettes.
    I hate bad research.
  7. Coconut
    It's an unfortunate reality that studies and papers can have accurate data but when its authors have an agenda they can twist said data into a completely ridiculous conclusion.
  8. realitybias
    By the way, want to know how they "Corrected for tobacco smoke"?
    Linear regression and saying "smoke x tobacco" and "smoke y cannabis" and then trying to compute the numbers that go in front of both of those variables. Want to know the problem with this methodology? Since the majority (if not all) of the cannabis smokers smoked tobacco, the study is not testing for "cannabis" effect on lung cancer. Its merely testing for extra tar's effect on lung cancer (as cannabis alone is not carcinogenic, as proven by many studies). Extra tar can irritate the lungs enough to allow the potent carcinogens of tobacco to activate cancer cells earlier. Tar alone will not cause cancer (and especially in the case of cannabis alone, as cannabis dilates the lungs instead of constricts, allowing it to be easily cleaned out).
  9. ironmics
    I've seen this kind of study pop up a lot, so it must have some validity, but no ones smoking a pack of joints a day. Any kind of smoke can do a lot of damage to your lungs over time though. Also I've seen studies where regular cigar smokers have a reduced risk of lung cancer to non smokers. I'm very skeptical about any study about this and this causing cancer and not causing cancer.
  10. cra$h
    since joints come in all shapes and sizes, swim has seen between .5g and 5g joints, so they need to be more specific on the amount of marijuana actually smoked. what they should do is compare one gram of marijuana, to one gram of tobacco. then we'll see the real numbers
  11. ironmics
    I believe there's numbers over on erowid comparing cannabis carcinogens to tobacco. It's not a study on cancer, but should give a decent idea of relative values per weight.
  12. guncow
    My cat hardly ever smokes a j without a filter thankfully.

    I'd like to see stats on Bong vs Vapo vs Joints vs etc... that'd be swell.
  13. TDIDriver
    If you pay "MRINZ" enough money they will do a study that will produce results that say any damn thing you want..if its true or not!
  14. Expat98
  15. Greenport
    Bongs filter many carcinogens :) THC's insolubility in water makes it miraculous for that reason.
  16. cosmicruler
    hahaha,i call BS.

    who funded/conducted this study??British American tobacco maybe??

    ....they probably conducted the study on those that smoke both tobacco and weed,or targeted those who smoke 'ice'(P) and weed(seen as according to the media this is an epidemic in NZ)
  17. endlessnes
    hey realitybias... thanks a lot for dissecting the study like this!

    we need more people like you that dont just believe things when they read ´study shows´, but rather check the details and think for themselves :)
  18. cra$h
    forgot to mention the carcenogens in the paper alone. I'm not sure if different papers have different amounts of carcenogens, but the paper is far from good for you.
  19. Alfa
    That makes sense when considering:

  20. FuBai
    Anyone ever see "Thank You For Smoking"? The Tobacco companies in it used simillar techniques to those used by governmental research organisations, such as NIDA and this "MRINZ" group, in which they created a scientific institution dedicated to disproving any negative health effects of tobacco. It's the same for illegal drugs, but in reverse.
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