Smoking cannabis causes lung damage. This inept Reuters report discusses a study done in England (it’s inept because of the extremely vague wording which I find often in Reuter’s reports). The study is of individuals who heavy smokers of tobacco or heavy smokers of tobacco and cannabis, and the article includes:
“Smoking cannabis on a regular basis actually depletes your lung of protective antioxidant substances…and this may have chronic long-term implications for young individuals,” said Dr Sarah Nuttall of the University of Birmingham in central England.
As correspondent Tim Meehan (who’s been on top of this story) pointed out, this is just plain dishonest, and he wrote Sarah Nuttall to tell her so. Her response:
Next time I suggest you get off your high horse and establish the facts before
labelling anyone or any work “dishonest” – apart from your own thoughts that
Despite Nuttall’s desire to have us look at the facts, very little is provided by her. No online description of the study, the British Thoracic Society’s website (where the report was given) appears to be offline, and the University of Birmingham where the study took place gives no information about the study on its website and merely lists Nuttall as a doctoral student.
So let’s look at the facts as we’ve been able to discover them, partly from news reports and partly from Dr. Nuttall’s email response:
- Dr. Sarah Nuttall and her team studied 20 people aged 19 to 30. This is an extremely small sample to draw any kind of conclusions.
- These 20 participants were broken into three groups: complete non-smokers, tobacco smokers, and tobacco plus cannabis smokers. There was not a group of cannabis only smokers.
- They took blood samples, measured lung function and tested for antioxidant markers.
- Tobacco smokers had impaired lung function compared to non-smokers (yeah, that’s a surprise)
- Tobacco plus cannabis smokers had lower levels of antioxidant and nitric oxide than tobacco only smokers.
- There was no possible evidence in this study that cannabis smoking alone affected lung function in any way.
- No direct evidence that changes in antioxidant levels were caused by cannabis smoking (ie., as opposed to other factors such as differences in diet, etc.) or that they would happen without tobacco smoking.
- The head of the British Thoracic Society said that more research is needed.
So, Dr. Nuttall’s broad statement that “Smoking cannabis on a regular basis actually depletes your lung of protective antioxidant substances…and this may have chronic long-term implications for young individuals,” is not supported by any scientific evidence from her study, and is in fact, dishonest. I would be happy to change my evaluation if she would provide evidence from her study that actually scientifically proves her claim as stated, but the way her study was structured (as it’s been described), that’s not possible.
What she should have said, given the results of her study, if she was an honest or competent scientist: “Based on a small number of subjects, those who smoke tobacco and cannabis regularly have lower levels of protective antioxidant substances than those who just smoke tobacco. Further study is recommended to determine if there is a direct connection between antioxidant levels and cannabis smoking and whether these levels suggest a health risk.”
But no, she made provocative inferences instead.
So you take a small study by an unknown researcher, distort the reporting of the result to appear more dramatic regarding the dangers of smoking pot, and then let the press sensationalize it even further.
And voilà! Within hours you have the New York Post reporting on Pot’s ‘High’ Risk of Cancer
Smoking weed is not the harmless recreational activity it may seem because it can cause lung cancer, researchers in England said yesterday.
Of course, you got less reporting on studies of not 20 participants, but 45,000 subjects in Sweden and 65,000 subjects in the United states, that showed no connection between cannabis and mortality. (See my post from September.) But “Pot doesn’t kill” apparently makes for poor headlines.