Irresponsible And Misleading Reefer Madness From The British Lung Foundation

The British Lung Foundation (BLF) has today published ‘The impact of cannabis on your lungs’, a report which claims to be “the most comprehensive review of research data yet compiled on the subject”.

In fact, although the report references a great deal of scientific research, the way it presents its conclusions is a dangerously irresponsible mix of conjecture, extremist opinion and scaremongering. In particular, the claim by Dame Helena Shovelton, Chief Executive of the BLF, that cannabis cigarettes are 20 times more dangerous than tobacco cigarettes is cherry picked sensationalism. It comes from a study in 2008 from New Zealand that looked at fewer than 80 lung cancer patients. This preposterous claim was calculated by “logistic regression”.

One of the largest case controlled studies of cannabis smokers ever undertaken was by Dr Donald Tashkin of UCLA in 2006. It looked at more than 2000 subjects. Extraordinarily, although the BLF report references a great deal of Dr Tashkin’s work, this, the most significant study of all, is not mentioned.

Dr Tashkin presented his study at the American Thoracic Society International Conference on May 23rd 2006. It showed that even heavy, long-term cannabis users do not appear to be at increased risk of developing lung cancer. Based on his earlier work, much of which is referenced in the BLF report, Tashkin fully expected cannabis to have more serious effects on the lungs than tobacco as cannabis smoke was already known to contain 50% more carcinogen content and up to four times as much tar.

He was surprised to discover that those who smoke cannabis alone develop fewer cancers and less COPD than those who smoke nothing at all and those who smoke cannabis with tobacco do better than those who smoke tobacco alone. He concluded that cannabis provides some protective effect against lung damage and particularly the carcinogenic effects of tobacco smoke.

One possible explanation for the new findings, he said, is that THC, a chemical in cannabis smoke, may encourage aging cells to die earlier (a process known as apoptosis) and therefore be less likely to undergo cancerous transformation.

The most recent study on the subject of cannabis smoking and pulmonary function was published in the Journal of the American Medical Association in January 2012. It looked at more than 5000 subjects over a 20 years period and concluded that exposure to cannabis smoke, even over the long-term, is not associated with adverse effects on pulmonary function.

The BLF report contains a number of other glaring inaccuracies and omissions. It also strays into areas which have nothing to with lungs attempting to stoke up the cannabis and psychosis scare story and citing highly misleading anecdotes and out of context evidence about cardiovascular disease and motor vehicle accidents.

The prejudice and bias which underpins the BLF report culminates in a dismissal of the therapeutic value of cannabis which is based on no scientific evidence at all. Instead, it seeks to adduce as evidence a Court of Appeal hearing from 2005 and an opinion by the British Medical Association which calls for “more research”.

The report calls for more research at nearly every opportunity, a common, self-serving ambition from such institutions. In fact, cannabis is probably the most intensively researched medicinal/recreational substance ever. The evidence for its efficacy as medicine and its safety is now overwhelming. The CLEAR TokePure campaign states that the most dangerous thing about cannabis is smoking it with tobacco. This is a scientific fact which seems to have completely escaped the BLF.

It is clear that this report was written not as a scientific document but as campaigning propaganda. As such it is misleading, inaccurate and dangerously irresponsible.