…and if you smoke a hell of a lot of it, it may even be worse than plain ol’ cigarettes.

I wrote previously about a study that claimed one joint of marijuana causes about as much damage to your lungs as a handful of cigarettes. I argued, though, that most people probably smoke a small enough amount of weed for it not to have as great an effect on overall lung health as the typical smoker could expect. Now, Christian over at Med Journal Watch has found a similar study in support of the same—even more lopsided—conclusion. This one says a single joint is equal to up to a whole pack of cigarettes! The difference here, though, is that median number of marijuana cigarettes smoked daily by subjects in the latter study was six. Six joints a day! Median! Meaning someone potentially smoked much more than that! Otherwise they probably would have just used the mean! And this was for almost nine years on average! 19,272 joints! How expensive must that be?

Emphysema and secondary pneumothorax in young adults smoking cannabis.
Beshay M et al. Eur J Cardiothoracic Surg. doi:10.1016/j.ejcts.2007.07.039

Background: We observed a remarkable increase in the number of young patients who presented with lung emphysema and secondary spontaneous pneumothorax (SSP) at our institution for over a period of 30 months; most of them have a common history of marijuana abuse.

Study design: Retrospective case series.

Methods: Seventeen young patients presented with spontaneous pneumothorax with bullous lung emphysema were systematically evaluated over a period of 30 months. All were regular marijuana smokers. Clinical history, chest X-ray, CT-scan, lung function test, and laboratory and histological examinations were assessed. We compared the findings of this group (group I) with the findings of non-marijuana smoking patients (group II) in the same period. The findings of this series were also compared with the findings of 75 patients presented with pneumothorax in a previous period from January 2000 till March 2002 (group III).

Results: In group I, there were 17 patients: the median age of the patients was 27 years (range 19-43 years), 16 males and 1 female. All were living in Switzerland. All but one smoked marijuana daily for a mean of 8.8 years and tobacco for 11.8 years. CT-scan showed multiple bullae at the apex or significant bullous emphysema with predominance in the upper lobes only in two patients. Only two patients had reduced forced first second expiratory volume (FEV1) and one reduced vital capacity (VC) below the predicted 50%. This correlated with the subjectively asymptomatic condition of the patients. All but two patients were treated by video-assisted thoracoscopic surgery (VATS) for prevention of relapsing pneumothorax. Histology showed severe lung emphysema, inflammation, and heavily pigmented macrophages. In group II, there were 85 patients: there were 78 males, the median age was 24 years (range 17-40 years), 74 patients smoked tobacco for 13.4 years but no marijuana. CT-scan in 72 patients showed only small bullae at the apex but no significant emphysema; other clinical, laboratory, and histopathological findings showed no significant difference in group I. In group III, there were 75 patients: there were 71 males and 4 females. Mean age was 25 years (range 16-46 years). Six smoked marijuana daily for a mean of 3.2 years, and 62 smoked tobacco for 14 years. CT-scan done in 59 patients showed few small bullae at the apex but no significant lung emphysema. The presence of lung emphysema on CT-scan in group I was significantly different than in groups II and III (p=0.14). No significant difference was found among all groups in the form of clinical, laboratory, and histopathological findings.

Conclusions: In case of emphysema in young individuals, marijuana abuse has to be considered in the differential diagnosis. The period of marijuana smoking seems to play an important role in the development of lung emphysema. This obviously quite frequent condition in young and so far asymptomatic patients will have medical, financial, and ethical impact, as some of these patients may be severely handicapped or even become lung transplant candidates in the future.”

Remarkable Finding #1: Either females rarely smoke in Switzerland, or they almost never get smoking-related pneumothoraces as a sequela of emphysema.

Remarkable Finding #2: This study is a piece of crap. There is zero rationale given for how this 1 joint:1 pack ratio was calculated, and there is very little analysis of their data beyond reporting the clinical findings. Did they control for tobacco smoking in the cannabis group? Not really. Why did the non-cannabis-smoking group present with spontaneous pneumothoraces if they didn’t have emphysema? Who knows. Maybe they all got stabbed. Why did the cannabis smokers in the third group not get emphysema? How much cannabis did they smoke? How much tobacco did they smoke? No clue. I think I have an explanation for why the cannabis and tobacco smokers developed emphysema while the tobacco smokers didn’t: They smoked more. What are those “histopathological examinations” examining exactly? Cannabis smokers? Tobacco smokers? Can we have some comparative slides please? I think we all know what emphysema looks like histologically and radiographically.

Remarkable Finding #3: Smoke a lot of anything, and apparently your lungs die. I think we knew this already.