THE EFFECTS OF CANNABIS ON PULMONARY STRUCTURE, FUNCTION AND SYMPTOMS

Sarah Aldington ¹, Mathew Williams ¹, Mike Nowitz ², Mark Weatherall ³, Alison Pritchard ¹, Amanda McNaughton ¹, Geoffrey Robinson ¹ and Richard Beasley ^1*

¹ Medical Research Institute of New Zealand, New Zealand
² Pacific Radiology, Wellington, New Zealand
³ Wellington School of Medicine & Health Sciences, New Zealand

^* To whom correspondence should be addressed. E-mail: richard.beasley{at}mrinz.ac.nz.

Accepted 6 June 2007

Abstract

Background: Cannabis is the most widely used illegal drug worldwide. Long term use of cannabis is known to cause chronic bronchitis and airflow obstruction, however the frequency of macroscopic emphysema, the dose-response relationship and the dose equivalence of cannabis with tobacco has not been determined.

Methods: A convenience sample of adults from the Greater Wellington Region was recruited into four smoking groups; cannabis only, tobacco only, combined cannabis and tobacco and non-smokers of either substance. Their respiratory status was assessed using high resolution CT scanning, pulmonary function tests and a respiratory and smoking questionnaire. Associations between respiratory status and cannabis use were examined by analysis of covariance and logistic regression.

Results: A total of 339 subjects were recruited into the four groups. A dose-response relationship was found between cannabis smoking and reduced FEV1/FVC and sGaw, and increased TLC. For measures of airflow obstruction, one cannabis joint had a similar effect to between 2.5 and 6 tobacco cigarettes. Cannabis smoking was associated with decreased lung density on HRCT scans. Macroscopic emphysema was detected in 1/75 (1.3%), 15/92 (16.3%), 17/91 (18.9%) and 0/81 subjects in the cannabis only, combined cannabis and tobacco, tobacco alone and non-smoking groups respectively.

Conclusions: Smoking cannabis was associated with a dose-related impairment of large airways function resulting in airflow obstruction and hyperinflation. In contrast, cannabis smoking was seldom associated with macroscopic emphysema. The 1:2.5 to 6 dose equivalence between cannabis joints and tobacco cigarettes for adverse effects on lung function is of major public health significance.

Keywords: CT scan, Cannabis, Lung function, Smoking, Tobacco

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

Relevant Article

Cannabis and the lung

Peter Lange
Thorax 2007 62: 1036-1037. [Extract] [Full Text] [PDF]

This article has been cited by other articles:

• Reece, A. S. (2009). Severe multisystem dysfunction in a case of high level exposure to smoked cannabis. BMJ Case Reports 2009: bcr0820080798-bcr0820080798 [Abstract] [Full Text]  
• Pinot, D., Breen, D., Peloni, J-M., Gaubert, J-Y., Dutau, H., Vervloet, D. (2009). An incidental finding in a 34-year-old male under investigation for haemoptysis. Eur Respir J 33: 1227-1229 [Full Text]  
• Tashkin, D. P. (2009). Does smoking marijuana increase the risk of chronic obstructive pulmonary disease?. CMAJ 180: 797-798 [Full Text]  
• Tan, W. C., Lo, C., Jong, A., Xing, L., FitzGerald, M. J., Vollmer, W. M., Buist, S. A., Sin, D. D., for the Vancouver Burden of Obstructive Lung Disea, (2009). Marijuana and chronic obstructive lung disease: a population-based study. CMAJ 180: 814-820 [Abstract] [Full Text]  
• (2009). ANSWER. Thorax 64: 74-74 [Full Text]  
• Agrawal, A., Pergadia, M. L., Saccone, S. F., Lynskey, M. T., Wang, J. C., Martin, N. G., Statham, D., Henders, A., Campbell, M., Garcia, R., Broms, U., Todd, R. D., Goate, A. M., Rice, J., Kaprio, J., Heath, A. C., Montgomery, G. W., Madden, P. A. F. (2008). An Autosomal Linkage Scan for Cannabis Use Disorders in the Nicotine Addiction Genetics Project. Arch Gen Psychiatry 65: 713-721 [Abstract] [Full Text]  
• Thomson, W. M., Poulton, R., Broadbent, J. M., Moffitt, T. E., Caspi, A., Beck, J. D., Welch, D., Hancox, R. J. (2008). Cannabis Smoking and Periodontal Disease Among Young Adults. JAMA 299: 525-531 [Abstract] [Full Text]  
• Lange, P. (2007). Cannabis and the lung. Thorax 62: 1036-1037 [Full Text]