“In a recent presentation given at the annual meeting of the American Association of Cancer Research, investigators from the university of California, Los Angeles provided the latest data reaffirming that cannabis consumption is not associated with an elevated risk of lung cancer. Below is a summary of the findings from The Oncology Report:
The study included data from six case-control studies conducted from 1999 to 2012 in the United States, Canada, the United Kingdom, and New Zealand, with a subject pool of 2,159 lung cancer cases and 2,985 controls. All of the studies were part of the International Lung Cancer Consortium (ILCCO), an international group of lung cancer researchers with the aim of sharing comparable data from ongoing and recently completed lung cancer studies from different geographical areas and ethnicities.
Dr. Zhang of the University of California, Los Angeles, performed two analyses. One compared all lung cancer cases and all controls, regardless of concurrent or past tobacco use. Then, to reduce confounding by tobacco, she restricted the analysis to those who had never smoked tobacco.
… When compared with cannabis smokers who also used tobacco, habitual pot smokers had no significant increase in cancer risk. In an analysis of marijuana smokers that excluded tobacco smokers, there were no significant differences in any of the comparisons, including habitual vs. nonhabitual use; number of joints smoked per day; duration of up to 20 years or duration of more than 20 years.
The abstract of the presentation, which concludes “Our pooled results showed no significant association between the intensity, duration, or cumulative consumption of cannabis smoke and the risk of lung cancer overall or in never smokers,” is available online here.