October 2013: http://www.ncbi.nlm.nih.gov/pubmed/23846283 http://www.ncbi.nlm.nih.gov/pubmed/23846283 > "In summary, the accumulated weight of evidence implies

October 2013: http://www.ncbi.nlm.nih.gov/pubmed/23846283 http://www.ncbi.nlm.nih.gov/pubmed/23846283 > "In summary, the accumulated weight of evidence implies far lower risks for pulmonary complications of even regular heavy use of marijuana compared to the grave pulmonary consequences of tobacco." Yeah, I think mostly this comes down to the above discussion of "greatly" -- marijuana seems to have some correlation with lung disease and cancer, but it seems to be less than tobacco.