Postado originalmente por
Ljc
BACKGROUND:
The association between marijuana smoking and lung cancer is unclear, and a systematic appraisal of this relationship has yet to be performed. Our objective was to assess the impact of marijuana smoking on the development of premalignant lung changes and lung cancer.
RESULTS: Nineteen studies met selection criteria. Studies that examined lung cancer risk factors or premalignant changes in the lung found an association of marijuana smoking with increased tar exposure, alveolar macrophage tumoricidal dysfunction, increased oxidative stress, and bronchial mucosal histopathologic abnormalitiescompared with tobacco smokers or nonsmoking controls.
Observational studies of subjects with marijuana exposure failed to demonstrate significant associations between marijuana smoking and lung cancer after adjusting for tobacco use. The primary methodologic deficiencies noted include selection bias, small sample size, limited generalizability, overall young participant age precluding sufficient lag time for lung cancer outcome identification, and lack of adjustment for tobacco smoking.
CONCLUSION: Given the prevalence of marijuana smoking and studies predominantly supporting biological plausibility of an association of marijuana smoking with lung cancer on the basis of molecular, cellular, and histopathologic findings, physicians should advise patients regarding potential adverse health outcomes until further rigorous studies are performed that permit definitive conclusions.
ADDepartment of Medicine, Case Western Reserve University, Cleveland, Ohio 44106-6003, USA.
[email protected]
PMID16832000
37
PubMed
TIMarijuana smoking and the risk of head and neck cancer: pooled analysis in the INHANCE consortium.
AUBerthiller J, Lee YC, Boffetta P, Wei Q, Sturgis EM, Greenland S, Morgenstern H, Zhang ZF, Lazarus P, Muscat J, Chen C, Schwartz SM, Eluf Neto J, Wünsch Filho V, Koifman S, Curado MP, Matos E, Fernandez L, Menezes A, Daudt AW, Ferro G, Brennan P, Hashibe M
SOCancer Epidemiol Biomarkers Prev. 2009;18(5):1544.
BACKGROUND: Marijuana contains carcinogens similar to tobacco smoke and has been suggested by relatively small studies to increase the risk of head and neck cancer (HNC). Because tobacco is a major risk factor for HNC, large studies with substantial numbers of never tobacco users could help to clarify whether marijuana smoking is independently associated with HNC risk.
METHODS: We pooled self-reported interview data on marijuana smoking and known HNC risk factors on 4,029 HNC cases and 5,015 controls from five case-control studies within the INHANCE Consortium. Subanalyses were conducted among never tobacco users (493 cases and 1,813 controls) and among individuals who did not consume alcohol or smoke tobacco (237 cases and 887 controls).
RESULTS:
The risk of HNC was not elevated by ever marijuana smoking [odds ratio (OR), 0.88; 95% confidence intervals (95% CI), 0.67-1.16],
and there was no increasing risk associated with increasing frequency, duration, or cumulative consumption of marijuana smoking. An increased risk of HNC associated with marijuana use was not detected among never tobacco users (OR, 0.93; 95% CI, 0.63-1.37; three studies) nor among individuals who did not drink alcohol and smoke tobacco (OR, 1.06; 95% CI, 0.47-2.38; two studies).
CONCLUSION:
Our results are consistent with the notion that infrequent marijuana smoking does not confer a risk of these malignancies. Nonetheless, because the prevalence of frequent marijuana smoking was low in most of the contributing studies, we could not rule out a moderately increased risk, particularly among subgroups without exposure to tobacco and alcohol.
ADLifestyle, Environment and Cancer Group, IARC, 69008 Lyon, France.
PMID19423532