Marijuana use protects tobacco smokers and alcohol drinkers from head and neck cancer! Legalization is on its way to the USA! A population-based case-control study of marijuana use and head and neck squamous cell carcinoma.Liang C, McClean MD, Marsit C, Christensen B, Peters E, Nelson HH, Kelsey KT.SourceDepartment of Community Health, Department of Pathology and Laboratory Medicine, Division of Biology and Medicine, Brown University, Providence, RI, USA.
Abstract: Cannabinoids, constituents of marijuana smoke, have been recognized to have potential antitumor properties. However, the epidemiologic evidence addressing the relationship between marijuana use and the induction of head and neck squamous cell carcinoma HNSCC is inconsistent and conflicting. Cases n = 434 were patients with incident HNSCC disease from nine medical facilities in the Greater Boston, MA area between December 1999 and December 2003. Controls n = 547 were frequency matched to cases on age +/-3 years, gender, and town of residence. After adjusting for potential confounders including smoking and alcohol drinking, 10 to 20 years of marijuana use was associated with a significantly reduced risk of HNSCC [odds ratio OR10-<20 years versus never users, 0.38; 95% confidence interval CI, 0.22-0.67]. Among marijuana users moderate weekly use was associated with reduced risk OR0.5-<1.5 times versus <0.5 time, 0.52; 95% CI, 0.32-0.85. The magnitude of reduced risk was more pronounced for those who started use at an older age OR15-<20 years versus never users, 0.53; 95% CI, 0.30-0.95; OR> or =20 years versus never users, 0.39; 95% CI, 0.17-0.90; Ptrend < 0.001. These inverse associations did not depend on human papillomavirus 16 antibody status. However, for the subjects who have the same level of smoking or alcohol drinking, we observed attenuated risk of HNSCC among those who use marijuana compared with those who do not. Our study suggests that moderate marijuana use is associated with reduced risk of HNSCC.