A research team found an association between cannabis use and reduced risk of oral cancer. Previous studies have reported conflicting evidence on the association between cannabis use and oral cancer incidence, so the findings published in the Journal of Ethnicity in Substance Abuse provide valuable insights into cannabis use and cancer rates. While other studies pointed to an increased cancer incidence for chronic cannabis consumers, this study suggested cannabis consumers are not at a greater risk for oral cancer.
An international research team analyzed data from six case-control studies involving over 15,000 participants. The researchers included only studies reporting quantitative risk estimates for cannabis consumption and oral cancer, and they performed subgroup analyses on duration of use, gender, and age at initiation of cannabis use. The analysis showed no observable clear dose-response relationship between cannabis use and a heightened oral cancer risk for all participants, regardless of duration of cannabis use.
The researchers used sensitivity analyses to confirm the robustness of findings (with oral cancer risk ranging from 0.599 to 0.708 across iterations). They found three individual studies showed statistically significant protective effects.
The findings suggested that cannabis may offer significant anticarcinogenic effects against cancer. The pooled odds ratio showed a statistically significant inverse association between cannabis use and oral cancer risk (OR = 0.66). The researchers recommended that future research studies include large-scale prospective cohort studies with standardized exposure measurements.
Three individual studies showed statistically significant protective effects, while three others were non-significant. This meta-analysis suggests marijuana use is associated with reduced oral cancer risk.
Sources: Journal of Ethnicity in Substance Abuse, NORML