- The study said smoke is one key reason for the association between smoking weed and head and neck cancers.
- Heavier tobacco use leads to even higher risk, and when alcohol is added, the risk is even greater.
Smoking marijuana daily over the years increases the risk of head and neck cancers up to five times, a new study shows.
The study used insurance data to look at the association of cannabis use disorder with head and neck cancers.
Dr Niels Kokot, a professor of clinical otolaryngology-head and neck surgery at the Keck School of Medicine at the University of Southern California in Los Angeles, US said a study showed people with a cannabis use disorder are more likely to develop head and neck cancers compared to those who do not use.
The study said people with cannabis use disorder smoke about a joint a day and do so for at least a couple of years, if not longer.
However, the study did not find an association between “the occasional recreational use of marijuana and head and neck cancer.”
The study, published in JAMA Otolaryngology–Head & Neck Surgery, analysed a database of 4 million electronic health records and found more than 116,000 diagnoses of cannabis use disorder among people with head and neck cancers.
It further showed that people with cannabis use disorder were about two and a half times more likely to develop an oral cancer; nearly five times more likely to develop oropharyngeal cancer, which is cancer of the soft palate, tonsils and back of the throat; and over eight times more likely to develop cancer of the larynx.
The study said smoke is one key reason for the association between smoking weed and head and neck cancers.
Smoking tobacco doubles the risk of developing head and neck squamous cell carcinoma, which makes up 90 per cent of all head and neck cancers.
Heavier tobacco use leads to even higher risk, and when alcohol is added, the risk is even greater.
The US Centres for Disease Control and Prevention says cannabis use disorder is diagnosed when a person has two or more of such symptoms as craving weed, becoming tolerant to its effects, using more than intended, using marijuana even though it causes problems in life, using it in high-risk situations, experiencing withdrawal and being unable to quit.