Increasing Cannabis Use Outpaces Alcohol Consumption

In the United States, more individuals are smoking cannabis daily than drinking alcohol. The 2022 National Survey on Drug Use and Health indicates there are approximately 17.7 million users who smoke cannabis every day or nearly every day. This change brings about pressing inquiries regarding the potential long-term effects of frequent cannabis use on health.

Researchers at the University of California San Diego observed over 45,000 patients and discovered that those diagnosed with cannabis use disorder (CUD) are 3.25 times more likely to develop oral cancer within five years compared to those who do not have this disorder. This increased risk remains significant even when considering factors like age, sex, body mass index, and tobacco use.

Raphael E. Cuomo, Ph.D., an associate professor in the Department of Anesthesiology at UC San Diego School of Medicine and a member of the Moores Cancer Center, led this analysis. He highlights that these findings align with toxicology studies indicating that cannabis smoke contains many of the harmful chemicals associated with tobacco-related cancers.

Cannabis Use and Oral Cancer Risk

The legalization of cannabis has broadened its availability, yet around three in ten regular users may have CUD, which is a clinical diagnosis indicating problematic use. Unlike casual use, CUD often involves almost daily smoking, deeper inhalation, and higher potency products that expose oral tissues to harmful combustion byproducts.

At the same time, the American Cancer Society predicts that about 59,660 Americans will be diagnosed with cancers of the mouth or throat in 2025. While smoking is a primary risk factor, there are new concerns with the addition of cannabis alongside heavy drinking and human papillomavirus (HPV).

Oral tumors typically begin as painless spots on the lip or tongue, complicating early detection. By connecting CUD to increased tumor incidence in health records, the UC San Diego team provides new insights for clinicians to monitor.

Understanding the Cancer Risk Linked to Cannabis Use

This study leveraged data from six academic medical centers from 2012 to 2019, monitoring participants for five years. Surprisingly, only 2.1% developed CUD, but this small group accounted for about one-third of the observed oral cancer diagnoses.

Although tobacco smokers are already at increased risk, those who smoke both cigarettes and have CUD were six times more likely to be diagnosed with oral cancer compared to smokers without CUD. The persistence of the cannabis-related risk within this group suggests mechanisms involved may go beyond mere smoke exposure.

Interestingly, the research found that older individuals and women, along with higher body mass index, seemed to somewhat reduce risk, similar to trends seen with tobacco-related cancers. However, these demographic factors did not negate the effects of CUD.

Impact of Smoke on Oral Tissue

Laboratory analyses reveal that marijuana smoke contains hundreds of harmful chemicals, many at concentrations comparable to or exceeding those found in tobacco smoke. Some of these compounds can directly damage the DNA of the cells lining the mouth. A 2020 study cataloged 2,575 chemical compounds in mainstream cannabis smoke, with 110 recognized as toxic to humans.

The particles released from smoke adhere to mucosal surfaces, prolonging exposure of carcinogens to vulnerable cells. Moreover, studies show that habitual marijuana smokers may develop precancerous changes in their bronchial tissues, even in the absence of tobacco.

Cannabis and Immune Function

Tetrahydrocannabinol (THC), the psychoactive component of cannabis, could impair immune pathways that typically help identify and eliminate rogue cells. This reduced immune surveillance might allow mutated cells in the mouth a better opportunity to progress toward cancer formation.

While edibles and vaporized products bypass the mouth, frequent users often utilize multiple consumption methods, making it unclear how these alternatives affect cancer risks. Future research separating smoke exposure from THC dosage may clarify these variables.

There’s also uncertainty regarding whether the increasing potency of commercial cannabis products accelerates carcinogen absorption or alters immune responses. Public laboratories are just starting to assess how today’s high-THC strains compare to those studied in previous decades.

Risks for Daily Cannabis Users

Individuals with CUD frequently face coexisting mental health issues, alcohol use disorders, and lower engagement in preventive dental care. These combined factors may heighten their cancer risk and result in later diagnoses.

Additionally, socioeconomic disparities could affect health outcomes, as uninsured individuals are less likely to receive regular oral exams. Integrating substance use counseling with dental screenings in community clinics could help bridge that gap.

For healthcare providers, the key takeaway is clear: when a patient meets the criteria for CUD, a brief oral inspection and a dental referral could be an easy yet effective way to catch potential problems early.

Consequences of Heavy Cannabis Use on Oral Health

Cannabis might not be just a milder version of tobacco; its smoke includes a complex chemical mix that can significantly impact human tissues. This UC San Diego study serves as a reminder that heavy and sustained cannabis use has consequences often overlooked in legalization discussions.

As policymakers consider retail expansion, it’s vital that cancer prevention messaging evolves alongside marketing strategies. Strong warnings similar to those seen on cigarette packs could support informed decision-making among users.

For those who smoke daily, switching to non-combustible products, spacing out usage, and maintaining regular dental check-ups can help mitigate risks. Researchers continue to explore dosage, delivery methods, and biological effects, but personal habits play a crucial role in health outcomes.

Cuomo emphasizes a simple truth: “Cannabis smoke contains many of the same carcinogenic compounds found in tobacco smoke, which are known to damage the epithelial tissue in the mouth.” Being aware of this fact might be a crucial first step toward making safer choices.

This study has been published in the journal Preventive Medicine Reports.