Co-Use of Tobacco with Alcohol and Cannabis

Addressing co-use of tobacco with alcohol and tobacco with cannabis are important targets for cancer prevention and control. Co-use includes concurrent use of substances as well as use of multiple substances within a given timeframe, such as past week or month. Further research using existing datasets is needed to enhance our understanding of the effects of co-use of tobacco with both alcohol and cannabis, as well as poly-use of all three substances. The National Cancer Institute (NCI), together with federal partners, funds and conducts research to advance science in these areas.

The information presented below summarizes key takeaways related to these areas of research and lists relevant funding opportunities, NCI-funded grants, and resources for researchers interested in co-use of tobacco with alcohol and cannabis.

Co-use of Tobacco and Alcohol

Alcohol and tobacco are both known carcinogens. Cigarette smoking causes nearly one-third of all cancer deaths in the United States, while alcohol use is responsible for approximately 6% of cancer deaths (1). A December 2020 NCI workshop highlighted the need for greater attention to alcohol as a cause of cancer, including awareness of the potential harm of combined use of tobacco and alcohol. Addressing co-use of alcohol and tobacco is particularly important, as epidemiological research shows that combined use of alcohol and tobacco has multiplicative effects on cancer risk at several sites, notably for oral and pharyngeal cancers (2, 3). Further, likelihood of cigarette smoking increases (4) as alcohol use increases, and alcohol use may lead to lower quit rates (5, 6) and higher rates of relapse among individuals who smoke daily or occasionally (7, 8). Research on tobacco and alcohol co-use has the potential to increase the success of both tobacco and alcohol cessation interventions and to inform research and practice concerning alcohol as a target for cancer prevention and control.

Co-use of Tobacco and Cannabis

Further research on tobacco and cannabis co-use is needed, particularly as the tobacco and cannabis landscapes rapidly evolve with new products and state policies being introduced. The introduction of state laws legalizing adult, non-medical cannabis use has been associated with increases in cannabis use (9) and may also impact tobacco use, as recent population-level data estimate that almost 30% of tobacco users regularly use cannabis (10). Studies have documented both an increased likelihood of initiation and use of cigarettes and e-cigarettes among youth who use cannabis (11) and an increased likelihood of cannabis initiation and use among those who have used e-cigarettes (12). Other research indicates that individuals who smoke cigarettes and use cannabis are less likely to successfully quit smoking (13, 14) and score higher on nicotine dependence measures than individuals who use cannabis but do not smoke (15, 16). More research is needed to determine whether and how cannabis use and cannabis policy influences tobacco use patterns and whether the recent changes have any impact on current tobacco control policy. Further, the measurement of cannabis product characteristics, behaviors, and contextual factors is another research need. A better understanding of the effects of tobacco and cannabis co-use will inform how behavioral and policy interventions can advance tobacco control to improve public health.

Poly-use of Tobacco, Alcohol, and Cannabis

There is a need for continued research investigating the effects of poly-use of tobacco, alcohol, and cannabis on cancer-related outcomes, particularly given the prevalence of poly-use of these three substances among young people (17). Such research, especially when addressing initiation and cessation, may also need to address other drugs. This research should build on findings from studies of the effects of co-use of tobacco with alcohol and tobacco with cannabis individually and improve our understanding of how poly-use of tobacco, alcohol, and cannabis affects cancer risk, as well as how interventions addressing poly-use can lead to positive behavior change.