1 in 7 US adults use marijuana

In the United States, about 14% of adults used marijuana in the past year, with smoking being the most frequently used form, according to a study published in Annals of Internal Medicine.

Perspective from Jeremy Hua, MD

“Marijuana is commercially available in increasingly novel forms, such as edibles and concentrates, and with tetrahydrocannabinol (THC) content at levels that have unknown health effects... Despite legalization of recreational marijuana in some states and the development of a multibillion dollar cannabis industry, national data on the prevalence of use of other forms of marijuana are not available,” Stacey Steigerwald, MSSA, from Northern California Institute for Research and Education and San Francisco VA Medical Center, and colleagues wrote.

Steigerwald and colleagues administered a survey to a nationally representative sample of U.S. adults aged 18 years or older (n = 16,280) to determine the how many adults used marijuana and which forms they used, including smoked, vaporized, edibles, concentrates and topicals, in 2017.

About 9,000 adults responded to the survey. Marijuana was used by 14.6% of respondents in the past year, including 8.7% of respondents in 30 days before answering the survey.

In the United States, about 14% of adults used marijuana in the past year, with smoking being the most frequently used form.

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In states where recreational use of marijuana is legal, the prevalence of use was highest at 20% (95% CI, 17.9-22.2) in 2017, compared with 14.1% (95% CI, 12.6-15.6) in states where medicinal use is legal and 12% (95% CI, 10.7-13.4) in states where no use is legal.

Smoking marijuana (12.9%) was the most commonly reported form of use, followed by edibles (6%), vaping (4.7%), concentrates (1.9%) and topicals (0.8%). Use of multiple forms of marijuana in the past year was reported by 6.7% of respondents. The most common forms of edibles used were baked goods/pastries and candies.

The likelihood of any use of marijuana decreased as age increased. Adults aged between 18 and 34 years reported the highest use of marijuana.

Smoking marijuana was prevalent in 16% (95% CI, 13.9-18) of states where recreational use is legal, in 12.6% (95% CI, 11.2-14.1) of states where medical use is legal and in 11.4% (95% CI, 10.1-12.7) of states where no use is legal.

Use of any other form of marijuana was prevalent in 14.1% (95% CI, 12.3-15.9) of states where recreational use is legal, in 7.3% (95% CI, 6.2-8.5) of states where medical use is legal and in 5.4% (95% CI, 4.5-6.3) of states where no use is legal.

Marijuana use in any form and multiple forms was more common among men than women. Race did not appear to affect prevalence of marijuana use.

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In 2017, the most prevalent form of marijuana use was smoking (55%). More than half (53%) of respondents who used multiple forms of marijuana reported smoking and using edibles and 31% reported smoking and vaping.

“Use of different forms of marijuana is common among U.S. adults and is more common among residents of states where recreational use is legal,” Steigerwald and colleagues concluded. “Given trends in legalization, annual epidemiologic data on the different forms of use will be necessary to inform public policy. Studying the health effects of marijuana will also require exposure assessment tools that capture different forms of use.” – by Alaina Tedesco

Disclosure: The authors report no relevant financial disclosures.

Perspective

Jeremy Hua, MD

The results of the work by Steigerwald and colleagues shed light on the burgeoning prevalence of use in states that have legalized marijuana for medical and recreational purposes. Their observations confirm prior epidemiologic studies indicating a direct association between liberal marijuana laws and use of marijuana in the U.S. Providers should be aware of laws governing marijuana sales in their practice area to understand the potential impact on patients in their care.

The high prevalence of inhaled marijuana, particularly smoked marijuana, was demonstrated in this investigation, although the effect of long-term inhaled marijuana products (particularly emerging methods, such as vaping) on lung health remains poorly described. Additionally, the investigation highlights a potentially increased consumption of marijuana in edible forms, vaporized forms, or for topical applications. Importantly, the dose of tetrahydrocannabinol in any product can vary widely and is influenced not just by the manufacturing process but by the user’s habits; tetrahydrocannabinol has numerous immunomodulatory effects that we do not completely understand.

It is important to recognize that PCPs may care for marijuana consumers in the context of a long-standing therapeutic relationship. In the same way that alcohol or substance use should be discussed in detail, conversations about marijuana use in this setting should focus on duration of engagement, frequency of use, mode of administration, as well as any resultant negative medical or social effects. Developing a firm grasp on marijuana use patterns will assist in identifying unhealthy use, and in the potential for early interventions on the personal and public health level.

Jeremy Hua, MD

Instructor of Medicine, Internal Medicine

University of Colorado School of Medicine

Ellen L. Burnham, MD

Associate Professor of Medicine

Pulmonary Sciences and Critical Care Medicine

University of Colorado School of Medicine

Disclosures: Burnham and Hua report no relevant financial disclosures.

Sources/Disclosures

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Source:

Steigerwald S, et al. Ann Intern Med. 2018;doi:10.7326/M18-1681.