Three years after Oregonians voted to legalize retail marijuana sales, reported exposure to marijuana advertising appears common among youths: most youths report seeing ads, and a large proportion of those exposed to ads reported seeing them in multiple ways. Exposure reported by Oregon youths in 2017 is higher than national estimates (58.7%) reported by Dai in 2014–2015, which did not specifically report on states with legal marijuana markets (4). Conversely, youth-reported exposure in Oregon was lower than levels reported by Whitehill et al (93.6%) from a 2018 online survey of 469 adolescents aged 15 to 19 years residing in 4 states with legal retail marijuana (not including Oregon); however, exposure to social media sources of advertising in that study was not limited to the past 30 days (9). Regardless of the exact level of exposure, these exposures to marijuana advertising are concerning given the scientific consensus that tobacco promotions cause youth tobacco use initiation (1,10), and alcohol advertising increases the likelihood of alcohol use initiation and heavier drinking if youths already use alcohol (2). Despite not observing significant increases in youth marijuana use following legalization in Oregon (11), marijuana advertising could work in the longer term to similarly increase the likelihood of initiation and heavier use among youths by fostering positive attitudes and expectations of substance use (1).

Marijuana advertising exposure was greater among some groups of youths, potentially putting them at increased risk for initiation. Higher odds of exposure among girls is consistent with a study on e-cigarette advertising that indicated that female youths may be more aware of product advertising in general (12). Youths who identified as LGB were more likely than straight youths to report seeing ads, which may be of particular concern given high rates of current marijuana use within the LGB community: 33% of LGB adults in Oregon currently used marijuana in 2014–2015 compared with 11% of all adults (11). Exposure to advertising was not significantly higher among communities of color compared with non-Hispanic White youths and was significantly lower among youths identifying as Hispanic or Latino. The potential “protective effect” of Hispanic or Latino ethnicity warrants further consideration. However, given historical targeting and relatively higher exposure to advertising from the tobacco and alcohol industries among vulnerable populations (13,14), continued monitoring of advertising exposure among LGB and racial/ethnic minority youths is warranted as the marijuana industry grows from cottage to corporate (15).

Community settings and retail presence may play an important role in advertising exposure. Youths living outside of urban settings were less exposed, which could reflect limited potential for any type of advertising exposure from billboards and storefronts given fewer retail stores generally. In models that controlled for community setting, youths in school districts with closer average proximity to retail marijuana stores were more likely to see ads for marijuana — more than 8 in 10 youths in either grade were exposed within districts where the average proximity to a retail store was less than 1 mile. Communities in Oregon are allowed to ban retail stores, and this may have reduced exposure to advertising for some youths, especially where contiguous geographic areas have done so. Local or state regulation of retail density may play a role in limiting advertising exposure not only by reducing storefront advertising but also by limiting market competition. Washington is the only state to implement a cap on the number of retail licenses allowed in order to support regulation of retail store density (16); the effect of a license cap on community-level store density, associated advertising, and ultimately youth marijuana perceptions and use will require further study. Limiting placement of retailers may limit exposure to their advertising.

Retail marijuana storefronts were among the leading source of advertising seen by youths. While Oregon restricts advertising deemed attractive to minors (ie, features cartoons, images of minors, symbols or celebrities commonly used to market to minors) (17), little else in the state’s rules curbs the influence of retail storefronts on social norms. Washington State, on the other hand, limits stores to 2 signs measuring a maximum of 1,600 square inches that may contain only the trade name, location, and nature of the business (18).

A large proportion of youths in our study reported exposure to online marijuana advertising, including a substantial increase from 8th graders (37.2%) to 11th graders (49.5%) that may reflect increases in media consumption and/or increase in marijuana use with age. This high level of online exposure persists despite state-level regulations that restrict internet advertising to locations where at least 70% of the audience is 21 or older (known as the 70/30 rule) (17), and voluntary policies such as Facebook’s restrictions on advertising illegal, prescription, or recreational drugs (19) and Google’s ban on ads for substances that induce highs (20). Digital marketing through social media — including peer-to-peer transmission through sharing and “likes” — is concerning given the potential for influencing young people and the difficulty of regulating and enforcing restrictions (21,22). Consequently, public health education and countermarketing efforts should include a social media component to reach youths in the digital environment.

About one-third of youths reported exposure to marijuana advertising on billboards and on the sidewalk (eg, signs and people waving or wearing signs). While billboard advertising is restricted by the aforementioned 70/30 rule and state advertising rules provide examples of restricted content, such as images of cartoon characters or toys, this may not be enough to reduce the appeal to youths. A recent letter to the editor in the Oregonian newspaper highlights the potential effect of billboards even without youth-oriented images: “Now when I am driving with my 6- and 7-year-old children, I need to explain what ‘Damn $5 a gram’ or ‘celebrate 420’ mean” (Figure 2 is a photograph of a related billboard) (23). In contrast, Colorado allows billboards as fixed signs on a marijuana store’s lot to identify the location but prohibits other forms of outdoor advertising, such as sign spinners and sandwich boards (24).

The American Public Health Association both urges restrictions on marijuana advertising as a public health priority and acknowledges the First Amendment protections of corporate free speech that make marketing regulations difficult (25). A recent analysis of marijuana regulatory frameworks in 4 US states echoes the difficulty of applying tobacco control best practices to advertising restrictions for marijuana, and asserts that existing controls are “limited and ineffective” for preventing youth access and use (26). Those authors further suggest that restrictions on advertising that targets youths may be allowed, and the continued status of marijuana as illegal under federal law may provide states with more regulatory flexibility (26). While outdoor advertising restrictions in Colorado and Washington offer examples of such regulatory flexibility, this latitude is likely state dependent. In Oregon, the limited restrictions on marijuana advertising may be a byproduct of the free speech guarantee in the state constitution, which is considered one of the nation’s strongest and is broader in scope than the First Amendment to the US Constitution (27).

These barriers to advertising regulations and young people’s high exposure to advertising highlight the need for other elements of a comprehensive approach to youth marijuana use prevention, consistent with effective approaches for alcohol and tobacco use prevention. Comprehensive approaches include implementing price controls, developing licensing and zoning laws to restrict and monitor licenses and licensees, restricting public consumption, and designing countermarketing messages (28,29). Our results support the consideration of specific groups of youths (eg, female, LGB) for marijuana countermarketing. Further, complementary parent education campaigns may be warranted given that 8th and 11th graders in our study had higher reported exposure to advertising if someone in the home (eg, parents) used marijuana. For example, the Oregon Health Authority developed the “Talk With Them/Habla Con Ellos” education campaign to support parents and educators in conversations with youths about marijuana. Finally, youth marijuana use should not be addressed in isolation; a truly comprehensive approach should also include tobacco, alcohol, and other drug use prevention given the high prevalence of substance co-use among both youths and young adults in the United States (30,31).

This study had several limitations. First, awareness of marijuana advertising may have been enhanced because this is a new and politically charged topic. Awareness and recollection may diminish over time as retail marijuana and associated advertising become normalized rather than actual changes occurring in the amount of advertising. Second, marijuana advertising questions were added to the youth survey in 2017, so we cannot assess how exposure changed with the opening of the retail market. Given survey space constraints, ad types assessed had to be prioritized and did not include all potential community exposures (eg, those on bus shelters, park benches, transit stations). Third, we used small-area population estimates to describe retail exposure as a population-weighted average by school district; some of Oregon’s school districts span large areas and exposure for individual youths could vary considerably by intradistrict location. Last, we found increased odds of marijuana ad exposure among youths who use marijuana; however, we cannot assert the direction of the association (ie, advertising exposure contributes to marijuana use or marijuana use primes youths to notice advertising). Longitudinal studies are needed to more fully understand this association.

Most youths reported exposure to marijuana advertising in Oregon’s legal retail market, especially youths who are female, LGB, or in school districts with a close average proximity to retail marijuana stores. Different types of advertising may have different potential for regulation. While some sources of youth advertising exposure may be difficult to regulate and enforce (eg, online), others may be within the purview of state authority (eg, billboards, storefronts) depending on state-specific interpretation of free speech protections. States may consider this information both as justification for regulating advertising practices and for selecting specific youth demographic groups to target with prevention messages.