Table 2 Summary of included studies

Barnoya J et al. (Guatemala, 2020) [35]

E-cig/HTP POS advertising

Cross-sectional

Convenience stores in gas stations

Age, SES

(1) E-cigs and HTPs found near candy, especially in high-SES neighborhoods. (2) More e-cigs and HTPs next to the cash register in high-SES than mid-SES neighborhoods. (3) More e-cig interior ads in mid-SES than high-SES neighborhoods.

D’Angelo et al. (US, 2020) [36]

E-cig POS availability/promotions/marketing

Longitudinal

Tobacco retailers that sell cigarettes (nationally representative in the contiguous US)

Age, race/ethnicity, SES

(1) About one quarter of retailers displayed e-cigs near candy and/or sweet beverage and had interior e-cig signs/ads located at child eye level. (2) More price promotions in disproportionately Hispanic, but not disproportionately Black, neighborhoods. (3) More exterior e-cig advertising at retailers in neighborhoods with the most, compared to the least, Black residents. (4) Neither e-cig promotion nor exterior e-cig advertising prevalence associated with neighborhood median household income.

Escobedo et al. (US, 2019) [37]

E-cig availability/marketing in low-income communities

Cross-sectional

Tobacco retailers

Race/ethnicity

(1) Retailers in African American, Korean American and Hispanic/Latino communities less likely to have e-cigs placed near youth-friendly items. (2) Retailers in Korean American and Hispanic/Latino communities less likely to have exterior e-cig advertising.

Emory et al. (US, 2019) [38]

Tobacco-related content exposure/channels

Cross-sectional

Adults (nationally representative)

Gender identity and sexual orientation

(1) LGBT more likely than non-LGBT to search for, share, be exposed to e-cig content in past 30 days. (2) LGBT not more likely to be exposed to anti-tobacco content in past 30 days. (3) Past 30-day e-cig ad exposure higher in LGBT smokers. (4) LGBT less likely than non-LGBT to be exposed to e-cigs on TV, more likely to be exposed on internet and social media.

Wagoner et al. (US, 2019) [39]

E-cig advertising exposure/channels

Cross-sectional

Individuals ages 13+ (nationally representative)

Age, education, sex, race/ethnicity

(1) Compared to older adults, adolescents more often exposed to e-cig ads on TV and digitally, and less often exposed in retail, radio, and print media. (2) E-cig ad exposure highest for those with some college, then those with a 4-yr degree or more, and then those with a high school diploma or less; higher among males than females; and highest for Whites, then Blacks, and then other races.

Pike et al. (US, 2019) [40]

E-cig ads and e-cig/cigarette/cigar use

Cross-sectional

High-risk youth with poor academic performance, conduct problems, and/or extenuating life circumstances

Sex

(1) Relation between ad exposure and e-cig use stronger among females than males.

Tan et al. (US, 2019) [41]

E-cig/cigarette/cigar/smokeless ad exposure

Cross-sectional

Young adults (nationally representative)

Gender identity and sexual orientation, race/ethnicity

(1) E-cig ad exposure higher for bisexual than heterosexual and lesbian women and gay and heterosexual men than men who identified as ‘something else’. (2) Controlling for covariates, no differences found between gay or bisexual men and heterosexual men. (3) E-cig ad exposure lower for heterosexual ‘other race’ than heterosexual white women and higher for bisexual Hispanic than heterosexual non-Hispanic women.

Simon et al. (US, 2018) [42]

E-cig ad exposure and use

Cross-sectional

High school students

SES

(1) Higher ad exposure for higher SES than lower SES students.

Wan et al. (US, 2018) [43]

E-cig POS ad density

Cross-sectional

Tobacco retailers

Age, race/ethnicity, SES, urban/rural

(1) Higher e-cig POS ad density in areas with lower proportion of adolescents, higher proportion of young adults, higher proportion of Hispanics, lower proportion of Whites, and higher proportion of Blacks, lower median family income, and in urban than rural areas.

Singh et al. (US, 2016) [44]

E-cig ad exposure

Cross-sectional

Mid/high school students (nationally representative)

Age, sex, race/ethnicity

(1) Higher e-cig ad exposure for students in higher grades across all ad sources. (2) Higher e-cig ad exposure on the internet and in newspapers/magazines for females than males. (3) Higher e-cig ad exposure in retail stores for Whites than Blacks and other non-Hispanic races. (4) Higher e-cig ad exposure from TV/movies for Blacks and Hispanics than Whites.

Sowles et al. (N/A, 2016) [45]

Characteristics of vaping-related Twitter

Cross-sectional

Vaping-related advertisements on Twitter

Sex, race/ethnicity

(1) Highly White and male audiences for vaporizers and e-liquid ads compared with the Twitter median average.

Baumann et al. (US, 2015) [46]

E-cig ad exposure

Cross-sectional

Hospitalized adult cigarette smokers

Race/ethnicity

(1) E-cig ad exposure higher for Whites than Blacks. (2) Increase in e-cig ad exposure over time greater for Whites than Blacks. (3) E-cig ever use related to ad exposure for Blacks but not Whites. (4) Different sources of ads for Blacks (radio, TV) and Whites (stores, internet).

Roberts et al. (US, 2015) [47]

External tobacco POS marketing

Cross-sectional

Tobacco retailers

Race/ethnicity, urban/rural

(1) Increased e-cig promotions in higher percentage African American communities. (2) Higher POS e-cig marketing in urban Columbus than rural Ohio.

Emery et al. (US, 2014) [48]

E-cig information exposure/channels

Cross-sectional

Adults (nationally representative)

Age, education, sex, gender identity and sexual orientation, race/ethnicity, SES

(1) E-cig info exposure associated with younger age, more education, male gender, and White race. (2) E-cig ad exposure not associated with LGB status or income.

Richardson et al. (US/Canada, 2014) [49]

Non-POS non-combustible product ads

Cross-sectional

Non-POS non-combustible product ads

Sex, race/ethnicity

(1) E-cig ads printed on magazines whose audiences are mainly White males, though Blu ads printed on some magazines targeting White women. (2) Ads tended to feature White males and females above those of other races.