Influencers, not just adverts: social media influencer exposure and tobacco use among urban youth in Kampala and Nairobi - a comparative mixed methods study

Tobacco control treaties were written for billboards and television, not for the people now selling lifestyles to young Africans. As mobile internet saturates East African cities, social media influencers have become an unmeasured channel, especially when it comes to tobacco promotion. We assessed the prevalence of tobacco use, its association with influencer exposure, and how urban youth interpret that exposure in two capitals with different tobacco laws. We conducted a comparative mixed-methods study among youth aged 18-29 years in Kampala, Uganda, and Nairobi, Kenya (January-August 2025), combining (i) a cross-sectional survey using systematic sampling at youth-dense venues (n=772), (ii) four online focus group discussions (FGDs; n=40), and (iii) content analysis of 30 tobacco-related posts from high-reach influencers (greater than 50,000 followers). We used chi-square tests and multivariable logistic regression, thematic analysis (Braun and Clarke), and descriptive engagement metrics. Ever tobacco use among urban youth in East Africa was 29.3% (226/772), similar in Kampala (30.7%) and Nairobi (28.0%; p=0.409). After adjustment, exposure to influencers promoting tobacco independently predicted ever use (adjusted odds ratio [aOR] 1.90, 95% confidence interval [CI] 1.29-2.82; p=0.001), alongside male sex (aOR 2.35) and age 26-29 years (aOR 1.99). Tertiary education (aOR 0.45) and never seeing tobacco content (aOR 0.26) were protective. Posts framed tobacco as aspirational lifestyle; 77% of sampled comments were positive and 47.5% expressed interest in trying the product. Influencer exposure behaved as a modifiable risk factor of a magnitude comparable to established demographic drivers. Tobacco control in the region must move from print-era advertising bans to platform governance, mandatory disclosure of paid promotion, and youth-led counter-marketing.