Minoritized Sexual Identity and Perceived Effectiveness of Instagram Public Health Messaging about E-cigarettes.

E-cigarette (EC) use in young adult sexual-minoritized women (SMW) is disproportionately higher than among heterosexual women and sexual-minoritized men. Public health messaging utilizing social branding, a method used to tailor health messages to one's identity, may help combat this problem. We conducted an online study with SMW (N= 457) and asked them to complete scales assessing their sexual minoritized identity affirmation and centrality. Participants were randomized to view socially branded messages discouraging EC use across three themes (general wellness, pride, health harms). Results revealed that overall lesbian, bisexual, or queer (LBQ) identity (affirmation and centrality) was significantly positively associated with perceived message effectiveness (PME) (p < .001). Identity affirmation was significantly associated with PME when controlling for identity centrality (p = .004). Interaction between identity affirmation and theme was significant (p= .02), as positive effects of identity affirmation on PME were greater when participants viewed pride-themed messages versus wellness (p= .03) or harms messages (p = .01). The findings suggest that socially branded EC prevention messages emphasizing sexual minoritized identity may be more effective for SMW with a strong connection to their LBQ identity. Future research should examine how identity and socially branded messages can impact health behaviors.