Examining sexual identity stability and change over time and associations with tobacco use in a nationally representative US sample

•This study examined change in sexual identity over three years.•Individuals coming out as a sexual minority had greater odds of tobacco outcomes.•Those with multiple changes in sexual identity had greater odds of tobacco outcomes.•Gay-stable men had lower odds of increasing tobacco use disorder symptoms.•Coming out as a sexual minority may be a particularly vulnerable period for tobacco use. Epidemiologic research has found sexual minority identifying individuals are disproportionately burdened by tobacco use and tobacco use disorder (TUD). However, these studies often conceptualize sexual identity as time-invariant. This study examined sexual identity over time and whether a transition to a sexual minority identity was associated with tobacco outcomes. This study used data from Waves 1–4 of the Population Assessment of Tobacco and Health (2013/14–2016/18) study (adolescents and adults aged ≥ 14 years; n = 26,553). We examined associations of sexual identity stability and change with changes in the number of tobacco products used and TUD symptoms. Males and females who experienced two or more changes in sexual identity and females who changed from a heterosexual to a sexual minority identity were more likely to have an increase in two or more tobacco products and increase TUD symptoms compared to heterosexual-stable males and females. Gay-stable males were less likely to increase TUD symptoms compared to heterosexual-stable males. Experiencing a change in sexual identity may be a particularly vulnerable period for increases in tobacco products used and TUD. It may be important to provide tobacco use intervention and support resources to individuals coming out as a sexual minority and those fluid in their sexual identity.