Flavored combustible tobacco product initiation in two longitudinal youth cohorts in the US Population Assessment of Tobacco and Health Study: 2013–2016 and 2016–2019

•Two representative US youth cohorts each with three annual waves of data.•Compares flavored and non-flavored initiation of combustible tobacco products (CTPs).•Baseline social media use associated with flavored CTP initiation.•Vaping and Black racial identity negatively associated with flavored CTP initiation. Flavored tobacco products increase appeal and lower barriers to nicotine addiction for young people. We compared environmental, psychosocial, behavioral, and demographic characteristics between youth who started with flavored and non-flavored (i.e., tobacco-flavored) combustible tobacco products (CTPs). We analyzed two representative US youth cohorts (baseline age 12–15) from the Population Assessment of Tobacco and Health (PATH) Study (Wave 1 Cohort (W1) 2013–2016; Wave 4 Cohort (W4) 2016–2019). We first assessed baseline characteristics associated with any subsequent CTP initiation among youth with baseline never CTP use (W1 n=5,946; W4 n=8,240). Then, for baseline CTP-naïve youth with subsequent CTP initiation (new experimentation; W1 n=519; W4 n=538), we assessed baseline characteristics associated with subsequent initiation with flavored CTPs versus non-flavored. Most youth reporting new CTP experimentation initiated with flavored CTPs (W1:67.8%; W4:74.2%). Household norms, susceptibility, baseline experimentation with vaping, alcohol, and/or cannabis; and White race were associated with CTP experimentation. For both cohorts, frequent social media use was associated with flavored CTP initiation (W4 AOR:2.50, 95%CI:1.22,5.12) and Black youth (W4 AOR:0.12, 95%CI:0.06,0.25) were less likely to initiate with flavored CTPs than White youth. Among W1 Cohort youth, perceiving flavored product use as easier was positively associated with flavored CTP initiation (AOR:1.48, 95%CI:1.01,2.17). Among W4 Cohort youth, baseline vaping was negatively associated with flavored CTP initiation (AOR:0.10, 95%CI:0.05,0.20). Frequent social media use was associated with flavored CTP initiation among youth who used CTPs. Youth who had ever vaped and Black youth were less likely to initiate with flavored CTPs.