In one assessment using data from the first two waves of the school-based National Longitudinal Study of Adolescent Health (Add Health), Easton et al. (2008) found that adolescents reporting sexual attractions to or relationships with both males and females, but not same-sex-only attractions/relationships, were inhibitor Regorafenib more likely than adolescents reporting only opposite-sex attractions/relationships to have smoked in the past month at the beginning of the study as well as to become smokers at follow-up 1 year later. In another study using three waves of Add Health data spanning 8 years, sexual-minority youths had higher frequency of cigarette smoking at the beginning of the study and faster increases in smoking frequency over time, compared with heterosexuals (Marshal et al., 2009).

Notable differences were observed by sexual-orientation subgroup. Mostly heterosexual and bisexual youths had higher smoking frequency initially, but similar increases in smoking frequency over time, when compared with heterosexual youths. Lesbian/gay youths were similar to heterosexual youths in their initial smoking frequency, but had a faster increase in smoking frequency over time. Similarly, findings from a longitudinal study of college students revealed that minority sexual orientation was associated with higher frequency of cigarette smoking at the beginning of the study (Talley et al., 2010). However, in contrast to Marshal and colleagues, heterosexual and sexual-minority participants had similar patterns of changes in smoking over time. This divergence may be attributable to study differences such as age (adolescence vs.

emerging adulthood). Despite advances in the use of longitudinal designs, additional research is necessary to identify sexual-minority subgroups that are most at risk for smoking. Gender has been identified as a modifier of the relationship between sexual orientation and substance use, with sexual-minority females displaying great or similar substance use compared with sexual-minority males (Corliss, Rosario, Wypij, Fisher, & Austin, 2008; Corliss et al., 2010; Hahm, Wong, Huang, Ozonoff, & Lee, 2008; Marshal et al., 2008). In contrast, studies with general youth samples typically find that males are more likely to smoke than females (Nelson et al., 2008). Some evidence suggests that age may also be an important modifier, with sexual-orientation disparities greater during adolescence compared with emerging adulthood (Corliss et al., 2010). However, not all studies have found larger disparities during adolescence. A study of Asian Americans and Pacific Islanders found sexual-orientation disparities in substance use appeared during emerging adulthood, but not in adolescence Anacetrapib (Hahm et al., 2008).