Optimization of an Online STI Preventive Intervention Targeting College Students

Drinking alcohol is often implicated in the sexual behaviors that increase college students STI risk. Most existing interventions target alcohol and sex separately, rather than focus on the intersection of alcohol and sexual risk behaviors. The current study presents preliminary results from itMatters, an online intervention focused at the alcohol-sex intersection with five intervention components grounded in behavioral change theories (i.e., descriptive norms, injunctive norms, expectancies, perceived benefits of protective behavioral strategies (PBS), and self-efficacy to use strategies). The first optimization trial (conducted fall 2016) indicated only injunctive norms were changed after two weeks of intervention; curriculum changes were made to the four ineffective components. This presentation will highlight preliminary results from the second optimization trial of the revised intervention (to be completed in fall 2017). Using a 2⁵ factorial experiment, the second optimization trial sought to evaluate which components were effective at ultimately decreasing alcohol use, increasing the use of PBS, and decreasing sexual risk behaviors. First-year students from 4 geographically diverse universities were recruited and randomized to 1 of 32 experimental conditions that included a combination of the aforementioned components. Of the 2,135 students who completed the baseline survey, the majority were female (65%), White (55%), heterosexual (91%), and lived on campus (59%). Most students reported past alcohol use (59%) and sex (oral, anal, and/or vaginal; 54%). Among those who had had sex, 44% reported using alcohol prior or during their most recent sexual encounter and 35% did not use a condom at their most recent vaginal sex. Among the 31% of students who reported a hookup, 22% used alcohol prior or during their most recent hookup and 36% did not use a condom for vaginal sex. The effect of the intervention on descriptive norms, injunctive norms, expectancies, perceived benefits of PBS, and self-efficacy to use strategies will be presented. The complete results from this optimization trial and the iterative approach to overall study design will be discussed in the context of the multiphase optimization strategy (MOST).