The objective of this study is to determinate the factors that mediate in the self-reported consistent condom use over the 24-months post-intervention period in adolescents who received COMPAS, a sexual health promotion intervention targeted to Spanish adolescents. Twelve high schools located in Spain were randomized to an intervention or a control group with baseline, immediate-post, 12 and 24-month post-intervention assessments. Self-reported consistent condom use by 24 months post-intervention was the primary outcome. Based on the theory of planned behavior, we identified which theory-based variables mediated the intervention's effect on consistent condom use. Serial multiple mediation analysis indicated that attitudes toward condom use, when there are obstacles to use it, and self-efficacy mediated the COMPAS's effect in increasing consistent condom use. This is the first study that identifies the theoretical constructs that mediate the efficacy of a school-based intervention to promote sexual health in adolescents from Spain.
Keywords: Adolescents; Consistent condom use; Mediation analysis; Sexual health promotion intervention; Theory of planned behavior.