Mediation and moderation of an efficacious theory-based abstinence-only intervention for African American adolescents

Abstract

Objective: This secondary data analysis sought to determine what mediated reductions in self-reported sexual initiation over the 24-month postintervention period in early adolescents who received "Promoting Health among Teens," a theory-based, abstinence-only intervention (Jemmott, Jemmott, & Fong, 2010).

Method: African American Grade 6 and 7 students at inner-city public middle schools were randomized to 1 of 5 interventions grounded in social-cognitive theory and the theory of reasoned action: 8-hr abstinence-only targeting reduced sexual intercourse; 8-hr safer-sex-only targeting increased condom use; 8-hr and 12-hr comprehensive interventions targeting sexual intercourse and condom use; 8-hr control intervention targeting physical activity and diet. Primary outcome was self-report of vaginal intercourse by 24 months postintervention. Potential mediators, assessed immediately postintervention, were theory-of-reasoned-action variables, including behavioral beliefs about positive consequences of abstinence and negative consequences of sex, intention to have sex, normative beliefs about sex, and HIV and sexually transmitted infection (STI) knowledge. We tested single and serial mediation models using the product-of-coefficients approach.

Results: Of 509 students reporting never having vaginal intercourse at baseline (324 girls and 185 boys; mean age = 11.8 years, SD = 0.8), 500 or 98.2% were included in serial mediation analyses. Consistent with the theory of reasoned action, the abstinence-only intervention increased positive behavioral beliefs about abstinence, which reduced intention to have sex, which in turn reduced sexual initiation. Negative behavioral beliefs about sex, normative beliefs about sex, and HIV/STI knowledge were not mediators.

Conclusions: Abstinence-only interventions should stress the gains to be realized from abstinence rather than the deleterious consequences of sexual involvement.

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Figures

Figure 1

Flow of participants through the Promoting Health among Teens (PHAT) trial.

Figure 2

Serial mediation model of the effect of the abstinence-only intervention on theoretical variables and self-reported sexual initiation by the 24-month follow-up among African American adolescents estimated using structural equation modeling. All paths to self-reported sexual initiation are unstandardized coefficients (SE) from probit regression; all other paths are unstandardized coefficients (SE) from linear regression. *p < .05, **p < .0001.