Women’s Relationship Power Modifies the Effect of a Randomized Conditional Cash Transfer Intervention for Safer Sex in Tanzania

This study tests whether women’s relationship power modifies the effect of a conditional cash transfer (CCT) on STI risk. We analyzed 988 women enrolled in the RESPECT study in Tanzania, a yearlong, randomized-controlled trial testing the effectiveness of a CCT to reduce STI incidence. Women were randomized at the individual level to a no-cash control group, a low-cash, or a high-cash study arm. After one year, there was no main effect of study arm on risk of having an STI among women. However, in tests of heterogeneity, the effect of the CCT varied by a woman’s relationship power (adjusted RRs of the interaction term for women with higher relationship power: RR 0.567 (95% CI 0.240–0.895) for high cash and RR 1.217 (95% CI 0.794–1.641) for low cash). Specifically, women with higher relationship power in the low cash transfer arm had an elevated risk of testing positive for an STI, whereas women with high relationship power in the high cash transfer arm had a decreased risk of testing positive for an STI.