A cluster randomised controlled trial to evaluate the impact of a gender transformative intervention on intimate partner violence against women in newly formed neighbourhood groups in Tanzania

Introduction Violence against women is a global public health concern; around a quarter of women will experience intimate partner physical or sexual violence during their lifetime. We assessed the impact of a gender transformative intervention for women designed to prevent intimate partner violence (IPV).Methods We conducted a cluster randomised controlled trial in Mwanza city, Tanzania, among women in newly formed neighbourhood groups to evaluate a 10-session participatory intervention that aims to empower women, prevent IPV and promote healthy relationships. Following a baseline interview, groups were randomly assigned (1:1 ratio) to the intervention or control arm. An intention-to-treat analysis was conducted to assess the impact of the intervention on the main outcomes, assessed 24 months postintervention. These included past-year physical IPV and sexual IPV (primary); past-year emotional abuse; and acceptability and tolerance of IPV.Results Between September 2015 and February 2017, 1265 women were recruited in 66 neighbourhoods and randomly allocated to intervention (n=627 women in 33 neighbourhoods) or control (n=638 women in 33 neighbourhoods). Assessment of outcomes was completed for 551 (88%) intervention and 575 (90%) control women. Among intervention women, 113 (21%) reported physical IPV compared with 117 (20%) control women (adjusted OR (aOR) 0.98, 95% CI 0.72 to 1.33, p=0.892), and 109 (20%) intervention women reported sexual IPV compared with 121 (21%) control women (aOR 0.98, 95% CI 0.72 to 1.32, p=0.881). Intervention women reported less emotional abuse (aOR 0.74, 95% CI 0.56 to 0.98, p=0.035), and were less likely to express attitudes accepting of IPV (aOR 0.49, 95% CI 0.36 to 0.66, p