Impact of behaviour change communication interventions on sales of fortified sunflower oil in Tanzania: A spatial-temporal analysis and association study

The Masava project was implemented in Manyara and Shinyanga regions in Tanzania to improve vitamin A intake by making available vitamin A-fortified sunflower oil with a subsidy through a mobile phone-based e-Voucher system. This study was conducted to assess the impact of the behaviour change communication (BCC) campaign of the project on volume of sales of vitamin A-fortified sunflower oil. The e-Voucher system provides real-time data on the number of e-Vouchers redeemed. The number, type, and locations of BCC events were obtained from the implementation agency. Multivariate linear regression was used to examine the associations between (a) the number and type of BCC events conducted in a ward and the volume of subsequent fortified oil redeemed in the ward and (b) distance of clinic shows, a component of the BCC campaign, from participating retailers and the volume of fortified oil redeemed in the store. After 1 year of the campaign, the volume of fortified oil redeemed monthly increased by more than 5 times in Manyara and by more than three times in Shinyanga. Among the different types of BCC events conducted, only clinic shows and cooking shows were significantly associated with the volume of redemptions (p < .05). Compared with retailers where at least one clinic show was conducted within 0.5 km from its location, the volume of redemptions was significantly lower at retailers where no clinic show conducted within 3.0 km from its location (p < .05). These findings suggest that future health promotion interventions in rural Africa should involve health clinics.