Recruitment and retention of mothers of preschoolers and school-aged children in a social media-delivered healthy eating intervention: lessons learned from a randomized controlled trial

BACKGROUND: Social media represent cost-effective platforms to advance the dissemination and uptake of health research to improve population health. However, there is limited evidence available to support researchers overcome methodological challenges related to recruitment and retention of participants in studies using social media for delivering behavior change interventions. This study aims to describe the recruitment and the retention strategies used in a randomized controlled trial (RCT) that evaluated a blog-delivered healthy eating intervention among mothers of preschoolers and school-aged children. METHODS: Eighty-four adult mothers of children aged between two and 12 years old living in Quebec City, Quebec, Canada, were recruited between October 2015 and February 2017 using traditional methods (e.g. institutional email lists, flyers, newspapers, and word of mouth) and Facebook advertisements. Retention rates were calculated at the end of the 6-month intervention and at a 12-month follow-up assessment. Sociodemographic characteristics, Internet use behaviors and retention rates of mothers recruited through traditional methods and Facebook were compared using Wilcoxon-Mann-Whitney tests and Fisher exact tests. RESULTS: Of the 196 mothers who responded to the recruitment call, 87 (44.4%) were eligible and 84 (42.9%) were randomized to the trial, representing a recruitment success of 76.4% (84/110) from the planned sample size target. Among those, a minority (3.6%) were recruited using Facebook. Those mothers presented similar sociodemographic characteristics to those recruited using traditional methods. Retention rates were 73.8% and 66.7% at 6 and 12 months, respectively, with similar rates between mothers recruited using Facebook and traditional methods. Various challenges associated with population retention were highlighted with lack of time being mothers’ main reason for withdrawing from the study. CONCLUSIONS: The methodological challenges experienced during the conduct of the blog-delivered healthy eating intervention allowed to draw upon several lessons regarding the recruitment process and the retention of mothers of preschoolers and school-aged children to inform future social media-delivered research. Recommendations for future research include exploring mothers’ perceptions and preferences to tailor social media recruitment, ensure that interventions are delivered to them using social media platforms that are already integrated into their routine, and are providing remote outcome assessments to increase participant retention. TRIAL REGISTRATION: Clinical Trial Protocol NCT03156803. Registered on 17 May 2017, retrospectively registered.