title: Effective Strategies to Recruit Young Adults Into the TXT2BFiT mHealth Randomized Controlled Trial for Weight Gain Prevention.
abstract: BACKGROUND
  Younger adults are difficult to engage in preventive health, yet in Australia they are gaining more weight and increasing in waist circumference faster than middle-to-older adults. A further challenge to engaging 18- to 35-year-olds in interventions is the limited reporting of outcomes of recruitment strategies.
  
  
  OBJECTIVE
  This paper describes the outcomes of strategies used to recruit young adults to a randomized controlled trial (RCT), healthy lifestyle mHealth program, TXT2BFiT, for prevention of weight gain. The progression from enquiry through eligibility check to randomization into the trial and the costs of recruitment strategies are reported. Factors associated with nonparticipation are explored.
  
  
  METHODS
  Participants were recruited either via letters of invitation from general practitioners (GPs) or via electronic or print advertisements, including Facebook and Google-social media and advertising-university electronic newsletters, printed posters, mailbox drops, and newspapers. Participants recruited from GP invitation letters had an appointment booked with their GP for eligibility screening. Those recruited from other methods were sent an information pack to seek approval to participate from their own GP. The total number and source of enquiries were categorized according to eligibility and subsequent completion of steps to enrolment. Cost data and details of recruitment strategies were recorded.
  
  
  RESULTS
  From 1181 enquiries in total from all strategies, 250 (21.17%) participants were randomized. A total of 5311 invitation letters were sent from 12 GP practices-16 participating GPs. A total of 131 patients enquired with 68 participants randomized (68/74 of those eligible, 92%). The other recruitment methods yielded the remaining 182 randomized participants. Enrolment from print media was 26% of enquiries, from electronic media was 20%, and from other methods was 3%. Across all strategies the average cost of recruitment was Australian Dollar (AUD) $139 per person. The least expensive modality was electronic (AUD $37), largely due to a free feature story on one university Web home page, despite Facebook advertising costing AUD $945 per enrolment. The most expensive was print media at AUD $213 and GP letters at AUD $145 per enrolment.
  
  
  CONCLUSIONS
  The research indicated that free electronic media was the most cost-effective strategy, with GP letters the least expensive of the paid strategies in comparison to the other strategies. This study is an important contribution for future research into efficacy, translation, and implementation of cost-effective programs for the prevention of weight gain in young adults. Procedural frameworks for recruitment protocols are required, along with systematic reporting of recruitment strategies to reduce unnecessary expenditure and allow for valuable public health prevention programs to go beyond the research setting.
  
  
  BACKGROUND
  Australian New Zealand Clinical Trials Registry (ANZCTR): ACTRN12612000924853; https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=362872 (Archived by WebCite at http://www.webcitation.org/6YpNfv1gI).
authors.affiliation: School of Molecular Bioscience, The University of Sydney, Sydney, Australia. stephanie.partridge@sydney.edu.au.
authors.forename: Stephanie R
authors.identifier: http://orcid.org/0000-0001-5390-3922
authors.initials: SR
authors.lastname: Partridge
authors.forename: Kate
authors.identifier: http://orcid.org/0000-0002-3653-3963
authors.initials: K
authors.lastname: Balestracci
authors.forename: Annette Ty
authors.identifier: http://orcid.org/0000-0002-0919-330X
authors.initials: AT
authors.lastname: Wong
authors.forename: Lana
authors.identifier: http://orcid.org/0000-0003-1017-5827
authors.initials: L
authors.lastname: Hebden
authors.forename: Kevin
authors.identifier: http://orcid.org/0000-0002-9679-9827
authors.initials: K
authors.lastname: McGeechan
authors.forename: Elizabeth
authors.identifier: http://orcid.org/0000-0001-9879-4969
authors.initials: E
authors.lastname: Denney-Wilson
authors.forename: Mark F
authors.identifier: http://orcid.org/0000-0002-0705-8913
authors.initials: MF
authors.lastname: Harris
authors.forename: Philayrath
authors.identifier: http://orcid.org/0000-0003-2460-5031
authors.initials: P
authors.lastname: Phongsavan
authors.forename: Adrian
authors.identifier: http://orcid.org/0000-0002-0369-4621
authors.initials: A
authors.lastname: Bauman
authors.forename: Margaret
authors.identifier: http://orcid.org/0000-0002-6478-1374
authors.initials: M
authors.lastname: Allman-Farinelli
keywords: cost; eHealth; external validity; mHealth; recruitment; weight gain prevention; young adults