Striking the right balance: co-designing the Health4Me healthy lifestyle digital health intervention with adolescents
Authors: Raeside Rebecca , Todd Allyson , Wardak Sara , Gardner Lauren , Champion Katrina E. , Kang Melissa , Mihrshahi Seema , Steinbeck Katharine , Redfern Julie , Partridge Stephanie R. ,   The Health Advisory Panel for Youth at the University of Sydney (HAPYUS), Valanju Radhika , Barani Meera , Mautner Dominik , Hadaya Imeelya Al , Cross Alexi , Gunawardana Melani , Lambie Ava , McMahon Emily , Narula Arnav , Ren Bowen , Rose Dominique , Sharda Aviral , Sinnett Alexander , Tanvir Azman , Yan Fulin ,   The Health4Me Team, Hyun Karice , Hackett Maree L. , Figtree Gemma , Gallagher Robyn , Spielman Karen , Maguire Sarah , Sim Kyra A. , Usherwood Tim , Hepse Charlotte , Skinner John , Laranjo Liliana , Williams Kathryn , Castles Danielle 
Published: December 2023

Abstract
Background
Adolescents are navigating a period of rapid growth and development within an era of digitalization. Mobile phone ownership among adolescents is nearly ubiquitous, and this provides an opportunity to harness text messaging to promote a healthy lifestyle and reduce chronic disease risk factors. Inclusion of adolescents throughout the design process has been recognized as essential for engagement and future implementation of such interventions. This study aimed to co-design a bank of text messages to promote a healthy lifestyle which are useful, acceptable, and engaging for adolescents aged 12–18 years old.

Methods
Iterative, mixed-methods design with consumer partnership. Co-design occurred over three stages: text message development, text message review and final refinement and testing. The text message development included literature searches and consumer partnership with an established youth advisory group (n = 16). Participants who gave e-consent participated in text message review. Demographic characteristics were collected, and quantitative surveys were distributed to adolescents (n = up to 50) and health professionals (n = up to 30), who rated text message content for understanding, usefulness and appropriateness (total score out of 15). Final refinement was completed by the research team to edit or remove messages which had low scores and to assess readability and interactivity of the text messages.

Results
The Heath Advisory Panel for Youth at the University of Sydney (HAPYUS) identified the top six lifestyle health issues for young people today in relation to chronic disease prevention, which became the key content areas for the text message bank and drafted new text messages. Following text message development, 218 messages were available for review. Adolescents (n = 18, mean age 16.3 [SD 1.4]) and healthcare professionals (n = 16) reviewed the text messages. On average, all reviewers found that the text messages were easy to understand (mean = 13.4/15) and useful (mean = 12.7/15). Based on scoring and open ended-feedback, 91 text messages were edited and 42 deleted. The final text message bank included 131 text messages. The overall program is suitable for a seventh-grade reading level, and interactive.

Conclusions
This study describes the process of effectively engaging adolescents to co-design a text message bank intervention, which are useful, acceptable and engaging for an adolescent audience. The effectiveness of the co-designed text message bank is currently being tested in the Health4Me RCT.