Effects of a Short Mobile Intervention on Digital Health Literacy in Adolescents and Teachers: Randomized Controlled...

Digital health literacy is an essential skill for processing health-related information in today's technology-driven society. Recent literature highlights deficits in digital health literacy among adolescents and legislative initiatives to secure its promotion have been introduced (eg, in the German Social Code Book V). However, few interventions target adolescents; existing programs often overlook critical aspects like graph literacy or lack applicability in schools and rigorous scientific evaluation. To overcome these limitations, short mobile interventions-optimized for mobile devices and flexible deployment in schools-were developed to promote digital health literacy.

This study aimed to evaluate the effectiveness of one of these interventions (focusing on graph-based health information) and to assess its quality and applicability within educational settings as a proof-of-concept for the further development of similar interventions for adolescents.

A randomized-controlled pre-post trial with an active control group was conducted across two independent samples in a web-based survey: adolescents in secondary schools (14-17 years) and teachers. Participants in each sample were randomly assigned (1:1 allocation) to the experimental or control group. Following baseline data collection (T1), participants completed their assigned interventions, immediately followed by postassessments (T2). The experimental intervention is a mobile-friendly e-learning module (approximately 10 minutes) featuring interactive tasks focused on interpreting graph-based health information. The control intervention followed the same design and logic but covered a different topic. The primary outcome was subjective knowledge regarding the intervention's topics. Secondary outcomes included objective knowledge (quiz scores) and 2 adapted subscales of the Digital Health Literacy Instrument (DHLI: "evaluating reliability" and "determining relevance"). Educational quality, visual aesthetics, and practical applicability were also assessed at T2.

Among adolescents (experimental group: n=251; control group: n=249), a significant interaction effect was observed only for objective knowledge (F_1,498=70.42, η²_p=.124; P<.001), but not for the other three outcomes (subjective knowledge: F_1,498=2.04, η²_p=.004; P=.15; evaluating reliability: F_1,498=0.28, η²_p<.001; P=.60; determining relevance: F_1,498=0.25, η²_p<.001; P=.62), meaning that the intervention improved fact-based but not subjective knowledge and no broader health literacy related skills. For teachers (experimental group: n=301; control group: n=302), the results showed significant interaction effects for subjective knowledge (F_1,601=32.42, η²_p=.051; P<.001), objective knowledge (F_1,601=128.79, η²_p=.177; P<.001), and one facet of digital health literacy (evaluating reliability: F_1,601=6.21, η²_p=.010; P=.01), while the interaction effect for "determining relevance" was not significant (F_1,601=1.97, η²_p=.003; P=.16), suggesting that the intervention improved teachers' knowledge and one facet of digital health literacy. Both samples evaluated the visual and educational quality of the intervention as positive.

This study demonstrates that short mobile interventions hold significant promise for the promotion of digital health literacy (eg, graph literacy) within school environments. These interventions can effectively teach objective knowledge to adolescents and teachers, but improving their digital health literacy may require more comprehensive or multimodule approaches.

German Clinical Trials Register DRKS00037830; https://drks.de/search/de/trial/DRKS00037830/details.