The prevalence of childhood obesity in the United States, especially among racial and ethnic minority communities with low incomes, remains consistently high and shows no signs of stabilizing. Specifically, Hispanic and Black or African American children have markedly higher rates of obesity (25.8% and 22%, respectively) compared to the national prevalence of 18.5% [1], with rates rising as age progresses, especially in African American and Hispanic children [2]. Compared to school-age children (18.4%) and preschoolers (13.9%), adolescents (20.6%) have a higher prevalence of obesity [3,4]. In the short term, obesity in youth may lead to issues such as an increased risk of elevated blood pressure and lipid concentrations, anxiety, and depression [5,6]. In the long term, adverse health conditions, including cardiovascular disease, diabetes, and disabilities, can manifest in youth who are obese and be maintained into adulthood [7-10].

Childhood obesity has been linked to several behavioral determinants, namely, increased consumption of highly processed, energy-dense foods and sugary beverages and a decreased intake of fruits and vegetables [11-13]. With the pervasiveness of daily technology and new media use in youth, particularly within the Hispanic and African American population [14], digital platforms are increasingly being used to deliver creative messaging around health and nutrition to children and their caregivers [6]. These tools, which include mobile apps and interactive websites, are emerging as promising approaches to engage and deliver tailored interventions to support health behavior change [15]. However, knowledge gaps in the usability, engagement, and usefulness of such applications still exist, limiting their potential effectiveness [16]. Furthermore, there is a shortage of effective health promotion interventions that are culturally tailored to address the needs and preferences of populations with disproportionately high rates of chronic disease. Even fewer interventions have been designed specifically for children, particularly those transitioning from childhood to adolescence [17]. It is crucial to intervene during this development stage as food preferences established during this period often persist into adulthood [18-20]. In addition, children at this age are gaining autonomy and developing decision-making skills related to dietary behaviors [21], which highlights the importance of intervening at this critical period.

The primary purpose of this pilot study was to assess the feasibility and participant acceptability of Intervention INC (Interactive Nutrition Comics for Urban, Minority Preadolescents), an interactive, web-based health promotion tool. In addition, this study aimed to explore tool effectiveness by determining if it improved attitudes, beliefs, and behaviors related to obesity. Taken together, these data will provide insight for further improvements to the tool and reveal user preferences, which is important feedback for developing culturally tailored, effective, and engaging digital tools, particularly for populations at risk for childhood obesity.

The Intervention INC study was a pilot, 2-group randomized controlled trial (RCT) that evaluated a 6-week intervention promoting fruit, vegetable and water consumption, with a 3-month follow-up (T4) period. A protocol for this feasibility trial was published and registered with the Clinical Trials Registry (NCT03165474) [22]. Parent-child dyads were randomized into either the experimental or comparison group, with both child and parent participants blinded to their assigned group. Details regarding the randomization process are provided in the protocol paper [22].

Children residing in New York City (NYC) were recruited based on the following inclusion and exclusion criteria: self-identified as Black, African American, or Latino; aged between 9 and 12 years (preadolescents) at the time of scheduled baseline (T1) visit; read and spoke in English; had a BMI percentile ≥5% at T1 (categorized as healthy, overweight, or obese); had regular internet access via a tablet device, mobile phone, or computer or laptop; had regular access to a phone with texting capability; was comfortable reading or viewing material on electronic devices; was comfortable speaking with study staff about thoughts or experiences while participating in the study; had no allergies, food aversions, food disorders, or medications with side effects that may impact participation in the study; did not have a pacemaker or heart condition; and had a legal parent or guardian willing to participate in the study. While parents or guardians were a part of this study, the focus of this paper is to present primary outcome data for the child participants.

Multiple recruitment approaches were implemented between August and November 2017. Initially, mailings were sent to parents or guardians of potentially eligible child patients of a community-based clinic (partnering organization) in Harlem, NYC. Recruitment efforts were expanded to include community flyers in East Harlem and Upper Manhattan as well as posting notices in and around local businesses, housing complexes, community centers, schools, and churches. Through partnerships with local schools and community initiatives, recruitment efforts also occurred via tabling at community and school events. Further details regarding study recruitment and sample size considerations are included in other publications [22,23].

Content for the child participants, regardless of group assignment, was tailored (to include more information related to either fruit and vegetable or water) based on responses to initial screening questions, at T1, related to child fruit, vegetable and water intake, child self-efficacy to increase fruit, vegetable and water intake, and parent self-efficacy to support the child in increasing fruit, vegetable and water intake.

All study activities were approved by the Institutional Review Board at Hunter College in New York, New York (2015-0547). Participation was entirely voluntary, and study participants could choose to withdraw from the study, without any reason, at any point in time during the study. Informed consent, child assent and parental permission were obtained before study participation. Both child and parent participants were compensated. Children received up to US $70 and parents or guardians received up to US $65 (in the form of gift cards) for completing data collection. To maintain participant privacy and confidentiality, all study data have been deidentified.

A total of 89 child-parent dyads were recruited and completed T1 measures. There were no differences in characteristics between the 2 groups. The mean age of child participants was 10.38 (SD 1.03) years; the majority were female (54/89, 61%), Black or African American (42/89, 47%) or Hispanic (29/89, 33%), and overweight or obese (47/89, 53%). The mean age of parent participants was 40.83 (SD 8.87) years; nearly all were female (84/89, 94%), born in the United States (63/89, 71%), with some college education or more (61/89, 68%), and single (40/89, 45%). One-third (30/89, 34%) of the dyads reported an annual household income of <US $20,000, and nearly two-thirds (54/89, 61%) reported receiving Supplemental Nutrition Assistance Program benefits. Refer to Table 3 for additional demographic details. The CONSORT (Consolidated Standards of Reporting Trials) diagram (Figure 1) shows the randomization and retention progress throughout the study. Retention rates were high: T2, 87% (77/89); T3, 89% (79/89); and T4, 84% (75/89) [23].

The primary purpose of this study was to assess the feasibility and participant acceptability of an interactive, web-based comic tool. In addition, this study explored the tool’s potential impact on dietary behaviors, related psychosocial variables, and BMI-for-age percentile.

There was a decline in use of the digital tool (in both groups) over the 6-week intervention period. While direct comparisons are difficult due to the lack of standardization in how engagement has been defined and measured in previous research [44], low to moderate engagement and a decline in use as an intervention progresses are commonly reported [45-47]. This is concerning given that engagement is critical to the effectiveness of digital health interventions [48]. This was a key consideration during the design process for our tool as we used user-centered design principles throughout the development process [49], with the goal of ultimately developing a culturally relevant and meaningful tool. To enhance potential engagement, we incorporated interactive features into the tool, such as tap or click icons that opened pop-up windows (highlighting health facts, food-related fun facts, or character information, such as a character’s favorite healthy food and beverage).

While engagement did decline in both groups, the use data appear to support the feasibility and acceptability of the comic tool as children in the experimental group were more engaged; an average of 72% (33/45) of the experimental group accessed their tool weekly compared to 60% (27/44) of the comparison group. Furthermore, most of the children in the experimental group, who accessed the comic, actually read the complete chapter (which ranged from 18 to 34 pages) each week. In addition to a higher level of engagement, the experimental group also reported higher usability of their tool, which is an indicator of tool acceptability and satisfaction [50,51].

Other interactive features included embedded audio recordings for certain character dialogue, which also presented opportunities to deliver health messages in another format. Such a format can help with the understanding of the health messages promoted within the comic [52], particularly as low literacy levels continue to exist in our intended population [53-55]. Research has found that Black and Hispanic students begin high school with literacy skills 3 years behind those of White and Asian students [53]. In addition, students from families with low incomes enter high school with literacy skills that are 5 years behind those of students from families with high incomes [55]. Feedback from participants acknowledged the benefits of the embedded interactive features as 1 child noted that the audio effects allow the tool to read for the children, “if you don’t want to or can’t read.” Such features can also add to the immersion of the reader into the story, as studies have found that audio features can improve the manga reading experience provided it connects the reader with the objects represented in the scene [56]. This could lead to enhanced persuasion of the story’s health messages and, thus, motivate positive behavior change, as suggested by the Narrative Transportation Theory [57,58].

While several BCTs were incorporated into the digital comic tool, a key component of the tool was the goal selection and assessment activity. Research has shown that the BCT of goal setting is associated with positive health outcomes, although primarily related to BMI measures in children above a healthy weight [59]. Children in our study acknowledged that goal achievement was easier if the appropriate support was in place, which included fruit, vegetables, and water being available at home and if parental help was accessible. This highlights the importance of ensuring that healthy foods are accessible to allow the children to be empowered to make positive choices. It also reinforces the importance of engaging parents to not only be positive role models but to also provide a supportive home environment as parent-directed interventions can improve the self-efficacy of their children [60]. Prompts and cues were also included in the comic tool in the form of 4 reminder messages each week from the characters themselves. The frequency of the reminder messages was informed by formative research with our intended population, as the literature is quite limited in this area [61]. While a few children did note that they received too many, overall, the children acknowledged that the reminder function, comprising 4 texting or email messages each week was “enough” and an important feature to promote sustained engagement [61].

Secondary outcomes of this study included changes in psychosocial variables related to specific diet-related behaviors, dietary intake, and BMI-for-age percentile. Results showed that while changes in psychosocial variables for certain diet-related behaviors were observed in both the experimental and comparison groups from T1 to T3, most improvements were diminished by T4. However, improvements in intake related to fruit, vegetable, and water behaviors observed in the experimental group were maintained at T4. Furthermore, while no differences were observed in BMI-for-age percentile change between both groups from T1 to T4, a post hoc analysis found that BMI percentile tended to decrease in the experimental group for male participants and in the comparison group for female participants. The improvement in fruit, vegetable, and water intake that was maintained through the T4 period in the experimental group may partially explain the anthropometric findings observed in the male participants, as such behaviors are recommended to reduce obesity risk [62,63]. Further research is warranted to better understand the mechanisms that may have resulted in the observed trend of the decreased BMI percentile in both groups, particularly as no sustained changes were found in related psychosocial variables and no significant improvements in dietary behaviors were observed in the comparison group.

Sex differences in the BMI percentile outcome are interesting to note. Health-promoting comics have been used effectively to reach children of both genders [41,64,65]; however, in our study, it appears that male participants may have responded more positively to the comic tool. While extensive formative research was conducted with both genders from our intended population, with the goal of developing a broad-reaching, meaningful, and engaging narrative, the main character of the story was male. This may have led to unintended differences in how male and female participants responded to the health messages. Interestingly, prior research by the team found that both male and female children often selected a male character when asked who their favorite comic character was [42]; however, other research has shown that gender does play a role in how people relate and respond to media characters [43,66]. Furthermore, while we aimed to address a broad range of genres in the comic to appeal to both genders, differences in genre preferences do exist between the sexes as females tend to prefer romance, fantasy, and action, while males tend to prefer humor and action when reading comics [67].

Further research is needed to not only understand the elements that influence tool engagement but to also gain a better understanding of the comic tool’s key components that influenced the observed health-related outcomes. This pilot and feasibility study suggests that such a comic tool could be an appealing format to promote positive beliefs and behaviors related to a healthier diet in racial and ethnic minority preadolescents (particularly in male children). In addition, our study had successful recruitment and high retention with our participants [23]. Furthermore, 81% (61/75) of the children reported at T4 that they were very satisfied or extremely satisfied with their interactions with the study staff [23]. Therefore, a full-scale RCT with a longer follow-up period is warranted to determine the effectiveness of Intervention INC. However, given potential gender differences in character relatability and genre preferences, the development of future health-promoting comic tools should more carefully consider how to frame storylines and messaging to effectively impact both genders. Moreover, as newly adopted behaviors often diminish once an intervention ends [68], a maintenance intervention should be considered following the initial intervention period, as it could provide critical continued support and reinforce newly adopted behaviors. In addition, this tool’s messages mainly focused on obesity-related dietary behaviors. As physical activity is a key contributing factor to reducing obesity risk, the inclusion of a physical activity component should be considered to produce a more comprehensive tool focused on additional influences related to childhood obesity.

It is important to acknowledge that this study is not without its limitations. We were unable to capture more granular use data, such as the minutes participants used the tool itself. Self-report data are always a challenge, in particular with dietary intake data. This limitation is further exacerbated by the fact that our questionnaires, while informed by validated questionnaires commonly used in the literature [25-30], were not validated tools and were completed by the children themselves. However, it should be acknowledged that T1 and T4 data were collected in person where a research team member was present and available to answer any questions and assist the children in completing the questionnaire. Seasonality issues may be a concern with the outcome measures, as recruitment was conducted on a rolling basis over a 3-month period. Thus, some participants completed the study during the fall season, while others completed it during the spring season. Another limitation is the small sample size, thus limiting statistical power. The generalizability of these findings is also limited as the data are unique to racial and ethnic minority preadolescent children residing in underserved NYC communities. In addition, all study participants had to have ongoing access to the internet, further limiting the study’s generalizability.

This pilot and feasibility study suggests that the multimedia platform of comics could be an appealing and engaging format to promote healthy diet-related beliefs and behaviors in racial and ethnic minority, urban preadolescents at risk of childhood obesity. Furthermore, as comics are popular among US youth and can be easily disseminated, particularly in digital format, the graphics and minimal text make it a promising format for low-literacy populations. The sex differences observed in BMI percentile suggest that boys may respond more positively to health messages delivered in such a format; however, the comic’s main character (who is male) may have been more relatable to our male participants. Thus, future iterations of the comic should carefully consider the main character to ensure they are relatable to all genders. While the results are promising, further research is needed, including a full-scale RCT, to determine the effectiveness of Intervention INC.