Virtual prevention of eating disorders in children, adolescents, and emerging adults: a scoping review

Background During the COVID-19 pandemic, there was a necessity for eating disorder (ED) outpatient treatment to be delivered virtually. Given this transition, and the surge in new ED cases, there was an urgent need to investigate virtually delivered ED prevention programs. This review aimed to identify the available evidence on virtual ED prevention programs for children, adolescents, and emerging adults. Method Using scoping review methodology, seven databases were searched for studies published from January 2000 to April 2021 reporting on virtually delivered ED prevention interventions for children and adolescents (< 18 years) and emerging adults (18–25 years). Studies were excluded if they contained adults (> 25 years) and individuals with clinical ED diagnoses. Abstracts and full-text papers were reviewed independently by two reviewers. Data was extracted on study type, methodology, age, sample size, virtual intervention, outcomes, and results. In April 2022, we used a forward citation chaining process to identify any relevant articles from April 2021 to April 2022. Results Of 5129 unique studies identified, 67 met eligibility criteria, which included asynchronous (n = 35) and synchronous (n = 18) internet-based programs, other e-technology including mobile apps (n = 3) and text messaging interventions (n = 1), computer-based programs (n = 6), and online caregiver interventions focused on child outcomes (n = 4). Few studies mainly included children and adolescents (n = 18), whereas the vast majority included emerging adults (n = 49). For children and adolescents, the most widely researched programs were Student Bodies and its adapted versions (n = 4), eBody Project (n = 2), and Parents Act Now (n = 2). For emerging adults, the most widely researched programs were Student Bodies and its adapted versions (n = 16), eBody Project (n = 6) and Expand Your Horizon (n = 4). These interventions were effective at reducing various symptoms and ED risk. Some studies demonstrated that virtual prevention intervention efficacy resembled in-person delivery. Conclusion Virtual prevention interventions for EDs can be effective, however more research is needed studying their impact on children and adolescents and on improving access for vulnerable groups. Additional efficacy studies are required, such as for text messaging and mobile app ED prevention interventions. Evidence-based recommendations for virtual ED prevention for children, adolescents, and emerging adults at-risk for EDs should be prioritized. Supplementary Information The online version contains supplementary material available at 10.1186/s40337-022-00616-8.


Introduction
Eating disorders (EDs) cause significant impairment in mental and physical health-related quality of life, [1] and are potentially life-threatening, as they have one of the highest mortality rates of all psychiatric illnesses [2]. Known for being complex, chronic, and difficult to treat, especially if treatment is not pursued within the first three years of symptom onset [3], ED prevention interventions are warranted-particularly among vulnerable youth. Initial ED prevention programs were mostly psychoeducational, integrated into health curriculums, and taught in classroom settings, but no meaningful impact on ED risk factors was demonstrated [4]. After decades of research, it is now known that the most effective preventative interventions for EDs are multi-sessional and interactive, target high-risk individuals, and focus on specific risk factors for EDs, such as body dissatisfaction and thin-ideal internalization [5]. As technology has evolved, ED prevention programs followed suit, being delivered virtually as well as in-person. Past systematic review and meta-analysis research examined e-therapy and other e-mental health interventions for the prevention and treatment of EDs, with evidence suggesting virtually delivered programs can be effective in reducing ED risk factors and symptoms, such as shape/weight concerns, dietary restraint, ED psychopathology, drive for thinness, and thin-ideal internationalization; however, the reviews included a mix of youth and adult populations [6,7]. A specific focus on virtual prevention for EDs among youth is warranted, especially during the COVID-19 pandemic.
During the COVID-19 pandemic, there has been a dramatic increase in the number of youth suffering from EDs (particularly Anorexia Nervosa) and requiring hospitalization [8]. Waitlists for outpatient treatment have nearly doubled, and programs are struggling to accommodate the growth in new ED cases [9]. To follow social distancing regulations, outpatient ED treatment around the world rapidly transitioned to virtual delivery. Our team recently published virtual care recommendations for children, adolescents, and emerging adults during the COVID-19 pandemic and beyond [10]; however, these did not include recommendations for virtual prevention for EDs. With the transition to predominantly virtual outpatient treatment delivery, as well as the surge in new ED cases among youth, it is imperative to evaluate and implement evidence-based, virtually delivered ED prevention programs.
The main aims of this scoping review were to identify the types of available evidence on virtual ED prevention programs for youth, specifically child, adolescent, and emerging adult populations, to summarize best practices in virtual prevention offerings, as well as to identify knowledge gaps in this field, prior to and during the COVID-19 pandemic.

Overview
Given the aims of our study, we used scoping review methodology [11][12][13][14] to ensure we collated a variety of evidence on virtual prevention for EDs for children, adolescents, and emerging adults as well as to identify any knowledge gaps.
This review followed the five stages outlined in the Arksey and O'Malley scoping review framework [11]: impose any language restrictions. The searches contained a combination of keyword and subject headings for each concept. The sample search strategy included, but was not limited to, various combinations of the following terms as appropriate for the research question: disordered eating OR body dissatisfaction OR eating concerns OR shape concerns OR weight concerns OR dietary restraint AND virtual prevention OR internet-based prevention OR computer-based prevention OR virtual self-help OR virtual psychoeducation. The references of relevant articles obtained were also reviewed. Please see Additional File 1 which contains our full search strategy.

Forward citation chaining
In April 2022, we used a forward citation chaining process to search each included article to see if it had been cited by any additional articles since April 2021 up until April 2022. We then screened the newly found articles to decide whether to include them. The forward chaining process involved the use of Google Scholar to locate all articles citing our included articles from the primary search.

Stage 3: study selection
Two authors independently screened the results generated by our searches and came to consensus on which studies met eligibility criteria. We used Endnote and DistillerSR software to organize our studies. Duplicate records were removed. DistillerSR was used for article screening and data extraction. Titles and abstracts were used to exclude obviously irrelevant reports by the two reviewers. Potentially relevant articles were reviewed in full text by two reviewers who had to agree on inclusion. Articles in other languages were translated into English using Google Translate (n = 2). References of included reviews and book chapters were examined to find other potentially relevant studies. If agreement on abstract or full article inclusion could not be reached between the two reviewers, an opinion was requested from a third reviewer. There were no disputes.

Stage 4: data charting process
A data-charting electronic form developed using Dis-tillerSR was jointly developed by two reviewers to determine which variables to extract. Two authors independently extracted data, while continuously updating the data-charting form as needed. We extracted the following data items: general data (title, year of publication, author's name), type of paper, methodology, mean/ median age, sample size, description of virtual intervention, outcomes, and results. In line with standard scoping review practice and methodology, we did not perform a formal critical appraisal of primary studies [18,19].

Step 5: summarizing results
The results were organized under the following categories of prevention: asynchronous internet-based programs, synchronous internet-based programs, other e-technology (e.g., mobile apps, text messages), computer-based programs, and online caregiver prevention interventions focused on child outcomes.
We reported the review following the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines-extension for scoping review [20].

Characteristics of included studies
Five thousand, seven hundred and thirteen abstracts were identified for review (see PRISMA flow diagram, Fig. 1). Seven were added with forward citation chaining up to April 23, 2022, and two more through reference list review. After duplicates were removed, abstracts were screened, where any disagreements went forward to be reviewed. Of the 253 full-text articles reviewed, 67 papers were included in our scoping review. Of these 67 papers, 58 (87%) were initially agreed upon for inclusion by the two authors at the full-text screening stage; disagreements were resolved during a consensus meeting.

Asynchronous internet-based prevention Body functionality programs
Emerging adults Three randomized controlled trials (RCTs) examined participants randomized to Expand Your Horizon (total n = 233), versus a control group (total n = 222) [21][22][23]. At post-test and/or 1-week follow-up, intervention participants had greater appearance satisfaction, body esteem, and body appreciation versus controls [21,23], which were also maintained at 1-month followup [22]. In an adapted version of Expand Your Horizon, both intervention (n = 72) and active control (n = 63) participants had improvements in weight bias internalization, functionality appreciation, and self-compassion at follow-up, but effects were significantly stronger for the intervention group [24] (Table 1).
One RCT studied young women completing a comparable body functionality program (n = 54) versus a stress management program (n = 63), where the body functionality program participants had significantly greater improvements in their appearance satisfaction and body appreciation compared to those in the stress management program [25] (Table 1).

Cognitive-behavioural programs (without discussion groups)
Children and adolescents One mixed methods study observed usability of Healthy Teens @ School, among 10 students [26]. Program usability ratings increased over time, and intervention participants reported that they would recommend the program to others with mental or physical health problems (Table 2).
One RCT studied an unguided internet cognitive behaviour therapy program for perfectionism (ICBT-P; n = 36), an unguided internet cognitive behaviour therapy for nonspecific stress management program (ICBT-S; n = 34), and a waitlist control group (n = 24) [27]. Compared to ICBT-S and controls, ICBT-P resulted in the most favourable outcomes in preventing perfectionism, ED, and depressive symptoms at 3-and/or at 6-month follow-up ( Table 2).

Cognitive-behavioural programs (with discussion groups)
Children and adolescents One open trial studied Staying Fit, where adolescents were directed to either the Healthy Habits track (BMI percentile < 85th for age and sex; n = 225) or Weight Management track (BMI percentile ≥ 85th for age and sex; n = 111) [28]. From baseline to post-intervention, BMI percentile and zBMI (standardized BMI) significantly decreased among adolescents in Weight Management. Individuals in Healthy Habits maintained their weight, and weight/shape concerns significantly decreased (Table 3).
One RCT studied Student Bodies2 (SB2; n = 40) versus usual care (n = 40) [29] and another RCT studied Student Bodies2-Binge Eating Disorder (SB2-BED, specific to Binge Eating Disorder; n = 44), versus a waitlist control (n = 43) [30]. Compared to usual care, the SB2 group had significant reductions in zBMI at post-intervention, which were maintained at 4-month follow-up, but no longer significantly different from the usual care group; ED attitudes and behaviours were not significantly improved among either group at post-intervention or follow-up [29]. Compared to waitlist controls, BMI as well as binge episodes and weight/shape concerns of SB2-BED participants significantly decreased from baseline to post-treatment and 9-month follow-up [30] (Table 3).
One RCT studied an accelerated version of Student Bodies (SB) [31]. Students were randomized to either a higher-risk, higher-motivated SB group (HRHM-only; n = 22), lower-risk or lower-motivated SB group (Otheronly; n = 30), or a SB group of HRHM and Others combined (n = 11, n = 12 respectively). From pre-to postintervention, all groups demonstrated improvements (e.g., reduced weight and shape concerns) ( Table 3).
Emerging adults Seven RCTs [32][33][34][35][36][37][38] and one crosssectional study [39] studied Student Bodies (SB) among young adult females. In four RCTs, SB participants (total n = 304) demonstrated significant improvements in weight/shape concerns, from pre-post-intervention and maintained at follow-up, compared to waitlist controls (total n = 314), specifically among high-risk subgroups [32,33,35,37]. Two RCTs compared SB with moderated (total n = 88) and/or unmoderated (total n = 14) discussion groups, to SB with no discussion groups (total n = 91), concluding that moderation of discussion groups may not be essential for successful outcomes [34], but that including a discussion group with SB significantly reduced weight/shape concerns from pre-to post-intervention, compared to SB without a discussion group [38]. When compared to an in-person ED psychoeducational class (n = 25), highrisk SB participants (n = 27) in one RCT significantly reduced weight/shape concerns to a greater extent at post-intervention and at 4-month follow-up [36]. A cross-section of a previous RCT [33] found increased participation in and utilization of the SB program predicted some improvements in ED behaviours [39] ( Table 4). Full-text arƟcles excluded, with reasons N = 186 One RCT [40] determined that SB + (variation of SB) participants (n = 51) significantly improved in ED-related attitudes versus waitlist controls (n = 52) at 6-month follow-up, however a subsequent study [41] found SB + effects on ED pathology were weaker for participants with higher baseline purging and restrictive eating. One RCT studied another adapted version of SB (Image and Mood; n = 91), versus waitlist controls (n = 94), and among those with the highest shape concerns at baseline, ED onset rate was significantly lower in the intervention group (20%) compared to controls (42%) at 2-year follow-up [42]. One pilot RCT studied Student Bodies-Eating Disorders (SB-ED), and found SB-ED (n = 14) significantly reduced eating-related psychopathology, weight concerns, and psychosocial impairment, versus waitlist controls (n = 27) from pre-to post-intervention [43]. In a pilot open trial testing Student Bodies-Anorexia Nervosa (SB-AN), intervention completers demonstrated significant improvements in disturbed eating attitudes and behaviours at post-intervention (n = 32) and maintained at 6-month follow-up (n = 26) [44] (Table 4).
Three meta-analyses reported similar results of SB and its adapted versions, highlighting the effect of the interventions in significantly decreasing body dissatisfaction, thin-ideal internalization, ED symptoms, and weight/shape concerns at post-intervention and various Table 2 Cognitive-behavioural programs (without discussion groups) for children and adolescents (< 18 years) RCT randomized controlled trial, SUS system usability scale, ICBT-P internet cognitive behaviour therapy program for perfectionism, ICBT-S internet cognitive behaviour therapy for nonspecific stress management program, CBT cognitive behaviour therapy, CPQ clinical perfectionism questionnaire, EDE-Q eating disorder examination questionnaire, RCADS revised children's anxiety and depression survey, RSES Rosenberg self-esteem scale, ED eating disorder     in SB, n = 12 in control), achieving significantly better changes from preto post-intervention and sustained at 3-month follow-up weight/shape concerns and knowledge test with larger effect sizes than for total group

Results
Beintner et al. [46] Meta-analysis n = 10 studies (6 US and 4 Germany) n = 990 (504 SB, 486 waitlist control) SB: 8-weekly sessions of a cognitivebehavioural program with asynchronous moderated discussion group, journals, psychoeducation WCS, BSQ, EDI/EDI-2-drive for thinness, bulimia and body dissatisfaction, EDE-Q-restraint, eating concern, weight concern, shape concern At post-intervention, moderate effect sizes were found across all studies for EDI-drive for thinness, WCS, BSQ; small effect sizes for EDI-bulimia and EDE-Q-restraint, eating concern, weight concern, shape concern. At follow-up (12 weeks-12 months), a moderate effect size was found for EDI-drive for thinness and body dissatisfaction subscales, WCS, BSQ, EDE-Q restraint, shape concern subscales. Effect sizes for EDI-bulimia and EDE-Q eating concern and weight concern subscales were small. SB associated with mild to moderate improvements in ED attitudes (especially reductions of negative body image and desire to be thin); reported effects generally maintained Beitner et al. [47] Meta-analysis n = 10 studies (  follow-up times [45,46], as well as demonstrating high adherence to SB interventions across different trials, settings, and countries [47] (Table 4).

Cognitive-restructuring and gratitude intervention
Emerging adults One RCT compared three e-workbook conditions: a gratitude intervention (n = 35), a cognitive restructuring intervention (n = 28), and a control group (n = 45) [48]. The gratitude intervention outperformed the other conditions, evident through improvements such as increased body esteem and decreased body dissatisfaction from pre-to post-intervention; the cognitive restructuring intervention did not seem to provide much benefit (Table 5).

Imagery rescripting program
Emerging adults One RCT studied Body Image Rescripting (BIR; n = 28), General Image Rescripting (GIR; n = 31), psychoeducation (n = 34) and a control group (n = 25) [49]. All three active interventions had a significant impact on reducing global eating pathology and increasing body acceptance. Compared to controls, BIR participants improved in self-compassion, while those in the GIR group improved dysfunctional attitudes such as clinical perfectionism, versus controls (Table 6). Similarly, another RCT studied imagery rescripting (n = 37), cognitive dissonance (n = 35), and a control group (n = 35) [50]. Those in the imagery rescripting condition had significant improvements in body image acceptance compared to the cognitive dissonance group, and significant improvements in self-compassion and levels of disordered eating compared to control group (Table 6).

Media literacy programs
Emerging adults Two RCTs studied Media Smart-Targeted (MS-T). One RCT compared MS-T (n = 122) to a control group (n = 194), and found MS-T participants were 66% less likely than controls to develop an ED by 12-month follow-up (non-significant) [51]. Another RCT compared the same intervention and control groups, to a group completing SB (n = 98) [52]. MS-T participants had significant improvements in depression (at 6-and 12-month follow-up), internalization (post-intervention), and clinical impairment [12-month follow-up] versus SB participants (Table 7).

Self-compassion exercises
Emerging adults One RCT studied undergraduate women completing a self-compassion meditation podcast intervention (n = 40) or a waitlist control (n = 40) [53]. Compared to controls, there were significantly greater pre-post changes among the intervention group on body appearance, body surveillance, and appearance contingent-self-worth, however no significant improvements in total self-compassion or body shame/dissatisfaction were observed. A different RCT studied female college students randomized to self-compassion (n = 51), traditional expressive (n = 50) or control (n = 51) online writing exercises [54]. Contrary to the RCT described previously [53], there were significantly greater increases in self-compassion among the self-compassion writing group compared to the traditional expressive writing and control groups (Table 8).

Psychoeducation programs
Children and adolescents One RCT studied high school males (n = 39) and females (n = 86) randomized to Bodi-Mojo, (website version) or a control [55]. The intervention decreased body dissatisfaction and increased appearance esteem in females, but this was not maintained at 3-month follow-up. Compared to females, males were not as engaged in the intervention (Table 9).

Internet-based chatrooms
Children and adolescents One RCT compared My Body, My Life: Body Image Program for Adolescent Girls intervention (n = 28) to a delayed treatment control (n = 34) [56]. Among intervention completers, clinically significant improvements in body dissatisfaction, disordered eating, and depression were observed at post-intervention and maintained at 2-and 6-month follow-up. Internet-delivery was also enthusiastically endorsed (Table 10).
Emerging adults One pilot open trial found significant improvements in ED symptoms at post-intervention and 10-week follow-up, following a 7-week moderated, online chatroom program [57]. In an RCT testing the same chatroom program (but 8-weeks in duration), participants were randomized to either the chatroom (n = 28), or a waitlist control (n = 30) [58]. Like the open trial, chatroom participants showed significantly reduced body shape and eating concerns and improved self-esteem over controls at post-treatment and 10-week follow-up. In both studies, participants reported a preference for online instead of face-to-face discussions surrounding their ED-related issues (Table 11).

Dissonance-based programs
Children and adolescents One RCT studied virtual Body Project (vBP; n = 149), an expressive writing condition (EW; n = 148), and a control group (n = 149) [59]. Participants in vBP had a significantly greater reduction in ED symptoms, body dissatisfaction, and internalization of thin-ideal versus EW at post-intervention, and up to 24-months follow-up (Table 12). In another RCT, participants were randomized to eBody Project (eBP; adapted version; n = 21), or a control group (n = 128) [60], where eBP participants reported significant improvements in body dissatisfaction and restrained eating, compared to controls at 6-month follow-up (Table 12).
Emerging adults Of all synchronous internet-based prevention interventions, the eBP program was the most studied amongst young adult women, although findings were mixed. Two RCTs studied facilitator-led, in-person Body Project (BP; total n = 39), eBP (internet-based; total n = 19), educational video control (total n = 29), or educational brochure control (total n = 20) [61,62]. BP and eBP participants similarly showed greater pre-post reductions in some ED risk factors (e.g., body dissatisfaction and self-reported dieting) than both controls [61]; longer term follow-up suggests that effects faded more quickly for eBP than BP [62]. Three larger RCTs and one qualitative study investigated clinician-led BP (total n = 173), peer-led BP (total n = 162), eBP (total n = 184), or educational video control (total n = 161) [63][64][65][66]. One of these studies found significant reductions in ED risk factors (thin-ideal internalization, body dissatisfaction, negative affect), and ED symptoms in eBP participants at post-test versus controls, however, clinician-and peer-led BP groups showed significantly greater effects than eBP [65]. In a follow-up study, clinician-, peer-led, and eBP groups had larger reductions in ED risk factors and symptoms versus controls at various follow-up periods, but peer-led groups had greater improvements in some ED risk factors (e.g. body dissatisfaction) compared to eBP [63]. Another study indicated that age moderated intervention effects, such that in-person BP was superior to eBP in reducing ED symptomatology in women up to 20 years old [64]. Additionally, qualitative reports indicate that some eBP participants felt more support was needed to improve experiences in the program [66] ( Table 13).
One RCT studied an internet dissonance-based intervention (DBI-I; n = 90), internet cognitive-behavioural intervention (CBI-I; n = 88) and no intervention (n = 93) [67]. At post-intervention, both DBI-I and CBI-I led to greater reductions in body dissatisfaction, thin-ideal internalization, and depression than no intervention, but CBI-I was effective at reducing dieting and eating pathology relative to no intervention. In a secondary analysis of this RCT, the results suggest that DBI-I is a more effective strategy for reducing reward-based eating drive relative to the no intervention group, as the CBI-I intervention had no effect on reward-based eating drive [68]. Another RCT compared a similar online dissonancebased intervention (online DB; n = 112) to a face-to-face dissonance-based intervention (face-to-face DB; n = 107), and a control group (n = 114) [69]. Body dissatisfaction improved among participants in face-to-face and online DB compared to controls at post-test (no significant differences), however thin-ideal internalization and ED symptoms did not change in either active condition (Table 13).

Psychoeducation programs
Children and adolescents One open trial studied a general student sample (n = 453) using ProYouth [70]. The study demonstrated the impact that ProYouth has on early intervention and help-seeking among adolescents. Within three months of participation, 9.5% of participants took up treatment, 7.8% intended to start treatment, and 43.1% of the remaining sample reported that they would seek professional help if needed (Table 14).
Emerging adults One open trial studied the impact of Appetite for Life among a general sample of college students (n = 34), where 20.6% indicated that they gained knowledge about EDs by participating in the program, 14.7% said participation helped to clarify their questions, and 8.8% stated that they would not have known who to share disordered eating concerns with without the program [71] (Table 15).
One open trial studied ProYouth in a general population of young adults (n = 173), where 22% stated that without the program, they would not have known who to share their concerns or questions with regarding disordered eating [72]. One RCT studied an adapted version of ProYouth, aiming to specifically target young adults at high-risk for developing an ED (based on Weight Concerns Scale [WCS] score); participants were randomized to either ProYouth OZ (n = 17), ProYouth OZ Peers (included peer support; n = 17) or waitlist control (n = 16) [73]. More participants in ProYouth OZ Peers showed a decrease in disordered eating than those in ProYouth OZ immediately after the intervention, although there was limited outcome data, so strong conclusions were not possible (Table 15). Primary ITT analyses revealed no differences between groups; measure completer analyses found MS-T had significantly lower EDE-Q Global than controls at 12-month follow-up. Secondary ITT analyses found MS-T participants reported significantly higher quality of life-mental relative to SB and controls (6-month follow-up). Of those with baseline disordered eating, MS-T participants were significantly less likely than controls to report it at 12-month follow-up. Small to medium effect sizes between MS-T and SB (favouring MS-T; significant) on depression, (6-and 12-month follow-up), internalization (post-program), clinical impairment (12-month follow-up), etc

Other e-technology prevention Mobile applications ('apps')
Emerging adults One RCT randomized a group of students to immediate use of GGBI Body Positive app (n = 25), or use of the app 16 days later (n = 25) [74]. Compared to those that used the app later, immediate use showed a greater decrease in body dysmorphic disorder symptoms and body dissatisfaction. Though not significant, the desire to be thin and risk for developing an ED decreased in both groups after using the app (Table 16). One RCT recruited young adults (n = 237) to an intervention group where participants had to use the Bodi-Mojo app (based on the website version [55]), or a control group [75]. Participants in the BodiMojo group reported   improved appearance esteem and self-compassion compared to controls. (Table 16).
One RCT involving young adult women studied daily exposure to Instagram app profiles (created by the research team) with either body positive (n = 41), fitspiration (n = 41), or neutral (n = 40) images and related hashtags [76]. Overall, exposure to body positive content had the highest rates of growth for positive mood and body satisfaction, whereas exposure to fitspiration content had the highest rates of growth of negative mood and appearance comparison (Table 16).

Text messaging prevention
Emerging adults One open trial invited students with high levels of body checking (n = 44) to take part in a text messaging intervention, involving one text message sent per day for five days [77]. A positive impact of the intervention was observed-across the five-day intervention period, there was an overall decrease in body checking behaviours and body satisfaction increased (Table 16).

Cognitive-behavioural programs
Children and adolescents One RCT randomized adolescent girls at high-risk for EDs (based on WCS score) to either AcceptME, intervention (n = 62) or waitlist control (n = 30) [78]. Compared to controls, participants in the intervention group had significantly lower weight and shape concerns at the end of the program, with effects maintained at 1-month follow-up. ED risk also decreased amongst AcceptME participants compared to controls (Table 17).
Emerging adults One RCT studied participants in the Food, Mood, and Attitude (FMA) program (n = 116) versus a control group (n = 115) [79]. FMA participants improved on all ED symptom-related measures compared to controls from baseline to 3-month follow-up. A Table 11 Internet-based chatrooms (with synchronous discussion group) for emerging adults (18-25 years) RCT randomized controlled trial, WCS weight concerns scale, ED eating disorder, EDE-Q eating disorder examination questionnaire, RSES Rosenberg self-esteem scale, MSPSS multidimensional scale of perceived social support, OSSS online social support scale, BSQ body shape questionnaire, EDI eating disorder inventory

References Type of study Sample size Intervention Outcomes Results
Zabinski et al. [58] RCT Undergraduate females who scored > 57 on WCS, at risk of ED n = 28 intervention chatroom n = 30 waitlist control Internet chatroom: once per week for 8 weeks, used a private chatroom for a 1-h moderated discussion focused on improving body image and eating behaviours; also included psychoeducation, asynchronous support, homework EDE-Q (eating concern, restraint, shape concern and weight concern), RSES, MSPSS, OSSS, satisfaction questionnaire Intervention participants significantly reduced eating pathology (EDE-Q shape concern, eating concern) and improved self-esteem over controls at posttreatment, and 10-week follow-up. High satisfaction with intervention mode (86% satisfied or very satisfied with program; 79% felt chats were better or much better than face-to-face)  [80]. Unlike the previous RCT, the intervention did not produce any significant effects related to ED symptoms (Table 18). One RCT, involving females at high-risk for an ED (based on WCS score), randomized participants to a chatbot intervention (n = 352) or a delayed control group (n = 348) [81]. Intervention participants had significantly greater reductions in weight and shape concerns versus controls at 3-and 6-month follow-up. The results also suggest that the chatbot intervention may reduce ED onset (Table 18).

Psychoeducation programs
Children and adolescents One RCT involved middle school students randomized to Trouble on the Tightrope: In Search of Skateboard Sam (n = 92), or a control group (n = 98) [82]. Participants in the intervention group for whom puberty was underway showed greater improvements in body esteem from baseline to post-test, relative to controls (Table 19).
One RCT recruited grade 7 girls to a puberty videotape intervention (n = 104) or control group (n = 114) [83]. Compared to controls, girls that watched the video had significant improvements in drive for thinness, intention to diet, and knowledge regarding body image and      Within 3 months of participation, 43 (9.5%) took up treatment, 32 (7.8%) intended to start treatment, and 163 (43.1%) of the remaining reported that they would seek professional help in case of need (potential help-seeking). Approximately 50% of (potential) help-seekers stated that participation in ProYouth has changed their attitude towards help-seeking Table 15 Psychoeducation programs (with discussion group) for emerging adults ( 2) over concern with body weight and shape, 3) unbalanced nutrition and dieting, and 4) binge eating and compensatory behaviors, acceptability, feasibility 7 out of 34 (20.59%) indicated that they had gained knowledge on ED by participating, 5 (14.71%) said that their participation had helped them to clarify certain questions, 3 (8.82%) said that without it, they would not have known who to share their problems with, and 12 (35.29%) indicated that overall, they were pleased with it. 15 out of 34 (44.12%) said that it was 'helpful' . The concepts of the various components were rated more positively by the "moderate risk" group, whereas participation in Appetite For Life in general was rated more positively by "high risk" participants Minarik et al. [72] Open trial General population of young adult users n = 173 completed satisfaction survey ProYouth: internet-based program for ED prevention and early intervention. Aims to inform about EDs and improve mental health literacy, to prevent ED development, and refer early to professional healthcare if needed. Has comprehensive psycho-educative materials, moderated forums, psychologist-led group chat sessions, blogs; can also book individual chat sessions with a counsellor

WCS, SEED, satisfaction survey
The most important reasons given for using ProYouth were anonymity and the possibility of free advice. 73% rated the statement "Overall, I am satisfied with ProYouth" as applicable.
70% would recommend ProYouth to friends if they were worried about their eating habits. 22% stated that without ProYouth they would not have known who to talk to about their questions and problems. Dissemination of the program must be actively pursued. An active, outreach form of dissemination (e.g., via workshops in schools) has proven its worth; approx. two thirds of participants stated that they had heard  completed a post-intervention assessment), and therefore it was not possible to conduct group comparisons or to test for any pre-to post-intervention changes between the groups over time. Individual outcome profiles of participants in each intervention (where pre-and post-intervention data was available) were examined. In ProYouth OZ, 1 (of 6) participant had decreased ED symptoms, and in ProYouth OZ Peers, both (2 of 2) participants reported decreased ED symptoms immediately after the intervention. Of the 6 participants in ProYouth OZ, 1 reported being very satisfied with the program. Of the 2 participants in ProYouth OZ Peers, both were very satisfied with the program Daily exposure to body positive images was associated with the highest rate of growth of positive mood and body satisfaction (vs. those exposed to fitspiration or neutral content). Daily exposure to fitspiration images was associated with the highest rates of growth of negative mood and appearance comparison (vs. those exposed to body positive images). There was no difference in the growth of negative mood and body satisfaction between participants exposed daily to fitspiration and neutral content

Results
Karekla et al. [78] RCT High school and university female students showing signs and symptoms of an ED and at high-risk for an ED (> 52 score on WCS) n = 62 AcceptME intervention n = 30 waitlist control AcceptME: digital gamified Acceptance and Commitment Therapy (ACT; based in CBT that targets ineffective internal control strategies and inflexibility) early-intervention program consisting of 6 sessions (30 min each). AcceptME portrayed the story of a young girl contemplating whether to enter a reality television fashion contest. Participants followed the main character through making the decision and faced situations eliciting common challenging situations, thoughts, and emotions related to body image. Participants completed exercises in the program aiming to teach and apply ACT skills (e.g., acceptance, present moment awareness, values-consistent living) WCS, EDDS, EDE-Q, YQOL-SF, BSQ-8C, BI-AAQ, BIAQ Users of AcceptME had significantly lower EDE-Q weight and shape concerns at end-of-intervention vs. waitlist controls, with large effects; effects appeared to be maintained at 1-month follow-up. Most participants scored below the at-risk cut-off (WCS score < 52) in the AcceptME group at end-of-intervention (57.1%) vs. controls (7.1%), with odds of falling into the at-risk group being 14.5 times higher for controls. At 1-month follow-up, 72% of completers reported scores below the at-risk cut-off in AcceptME. The main effect of time was statistically significant for BSQ-8C (body dissatisfaction) and BI-AAQ and BIAQ (body image) between baseline, end-of-intervention, and/or 1-month follow-up scores. There was no significant time effect for quality of life puberty, but this was not maintained at 1-month followup (Table 19).

Online caregiver prevention interventions focused on child outcomes Caregiver-focused prevention for caregivers of children and adolescents with disordered eating
Children and adolescents One pilot open trial recruited girls at-risk (n = 12) or at high-risk (n = 22) of developing Anorexia Nervosa along with their parents/guardians to take part in Parents Act Now; Anorexia Nervosa risk level was based on pre-determined screening criteria, where those at-risk exhibited high levels of weight/shape concerns and perfectionism, and those at high-risk exhibited specific weight-related criteria in combination with high levels of weight/shape concerns and/or perfectionism [84]. Parents of high-risk children actively used the program to a greater extent than parents of at-risk children, however both groups demonstrated improvements in early symptoms and risk factors, ED attitudes and behaviours, and remained stable or increased in body weight from pre-to post-intervention. One RCT studied a similar population and the German version of Parents Act Now (Eltern als Therapeuten) [85]. Between preintervention and 12-month follow-up, girls in the intervention (n = 32) gained significantly more weight than waitlist controls (n = 34) (Table 20). One controlled trial studied high school females in Student Bodies (SB; n = 102) versus a comparison group (n = 51), as well as their parents participating in a parent version of SB (n = 22) versus a control group (n = 47) [86]. Students in SB reported significantly reduced eating restraint than students in the comparison group from baseline to post-intervention. Parents in the SB parent intervention significantly decreased their critical attitudes toward weight and shape compared to parents in the control group, from baseline to post-intervention (Table 20).  Low intervention acceptance/use, but participating parents rated the program quite favorably as "good" and would recommend to other parents.
Of the primary outcomes, only 1 significant difference between the intervention and the control group was found: between preintervention and 12-month FU, girls of the intervention group gained significantly more weight more quickly as indicated by change in percentage of EBW compared with girls in the control group. Parent-reported reasons for unwillingness to participate: The majority of these parents responded that they did not perceive the identified risk factors and early symptoms in their daughters as problematic and participation in a preventive interven-  likely than controls and just over 2.5 times more likely than mothers in the website-unstructured condition to report that they had sought additional support around body image for their daughters. Daughters whose mothers viewed the website had higher selfesteem and reduced negative affect at 6-week follow-up (not maintained at 12 months). There were no differences on daughters' body image, and risk factors among mothers or daughters, at post-exposure or follow-up. Tailoring website content appeared beneficial AN anorexia nervosa, R at risk, HR at high risk, ED eating disorder, P@T parents act now, PvA parents versus anorexia scale, WCS weight concerns scale, EDE-Q eating disorder examination questionnaire, EDE eating disorder examination, EDI-2 eating disorder inventory-2, FMPS Frost multidimensional scale, RSES Rosenberg self-esteem scale, PACS physical appearance comparison scale, BES body esteem scale, SATAQ-3 sociocultural attitudes towards appearance scale-3 One RCT studied mother-daughter dyads completing either a website-unstructured (n = 53 dyads) or websitetailored intervention (n = 57 dyads), or an assessmentonly control (n = 48 dyads) [87]. Mothers in both website conditions reported having significantly more conversations with their daughters about body image at post-test and 6-week follow-up, relative to controls. There were no differences in daughters' body image and risk factors among mothers or daughters at post-test or follow-up (Table 20).

Discussion
To our knowledge, this is the first scoping review identifying all evidence on virtual ED prevention focused specifically on children and adolescents (< 18 years) and emerging adults (18-25 years) at-risk for EDs. Our review identified 67 studies, examining asynchronous (n = 35) and synchronous (n = 18) internet-based programs, other e-technology including mobile apps (n = 3) and text messaging interventions (n = 1), computer-based programs (n = 6), and online caregiver interventions focused on child outcomes (n = 4). Few included studies focused on children and adolescents (n = 18), while the vast majority focused on emerging adults (n = 49). For children and adolescents, the most widely researched programs were Student Bodies and its adapted versions (n = 4), virtual/ eBody Project (n = 2), and Parents Act Now (n = 2). For emerging adults, the most widely researched programs were Student Bodies and its adapted versions (n = 16), eBody Project (n = 6), and Expand Your Horizon (n = 4). The scoping review determined that a variety of evidence exists suggesting virtually delivered ED prevention programs can be effective at reducing ED symptoms and risk, and in some cases, demonstrate comparable efficacy to in-person delivery.
Virtual prevention interventions have been successfully implemented in other areas of mental health, specifically within suicide prevention. A systematic review on weband mobile-based suicide prevention interventions for youth found that the interventions significantly reduced risk factors for suicide, including suicidal ideation, depression, and hopelessness in participants [88]. Reductions in risk for EDs were similarly found in our review, among children, adolescents, and emerging adults in various virtual prevention programs for EDs, including Student Bodies and eBody Project, which significantly reduced ED onset and symptomatology, as well as cognitions related to body image, weight, and shape. These effects were found across a range of measures, including the Eating Disorder Examination Questionnaire (EDE-Q) and Body Shape Questionnaire (BSQ). Online and social media-based interventions for suicide prevention have also demonstrated high feasibility and acceptability, with users reporting satisfaction with online group interventions at enhancing feelings of connectedness between young people [89]. Comparable findings were illustrated in our scoping review, as children, adolescents, and emerging adults in internet-based group chatrooms aiming to improve body image and eating behaviours reported a strong preference for online instead of faceto-face communication surrounding ED-related concerns [56][57][58].
With unprecedented increases in new ED diagnoses and behaviours during the COVID-19 pandemic among children, adolescents, and emerging adults worldwide [90][91][92], there is a clear need to rapidly implement effective ED prevention interventions to reduce the onset of illness. As services may never return to in-person delivery only, it is important to consider the use of evidence-based virtual ED prevention interventions, such as Student Bodies and eBody Project among children, adolescents, and emerging adults at-risk for EDs, as well as ensure that programs such as these are widely available and free of charge. Our scoping review determined that these programs and their adapted versions have the greatest evidence to suggest that they are successful at reducing ED symptoms, such as weight/shape concerns, body dissatisfaction, and internalization of the thin-ideal. When compared to in-person delivery, Student Bodies programs consistently improved ED signs and symptoms, while eBody Project was not always superior to its inperson delivered counterparts. However, it is evident that the use of virtually delivered ED prevention programs such as these provide some benefit to users, compared to those who do not use any program.
While our findings are particularly relevant given the current COVID-19 restrictions, they may also be important to consider for the post-pandemic era. Virtual delivery of mental health services, including telepsychiatry and telepsychology, has increased dramatically since March 2020, and is predicted to continue at a high rate in the post-pandemic era, once all restrictions are lifted [93,94]. It is possible that continued use of virtual modalities for ED treatment may indicate a transition for virtual delivery for prevention services as well. Remote areas where in-person specialized care or services may be unavailable or inaccessible, may especially benefit from continued virtual delivery of ED treatment, as well as virtual prevention interventions.

Strengths
The strengths of our review are numerous. We used a rigorous and evidence-based methodology for our scoping review, which included a thorough review of literature from seven databases, without language restrictions, and we had few exclusion criteria. We translated several papers into English for full-text review and examined the references of included reviews and book chapters to ensure we did not miss any relevant studies. We also conducted a forward citation chaining process to update our search. Additionally, we were able to include an abundance of high-quality data (47 RCTs and 3 meta-analyses) in the field of virtual prevention for our populations of interest. This data had large sample sizes as well as a wide variety of sample characteristics, including general populations, those with self-reported ED symptoms, and individuals deemed at-risk according to screening questionnaires.

Limitations
Although thorough, our search strategy had limitations. We were unable to retrieve four citations as full-text articles, as they could not be located. Our evidence involving emerging adult populations was also more than double that of our evidence for child and adolescent groups, making it difficult to form strong conclusions for this younger age group. Many studies enrolled participants based on symptom evaluation using instruments rather than diagnostic interview, and as a result, some high-risk participants might have actually met diagnostic criteria for EDs. As rating the quality of evidence is not a component of scoping review methodology [11], our findings cannot comment on this. However, our work lays the foundation for a systematic review, which would involve an evaluation of the strength of the evidence and is a feasible and logical next step in advancing knowledge in this particular field. Despite these limitations, this review represents a significant step forward in understanding the types of virtual ED prevention programs that exist, as well as those with the greatest evidence base demonstrating the effects of these programs.

Future directions
Several gaps were noted, which should be a focus for future study. First, more research on virtual prevention programs specifically for children and adolescents (< 18 years) is required. Second, large-scale studies of efficacy with long-term follow-up for ED prevention interventions, including text messaging, mobile apps, online cognitive restructuring, and online imagery rescripting interventions are needed. Evidence-based recommendations for virtual ED prevention interventions that have been reviewed and rated by a diverse consensus panel, similar to our virtual care recommendations for children, adolescents, and emerging adults during the COVID-19 pandemic and beyond [10] would also be beneficial so clinicians can direct individuals experiencing early signs and symptoms of EDs to effective prevention programs. As not all of the researched ED prevention programs are widely available and freely accessible, additional research on how to improve access to virtual ED prevention services for vulnerable populations (e.g., equity-seeking and marginalized youth) and gender diverse groups is also necessary.

Conclusions
This scoping review identified a variety of evidence for ED prevention programs for children, adolescents, and emerging adults. For children and adolescents, the most widely researched programs were Student Bodies and its adapted versions, eBody Project, and Parents Act Now. For emerging adults, the most widely researched programs were Student Bodies and its adapted versions, eBody Project, and Expand Your Horizon. Most studies included emerging adults rather than children and adolescents, and therefore, additional research focusing on ED prevention interventions for those under 18 years of age is required to form stronger conclusions for this population. Future research should also be conducted to determine the long-term efficacy of several understudied ED prevention interventions, including text messaging, mobile apps, online cognitive restructuring, and online imagery rescripting programs, as well as evidence-based recommendations for virtual ED prevention for children, adolescents, and emerging adults at-risk for EDs. Research for improving access to virtual ED prevention services for vulnerable and gender diverse groups should also be prioritized.