Virtual Pedagogy and Care: Systematic Review on Educational Innovation with Mobile Applications for the Development of Healthy Habits in the Adolescent Population

Background: The scientific literature was reviewed to determine the state of the art regarding innovative educational practices that employ mobile health applications with the aim of establishing healthy habits in the adolescent population, following a strategy based on spiral curriculum. Methods: The search was conducted in the WOS, Scopus and PubMed databases, discarding any articles that were not published in English, Spanish or French. The search was limited to studies performed in the last 6 years, that is, from 1 January 2017 to 18 March 2023. Results: From the initial sample of 132 articles selected, the final sample included 9 articles that met the eligibility criteria after a more exhaustive analysis. This systematic review identified one application (11.11%) with topics about sex and reproductive health, two applications (22.22%) that tackled mental health, six applications (66.66%) with topics about nutrition, three applications (33.33%) that contemplate physical activity, and two applications (22.22%) with aspects related to the prevention of harmful habits. The results show a positive relationship between the use of mobile health applications used as innovative didactic resources and the establishment of healthy habits in the adolescent population. Conclusions: Digital devices have been incorporated to the lives of humans as fundamental tools for their daily living. Specifically, adolescents are especially attracted to mobile phones. If this resource is used in this population to improve health, it is possible to attain very satisfactory objectives. The results of this review indicate that these devices can be used as a didactic resource in the promotion of health by implementing healthy habits at early ages, thereby contributing to the prevention of chronic diseases in future adulthood.


Introduction
Chronic diseases are the main cause of death and disability worldwide.At the global level, it is estimated that up to 80% of cases of heart diseases, strokes and type 2 diabetes, and over 30% of cases of cancer, can be prevented by reducing smoking and alcohol consumption, improving diet and practising physical activity regularly [1].
Disease prevention seeks to achieve the highest possible level of health in the population.However, aiming at improving health does not mean trying to reach immortality, and fighting for health is not equal to merely avoiding death.The aim is to fight certain types of deaths and to increase our life expectancy.The fact that we can live more years implies that, despite the increase in the probability of suffering from certain types of chronic-degenerative diseases that worsen our quality of life, we can delay their appearance, control them, know how to cope with them and, ultimately, add life to the years.In the family and school educational practice, the aim is to transmit applicable knowledge in their daily living and in their future as adults.
As basic knowledge taught from childhood, population health and lifestyles are addressed with their physical, chemical, biological and social components [2].As was demonstrated by Jerome Bruner [3], the acquisition of knowledge, abilities and skills in childhood and adolescence consists in a spiral-learning method, where increasingly complex knowledge is progressively presented, integrating it by increasing the competencies related, in this case, to contents about healthy habits.
In the Ottawa Charter, the World Health Organisation [4] defines health promotion as the process that allows people to increase their control over determinants of health and, consequently, improve it.Similarly, they set requirements to reach good health, which depend on external determinants such as peace, education, housing, diet, decent work, healthy environment, social justice and equity, as well as on internal determinants such as beliefs, convictions, education, intelligence and emotions.
Health behaviours generally emerge during adolescence, persist in adulthood and commonly coexist [5][6][7].Therefore, adolescence is a critical age to intervene and interrupt a trajectory toward poor adult health [8,9].Physical inactivity, bad eating habits and practising harmful leisure activities are nowadays among the fundamental problems of the world society.Thus, it is necessary to generate some good health habits in the adolescent population, to ensure that they establish healthy behaviours and reach adulthood with good biopsychosocial health.
Moreover, this young population uses new technology very frequently, with smart phones becoming an integral part of their daily living.This circumstance can be used as an opportunity, since the use of mobile applications that foster healthy habits can be attractive and easy-to-access tools that transform learning into an innovative, creative, motivating and constructive process.To establish a habit in the population, a learning procedure is necessary.Mobile applications on healthy habits inherently carry a pedagogical process.In addition, since it is virtual learning, an innovative strategy is achieved [10].
For all of the above, the aim of this study was to carry out a systematic review of the scientific literature in order to identify intervention studies in adolescent populations that used mobile applications as an innovative didactic strategy to improve healthy habits, based on spiral curriculum.It is about investigating possible new health promotion strategies, in which new technologies are used for young people to establish healthy habits.If positive evidence is observed in this regard, personalized innovative health promotion strategies could be implemented.

Materials and Methods
In this study, a systematic review of the scientific literature was conducted, analysing studies with interventions aimed at promoting healthy habits through mobile applications in adolescent populations.The PRISMA criteria [11,12] for systematic reviews were applied, exclusively exploring the selected articles.

Selection Criteria
This systematic review was conducted in the months of February and March 2023 in the Web of Science (WOS), SCOPUS and PubMed databases, discarding articles that were not published in English, Spanish or French.The search was limited to studies performed in the last 6 years, that is, from 1 January 2017 to 18 March 2023, selecting open-access articles only.

Search Strategy
Regarding the search strategy, the following search criteria were selected: for WOS

Inclusion and Exclusion Criteria
The following inclusion criteria were used: (a) studies in which some type of intervention with mobile applications was used; (b) the mobile applications were related to the area of health sciences; (c) the articles were published in scientific journals; and (d) studies whose sample was constituted by adolescent populations.Therefore, only original articles were included, selecting those with open access.
Since one of the inclusion criteria was the existence of intervention in the studies, the following documents were excluded: reviews, letters to editors, commentaries, opinions, perspectives, guidelines and rules, cases or case series, and systematic reviews.The adaptation of the selected articles to the objective and inclusion criteria of this review, with the aim of increasing the reliability and safety of the process, was independently carried out by three of the authors of this investigation (C.A.-A.; F.-J.G.-V.; and E.M.-S.).After reviewing the title, abstract and keywords of the article, if there were doubts about the inclusion of some articles, the other two authors (D.G.-A.and Y.C.-A.) made the final decision on their inclusion or exclusion.
The identification and selection of articles (both included and excluded), and the reason for exclusion in the screening and selection phase, are shown in the flow chart of Figure 1.

Data Extraction
The data extraction process was carried out with numerous judgements and actions after the search.To this end, the first step was to exhaustively review the title, abstract, method, results and conclusions of each article.The data were extracted as they were published in their respective studies when they were reviewed.
This systematic review included variables following the PICOS acronym (P: participants; I: interventions; C: comparisons; O: outcomes; S: study design).Furthermore, this investigation included other variables that were considered relevant: authors, year of publication, country, reference of the article, study objectives, measurement variables, and scales.

Data Extraction
The data extraction process was carried out with numerous judgements and actions after the search.To this end, the first step was to exhaustively review the title, abstract, method, results and conclusions of each article.The data were extracted as they were published in their respective studies when they were reviewed.
This systematic review included variables following the PICOS acronym (P: participants; I: interventions; C: comparisons; O: outcomes; S: study design).Furthermore, this

Presentation of the Results: Adherence to Quality Initiatives (PRISMA)
The results of the primary studies, obtained through a systematic and reproducible methodology, are presented in a qualitative and quantitative manner (Figure 1).

Quality Evaluation
For the selection of the articles, a quality analysis was conducted following the quality evaluation components and scores of the EPHPP (Effective Public Health Practice Project) instrument [13].With this instrument, a general assessment of each study was performed, evaluating six components (Table 1).Those studies without weak scores and at least four strong scores were considered strong.Those with less than four strong scores and one weak score were considered moderate.Lastly, the studies with two or more weak scores were considered weak [13].
The conclusions of this analysis are shown in Table 1.Of the nine articles included, four of them had a moderate global score [14][15][16][17], whereas the other five had a weak global score [18][19][20][21][22].However, despite the fact that five of the articles presented global weak scores, they had strong internal components in variables such as data gathering and the percentage of participants who reached the end of the intervention.These internal components are relevant and can be prioritised with respect to other components since they are more strongly related to the study object of this systematic review.Therefore, although these five articles presented a global weak score, since their most relevant internal components were strong, they were included in this study.It is worth highlighting that six of the nine articles presented a strong score in the percentage of participants who reached the end of the interventions [14,[16][17][18][19]22].Another aspect worth pointing out is the use of validated instruments in most of the studies (60%) for data gathering, with strong scores in this component [14,15,[17][18][19].

Selection of Studies and Data Extraction Process
After the search, the title, abstract and keywords of each article were reviewed with the aim of selecting those that could be relevant and discarding those that did not meet the inclusion criteria.
The searches were carried out and the inclusion criteria were applied, obtaining a total of 132 articles.The first search was performed in the Web of Science (WOS), where 31 articles were found; the second search was conducted in the Scopus database, gathering 7 articles; and the third search was carried out in PubMed, obtaining 94 articles.
Five articles were duplicates, and they were thus excluded, reducing the sample to 127 articles for full-text review.After applying the eligibility criteria, 118 articles were excluded, with 9 articles remaining in the final sample.The reasons for excluding 118 articles from the systematic review were that, although they initially met the inclusion criteria, after a more exhaustive reading, some of them were identified as systematic reviews (n = 19) or studies without intervention (n = 8), whereas others did not meet the study objective (n = 39), did not correspond to the study population (n = 49) or were studies in which intervention projects were proposed, but had not been carried out yet (n = 3).With the aim of reducing the selection bias, each article was reviewed independently by three of the researchers (C.A.-A.; F.-J.G.-V.; and E.M.-S.), who decided whether each document met the established criteria.In those cases in which these researchers did not reach consensus on the inclusion of an article, the other two researchers (D.G.-A.and Y.C.-A.) mediated the decision.

Characteristics of the Studies: Results Synthesis
Table 2 presents the following data of each of the studies: authors, year of publication, country, type of study, comparisons, study objectives, participants, variables and measurement instruments, interventions, and results.
Of the nine articles analysed, eight (88.88%) of them concluded that the health applications used in their studies were useful for learning and improving health habits in the adolescents [14][15][16][17][18][19][20][21], and one (11.11%)demonstrated that the application used did not offer optimal functions and that it was fundamental to optimise the usability of the mobile health interventions in it [22].The participants were granted access to the Health4Life application, in which they had to record their health behaviours.Additionally, they had to complete an online questionnaire that evaluated the application, in order to generate information about its usability and acceptability.
In general, the students gave a favourable score to the Health4Life application.They considered it to be highly acceptable and usable, and they believed that it had the potential to efficiently and effectively modify important risk factors for chronic diseases among young people.The group that received the intervention with the mHealth App "W8Loss2Go" [17] obtained better results in the improvement of BMI and in the effective completion of the therapeutic treatment, compared to the group that received the intervention in the clinic with conventional treatments.

Association between the Different Mobile Applications with Didactic Strategies for the Promotion of Healthy Habits
It was observed that the application used by one of the analysed studies offered information about providers of sex health services and contraceptive methods [18].Two studies described applications with different didactic resources for the improvement of mental health, which included strategies to cope with stress and difficult situations [19] and skills to improve depressive symptoms, self-esteem, quality of life, self-control and health promotion in adolescents [14].Six studies used applications that had resources to work on aspects related to nutrition, sport and the prevention of unhealthy habits; thus, the study of Villasana et al. [20] showed strategies aimed at monitoring, counselling and educating about nutrition and physical activity; Caón et al. [15] described resources for the proactive promotion of health (better eating behaviours: greater consumption of fruit and vegetables, and lower breakfast skipping); Thornton et al. [21] reported on activities in the application that were aimed at improving the six main health risk behaviours (bad diet, physical inactivity, smoking, alcohol consumption, sedentary recreational screen time and lack of or excess sleep); Müssener et al. [22] contemplated resources to promote healthy eating, physical activity, quitting smoking and reducing alcohol consumption; Lei et al. [16] identified as useful the application to facilitate weight loss in overweight and obese adolescents in the short and medium term, as well as to promote the practice of physical activity; and, lastly, Vidmar et al. [17] contemplated a series of activities to lose weight through physical training.

Discussion
The aim of this systematic review was to identify mobile applications that are used as an educational resource in health-related behaviours in adolescent populations.
The scientific literature shows that mobile applications can be useful and beneficial in the management and treatment of mental diseases, in combination with conventional therapy [23].These applications represent new health promotion strategies with innovative and educational methodologies for the population.In this line, Pérez Márquez et al. [24] stated that the development of apps to favour mental health can be considered to be innovative ways of approaching the adolescent population.These findings are in line with the results of the present review, which shows outcomes of different applications that innovatively promote mental health through mobile applications that have been positively evaluated by the users [19].However, these findings are not reported in similar studies that do not support the effectiveness of applications through goal attainment [25].Education, self-control and goal setting are common components in the interventions of behavioural change designed for adolescents [26].
Nagamitsu et al. [14] showed that a well-care visit (WCV) with an interview of risk evaluation, counselling and self-control, and a mobile application of behavioural cognitive therapy (BCT/CBT) was more effective than receiving only WCV.The results were demonstrated by the attainment of self-control and depressive symptoms reduction skills.This finding shows the rapid acquisition of skills in this population, establishing the idea that health promotion during adolescence contributes to preventing the later appearance of mental health diseases, since the good habits are established at these ages are very likely to persist in adulthood [27].
Roldán [28] highlighted the need to use sex health apps not only in society, but also in the educational scope, both for adolescent students and for teachers and parents, since the latter would reduce their refusal or embarrassment toward addressing this topic.The review demonstrated a mobile application is an innovative way of covering important gaps in adolescent sex education and helping teachers to prepare their classes, ensuring that girls and boys understand everything.This would help to prevent and reduce the cases of STD (sexually transmitted diseases), sexual abuse and/or unwanted pregnancy.One of the studies analysed in this systematic review used a mobile application to promote sex and reproductive health among adolescents, obtaining promising results, which showed that the application helped the adolescents to discover and access a wide range of sex health services, including the least frequently used contraceptives [18].
Regarding the health education strategies related to nutrition and the promotion of active lifestyles, it is considered that the use of mobile applications is an effective resource for the acquisition of skills.Moreover, this helps to reduce long-term health risks [29].This finding is reported in some of the studies analysed in this review, which conclude that health apps are useful for the promotion of healthy lifestyles, fostering the adoption of healthy eating habits, as well as good physical activity habits [20]; encouraging the change of behaviours and the improvement of eating habits [15]; indicating that they help to change life habits [21,22]; and pointing out their efficacy in weight loss among overweight adolescents [16,17].According to several researchers, there are insufficient empirical data that determine the effect of motivation and of the use of apps in relation to some areas of the promotion of healthy habits, such as the practice of physical activity in adolescents [30].
There is an important prevalence in the perception of barriers to initiate or maintain physical activity habits, especially the lack of time or resources [31].This variable could be palliated with the use of effective mobile health applications including motivating suggestions, dynamic advices and tips, gamification, challenges and the possibility to earn points [20], personalised suggestions, a virtual trainer, challenges and badges [15], rewards and notifications in the application to improve commitment [16,17,21], and personalised counselling [17], as was observed in many of the studies analysed in this systematic review.
Many of the studies analysed in this review conclude that an important strategy to promote the commitment and participation of the adolescent population in the use of mobile health applications is to involve them in the development of the latter [15,18,19,21].The target population for the intervention should be involved in the design, aesthetics, usability and functionality [22].The appearance of the application must be thoroughly worked on, since it must include an aesthetic value translated into colours, textures, sceneries, images, illustrations, icons, interactive widgets and effects that motivate adolescents, and it must also have a high functionality that leads to significant usability [32].
It must be taken into account that health apps pose a social advance and, a priori, an advantage in the world of health.They demonstrate the problem that most of the health applications that exist in the market are neither safe nor useful in terms of functionality.This difficulty can be palliated when there is professional supervision and satisfaction in terms of usability [33].Many of the applications that have been pointed out in different studies of this systematic review have been analysed by experts and adolescents, presenting good results regarding safety and benefits [19][20][21][22].
With respect to the use of mobile health applications as a function of sex, it is demonstrated that, in one of the analysed studies, female adolescents presented more commitment with a mobile application to improve their diet and to have a healthy life compared to male adolescents [15].This finding could be explained by the current information in the scientific literature, which shows that females choose to use more health-related applications, whereas males use more applications related to leisure and entertainment [34].
It is relevant to discuss limitations of the study, such as the relative scarcity of studies analysing the research question of this review.The search was only conducted in English, Spanish and French.In order to delve into the relationship between the use of mobile health applications in adolescent populations and the establishment of healthy habits, it would be interesting to perform more thorough systematic reviews, with more articles and languages, and with a meta-analysis.It would also be convenient to include more databases.Additional randomized controlled trials with different interventions and different mobile apps would improve our knowledge in this area.

Conclusions
It has been demonstrated there are different and varied applications focused on facilitating and/or improving health habits.The potential offered by this technology is very ambitious and can be used beneficially for the improvement of healthy habits in adolescent populations, as well as in the health education curriculum in the school and family scopes.The findings found in the nine articles reflect different health promotion strategies through new technologies, which is why educational innovation is evident.
The conclusion of this review is the positive relationship between the use of mobile health applications and the improvement of health habits.Their didactic use and contents with spiral structure enable their use in educational scopes, fostering cognitive, physical and social development and transforming educational organisations into health promotion spaces.Teaching healthy habits through new technologies represents a new approach to health promotion.More and more mobile applications are being developed for different fields.Specifically, those found in this review point towards a possible new perspective of teaching, a virtual pedagogy.
This study shows the usefulness of mobile health applications as a pedagogical tool for the establishment of healthy habits in adolescent populations, thereby contributing to the prevention of comorbidities in adulthood.

Figure 1 .
Figure 1.Flow chart of the systematic review process according to the declarations of the PRISMA protocol.

Figure 1 .
Figure 1.Flow chart of the systematic review process according to the declarations of the PRISMA protocol.

Table 1 .
Quality assessment components and ratings for the EPHPP instrument.

Table 2 .
Characteristics of the studies included in the systematic review.