To effectively address the complex factors influencing (digital) lifestyle behavior change, the OSFB program follows a quadruple helix model, bringing together key stakeholders from 4 domains: society (eg, (pre)pregnant couples, networks, and community organizations), academia (eg, researchers in public health and digital innovation), industry (eg, app developers and health tech companies), and government (eg, local municipalities and public health services) [18]. These stakeholders are selected based on their experience, knowledge, and expertise and collaborate in 6 interrelated work packages (WPs). Each WP is composed of several experts from different organizations and contributes to a specific aspect of the development of the social environment and the Family Buddy platform prototype, further referred to as the Family Buddy.

The project was funded in 2022. The planned duration of the OSFB program is 6 years, divided into 3 (semioverlapping) phases, as illustrated in Figure 1: phase 1, preparation and exploration (2022‐2025); phase 2, cocreation, design, and technological development (2024‐2026); and phase 3, prototype evaluation and optimization (2026‐2028).

These 3 phases, guided by the program’s coordination WP (WP0) and supported by the societal embedding WP (WP2) and ethics WP (WP5), are described in more detail in the following section.

The societal embedding of the program and the social part of the Family Buddy is facilitated by WP2. This is established through leveraging existing resources and networks of organizations and communities of individuals within the neighborhood in 4 field labs [35]. In phase 1, WP2 focuses on the development of field lab methodology and guidelines based on existing literature using a scoping review. In phase 2, 4 field labs are established, focusing on different aspects of a healthy living environment: food, movement, mental or social health, and health care providers. These field labs serve as cocreation environments, where stakeholders, including the target population, local health care providers, and community organizations, cocreate a vision and insights on the barriers and possible actions in a transformation toward a healthier living environment in the neighborhood. The networks strengthened in these field labs facilitate the societal embedding of the Family Buddy and facilitate its cocreation, testing, and implementation. The research outcomes of WP2 include insights into community needs, community dynamics, and transformative potential of the neighborhood to create a healthier and supportive living environment to facilitate the dissemination and implementation of the Family Buddy in phase 3 through societal embedding in the neighborhood.

The OSFB program comprises multiple studies conducted across different participating institutions and universities. For all studies, ethical approval has been obtained and will be obtained separately for each study in accordance with institutional policies. For each study involving human participants, ethical approval is obtained from the relevant institutional review board or medical ethics committee of the participating institution(s), that is, Erasmus University Medical Center Medical Ethical Committee and TU Delft Human Research Ethical Committee. Approval details, including committee names and application or reference numbers, are reported in the respective individual publications and in the overview of the conducted OSFB studies within each of the WPs.

For all studies involving primary data collection, written informed consent is obtained from all participants prior to participation, in line with Medical Research Ethics Committee requirements. For studies using secondary or existing data, ethical approval and consent procedures are covered within the original study protocols in accordance with applicable regulations.

Regarding privacy and confidentiality, all data are handled in accordance with the General Data Protection Regulation and national data protection laws. Data are anonymized or pseudonymized prior to analysis and determined at the level of individual studies within the program. Access to identifiable data is restricted to authorized consortium members only.

Participant compensation is also determined at the level of individual studies within the program and approved by the ethics committees. Details regarding data collection and participant compensation are described in the respective research papers.

Additionally, the ethical challenges of developing and implementing the Family Buddy are addressed by WP5. In phase 1, an ethical framework will be developed based on the findings of a narrative review. This review examines existing ethical frameworks for public health, lifestyle interventions, and digital lifestyle interventions. The resulting ethical framework will facilitate the development of the Family Buddy in phases 2 and 3, adhering to ethical principles, among which are justice, privacy, and inclusivity [24]. Furthermore, WP5 provides guidance on the moral acceptability of the use of possible manipulative influences (eg, rewards) through an ethical analysis of the findings of an interview study with potential users of the Family Buddy (see Supplementary info 2 for interview guide in Multimedia Appendix 1). WP5 is also responsible for ethical monitoring during all 3 project phases to identify ethical concerns of OSFB users regarding the responsible use of AI and the development and long-term deployment of the Family Buddy with particular attention to issues of justice and health inequity.

Monitoring, evaluation, and dissemination activities are integrated throughout all phases of the program to ensure continuous learning and adaptation to emerging insights from the target population and other stakeholders. As the program progresses, the insights collected from cocreation sessions, interviews, and literature reviews will inform ongoing design decisions and guide the development process. An iterative monitoring approach enables timely adjustments to keep the Family Buddy aligned with the needs and values of the target population and with the societal context.

In parallel, dissemination is treated as an ongoing process, with regular program updates shared with stakeholders and the community, to maintain engagement and foster a sense of ownership. Research findings, program progressions, and recruitment campaigns are shared through presentations and consortium meetings, as well as through local key persons in the neighborhood. As the program progresses, more formal dissemination pathways, including scientific publications and conference presentations, will be used to share outcomes and insights with a broader academic and professional audience.

Stakeholders within the OSFB consortium are selected based on their specific expertise, professional roles, and capacity to contribute to the development, implementation, and evaluation of the program, ensuring alignment with the quadruple helix model (academia, industry, government, and society) [18]. Academic stakeholders were included based on their established research expertise in either periconceptional health, lifestyle, public health, or prior relevant collaborations. Governmental and public health stakeholders (including municipality, youth health care providers, and policymakers) were selected based on their formal roles in local health policy, implementation knowledge, and access to the target population. Industry partners were primarily selected based on their ability to contribute to the digital infrastructure, innovation, and scalability of the intervention. In addition to the initial stakeholders involved in the original grant application, the consortium remains open and adaptive, allowing for the inclusion of additional stakeholders, such as local entrepreneurs and community partners, throughout the program to further strengthen its impact and contextual relevance.

Stakeholders representing the societal domain, including the target population, are identified and reached through existing community networks, local initiatives, and the 4 field labs set up by WP2 in phases 1 and 2. Particular attention is given to including individuals who are embedded in the local community, including key figures, community and health care workers, representatives of local programs and initiatives, and (future) parents themselves. To ensure that the perspectives of the target population are well represented, we aim to involve a diverse group of participants from IJsselmonde reflecting variation in family composition and socioeconomic background. Potential participants will be informed about the study and recruited through key organizations in Rotterdam-South, social activities targeting vulnerable groups, social media, and other promotional initiatives. Members of the research team will attend these social activities to speak with potential participants and explain the study in person. Stakeholders interested in participating can visit the program website [36]. The potential users of the Family Buddy will be referred to the landing page [37] to obtain further information, register for the study, review the patient information folder, and provide informed consent. Alternatively, users can register and provide informed consent in person with a member of the research team or with an employee of one of the key partner organizations. All recruitment materials will be available in both Dutch and English.

In phase 1, we selected a deprived area of Rotterdam (IJsselmonde) as our research, development, and implementation setting of the Family Buddy. This decision was informed by the demographic, socioeconomic, and health characteristics of the area, which indicate a high prevalence of potential vulnerability factors, aligning with our aim to engage (pre)pregnant couples and young families at increased risk for health inequities. Furthermore, we ensured that no other research projects were hosted in the neighborhood that could either overburden the population or compete with our initiative. Table 1 summarizes the characteristics of the population in IJsselmonde in comparison to the general population of the Netherlands.

We defined the target population as women or couples with an active child wish, pregnant, or parents of at least one child below the age of 4 years, residing in IJsselmonde.

To assess the characteristics of our study population, a questionnaire was developed to assess (un)favorable lifestyle behaviors, mental illnesses, stressors, and other factors. This questionnaire is based on the Rotterdam Reproduction Risk Reduction questionnaire, a validated questionnaire used in health care practices in the Netherlands to assess the presence of potential vulnerability factors and unfavorable (lifestyle) behaviors [40,41]. Furthermore, we selected nutrition as a lifestyle target and stress reduction as interrelated targets to be improved by using the Family Buddy.

The OSFB program has focused on building the quadruple-helix consortium within the neighborhood in phase 1, creating visibility and gaining trust, and inviting (pre)pregnant couples and young families to participate in interviews and cocreation sessions. A large consortium of more than 40 partners has been established and is sustained through regular meetings and collaborative sessions. By June 2025, more than 30 (pre)pregnant couples and young families were interviewed, and a user board was installed. Inclusivity of the program was increased by recruitment of families and parents within the neighborhood and offering the option of having the interview at the place of choice of the participants. Another 20 additional stakeholders, including health care professionals and local key persons, engaged in cocreation. Furthermore, 300 women contemplating parenthood have finished the digital Pregnant Faster study.

Phases 1 and 2 of the program have generated valuable insights and research outputs across the WPs, laying the groundwork for the development and implementation of the Family Buddy. Table 2 summarizes the research aims, activities, and outcomes. While the initial grant proposal and first methodology of the OSFB program outlined the development of a primarily digital platform embedded within a social environment, the program activities and insights during phases 1 and 2 revealed that a stand-alone digital platform would not sufficiently address the social, relational, and contextual barriers experienced by the target population.

The cocreation process was informed by 4 complementary substudies that explored families’ lived experiences, needs, and perspectives from different angles, thereby increasing context specificity and strengthening the conditions for future implementation. The first qualitative substudy explored parental value tensions related to nutrition decisions for young children among 20 parents living in disadvantaged neighborhoods. This study demonstrated that parents frequently experienced tensions between the dietary health of their child and competing values, such as child enjoyment, parental convenience, and parental well-being, particularly in situations characterized by stress, financial strain, limited social support, or challenging child behavior. Parents described social and material support, including informal household help and access to healthy and convenient foods, as important protective factors that reduced stress and facilitated healthier nutrition choices. These findings highlighted the importance of designing interventions that are sensitive to parents’ daily realities and underlying value conflicts [38]. The second qualitative substudy, conducted by the Department of Neonatal and Pediatric Intensive Care of the Erasmus MC - Sophia's Children Hospital, explored barriers and facilitators for engagement with eHealth lifestyle interventions among 15 parents (13 women and 2 men). This study demonstrated that engagement with digital lifestyle support is shaped by factors such as digital accessibility, trust, motivation, and alignment with families’ daily realities. Ethical approval was obtained from the Erasmus MC Ethics Committee (MEC-2024‐0268). The third substudy, conducted by Delft University of Technology, explored parents’ preferred forms and delivery of social support related to parental well-being and healthy child nutrition among 19 parents (17 women and 2 men). Findings highlighted the importance of tailored informational support combined with locally embedded emotional and practical peer support. The fourth substudy, conducted by the Section Medical Ethics, Philosophy and History of Medicine of Erasmus MC, evaluated the acceptability of different forms of influence within digital lifestyle interventions among 16 parents (14 women and 2 men). Parents considered digital influence acceptable when it was transparent, motivating, effective, and preserved freedom of choice and autonomy. The latter 3 studies are submitted for publication. Together, these substudies addressed complementary social, behavioral, practical, and ethical dimensions that are essential for the cocreation, acceptability, and future implementation of a meaningful socially embedded digital lifestyle intervention for families living in vulnerable circumstances.

Insights from the literature reviews, the qualitative substudies, and the cocreation sessions consistently highlighted the need for stronger interpersonal support within the neighborhood, involving local key actors and existing networks within the community. In response and as a result of iterative development cycles, the program’s focus shifted from a predominantly digital Family Buddy concept toward a more integrated socially embedded-digital intervention that combines an individual digital Family Buddy lifestyle coaching platform with a structured and supporting social component consisting of group meetings and workshops in the local environment.

This paper describes the methodology and summarizes the first research insights from the OSFB program, with the primary aims of improving nutrition and sleep in young (future) families living in deprived circumstances. The first 3 research years, spanning phase 1 and (part of) phase 2, provided key insights into consortium building, engagement of the target population and their needs, the establishment of community-based field labs, and the development of an ethical framework for OSFB.

A key finding from the first 3 research years is the need for strong societal embedding of the OSFB program by implementing in already existing community initiatives. One of the field labs organized by WP2 is meal prep programs, during which inhabitants of IJsselmonde cook together while discussing topics relevant for a healthy lifestyle. These programs are guided by professional chefs. Other examples include parent-child groups and involving key community figures through train-the-trainer approaches. This led to the development of a socially embedded digital Family Buddy. Rather than targeting systemic change, the OSFB program emphasizes the role of small, supportive communities in fostering sustainable behavior change, with the social-digital Family Buddy supporting both individuals and community.

Literature reviews from phase 1, as well as interview studies in phase 2, conclude that current digital tools to change, adopt, and sustain healthy lifestyle behaviors and support coping with mental stress show limited effectiveness in reaching and benefiting underprivileged (pre)pregnant couples and young families [22]. This may not only reflect gaps in user-centered development but could also relate to the broader reality that many couples and families face systemic stressors, which might reduce their cognitive and emotional capacity to meaningfully engage with such tools. In addition, some individuals, couples, and families may experience limited trust in formal institutions, particularly when (digital) tools are perceived as extensions of those institutions. Research suggests that a sense of not being recognized or mentalized can hinder the development of epistemic trust, which is critical for engagement and uptake of supportive interventions [44]. Many tools on the market have been developed without the direct involvement of the target population as well as other involved stakeholders, leading to low user engagement and usability issues among these groups [14]. Studies indicate that tools not developed specifically for or with underprivileged populations often face barriers in implementation, as they may not adequately consider the unique needs, values, challenges, and environment faced by these users [15]. Consequently, such tools often fail to integrate into the users’ daily routines and do not achieve the desired health outcomes [45]. Ultimately, these tools exacerbate health inequities, as underprivileged populations are unable to benefit from them while their wealthier counterparts may gain increasing health advantages.

The cocreation process and field lab method are central to the development and societal embedding of the Family Buddy and its broader implementation strategy. By involving women, couples, families, health care providers, and local stakeholders throughout the design and evaluation stages, the Family Buddy becomes more aligned with the needs of families living in deprived neighborhoods [16,46]. However, long-term uptake and ownership cannot rely on field labs alone. Sustainable success requires active collaboration, trust building, and shared responsibility with community partners. Early signs of ownership are emerging—for example, local organizations are co-hosting activities and expressing interest in continued use—but formalizing these partnerships and exploring long-term governance models remain priorities. Further research is needed to understand how to achieve lasting community ownership beyond the project phase.

The OSFB program has several strengths and limitations. The key strength is its large, transdisciplinary quadruple-helix consortium and its comprehensive cocreation design process embedded within existing communities in a deprived neighborhood. By engaging the community and the target population involved through cocreation and field labs, the program aims to explore and address the needs of underprivileged populations, resulting in a comprehensive and well-accessible tool. Another strength is the exploration of the integration of a conversational agent for real-time tailoring of advice based on the user’s needs and input, a feature likely to enhance engagement and effectiveness [45]. An additional strength is the ongoing critical exchange of knowledge and experience within and between the WPs, which has led to new insights that contribute to the development of a complementary social intervention within OSFB to address collective and environmental factors alongside individual support.

This program faces several limitations as well. First, the inherent complexity of coordinating a large transdisciplinary consortium, where progress depends on a shared vision, mutual trust, ownership, and alignment among diverse stakeholders, poses a significant challenge. Moreover, it is difficult to integrate all insights into clearly defined cocreative designs and field labs; to address this, we will organize sprint sessions within the consortium to better delineate the process and enforce alignment. In addition, the resource- and time-intensive nature of our extensive cocreation and iterative field lab methodology may limit the generalizability of our findings to other contexts. The reliance on digital access and literacy could also restrict the reach of the Family Buddy among subgroups lacking internet connectivity or smartphone access [15]. Another limitation lies in the complex implementation context for (pre)pregnant couples and young families, who are supported not only by health care professionals but also by a wide range of stakeholders within the social domain. These systems often operate in parallel with limited coordination, making it challenging to ensure continuity, alignment, and shared responsibility across sectors, a known barrier in integrated and person-centered care implementation [47]. Finally, the actual development and maintenance of the platform when the OSFB research program concludes demand substantial infrastructural investments and ongoing costs, especially which may constrain scalability if not managed effectively. To ensure sustainable evaluation and improvement, the digital functionalities included and developed within the Family Buddy have to provide secure access to usage data and include clear agreements on data ownership and ownership of OSFB, safeguarding transparency and long-term usability beyond the research program.

The OSFB program aims to develop a socially embedded Family Buddy to support coping with mental stress and improve nutrition within a supportive living environment for (future) parents before and during pregnancy and families with at least one child under the age of 4 years. The program combines cocreation with existing interventions tailored to the needs of families living in IJsselmonde, a deprived neighborhood in Rotterdam. By involving the target population and community stakeholders at every stage, the program aims to ensure that the Family Buddy is relevant, accessible, and capable of supporting sustainable lifestyle changes. This tailored, user-centered, and life course care approach intends to foster long-term health improvements and social cohesion within communities, positioning the program as a scalable model for reducing health disparities and enhancing quality of life in deprived neighborhoods in the coming years.