Despite major achievements in risk factor control (primary prevention) and clinical care (secondary prevention) over the last decades, cardiovascular disease (CVD) continue to have tremendous substantial societal impact affecting 6 million people and costing 210 billion euros each year in the European Union (EU).1 CVD has a profound negative impact on quality of life of affected individuals and has significant societal consequences including major costs and premature loss of the labor force.1 Projections are pessimistic given the global ageing population, obesity epidemic, high levels of physical inactivity and sedentary behavior, poor diet, increased health inequalities, and poor mental health. Added to this, the COVID-19 pandemic has exacerbated unhealthy behaviors, health inequalities and increased the burden of mental health especially among the young. CVD is preventable: 70 to 80% of CVD incidence has been attributed to behavioral risk factors such as smoking, poor diet and physical inactivity, that subsequently impacts weight gain, blood pressure, blood glucose and blood lipids. Therefore, preventing risk factors in the first place (i.e. primordial prevention) and promoting optimal cardiovascular health (CVH) across the life course may be a new and relevant strategy to prevent the incidence of CVD. Many CVD risk factors already occur in childhood, track into adulthood, and are predictors of fatal and non-fatal CVD events in adulthood. Furthermore, early life habits are the strongest predictors of later life habits. Taken together, programs that promote healthy habits among children and their families will likely have a lasting positive impact on adult (cardiovascular) health and therefore an important societal impact. In order for such programs to be effective, sustainable and scalable, including among socially disadvantaged groups, it is critical that a holistic and trans-disciplinary codesign approach is taken accounting for the contexts of children’s family, health literacy of the children’s family, children’s well-being, and contextual factors such as their place of residence, school environment, built environment (green space, recreational places for physical activities, food supply, noise exposure). Such programs should be designed to be responsive and easily implementable, ensuring the needs and rights of children and their families are accounted for. This can be achieved through authentic engagement with all stakeholders (beneficeries as well a service providers) in contemporary codesign in diverse contexts.

Project ambition
• To inform about contextual and individual determinants of CVH and the associated health outcomes in children & adolescents
Most studies in children and adolescents have evaluated the distribution of a single CVD risk factor, especially behavioral ones, at a specific age. The few studies that have addressed the distribution of multiple risk factors focused on behavior-related factors such as weight, physical activity, diet and more recently, sleep. In fact, only three small studies (n<500), conducted in the US and France, reported the distribution of the complete CVH score and examined the determinants of CVH in children. Importantly, none evaluated the possible health benefits associated with higher CVH.
SO1 has the ambition within one year , to rapidly inform the international scientific community and the relevant stakeholders from the EU member states on (i) the level of the CVH of European children and adolescents including those from socially disadvantaged backgrounds, (ii) the individual and contextual determinants of CVH, and (iii) the potential health benefit associated with higher CVH. This will be achieved by using harmonized and readily available birth cohort data from four diverse European countries already participating to the EU Child Cohort Network (n??). This will provide the first European evidence-based data to (i) inform the general public, scientific community and policy makers on the key drivers of CVH in children; (ii) estimate the long-term health and cost savings associated with higher CVH early in life and; (iii) support recommendations for primordial prevention implementation at school across Europe.
• To develop a digital solution to support the promotion of CVH in children
The widespread availability of smartphones, tablets, and computers has opened opportunities for incorporating digital health solutions into educational settings. However, few are knowledge-based and their potential to help promoting CVH in primary-school children is currently unknown.
SO3 of ICARHE has the ambition to develop a serious game to make CVH health promotion more enjoyable and engaging for children that is safe (i.e. preventing digital addiction), effective and cost-effective, generating sustained benefits, implementable, inclusive (promoting health equity) and scalable for the EU member states. An exploitable strategy for the developed serious game will be put in place in the EU market (SO5).
• To conduct a large-scale European cRCT on CVH in primary school children aged 6 to 8 years
Most randomized controlled interventions in children and adolescents have focused on behavioral outcomes including diet, weight control or physical activity. IThree cRCTs have addressed the benefit of promoting specific items of the CVH score in children. They were school-based cRCTs in pre-school children aged 3 to 5 years in specific areas in Colombia, Spain and socio-economically deprived areas in Harlem, New York City. These interventions consisted of school educational sessions for a full academic year on health knowledge and attitudes including diet, physical activity and body mass index. The feasibility, safety, and effectiveness of these interventions were demonstrated, whereby significant differences between the groups over two years of follow-up post intervention were observed.
SO 2 to 4 of ICARHE have the ambition to test the safety, and effectiveness of a a co-designed intervention to improve the CVH of primary-school children within a cRCT. The added value of this trial is as follows. Firstly, it will be conducted in four diverse European countries, making the intervention a possible scalable solution across Europe. Secondly, it will address a more comprehensive spectrum of CVH additionally considering the biological risk factors (blood pressure, glycemia and total cholesterol) together with sleep health. Thirdly, it will be co-designed with the children and their parents/guardians, teachers, and relevant stakeholders, thereby enabling the trial to be more relevant to the local needs of the target population, a key factor for effectiveness, scalability and sustainability. Fourthly,given increasing evidence on the importance of the social and psychological determinants of health, the extent to which improvement in parents’ health literacy and the children’s well-being contribute to CVH improvement will be explored.
• To provide evidence-based recommendations for primordial prevention implementation in primary-school children across Europe
EU member states have recently released national recommendations for the first 1000 days of life. These are broad recommendations addressing home environment, parent-baby interactions or maternal health during pregnancy. SO 5 of ICARHE has the ambition to provide evidence-based recommendations for the implementation of primordial prevention in primary schools that are scalable across EU member states.