Joanna Lane ^1,2 Rhiannon T. Edwards ^3* Balázs Babarczy ⁴ Holly Whiteley ³ Vidya Oruganti ⁵ Maureen Rutten-van Mölken ⁶ Caroline Costongs ⁷ Anant R. Jani ⁸ Sarah Wordsworth ⁹ Alison Maassen ⁷ Apostolos Tsiachristas ⁹ Jacob Davies ³ Bengt Stavenow ¹⁰ Jolanda Van Vliet ¹¹ Steve Wright ^1,12 Lina Papartyte ⁷ Jennifer Catherine Camaradou ¹ Rositsa Koleva-Kolarova ⁹

• ¹ Other, Amsterdam, Netherlands
• ² University of South-Eastern Norway (USN), Kongsberg, Vestfold, Norway
• ³ Bangor University, Bangor, United Kingdom
• ⁴ Syreon Research Institute, Budapest, Hungary
• ⁵ Norwegian School of Economics, Bergen, Hordaland, Norway
• ⁶ Erasmus University Rotterdam, Rotterdam, Netherlands
• ⁷ EuroHealthNet, Brussels, Belgium
• ⁸ Heidelberg University, Heidelberg, Baden-Württemberg, Germany
• ⁹ University of Oxford, Oxford, England, United Kingdom
• ¹⁰ Innovation Scania, Lund, Sweden
• ¹¹ Other, Kristianstad, Sweden
• ¹² Bartlett Faculty of the Built Environment, University College London, London, England, United Kingdom

The prevalence of preventable non-communicable disease (NCD) underpins the need for a lifecourse and cross-sectoral approach to population health that is grounded in health promotion and disease prevention. European Union (EU) countries typically spend 6% to 13% of gross domestic product (GDP) on health care, yet less than 3% of this is dedicated to prevention. The extent to which spending in other sectors prevents avoidable ill-health is largely unknown. The lack of fiscal space post-COVID-19 means shifting from models of care built around treatment to those with greater emphasis on prevention will require innovative, evidence-based investment within and between sectors. The term "smart capacitating investment" (SCI) has previously been used to understand how to best boost social infrastructure investment in education, health, transport and housing across the EU. Here we take that idea further by exploring the applicability of SCI to public health financing to improve population health and well-being.To explore and develop innovative SCI models and tools that enable collaboration and investment across health ecosystems for enhanced health promotion and disease prevention, test them in diverse real-world settings, and create a roadmap for large-scale implementation.The Invest4Health (I4H) project brings together transdisciplinary expertise in epidemiology, public health, health economics, population science, business management, finance, implementation and social sciences, digital health innovation, and regional health systems. The project consists of eight work packages which span the exploration and conceptualisation of SCI in public health; the characterisation of SCI-compatible business and finance models; piloting and evaluation of these models in four European testbeds (Sweden, Germany, Spain and Wales); and exploring the opportunities for sustainable replication and scaling of SCI and future research.We present an introduction to the I4H project, the concept of SCI applied to public health, plus key points for discussion internationally.