Unraveling why, how and under which conditions do green interventions improve health and wellbeing in deprived neighborhoods: a realist review

<p>Background: Approximately 75% of the European Union population lives in urban areas, a proportion expected to exceed 80% by 2050. Urban green spaces (UGS) are widely recognized for promoting health and well-being. Interventions that increase or improve UGS have been associated with greater use of green spaces and higher levels of physical activity, contributing to positive physical and mental health outcomes. Such interventions may be especially beneficial for lower socioeconomic status (SES) groups living in deprived neighborhoods. However, systematic reviews report inconsistent and sometimes contradictory evidence regarding the positive health effects of UGS interventions in these areas. Without understanding the essential elements and processes underlying effectiveness, it remains unclear why certain interventions succeed and how they can be transferred to other contexts. To address this gap, a realist review was conducted to identify and map the mechanisms and processes through which UGS interventions may improve health in deprived neighborhoods.Methods: An iterative realist review methodology was used to uncover why, how, for whom, and under what conditions UGS interventions are effective. Initial theory development drew on input from residents and professionals, as well as scientific and grey literature. The review followed the RAMESES Quality Standards for Realist Reviews. Retrieved studies were systematically screened and iteratively analyzed to develop Context–Mechanism–Outcome Configurations (CMOCs) and an overarching Realist Programme Theory.Results: Sixteen articles were synthesized, resulting in 17 CMOCs grouped into five themes: social capital, lower thresholds for physical activity, enjoyment of nature, safety, and community involvement. These themes clarify how and under which circumstances UGS interventions can positively influence health in deprived neighborhoods. Key mechanisms include social processes (e.g., increased social support and cohesion), physical processes (e.g., greater physical activity and reduced stress and fatigue), and psychological processes (e.g., mental restoration and improved concentration). Community participation emerged as a cross-cutting mechanism that can activate all pathways by bringing residents together across demographic differences. Environmental, individual, social, and cultural factors shape the extent to which these mechanisms are triggered.Conclusion: UGS interventions operate through multiple, interrelated dynamics. Effective implementation requires attention to diverse (environmental) improvements and to the local mechanisms at play. Tailoring interventions to community needs is essential to ensure that residents of deprived neighborhoods fully benefit from urban green spaces.</p>