Evaluating the protective effect of public open space on social connectedness: evidence from a natural experiment cohort study in three Canadian cities

Community design has the potential to address urban isolation and loneliness at a population level, but limited research on the causal effects of the built environment constrains evidence-based action in cities. This study examined the effect of public open space on changes in social connectedness among adults (n = 665) during the COVID-19 pandemic, using geospatial data from OpenStreetMap and health survey data from three cities (Montréal, Saskatoon, and Vancouver). Treating the pandemic as a natural experiment, we used multilevel models to analyze whether public open space exposure (defined as the ratio of land area within 500m of home) modified changes in community belonging, loneliness, and neighbouring from 2018 to 2020/2021. First, we found little evidence of changes in social connectedness in our cohort overall and within subgroups. On average, loneliness increased slightly, and belonging and neighbouring remained stable. Second, we found that higher public open space exposure (≥10 % neighbourhood land area) had a modest protective effect on community belonging only (0.14, 95 % CI = 0.01 to 0.27). These findings add to a limited but growing evidence base on the role of the built environment in shaping social connectedness, while highlighting challenges involved in examining causal impacts. As cities invest in public open space to support policy goals around sustainability and livability, evaluating co-benefits for social connectedness are critical opportunities for strengthening the evidence on built environment solutions to social isolation and loneliness.