Independent and joint associations of neighbourhood greenness and walkability with transportational and recreational physical activity among youth and adults in Canada.

Objectives: Greener neighbourhoods may support physical activity; however, it is also important to consider whether greener neighbourhoods are walkable. We assessed whether neighbourhood greenness and walkability were independently and jointly associated with transportational (PA Methods: We analyzed repeated cross-sectional data from 132,927 urban-dwelling youth (12-17 years) and adults (≥18 years) who participated in the Canadian Community Health Survey (2015-2018). To derive an indicator of neighbourhood greenness, for each survey year, we aggregated mean Normalized Difference Vegetation Index (NDVI) values within 2016 dissemination areas. As a proxy for neighbourhood walkability, we used 2016 Canadian Active Living Environments (Can-ALE) metrics. We used weighted linear regressions to examine whether, and the extent to which, neighbourhood NDVI and the Can-ALE index were independently and jointly associated with self-reported and log-transformed PA Results: Among adults, but not youth, higher NDVI was independently associated with higher PA Conclusion: Living in a neighbourhood that is both greener and more walkable was more strongly associated with higher transportational, but not recreational, physical activity, than either feature alone. These novel findings highlight the importance of designing cities that are both greener and more walkable to promote active living.