Benefit of urban greenness on patients after an ischaemic stroke: mortality or recurrence? A registry-based cohort study.

Abstract

Whether living environment may influence outcome of stroke survivors remains to be elucidated. This registry-based cohort study aimed to assess the relationship between urban greenness around the residence and one-year death or recurrence after a first-ever ischaemic stroke. Patients with a first-ever ischaemic stroke who directly returned home were identified from the population-based registry of Dijon, France. For each patient, after geolocation of residential building, two greenness indices were calculated: the distance by road and pedestrian networks to the nearest public green space, and the area of green spaces within radii of 100 and 400 metres. Atmospheric NO2 and PM10 outdoor concentrations around the residence and deprivation index were assessed. During the 2005-2008 study period, 360 patients were identified and included (median age: 75 years-old (IQR: 63-83), 56% women). Fifteen died and 17 had recurrent stroke during the one year of follow-up. In adjusted models, the distance between public green spaces and patients' residence was associated with stroke recurrence or death (HR = 1.26, 95% CI: 1.08-1.48, P < 0.01, for each 100 metre section of city network). In age-stratified analysis, this association remained significant only in patients aged 65-79 years (HR: 1.37, 95% CI: 1.10-1.71, P < 0.01). When considering separately stroke recurrence and death, this association remained significant for recurrence (HR = 1.30, 95% CI: 1.07-1.58, P < 0.01) but not for death (HR = 1.17, 95% CI: 0.89-1.52). This study highlighted a beneficial influence of greenness on post-stroke recurrence in an urban area. These results indicate that urban planning policy could impact secondary prevention.