Impact of neighbourhood walkability on the onset of multimorbidity: a cohort study

Multimorbidity has become highly prevalent around the globe and been associated with adverse health outcomes and cost of care. The built environment has become an important dimension in response to obesity and associated chronic diseases by addressing population sedentariness and low physical activity. OBJECTIVE: The aim of the following study was to examine whether there was an increased risk for multimorbidity for those living in less walkable neighbourhoods. It was hypothesised that participants residing in less walkable neighbourhoods would have a higher risk for multimorbidity. SETTING: City of Toronto and 14 neighbouring regions/municipalities within Ontario, Canada. PARTICIPANTS: Study participants who had completed the Canadian Community Health Survey between the year 2000 and 2012, between 20 and 64 and 65 and 95 years of age, residing within a neighbourhood captured in the Walkability Index, and who were not multimorbid at the time of interview, were selected. INTERVENTION: The Walkability Index was the key exposure in the study, which is divided into quintiles (1-least, 5-most walkable neighbourhoods). Participants were retrospectively allocated to one of five quintiles based on their area of residency (at the time of interview) and followed for a maximum of 16 years. PRIMARY OUTCOME MEASURE: Becoming multimorbid with two chronic conditions. SECONDARY OUTCOME MEASURE: Becoming multimorbid with three chronic conditions. RESULTS: Risk for multimorbidity (two chronic conditions) was highest in least compared with most walkable neighbourhoods with an HR of 1.14 (95% CI: 1.02 to 1.28, p=0.0230). While results showed an overall gradient response between decreased walkability and increased risk for multimorbidity, they were not statistically significant across all quintiles or in the older-adult cohort (65-95 years of age). CONCLUSION: Study results seem to suggest that low neighbourhood walkability may be a risk factor for multimorbidity over time. More studies are needed to examine whether neighbourhood walkability is a potential solution for multimorbidity prevention at the population level.