Association of neighborhood walkability with change in overweight, obesity, and diabetes

Abstract

IMPORTANCE: Rates of obesity and diabetes have increased substantially in recent decades; however, the potential role of the built environment in mitigating these trends is unclear. OBJECTIVE: To examine whether walkable urban neighborhoods are associated with a slower increase in overweight, obesity, and diabetes than less walkable ones. DESIGN, SETTING, AND PARTICIPANTS: Time-series analysis (2001-2012) using annual provincial health care (N ≈ 3 million per year) and biennial Canadian Community Health Survey (N ≈5500 per cycle) data for adults (30-64 years) living in Southern Ontario cities. EXPOSURES: Neighborhood walkability derived from a validated index, with standardized scores ranging from 0 to 100, with higher scores indicating more walkability. Neighborhoods were ranked and classified into quintiles from lowest (quintile 1) to highest (quintile 5) walkability. MAIN OUTCOMES AND MEASURES: Annual prevalence of overweight, obesity, and diabetes incidence, adjusted for age, sex, area income, and ethnicity. RESULTS: Among the 8777 neighborhoods included in this study, the median walkability index was 16.8, ranging from 10.1 in quintile 1 to 35.2 in quintile 5. Resident characteristics were generally similar across neighborhoods; however, poverty rates were higher in high-vs low-walkability areas. In 2001, the adjusted prevalence of overweight and obesity was lower in quintile 5 vs quintile 1 (43.3% vs 53.5%; P.05 for quintile 1 vs quintile 5 for each outcome) and were relatively stable over time. CONCLUSIONS AND RELEVANCE: In Ontario, Canada, higher neighborhood walkability was associated with decreased prevalence of overweight and obesity and decreased incidence of diabetes between 2001 and 2012. However, the ecologic nature of these findings and the lack of evidence that more walkable urban neighborhood design was associated with increased physical activity suggest that further research is necessary to assess whether the observed associations are causal.