The Local Food Environment and Obesity: Evidence from Three Cities.

OBJECTIVE: This study aimed to identify the association between the food environment and obesity. METHODS: BMI and waist circumference (WC) were measured in 8,076 participants from three cities. The number of fast-food restaurants, full-service restaurants, bars/pubs, markets, and liquor stores within 500 m of each participant was documented. The association between the food environment (ratio of fast-food to full-service restaurants, ratio of bars/pubs to liquor stores, and presence of markets) with obesity (BMI ≥ 30 kg/m2 ) and abdominal obesity (WC ≥ 102 cm for males or WC ≥ 88 cm for females) was investigated, adjusted for age, sex, education level, neighborhood deprivation, neighborhood type, and total hours per week of walking and taking into account city-level clustering. RESULTS: The ratios of fast-food to full-service restaurants and of bars/pubs to liquor stores were positively associated with obesity (OR = 1.05 [CI: 1.02-1.09] and OR = 1.08 [CI: 1.04-1.13], respectively). The ratio of bars/pubs to liquor stores was positively associated with abdominal obesity (OR = 1.10 [CI: 1.05-1.14]). There was no association between markets and either obesity or abdominal obesity. CONCLUSIONS: Features of the food environment have varying associations with obesity. These features have an additive effect, and future studies should not focus on only one feature in isolation.

Unpacking walkability indices and their inherent assumptions.

Walkability indices are used to characterize the relationship between health and place. Indices make assumptions that affect analysis of the built environment and resulting walkability scores. This study compares three walkability indices created by health researchers focusing on the methods, variables, and walkability scores resulting from differences in definitions and methods. This paper deconstructs the walkability algorithms utilized by each index and rebuilds them in Vancouver, Canada. We find that neighbourhoods in the northern core closer to the downtown area have similar walkability scores across all three indices, while the outer peripheral neighbourhoods with moderate to low walkability have more variation in walkability scores across indices. Most walkability variables - residential density, street connectivity, and land-use - lack a rationale for inclusion, often assumed by researchers. Walkability indices used in health research prove to be incongruent with each other and misrepresentative of actual human behavior. We explore the impact of variable selection and methodologies on indices in the interest of more rigorous health research.