Impact of policy and built environment changes on obesity‐related outcomes: a systematic review of naturally occurring experiments

Abstract

Policies and changes to the built environment are promising targets for obesity prevention efforts and can be evaluated as "natural"-or "quasi"-experiments. This systematic review examined the use of natural-or quasi-experiments to evaluate the efficacy of policy and built environment changes on obesity-related outcomes (body mass index, diet, or physical activity). PubMed (Medline) was searched for studies published 2005-2013; 1,175 abstracts and 115 articles were reviewed. Of the 37 studies included, 18 studies evaluated impacts on nutrition/diet, 17 on physical activity, and 3 on body mass index. Nutrition-related studies found greater effects due to bans/restrictions on unhealthy foods, mandates offering healthier foods, and altering purchase/ payment rules on foods purchased using low-income food vouchers compared to other interventions (menu labeling, new supermarkets). Physical activity-related studies generally found stronger impacts when the intervention involved improvements to active transportation infrastructure, longer follow-up time, or measured process outcomes (e.g., cycling rather than total physical activity) compared to other studies. Only three studies directly assessed body mass index or weight, and only one (installing light-rail system) observed a significant effect. Studies varied widely in the strength of their design and studies with weaker designs were more likely to report associations in the positive direction.

Neighbourhood built environment characteristics associated with different types of physical activity in Canadian adults

“…Natural experiments are needed to assess temporal relations between changes in the built environment and changes in physical activity. 52 The modifiable areal unit problem implies that chosen operational definition of the neighbourhood can impact estimated associations with physical activity. 53 Definitions of neighbourhood boundaries can influence the estimated associations between the built environment and physical activity.…”

Caractéristiques de l’environnement bâti du quartier associées à différents types d’activité physique chez les adultes canadiens

“…Le problème du changement d'unité spatiale suppose que la définition opéra-tionnelle choisie pour décrire le quartier peut avoir une incidence sur les associations estimées en lien avec l'activité physique 53 . Les définitions quant aux limites du quartier peuvent avoir une influence sur les associations estimées entre l'environnement bâti et l'activité physique 54,55 .…”

Characteristics of the environmental microscale and walking and bicycling for transportation among adults in Curitiba, Paraná State, Brazil

“…Other studies have shown the positive effect of environmental changes on commuting behavior 12,13,14,15 . However, a large share of the evidence comes from studies in high-income countries, which may not represent the urban and sociocultural characteristics of lower-income countries like those of Latin America 3,6,7 .…”