Study details | Description of variables | Results (for two different methods of analysis, when reported) | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
Independent variables | Dependent variables | Main method of analysis: | Alternative method of analysis: | |||||||||
More advanced analytical technique | Single equation analytical technique | |||||||||||
First author, date, journal | Study population | Description | Time varying | Areal unit precision | Description | Source | Description of analytical technique | Data type (time periods) | Effect sizes (95% confidence interval)1 | Method | Effect sizes (95% confidence interval)1 | |
Results where no statistically significant differences are observed between main and alternative analyses | Results where a mismatch between results is observed2 | |||||||||||
Cross sectional studies | ||||||||||||
Anderson, 2011, American Economic Journal [30] | U.S. adults (11 States) | Miles between home and fast-food restaurant | N/A | Telephone/ZIP codes | BMI | BRFSS | Instrumental variable derived from distance to the interstate highway | Cross sectional (1) | 0.09 (-0.17, 0.17) | Not reported | ||
Chen, 2012, Health Economics [31] | U.S. adults (Indianapolis, Indiana) | Number of | N/A | Individual addresses | BMI | Obesity Needs Assessment survey | Instrumental variable derived from distance to arterial roads and non-residential zones | Cross sectional (1) | OLS | None | Under-estimates: | |
(a.) restaurants, | (a.) 0.37* (confidence interval missing) | (a.) 0.06 (-0.03, 0.14) | ||||||||||
(b.) chain grocery stores, and | (b.) 0.90* (0.12, 1.682) | (b.) 0.14 (-0.21, 0.50) | ||||||||||
(c.) proportion of park land, within a 0.5 mile radius | (c.) 2.85* (0.03, 5.67) | (c.) 2.39 (-0.66, 5.45) | ||||||||||
Dunn, 2010, American Journal of Agricultural Economics [32] | U.S. adults (all States) | Number of fast food restaurants (at county level; author collected) | N/A | County level | BMI | BRFSS, 2004-2006 | Instrumental variable derived from number of interstate highway exits in the county | Cross sectional (1) | No statistically significant results were reported, except in two subgroup analyses: | OLS | No statistically significant results were reported, except in two subgroup analyses (see right). | Under-estimates were reported in two subgroup analyses: |
Female participants in medium density counties: 0.06* (0.01, 0.11) | Female participants in medium density counties: -0.01 (-0.02, 0.01) | |||||||||||
Non-white participants in medium density counties: 0.20* (0.02, 0.38) | Non-white participants in medium density counties: 0.01 (-0.02, 0.04) | |||||||||||
Dunn, 2012, Economics and Human Biology [33] | U.S. adults (Brazos Valley, Texas) | N/A | Individual addresses | Obesity likelihood | A mail survey | Instrumental variable derived from distance to nearest highway | Cross sectional (1) | No statistically significant results were reported, except in two subgroup analyses: | Probit model | No statistically significant results were reported, except in two cases (see right). | Under-estimates in just two cases: | |
e.g. Non-white participants: | Non-white participants: | Non-white participants: | ||||||||||
(a.) miles to nearest fast-food restaurant, and number of fast-food restaurants within a | (a.) -0.100* (-0.178, -0.022) | (a.) -0.088 (-0.188, 0.012) | ||||||||||
(b.) 1 mile and | (b.) 0.189* (0.030, 0.348) | (b.) 0.052 (-0.021, 0.125) | ||||||||||
(c.) 3 mile radius | (c.) 0.058 (0.005, 0.121) | (c.) 0.014 (-0.004, 0.032) | ||||||||||
Fish, 2010, Am J Public Health [34] | U.S. adults (Los Angeles County) | Resident perception of neighbourhood safety (self-reported dichotomous variable where 1= extremely or somewhat dangerous and 0=fairly or completely safe) | N/A | Individual level survey data | BMI | Los Angeles Family and Neighbourhood Survey | Instrumental variable derived from measures related to social cohesion and experience of household crime | Cross sectional (1) | 2.81* (0.11, 5.52) | OLS (using first wave 2001/2 data) | None | Under-estimate: -0.07 (-1.07, 0.93) |
Zick, 2013, IJBNPA [35] | U.S. females (Salt Lake, Utah) | Neighbourhood walkability | N/A | Census block (typically 1,500 people) | BMI | Utah Population Database | Instrumental variable derived from neighbourhood characteristics e.g. churches and schools | Cross sectional (1) | -0.24* | OLS | None | Under-estimate: 0.00 |
Longitudinal studies | ||||||||||||
Courtemanche, 2011, Journal of Urban Economics [36] | U.S. adults (all States) | Number of Walmart Supercenters per 100,000 residents (these stores provide low cost food and encourage sedentary lifestyles) | Yes | County level | BRFSS, 1996-2005 | Instrumental variable derived from distance to Walmart head office (expansion over time of Walmart stores was shown to be correlated with distance from the head office) | Repeated cross sectional (10) | OLS | None | Under-estimates: | ||
(i.) BMI | (i.) 0.24* (0.06, 0.41) | (i.) 0.02 (-0.00, 0.05) | ||||||||||
(ii.) Obesity likelihood | (ii.) 0.023* (0.011, 0.035) | (ii.) 0.001 (-0.001, 0.003) | ||||||||||
Zhao, 2010, Journal of Health Economics [3] | U.S. adults (all States) | Proportion of people living in densely populated areas with >9000 people per square mile | Yes (4; every 10 years) | MSA level (366 of these in U.S.) | (i.) BMI | National Health Interview Survey, 1976-2001 | Instrumental variable derived from exogenous expansion over time of the U.S. interstate highway system | Repeated cross sectional (25) | (i.) -0.01 (-0.03, 0.01) | Not reported | ||
(ii.) Obesity likelihood | (ii.) -0.0013* (-0.002, 0.000)3 |