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Does Unmeasured Confounding Influence Associations between the Food Environment and Body Mass Index over Time? The Coronary Artery Risk Development in Young Adults (CARDIA) Study

Citation

Rummo, Pasquale E.; Guilkey, David K.; Ng, Shu Wen; Meyer, Katie A.; Popkin, Barry M.; Reis, Jared P.; Shikany, James M.; & Gordon-Larsen, Penny (2017). Does Unmeasured Confounding Influence Associations between the Food Environment and Body Mass Index over Time? The Coronary Artery Risk Development in Young Adults (CARDIA) Study. International Journal of Epidemiology, 46(5), 1456-1464. PMCID: PMC5837451

Abstract

Background: Findings in the observational food environment and obesity literature are inconsistent, potentially due to a lack of adjustment for residual confounding.
Methods: Using data from the CARDIA study (n=12,174 person-observations; 6 exams; 1985-2011) across four U.S. cities (Birmingham, AL; Chicago, IL; Minneapolis, MN; Oakland, CA), we used instrumental-variables (IV) regression to obtain causal estimates of the longitudinal associations between the percentage of neighborhood food stores or restaurants (per total food outlets within 1-km network distance of respondent residence) with body mass index (BMI), adjusting for individual-level sociodemographics, health behaviors, city, year, total food outlets, and market-level prices. To determine the presence and extent of bias, we compared the magnitude and direction of results to ordinary least squares (OLS) and random effects (RE) regression, which do not control for residual confounding; and fixed effects (FE) regression, which does not control for time-varying residual confounding.
Results: Relative to neighborhood supermarkets (which tend to be larger and have healthier options than grocery stores), a higher percentage of grocery stores (mean=53.4%; SD=31.8%) was positively associated with BMI (

URL

https://doi.org/10.1093/ije/dyx070

Reference Type

Journal Article

Year Published

2017

Journal Title

International Journal of Epidemiology

Author(s)

Rummo, Pasquale E.
Guilkey, David K.
Ng, Shu Wen
Meyer, Katie A.
Popkin, Barry M.
Reis, Jared P.
Shikany, James M.
Gordon-Larsen, Penny

PMCID

PMC5837451