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Changes in Walking, Body Mass Index, and Cardiometabolic Risk Factors following Residential Relocation: Longitudinal Results from the CARDIA Study

Citation

Braun, Lindsay M.; Rodriguez, Daniel A.; Song, Yan; Meyer, Katie A.; Lewis, Cora E.; Reis, Jared P.; & Gordon-Larsen, Penny (2016). Changes in Walking, Body Mass Index, and Cardiometabolic Risk Factors following Residential Relocation: Longitudinal Results from the CARDIA Study. Journal of Transport & Health, 3(4), 426-439. PMCID: PMC5282825

Abstract

Background: While many studies have found the built environment to be associated with walking, most have used cross-sectional research designs and few have examined more distal cardiometabolic outcomes. This study contributes longitudinal evidence based on changes in walking, body mass index (BMI), and cardiometabolic risk following residential relocation.
Methods: We examined 1079 participants in the CARDIA study who moved residential locations between 2000 and 2006 (ages 32–46 in 2000, 49% white/51% black, 55% female). We created a walkability index from measures of population density, street connectivity, and food and physical activity resources, measured at participants’ pre- and post-move residential locations. Outcomes measured before and after the move included walking, BMI, waist circumference, blood pressure, insulin resistance, triglycerides, cholesterol, atherogenic dyslipidemia, and C-reactive protein. Fixed effects (FE) models were used to estimate associations between within-person change in walkability and within-person change in each outcome. These estimates were compared to those from random effects (RE) models to assess the implications of unmeasured confounding.
Results: In FE models, a one-SD increase in walkability was associated with a 0.81 mmHg decrease in systolic blood pressure [95% CI: (−1.55, −0.07)] and a 7.36 percent increase in C-reactive protein [95% CI: (0.60, 14.57)]. Although several significant associations were observed in the RE models, Hausman tests suggested that these estimates were biased for most outcomes. RE estimates were most commonly biased away from the null or in the opposite direction of effect as the FE estimates.
Conclusions: Greater walkability was associated with lower blood pressure and higher C-reactive protein in FE models, potentially reflecting competing health risks and benefits in dense, walkable environments. RE models tended to overstate or otherwise misrepresent the relationship between walkability and health. Approaches that base estimates on variation between individuals may be subject to bias from unmeasured confounding, such as residential self-selection.

URL

http://dx.doi.org/10.1016/j.jth.2016.08.006

Reference Type

Journal Article

Year Published

2016

Journal Title

Journal of Transport & Health

Author(s)

Braun, Lindsay M.
Rodriguez, Daniel A.
Song, Yan
Meyer, Katie A.
Lewis, Cora E.
Reis, Jared P.
Gordon-Larsen, Penny

PMCID

PMC5282825