A Time-Based Objective Measure of Exposure to the Food Environment.

Jason Scully,Anju Aggarwal,Adam Drewnowski,Anne Moudon,Philip Hurvitz

doi:10.3390/ijerph16071180

Abstract

Exposure to food environments has mainly been limited to counting food outlets near participants’ homes. This study considers food environment exposures in time and space using global positioning systems (GPS) records and fast food restaurants (FFRs) as the environment of interest. Data came from 412 participants (median participant age of 45) in the Seattle Obesity Study II who completed a survey, wore GPS receivers, and filled out travel logs for seven days. FFR locations were obtained from Public Health Seattle King County and geocoded. Exposure was conceptualized as contact between stressors (FFRs) and receptors (participants’ mobility records from GPS data) using four proximities: 21 m, 100 m, 500 m, and ½ mile. Measures included count of proximal FFRs, time duration in proximity to ≥1 FFR, and time duration in proximity to FFRs weighted by FFR counts. Self-reported exposures (FFR visits) were excluded from these measures. Logistic regressions tested associations between one or more reported FFR visits and the three exposure measures at the four proximities. Time spent in proximity to an FFR was associated with significantly higher odds of FFR visits at all proximities. Weighted duration also showed positive associations with FFR visits at 21-m and 100-m proximities. FFR counts were not associated with FFR visits. Duration of exposure helps measure the relationship between the food environment, mobility patterns, and health behaviors. The stronger associations between exposure and outcome found at closer proximities (<100 m) need further research.

Highlights

Exposure to the food environment may influence both diet quality and obesity rates [1,2,3]
Eight participants with workplaces outside King County were removed due to the possibility of daily daily unmeasured fast food restaurants (FFRs) exposures occurring outside the county
Using FFRs as stressors, this study showed that the amount of time spent daily near FFRs predicted FFR visits, but the number of FFRs along a person’s daily path did not

Summary

Introduction

Exposure to the food environment may influence both diet quality and obesity rates [1,2,3]. Much of the evidence underlying potential FFR restrictions has been derived from studies whose measures of exposure are counts of FFRs within some distance of a study participant’s home address [13,14]. These measures only capture food availability and accessibility near home, and ignore people’s daily mobility patterns, which frequently extend far beyond the home neighborhood and may or may not entail being near a FFR [15,16,17,18,19]. Researchers have repeatedly called for more nuanced exposure measures that capture the complex and dynamic spatial experiences of modern urban life [20,21,22,23,24,25,26]

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Discussion

Conclusion