[1155.1] Proximity To Supermarkets Modifies Intervention Effects on Diet and Body Mass Index Changes in an Obesity Randomized Trial

Lauren G. Fiechtner, Jason P. Block, Steven J. Melly, Mona Sharifi, Richard Marshall, Elsie M. Taveras. Department of Gastroenterology and Nutrition and Pediatric Health Services, Boston Children's Hospital, Boston, MA; Department of Internal Medicine, Brigham and Women's Hospital, Boston, MA; Department of Population Medicine, Harvard Medical School and Harvard Pilgrim Health Care Institute, Boston, MA; Department of Environmental Health, Harvard School of Public Health, Boston, MA; Division of General Pediatrics, Massachusetts General Hospital for Children, Boston, MA; Department of Pediatrics, Harvard Vanguard Medical Associates, Boston, MA.

BACKGROUND: Few studies have examined modifying influences of supermarkets on changes in diet and weight status.
OBJECTIVE: To examine the extent to which living in closer proximity to supermarkets modified the effects of an obesity intervention in changing diet and BMI z-score.
DESIGN/METHODS: We studied 486 children age 6-12 years with a BMI ≥ 95th percentile participating in an obesity cluster-randomized trial. 14 pediatric practices in Massachusetts were randomized to electronic decision support for clinicians alone (Ix1), decision support plus direct-to-parent heath coaching (Ix2) or usual care. The exposure was the intervention. Outcomes were changes in sugar-sweetened beverage, fruit and vegetable and fast-food intake and BMI z-score. We used a geographic information system to determine the distance to the closest large and small supermarket from the participants' address. We categorized proximity to supermarkets into: ≤2 and > 2 miles. We used stratified multivariable adjusted linear regression models to assess for effect modification by distance.
RESULTS: Baseline mean (SD) age was 9.7 years (1.9) and 48% were non-white. Mean (SD) change in fruit and vegetable intake was 0.2 (1.3) servings/day, 0.4 (1.4) servings/day, and 0.09 (1.4) servings/day in Ix1, Ix2, and controls respectively (p=0.11). Mean (SD) change in BMI z-score was -0.1 (0.2) units in Ix1 and Ix2 compared to -0.04 (0.2) units in controls (p=0.04). In stratified models, children in Ix2 living ≤ 2 miles away from a large supermarket increased their fruit and vegetable intake by 0.55 servings/day (95% CI: 0.21, 0.89)(v. a decrease of 0.21 servings/day among those living >2 miles), decreased their fast-food intake by 0.36 servings/week (95% CI:-0.66, -0.06) (v. an increase of 0.28 servings/day among those living > 2 miles) and decreased their BMI z-score by 0.07 units (95% CI: -0.13, -0.01) (v. an increase of 0.03 units among those living >2 miles). Estimates were similar in Ix1 and with small supermarkets as the effect modifier. Proximity to supermarkets was not an effect modifier of the relationship between the intervention and sugar-sweetened beverage intake.
CONCLUSIONS: Living in closer proximity to supermarkets was associated with greater improvement in fruit and vegetable intake and weight status, and reduction of fast-food intake among children in an obesity intervention.
First Author is a Fellow in Training

Session: Platform Session: General Pediatrics: Obesity I (8:00 AM - 10:00 AM)
Date/Time: Saturday, May 3, 2014 - 8:00 AM
Room: East 13 - Vancouver Convention Centre
Course Code: 1155


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