Abstract P235: The Association Between Neighborhood Walkability and Physical Activity in a Behavioral Weight Loss Trial Testing the Addition of Remotely Delivered Feedback Messages to Self-Monitoring

Abstract

Background: Adding feedback messages (FB) to self-monitoring (SM) may reinforce behavior change. However, socio-environmental conditions (e.g., limited access to parks and low walkability) may limit one’s ability to respond to FB focused on physical activity (PA). Hypothesis: Residents of high walkability neighborhoods will achieve higher PA levels at 12 months than those in low walkability neighborhoods regardless of whether FB was randomly assigned. Methods: This is a secondary analysis of a 12-month behavioral weight loss trial, where adults with overweight or obesity were randomized to SM+FB (n=251) or SM alone (n=251). The SM+FB group received a smartphone pop-up message every other day tailored to their PA data. Assessment included neighborhood walkability via Smart Walk Score (low [<50] vs. high [≥50]), moderate to vigorous PA (MVPA) minutes and step count via Fitbit Charge 2™, and weight via digital smart scales. We report adjusted regression coefficients (b) with 95% confidence intervals from linear mixed modeling. To normalize the residual distribution, we applied a natural log transformation (ln) to MVPA. Results: Participants (N=502) were primarily white (82.5%), female (79.5%), well-educated (16.4±2.8 years), mean age of 45±14.4 years with a body mass index (BMI) of 33.10±3.93 kg/m 2 . Compared to those from neighborhoods with high walkability, participants from neighborhoods with low walkability were more likely to be White (75.3% vs. 87.8%, P ==.0003) and older (41.4±14.7 vs. 47.7±13.6 years, P <.0001) at baseline. After adjusting for these characteristics, baseline BMI and exercise self-efficacy, neighborhood walkability did not moderate the effect of treatment assignment on lnMVPA (b±SE=-0.20±0.15, P =.170) or steps (b±SE=-816.48±484.83, P =.092) over 12 months. lnMVPA (b±SE=0.12±0.10, P =.244) and steps (b±SE=415.05±344.50, P =.228) were on average similar between walkability groups. Both lnMVPA (b 6mo ±SE=0.003±0.07, P =.968; b 12mo ±SE=-0.23±0.08, P =.009) and steps (b 6mo ±SE=-416.18±195.68, P =.034; b 12mo ±SE=-1443.75±227.49, P <.0001) declined over time. On average, the SM+FB group had greater lnMVPA (b±SE=0.23±0.12, P =.047) and marginally greater number of steps (b±SE=674.84±392.91, P =.086) than SM group. There were no significant interactions for group and time or group, time, and walkability ( P ≥.05). Conclusion: On average, FB had a small but significant positive impact on PA over 12 months, but neighborhood walkability did not moderate the treatment effect of FB on PA. The small effect of FB on PA may have limited our ability to detect moderation of neighborhood walkability on the treatment effects of FB on PA. Future studies need to replicate this analysis in a trial with larger treatment effects and a more diverse sample.