Walkable Neighborhoods and Obesity Over Time: Findings from the national REGARDs Study
Background: Previous studies reported that walkability is associated with increased physical activity and less obesity, although the evidence is mixed (1-6). Many of these previous studies are limited by their cross-sectional design and/or limited variability in terms of geography, age and race. Walk score, a valid measure of walkability, has been used in a number of studies across the globe to examine the association between walkability and various health outcomes. Although the calculation of walk score is propriety, its use allows uniformity of methods across studies.

Purpose: We examined the association between walk score and overweight/obesity status over time in a national sample of black and white adults aged 45 and older. Further, we examined whether the association between walk score and overweight/obesity status was modified by age, race or gender.
Methods: The Reasons for Geographic and Racial Differences in Stroke Study (REGARDs) enrolled 30,239 participants in 2003-7. Participants who completed both the baseline in-person examination (2003-2007) and the follow-up in-person examination approximately ten years later were included in this analysis (N=13,477). Walk score was categorized into 3 groups: car dependent, somewhat walkable, and very walkable/walker’s paradise. Body mass index (BMI) was calculated based on objectively measured height and weight and classified into weight status defined as overweight or obese versus normal weight or underweight. Logistic regression was used to calculate odds ratios (OR) of the association between walk score and weight status at follow-up, adjusted for baseline BMI, age, race, gender, income, education, marital status, urbanicity, neighborhood socioeconomic status and health conditions (diabetes, hypertension, dyslipidemia, and smoking status). Interactions between walk score and weight status by age, race and gender were examined in separate models.

Results: Participants living in very walkable neighborhoods had a 20% lower odds of being overweight or obese at follow-up compared to those who lived in a car dependent neighborhood even after controlling for baseline BMI (OR= .80; 95% CI: .65-.98). Adults in the lowest tertile of age had the strongest associations relative to older ages. Young adults in very walkable neighborhoods had a 29% lower odds of being overweight/obese at follow-up (OR = .71; 95% CI .50-.99). In addition, women had a stronger association relative to men. Women in very walkable neighborhoods had a 25% lower odds of being overweight/obese at follow-up (OR=.75; 95% CI .57-.98). There was no difference in the association between walk score and weight status by race.

Conclusion: This large national biracial study confirms other studies that reported positive health effects from neighborhood walkability. We advance knowledge by showing that weight status at 10 year follow up was associated with walkability even after accounting for baseline BMI in particular for women and younger adults. While the walk score obtained in our study was for the participant’s baseline address, the walk score reflects current neighborhood conditions and not the neighborhood conditions at baseline. The findings suggest that policies to improve the walkability of neighborhoods might have an important effect on obesity, which is associated with many negative health outcomes.

Presenter: Natalie Colabianchi
Agency Affiliation: University of Michigan

Presenter Biographical Statement: [biography]