Background
The built environment provides opportunities to promote physical activity and reduce obesity. The Trial of Activity for Adolescent Girls (TAAG) is a national randomized controlled intervention trial to promote physical activity among adolescent girls. We conducted a secondary analysis of these data to examine whether the environment in which the girls live may be associated with physical activity.
Objectives
To determine the association between proximity to parks and schools and MVPA in adolescent girls.
Methods
1,804 sixth grade girls from 6 study centers and 36 schools across the U.S. wore accelerometers for 7 days. In the first analysis girls' addresses were mapped and distances to schools were calculated along the shortest street network route. For the second analysis the number of public parks within a 1-mile radius of the girls' homes was determined. We developed two separate 3-level hierarchical models to study distance to schools and proximity to parks. The models nested girls within schools and schools within sites, controlling for neighborhood socioeconomic status, neighborhood percent African American, neighborhood percent Hispanic, and the girl's race/ethnicity. The outcome variable was MET-weighted minutes of MVPA outside of
school hours (after 3pm weekdays and weekends).
Results
The average number of intensity weighted MET minutes of MVPA per week after school was 617 with a range of 50 to 7,580. Girls lived an average 2.3 miles from their school, ranging from 0.1 to 19.9 miles. There was an average of 2.4 parks in a 1-mile radius of girls' homes, with a range of 0-17. On average, girls who lived closer to schools and had more parks in a 1 mile radius of their homes had more minutes of weekly MET-weighted MVPA per week than girls further away from schools and with fewer nearby parks, respectively. Girls living within 1/2 mile of the schools had 3, 7, and 12 more minutes of weekly METweighted MVPA than girls who lived 2.3, 3.6, and 6 miles from the school, respectively. Girls with 1,2, and 3 parks within a 1-mile radius of their home had 23, 46, and 71 more minutes of weekly MET-weighted MVPA, than girls with no parks, respectively.
Conclusions
Availability of parks appears to be an important correlate of MVPA. Distance to school is a significant correlate of MVPA, but the effect size is small. Our cross sectional data support the claim that the built environment may facilitate healthy behaviors.
