Factors Influencing Physical Activity among Adolescents Living in a Low-Income Neighborhood in Copenhagen, Denmark: The WCMC Study

Background and Purpose Moderate to vigorous physical activity (MVPA) has a range of social and health benefits for adolescents. Based on survey data, adolescents with a low Socio Economic Status (SES), and/or belonging to an ethnic minority, typically engage in less organized sports than Danish adolescents. However little is known about objectively measured MVPA among ethnic minority groups in Denmark, and the factors that influence their activity level. A large scale urban renewal project in a low-income neighborhood, with focus on increasing the possibilities for youth to be active, has been carried-out by the City of Copenhagen. This neighborhood renewal project provided a unique opportunity for a natural experiment in which the When Cities Move Children (WCMC) study could measure the changes in activity levels after changes in the built environment. The WCMC study uses a combination of accelerometer and GPS measurements to determine activity levels and movement patterns, both before and after the renewal project. Furthermore, qualitative data was collected to increase the understanding of why adolescents behave as they do.

Objective The overall objective of the WCMC study is to determine the effects of a large scale urban renewal project on objectively measured physical activity levels and activity patterns among adolescents (10-16yrs old) living in a deprived area with over 50 % having a multi-ethnic background. The specific objective for this paper is to explore the association of built environment, socio-demographic and social support variables on adolescents‘ daily physical activity using both quantitative and qualitative data.

Methods For our baseline study, 653 youth enrolled at four public schools were asked to wear an accelerometer (ActiGraph GT3X) and a GPS (Qstarz BT-Q1000X) for 7 days (5 week days, 2 weekend days) to determine their level of activity and movement patterns. Their GPS position was recorded every 15 seconds and their activity level was recorded every 2 seconds. All GPS and accelerometer data were compiled and joined using an internet based computer program, the Physical Activity Location Measurement System (PALMS). All PALMS outputs were imported into ArcGIS, which enabled inclusion of environmental data. Evenson cutpoints were used to determine mean daily time in MVPA. Exposure variables were based on questionnaire data, registry data, GPS/GIS derived variables and accelerometer data. Quantitative data were analyzed in STATA using a 3-level mixed multilevel model to examine both unadjusted and adjusted models.Qualitative focus group interviews were conducted with 20 boys, primarily belonging to ethnic minority groups, to shed light on the why they were as active as they were, and at which locations.

Results 291 participants provided valid accelerometer data (3 weekdays and 1 weekend day of at least 8hrs). Among these participants 45% were boys, 42.5% had at least one parent who did not work and 64.3% had at least one parent with an ethnic minority background. The adjusted analyses showed that boys engage in significantly more minutes of daily MVPA than girls (boys: 57.8, girls: 36.9, p<0.001) and that boys with a Danish family background accumulated 16.9 minutes less of daily MVPA compared to boys from families belonging to an ethnic minority (p<0.001). The focus group interviews revealed that the boys with an ethnic background spent a lot of time outdoors, close to where they live. Much of this outdoor time is spent together with friends, being active together. As reason for being outside so much, the boys stated that they lived in small apartments with little to do, and that they liked being outside with their friends. In the specific area these boys live in, there are relatively many good possibilities to be active together with friends.

Conclusions Boys with an ethnic minority background generated on average 16.9 minutes more MVPA per day compared to Danish boys. This contradicts the common notion, based on survey data, that adolescents with an ethnic minority background are less physically active than Danish adolescents. Focus group interviews seem to confirm the hypothesis that these boys spent the majority of their leisure time outdoors in their local neighborhood, being active together with their friends. Having sufficient opportunity to be active together close to home seems to be important for this group, but exactly how much the environment contributes to their activity level needs to be studied further.

Support/Funding Source This study is funded by TrygFonden and carried out under the Center for Intervention Research in Health Promotion and Disease Prevention in Denmark.