175094 Environmental influences on physical activity and obesity in African American adolescents-a multilevel perspective

Monday, October 27, 2008

Alice F. Yan, MD , Department of Public and Community Health, School of Public Health, University of Maryland, College Park, College Park, MD
Carolyn C. Voorhees, MS, PhD , Department of Public and Community Health, University of Maryland, College Park, MD
Objective: This study, recently funded by Robert Wood Johnson Foundation, is to evaluate the direct and indirect effects of individual, built, and psychosocial environmental factors on the body mass index (BMI) of African American adolescents, and to assess how the relationships may be mediated by physical activity (PA) levels in an urban setting. To achieve this goal, three environments (residential, commercial, and recreation) will be examined.

Aim1: To estimate the effects of multi-dimension factors (i.e., sociodemographic and three neighborhood environments) on PA levels among African American adolescents.

Aim2: To estimate the effects of multi-dimension factors on BMI and assess how the relationships may be mediated by PA levels.

Aim3: To test the theoretical pathways of complex relationships among multi-dimension factors, PA and BMI as hypothesized by the social ecological model.

Methods: A stratified random sample of 350 Students (58.4% female, 69% African American, and grade 9th -12th) was drawn from two urban magnet high schools in Baltimore City. The outcome measurements cover a broad array of variables, including BMI, walking behavior, overall PA measured using accelerometers, and travel mode measured by a one-week trip diary. The independent variables are measures of three environments and individual socio-demographic status. Given the multilevel nature of the data, the hierarchical linear model analysis will be employed. The mediation analyses will be conducted to examine the mediating effect of PA. Finally, structural equation modeling will be employed to test the theoretical pathways of complex relationships among study variables as hypothesized by the social ecological model.

Learning Objectives:
• By the end of the session the participant will know the measurements of residential, commercial, and recreation environment. • By the end of the session the participant will be able to identify factors within residential, commercial, and recreation environment that will influence adolescents’ physical activity. • By the end of the session the participant will be able to understand how environmental and individual factors interrelated and how such interactions may have different influence on walking and overall physical activity in a broader socioecological context.

Keywords: Environmental Health, Obesity

Presenting author's disclosure statement:

Qualified on the content I am responsible for because: I am principal investigator of the study. I conceived of the research questions and wrote the abstract.
Any relevant financial relationships? No

I agree to comply with the American Public Health Association Conflict of Interest and Commercial Support Guidelines, and to disclose to the participants any off-label or experimental uses of a commercial product or service discussed in my presentation.

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See more of: Environment