Cardiovascular disease is a leading cause of death in the United States, and high blood pressure, a precursor to its development, disproportionately affects African American adults. Engaging in recommended levels of physical activity has been associated with clinically significant reductions in blood pressure. In addition, social and physical environmental factors (social support, neighborhood walkability) have been shown to predict physical activity in longitudinal studies. Thus, social and physical environmental supports may positively influence physical activity, which may in turn reduce blood pressure as part of a causal pathway or mediated effect. In the present study it was hypothesized that peer social support for physical activity and neighborhood walkability (social and physical environmental supports) would predict physical activity (measured by 7-day accelerometry and reported walking and exercising) which would operate as a mediator in predicting blood pressure. Baseline data collected in a sample of African American adults (N =434) living in underserved (e.g. low income, high crime) communities and participating in the Positive Action for Today’s Health (PATH) trial were obtained to test this hypothesis. The sample was predominantly female (63%), overweight (body mass index [BMI]; MBMI=30.88, SD=8.43), and had low rates of physical activity (e.g. an average of 30 minutes of moderate to vigorous activity each week for the sample) and elevated BP with a mean systolic blood pressure of 132.37 (SD=17.89) and a mean diastolic blood pressure of 81.39 (SD=10.96). Neighborhood walkability was associated with physical activity measured via accelerometry (r=-.14, p<.01), which was correlated with SBP (r=-.19, p<.01). A main effect of neighborhood walkability to reported walking was demonstrated (β = .128 se = 3.907, T (433) = 2.268, p < .05). Hypotheses for mediation were not supported, with results indicating no mediated effects and no direct effects in the models which included accelerometry-measured physical activity and reported exercise and walking. Results of the current study demonstrate support for the role of social and physical environmental factors in influencing physical activity, but failed to demonstrate indirect effects in influencing blood pressure as part of a causal pathway or mediated effect. These findings are consistent with studies that have investigated similar theoretical models, which demonstrate a role for social environmental factors in predicting health behaviors and outcomes, but which have failed to support mediation. The mediation hypothesized may not be present in samples with low physical activity, and social and physical environmental supports may not operate independently of associated stressors. Further investigation is therefore needed with additional social and physical environmental supports and stressors modeled, and within larger and possibly more physically active samples.
|Advisor:||Wilson, Dawn K.|
|Commitee:||Fairchild, Amanda, Forthofer, Melinda|
|School:||University of South Carolina|
|School Location:||United States -- South Carolina|
|Source:||MAI 50/01M, Masters Abstracts International|
|Subjects:||Psychobiology, Behavioral psychology|
|Keywords:||Blood pressure, Environment, Neighborhood walkability, Physical activity, Social support|
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