Mediation Effect of Physical Activity on Obesity in Black Women.

Background And Objective: Sociodemographic and lifestyle factors, physical activity, diet, and nutrients are important in the understanding of obesity. The possibly direct or indirect nature of the associations among these factors and the eventual link to obesity is not well understood. In this study, we assess the indirect association between socio-demographic factors and obesity.

Design: A case-control study involving African American women conducted at Howard University Cancer Center.

Participants And Methods: One hundred ninety eight participants gave information on anthropometric measurements, intake of dietary supplements and nutrients, socio-demographic factors (age, marital status, income and education) and physical activity. Path analysis was utilized to assess associations between socio-demographic factors and obesity through physical activity, dietary supplements and nutrients, smoking or alcohol consumption.

Main Results: The mean age of the participants was (55 ± 12 years), with 50% being obese (BMI ≥ 30 kg/m). Obesity level decreased by approximately 7% for every one level increase in education via its prior effect on vigorous physical activity. Age had a significant positive indirect effect on obesity through vigorous physical activity - with obesity levels increasing by approximately 6% for every one year increase in age via its prior effect on vigorous physical activity.

Conclusions: Vigorous physical activity mediates the association between education and age on obesity.