Abstract/Project Summary
African American women experience a high burden of cardiometabolic disease conditions. Fifty-seven percent
are obese, 57% have cardiovascular disease, and 12% have diagnosed diabetes. Engaging in regular aerobic
physical activity is an established mechanism to prevent and manage these cardiometabolic diseases. The
purpose of this study is test the efficacy of a culturally tailored, theory-based smartphone-delivered physical
activity intervention to increase physical activity, promote adherence to national aerobic physical activity
guidelines, and improve cardiometabolic disease risk factors among African American women. In a 12-month,
two arm randomized trial, 240 sedentary (i.e., < 60 minutes/week of moderate-to-vigorous intensity physical
activity) African American women with obesity (i.e., BMI >30 kg/m2) will be assigned to receive either Smart
Walk, a culturally tailored, Social Cognitive Theory-based physical activity promotion intervention (n=120), or a
Fitbit-only comparison arm (n=120). The Smart Walk intervention group will receive a culturally tailored
physical activity intervention delivered via the Smart Walk smartphone app, virtual physical activity coaching,
and text messages. Features available on the Smart Walk app include: 1) personal profile pages, 2) culturally
relevant multi-media (i.e., text and video) physical activity promotion modules, 3) message/discussion boards,
and 4) physical activity self-monitoring/tracking feature that integrates with Fitbit activity monitors for
participants to track their daily, weekly, and monthly activity. Virtual physical activity coaches will actively
engage and facilitate group-based dialogue among participants on the discussion boards and provide
individualized, one-on-one physical activity coaching via telephone or commercially available app-based video
teleconferencing software, based on participant preference. Smart Walk participants also receive three
physical activity promotion text messages each week for the duration of the active 4-month intervention. The
Fitbit-only arm comparison arm will receive a Fitbit activity monitor and be encouraged to use the commercially
available device to increase physical activity. We hypothesize participants in the Smart Walk intervention group
will demonstrate significantly greater improvements in physical activity and cardiometabolic risk factors when
compared to the Fitbit-only comparison group. Primary outcomes include self-reported and accelerometer-
measured changes in physical activity. Secondary outcomes include traditional risk factors for cardiometabolic
disease (i.e., BMI, blood pressure, serum lipid profiles, glucose intolerance, insulin resistance) and more novel
and prognostic risk factors, including cardiorespiratory fitness, aortic pulse wave velocity, pro-inflammatory
biomarkers of TNF-a, IL-6, and anti-inflammatory biomarkers of IL-10 and IL-15. We will also explore
mediators and moderators of intervention effectiveness and determine the total societal cost per participant of
delivering the Smart Walk intervention and the cost-effectiveness of the two study groups to increase
minutes/week of moderate-to-vigorous physical activity.
