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 and improve cardiometabolic disease risk factors among
African American women. In a 12-month, two arm randomized trial, 210 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=105), or a Fitbit-only comparison arm (n=105). 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.
