ABSTRACT
BACKGROUND: Latinas are at increased risk for many lifestyle-related chronic diseases and are one of the least physically active populations in the US Innovative strategies are needed to help Latinas achieve the health benefits associated with physical activity (PA). This manuscript describes the study protocol of the Pasos Hacia La Salud II Study, which builds upon our previous research to test an enhanced individually-tailored, text-message and website-delivered, Spanish-language intervention (enhanced intervention), in comparison to the original web-based Pasos Hacia La Salud Intervention (original intervention). METHODS: Sedentary Latinas between the ages of 18-65 will be recruited and will complete an orientation and baseline assessments. Participants will be subsequently randomized to the original intervention, or the Enhanced Intervention, which has greater targeting of theoretical constructs such as self-efficacy, enjoyment, and social support, and which uses text messages and more dynamic and refined website features to encourage increased website use. Using a linear mixed effects regression model, we will simultaneously estimate the intervention effects on mean accelerometer-measured hours/week of moderate-to-vigorous PA (MVPA) at 6, 12, 18, and 24 months, with a subject-specific intercept (intent-to-treat sample). Change in self-reported MVPA, measured via the 7-day Physical Activity Recall, will be assessed as a secondary outcome using a similar model. We will investigate potential mediators of the intervention effect using a multiple mediation approach, and potential moderators by evaluating potential interactions. As an exploratory outcome, we will study the differences (among both study arms) in cost, in US dollars, per minute increases in weekly mean MVPA. DISCUSSION: The original Pasos PA intervention showed efficacy in helping Latinas increase PA; we expect the Enhanced Intervention to help a larger proportion of participants to increase and maintain their PA long term. This web- and text-based enhanced intervention could have great reach and dissemination potential, which could be capitalized on in the future to help to advance health equity. Adaptations made in response to the COVID-19 pandemic are also described in this manuscript. TRIAL REGISTRATION: Clinical Trial Number: NCT03491592 . First posted April 9, 2018.