Tailoring Mobile Health Technology to Reduce Obesity and ImproveCardiovascular Health in Resource-Limited Neighborhood Environments: A Multi-Level, Community-Based Physical Activity Intervention

华盛顿特区心血管（CV）健康和需求评估的女性数据为未来体育活动（PA）干预队列的移动健康用户参与度提供了初步见解。我们发现，在资源有限的社区中，移动健康技术与CBPR策略的部署可以帮助目标PA改善非裔美国妇女的心血管健康。

Data on women in the Washington, DC Cardiovascular (CV) Health and Needs Assessment provided initial insights into mHealth user engagement for the future physical activity (PA) intervention cohort. We showed that deployment of mHealth technology with CBPR strategies can help target PA for improving cardiovascular health among African American women in resource-limited communities. We gathered qualitative data to inform the development of a mobile app that promotes PA among African American women (N=16) from regions of the Washington, DC metropolitan area with the highest cardiovascular disease burden. Participants used an app created by the research team, which provided motivational messages and educational content to promote PA. Subsequently, participants engaged in semi-structured focus group interviews about participants experiences of using the app. Participants emphasized the need to improve the app by optimizing automation, increasing relatability (eg, photos that reflect the target demographic), increasing educational material (eg, health information), and connecting with community resources (eg, cooking classes and exercise groups). Involving target users in the development of a culturally sensitive PA app is an essential step for creating an app with higher likelihood of acceptance and use in a technology-enabled intervention. This may decrease health disparities in CVD by more effectively increasing PA in a minority population. To gain more insights into the utility of interventions targeting PA, we used epidemiologic data to examine PA as a mediator of the relationship between neighborhood social environment perceptions and depressive symptoms in the Jackson Heart Study, a prospective, community-based cohort study of African-American adults from Jackson, Mississippi (n=2209). Greater perceived neighborhood violence and problems were related to greater depressive symptoms. Neighborhood violence and problems were also indirectly related to depressive symptoms. Social cohesion was not directly or indirectly related to depressive symptoms. PA appears to mediate the relationship between perceived social environment and depressive symptoms. These results suggest that for African Americans, improving individuals neighborhood perceptions may be beneficial for increasing PA levels, which can influence psychological well-being and CV health. We also developed a standardized approach for defining valid wear time for commercial available PA trackers for use in the community-based, adaptive PA intervention. We examined two methods for defining a valid day from the Fitbit Charge 2. In Method 1, a valid day was defined as greater than or equal to 10 hours per day of wear time with heart rate data. Method 2 removed minutes without heart rate data, minutes with heart rate data less than or equal to 2 SDs below mean and less than or equal to 2 steps, and nighttime minutes. Within the context of pilot data from the PA intervention, we found that the new method (Method 2) resulted in significantly different total wear time than the more conventional Method 1. Additional studies are needed to understand the impact of new methods of processing PA tracker data because there are no gold standards for comparison. We used a mixed-method approach to examine the adoption of mHealth technology among African American women in the DC area community. Community members completed an informatics survey prior to participation in focus groups about their use of mobile technology and health apps. Based on survey data, we found that 69% reported using health-related apps mostly focused on physical activity and nutrition. The focus groups identified four overarching themes in the focus groups (user attachment, technology adoption, potential barriers and facilitators), where individual app tailoring could be a facilitator and software concerns could serve as a barrier to adoption of a mobile app for an mHealth intervention. Thus, early engagement of target end-users as part of a co-design and community-based participatory research process may help in creating tools for future mHealth interventions. We created a simulation model to test the effects of a place-tailored digital health app on PA levels and overweight/obesity prevalence among African American women in Washington, DC. The place-tailored app would help users identify PA locations and available recreational center classes in Washington, DC. Using this simulation model, we showed that a digital health app that helps identify recreation center classes would need high levels of app engagement to have significant increases in PA and reductions in overweight/obesity. In particular, at least 75% of women would need to be aware of the app, 75% of those aware of the app would have to download it, and 75% of those downloading the app would have to opt in for push notifications to see significant effects. However, the app does not overcome lack of access to recreation centers. Our findings demonstrate that this type of place-tailored, digital health app should be incorporated into multi-level interventions that also target the built environment and other social determinants of health to maximize its impact. Finally, we conducted pilot testing of the place-tailored remote messaging through a digital health app before the implementation of the full sequential, multiple-assignment, randomized trial (i.e. the Step It Up physical activity intervention). We showed that participants who received place-tailored remote messaging had physical activity increases between 1000 and 2000 steps a day compared with either baseline or to participants who received standard remote messaging. This increase in daily steps trended towards clinical significance. We also demonstrated that safety and social cohesion as neighborhood-level factors and social isolation as an individual-level factor were associated with digital app engagement in the pilot study. After community engagement throughout the iterative pilot testing of the intervention components, we are now implementing the Step It Up physical activity intervention in collaboration with community partners and have enrolled about 70% of the target study cohort.