Healthy immigrant community study protocol: A randomized controlled trial of a social network intervention for cardiovascular risk reduction among Hispanic and Somali adults

Background: Immigrants to the United States face structural barriers that contribute to rising cardiovascular risk factors and obesity after immigration. This manuscript describes the development of the Healthy Immigrant Community protocol and baseline measures for a stepped wedge cluster randomized trial to test the effectiveness of a social network intervention for cardiovascular risk reduction among two immigrant populations. Methods: We developed a social network-informed, community-based, participatory research-derived health promotion intervention with Hispanic and Somali immigrant communities in Minnesota consisting of mentoring, educational and motivational sessions, group activities, and a community toolkit for healthy weight loss delivered by culturally concordant health promoters (HPs) to their social networks. Using a stepped wedge cluster randomized design, social network-based groups were randomly assigned to receive the intervention either immediately or after a delay of one year. Outcomes, measured at baseline, 6 months, 12 months, and 24 months, were derived from the American Heart Association's "Life's Simple 7": BMI and waist circumference, blood pressure, fasting blood glucose, total cholesterol, physical activity level, and dietary quality. Results: A total of 51 HPs were enrolled and randomized (29 Hispanic; 22 Somali). There were 475 participants enrolled in the study, representing a mean social network group size of 8 (range, 5-12). The mean BMI of the sample (32.2) was in the "obese" range. Conclusion: Processes and products from this Healthy Immigrant Community protocol are relevant to other communities seeking to reduce cardiovascular risk factors and negative health behaviors among immigrant populations by leveraging the influence of their social networks.