Improving Cardiovascular Risk Factors in Black Young Adults

Overview

The objectives of the study are to conduct a randomized controlled trial to test the efficacy of the Smartphone intervention on % weight loss and maintaining % weight loss at 6 and 12 months in a sample (N=256) of Black community college students who are overweight or obese, ages 18-25 years. Investigators will also examine mediating variables of the intervention on weight at 6 and 12 months, including adherence to self-monitoring, discrimination, and dietary and physical activity self-efficacy. In addition, investigators will explore potential moderators of weight loss at 6 months and 12 months, including depressive symptoms, ideal body image, and motivation.

A total of 256 students, ages 18-25, who meet the inclusion and exclusion criteria will be recruited from Columbus State Community College (CSCC). A sample size of 256 subjects (n=128 per each trial arm) will have sufficient power (\>80%) to detect an average between-group difference with a moderate effect size of 0.4. The mixed effect modeling for repeated outcome measures at 6 and 12 months was used for the power calculation using two-sided significance level of 0.05 assuming 1) first-order autoregressive covariance structure, 2) the within-structure correlation of 0.8, and 3) 20% attrition rate at 12-month follow-up. The effect size of 0.4 was reasonably assumed based on data from published trials on weight-loss interventions (an effect size of 0.8 using 8-week social media, 0.3 using 12-week Smartphone intervention, and 0.6 using 4-month text messaging). Investigators will conduct stratified recruitment by gender (female vs. male) and ethnicity (Non-Hispanic Black vs. Hispanic Black) to achieve a study sample with 80% Non-Hispanic Black and 20% Hispanic and 50% male in each ethnic group. The recruitment and randomization will be equally distributed with approximately 10 subjects per month, which is a feasible enrollment target considering the pool of eligible participants and our previous recruitment success. Prospective participants who contact through telephone or email will undergo a preliminary screening via telephone and receive an explanation of the study. Included in this screening are four questions from the Eating Attitude Test-26 (EAT-26), which will be asked to determine symptoms of disordered eating in the past 6 months. Those who seem to meet eligibility criteria and are interested in participating will be scheduled for an in person visit for the informed consent and screening process. Following the informed consent process and baseline visit questionnaires, participants will be randomly assigned to intervention or the attention-control group. Investigators will use stratified randomization by sex (female vs. male) and ethnicity (Non-Hispanic Black vs. Hispanic Black). For each gender strata, randomization will occur in permuted blocks of varying block sizes. Subjects in each block will be randomly assigned to intervention arm or attention-control arm with an allocation ratio of 1:1. The advantage of permuted block randomization is that it will ensure balance in the number of subjects in the two trial arms during the entire study period.