Rationale and study protocol for Unidas por la Vida (United for Life): A dyadic weight-loss intervention for high-risk Latina mothers and their adult daughters.

BACKGROUND: Half of Mexican-American women are under-active and nearly 78% are overweight/obese. The high lifetime risk of developing type 2 diabetes necessitates a culturally appropriate lifestyle intervention. PURPOSE: Unidas por la Vida is a novel dyadic intervention that capitalizes on the centrality of family in Latino culture to mobilize an existing family dyad as a resource for health behavior change. The intervention aims to improve health behaviors and promote weight loss in two at-risk members of the same family: mothers with type 2 diabetes and their overweight/obese adult daughters who are at risk for developing diabetes. METHODS: Participants (N = 460 mother-adult daughter dyads) will be randomized into one of three conditions: 1) dyadic participation (mothers-daughters) in a lifestyle intervention; 2) individual participation (mothers alone; unrelated daughters alone) in a lifestyle intervention; and 3) mother-daughter dyads in a minimal intervention control group. RESULTS: The primary outcome is weight loss. Secondary outcomes include physical activity, dietary intake, physiological measures (e.g. HbA1c), and body composition. Both the dyadic and individual interventions are expected to produce greater weight loss at 6, 12, and 18 months than those in minimal intervention control group, with women assigned to the dyadic intervention expected to lose more weight and to maintain the weight loss longer than women assigned to the individual intervention. CONCLUSION: Because health risks are often shared by multiple members of at-risk families, culturally appropriate, dyadic interventions have the potential to increase the success of behavior change efforts and to extend their reach to multiple family members. TRIAL REGISTRATION: ClinicalTrials.gov identifier NCT02741037.