YOUTH: Decisions and challenges in designing an osteoporosis prevention intervention for teen girls

Background. This paper describes decisions about the experimental design for the Youth, Osteoporosis, and Understanding Total Health Project (YOUTH), a trial designed to test the efficacy of a health plan-based lifestyle intervention for increasing bone mineral density among adolescent women 14 to 16 years of age. Methods. This randomized controlled trial recruited adolescent women who were at higher risk for developing osteoporosis (body mass index 16-23) from a large HMO in the Pacific Northwest. The intervention focused on improving diet (high calcium foods, fruits, and vegetables) and increasing physical activity (high impact and spinal motion). The intervention included both group and individual activities. The primary endpoint in the study was total bone mineral density as measured by dual-energy X-ray absorptiometry (DEXA). Results. Baseline data were collected on the trial cohort of 228 adolescent women and their families. This paper discusses how researchers met the following challenges in designing and implementing the trial: determining appropriate dietary and exercise targets to affect bone mineral density in adolescents; choosing suitable assessments; and developing an intervention well suited for implementation in a non-school (health plan) setting. We also discuss the rationale for the specific study population chosen (females, younger adolescents). Conclusions. The YOUTH project is one of very few preventive research interventions with adolescents conducted in a health plan setting. Many of the recruitment and intervention strategies used in this trial may be appropriate for adoption in other health plan-based prevention studies.