BACKGROUND:
The high prevalence of obesity in Black women may be a contributing factor to their higher mortality from cardiovascular disease and higher prevalence of diabetes and hypertension compared with white and Hispanic women. Although Hispanic women also exhibit high prevalence of obesity, mortality from heart disease is less than for Black or white women and mortality from diabetes is less than for Black women.
The increased prevalence of obesity in Black females is present during childhood, and the prevalence of obesity is increasing faster in Black girls than in white girls. Recent data from the third National Health and Nutrition Examination Survey (NHANES III) showed that during preadolescence, age 6-11 years, 30.7 percent of Black girls, compared with 22.0 percent of white girls, were overweight. Furthermore, over the past 30 years the prevalence of obesity in this preadolescent age group has increased 150 percent in Black girls compared with 40 percent in white girls. The prevalence of obesity in the adolescent age of 12 to 17 years is similarly high, at 29.9 percent in Black girls compared with 20.7 percent in white girls. The 35 percent increase in obesity over the past 30 years is similar in the preadolescent and adolescent age groups for white girls, but for Black girls the increase is greater in the younger age group (150 percent more prevalent) than in the older age group (80 percent increase) .
The Special Emphasis Panel (SEP) on Intervention Studies in Children and Adolescents to Prevent Cardiovascular Disease was convened in September 1997 to review the efficacy and effectiveness of interventions to prevent and improve known cardiovascular disease risk factors in children and adolescents and to develop recommendations for future preventive intervention studies. The initiative was developed in response to recommendations of the SEP. The RFA was released in April 1998.
DESIGN NARRATIVE:
The Girl's health Enrichment Multi-site Studies (GEMS) is a collection of studies designed to develop and test interventions to prevent excessive weight gain by African-American girls as they enter and proceed through puberty. The research is being conducted as four inter-dependent, clinical trials. They are "inter-dependent" in the sense that they are considering similar study populations, following similar follow-up schedules and use a "core" set of evaluation procedures. Nonetheless, GEMS is not a "multi-center clinical trial" in the usual sense - each field center is evaluating its own intervention (and corresponding control). As a result, each study will have high internal validity and will be designed and analyzed as a study in its own right.
In Phase I, several distinct and separate interventions were developed. Interventions addressed diet, physical activity, and psychosocial and familial influences. There were four participating centers in Phase I, including the University of Memphis, Stanford University, the University of Minnesota, and Baylor College of Medicine. The coordinating center was located at George Washington University.
In Phase II, individual clinical trials will be supported to test the efficacy of interventions developed in Phase I. Although the interventions developed by each field center will be unique, the centers will collaborate to standardize key measurements, outcomes, and main analysis methods. The Memphis Field Center will conduct a full-scale two year, randomized, controlled clinical trial for weight gain prevention among 300 high risk, preadolescent African American girls and their parents. Body mass index is the primary endpoint. Secondary endpoints include dietary intake, physical activity, and psychosocial variables. The Stanford Field Center will conduct a two-arm parallel group, randomized controlled trial to test the efficacy of an after school dance program and a family-based intervention to reduce television, videotape, and video game use to reduce weight gain among 260 African American preadolescent girls. An active placebo group will receive an information-based community health education intervention. Interventions will last for two years. Body mass index is the primary outcome measure.
