Exercise Strategy to Prevent Pediatric Type 2 Diabetes

University Of California-Irvine, Irvine CA

Investigators

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Abstract

The overall aim of this research is to introduce an innovative approach to increase physical activity in schools, and thereby, decrease j risk factors for type 2 diabetes in children and adolescents. Since very little is known about the fundamental interrelationships j among fitness, body composition, and physiological markers of glucose homeostasis in growing children, the research is also aimed j at filling key gaps in this knowledge base. The Specific Aims of the proposal are to develop, implement, and test the effectiveness | of: a school-based physical activity enhancement program, Fitness Laboratory On Wheels (FLOW); and a complementary school-based teacher/student education program to enhance physical activity and reduce sedentary behaviors. A prospective, I repeated-measures, exercise-intervention/control study is planned. The intervention will span the 7th and 8th grades with an j additional two-year follow-up. To test the specific effects of the exercise program perse, but recognizing as well, the role of diet in ameliorating the risk of type 2 diabetes, a nutrition education program will be implemented in both control and exercise intervention j schools. The following hypotheses will be tested: the two-year intervention will lead to (1) Improved insulin sensitivity and/or \ improved recovery from the natural fall in insulin sensitivity that occurs during puberty; (2) An increase in physical fitness by at | least 10% (accounting for natural growth and development) and enhanced physical activity behaviors; (3) Improvement in anatomic j markers of type 2 diabetes risk; (4) Improvement in novel biochemical markers associated with diabetes risk; and (5) A sustained j improvement in these variables for at least 2 years following the intervention. Major outcome variables include: "traditional" j markers of glucose homeostasis - fasting insulin and glucose (all subjects) and insulin sensitivity, glucose effectiveness, and acute | insulin response (sub-study with frequently sampled intravenous glucose tolerance test - FSIVGTT); novel markers of type 2 diabetes risk - growth hormone binding protein (GHBP), insulin-like growth factor binding protein-1 (IGFBP-1), and tumor-necrosis factor-a (TNF-a); peak oxygen uptake from ergometer exercise tests; body composition by dual x-ray absorptiometry (DEXA); and i psychosocial tests of exercise-associated behaviors. A physiological assessment protocol that would be both feasible and fun for the j majority of volunteers was successfully pilot tested. It was demonstrated that in a single morning, groups of children can be j j transported from a target school to an available clinical research center and comfortably undergo a testing strategy called "BEDD" [(1) fasting blood sampling, (2) exercise testing, (3) DEXA measurements of body composition, and (4) diet recall]. Power analysis based on fasting insulin levels in healthy children suggests that a multi-center study (3-4 centers with 4-5 schools per center) would i be needed to achieve these aims. i . [unreadable]_[unreadable] .. [unreadable]__ ___ _ _ !