Thesis submitted to the faculty of Virginia Polytechnic Institute and State.
University in ... Department of Human Nutrition, Foods, and Exercise .... Study
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SKELETAL STATUS AND BONE TURNOVER IN OVERWEIGHT YOUNG MEN WITH AND WITHOUT SLEEP APNEA SYNDROME By Nadine Joëlle Guignel Thesis submitted to the faculty of Virginia Polytechnic Institute and State University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE IN Human Nutrition, Foods, and Exercise
Dr. William G. Herbert, Chair Dr. Frank Gwazdauskas Dr. Sharon M. Nickols-Richardson Dr. Warren K. Ramp
Date: 06/06/05 Blacksburg, Virginia
Key words: Sleep apnea syndrome, Bone mineral content, Leptin, Insulin-like growth factor-1, Osteocalcin, N-telopeptide of type I collagen cross-link
SKELETAL STATUS AND BONE TURNOVER IN OVERWEIGHT YOUNG MEN WITH AND WITHOUT SLEEP APNEA SYNDROME Nadine Joelle Guignel Committee Chair: William G. Herbert, Ph.D. Department of Human Nutrition, Foods, and Exercise Clinical Exercise Physiology ABSTRACT Obesity is a worldwide epidemic increasing at an alarming rate among youth who are facing similar health problems as adults. Sleep Apnea Syndrome (SAS) is an underdiagnosed comorbidity of obesity, characterized by repetitive nocturnal interruptions in breathing. Obesity is associated with delayed skeletal maturation in overweight youth, but mechanisms contributing to this problem are unclear. Obesity and SAS both have been shown to disrupt regulatory hormones and cytokines that influence bone accretion during adolescence. PURPOSE: The purpose of this study was to assess the combined effects of excess body weight and SAS on bone mineral density (BMD) and content (BMC), bone turnover, and on the regulatory hormones leptin and IGF-1 known to potentially influence bone accretion during adolescence. METHODS: Men aged 18-28 years were assigned to groups as follows: normal weight controls (CON: AHI 5, n=8). The apnea/hypopnea index (AHI) expresses the score for disrupted nighttime breathing events/hr and was obtained in this study with results from a home sleep screening test. Health history and Epworth Sleepiness Scale (ESS) questionnaires also were administered. Bone mineral parameters and body composition variables were measured with dual-energy X-ray absorptiometry. Serum osteocalcin, leptin, IGF1, and NTx-1 were measured, respectively, by radioimmunoassay and enzyme-linked immunoabsorbent assay. RESULTS: Fat-free mass, intra-abdominal fat, and fat mass were higher in the SAS and OWT groups (p
