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20 May 2008 | Volume 148 Issue 10
Background: Human growth hormone is reportedly used to enhance athletic performance, although its safety and efficacy for this purpose are poorly understood.
Purpose: To evaluate evidence about the effects of growth hormone on athletic performance in physically fit, young individuals.
Data Sources: We reviewed the MEDLINE, EMBASE, SPORTDiscus, and Cochrane Collaboration databases for English-language studies published between January 1966 and October 2007.
Study Selection: Randomized, controlled trials that compared growth hormone treatment with no growth hormone treatment in community-dwelling healthy participants between 13 and 45 years of age.
Data Extraction: 2 authors independently reviewed articles and abstracted data.
Data Synthesis: 44 articles describing 27 study samples met inclusion criteria. 303 participants received growth hormone, representing 13.3 person-years of treatment. Participants were young (mean age, 27 years [SD, 3]), lean (mean body mass index, 24 kg/m2 [SD, 2]), and physically fit (maximum oxygen uptake, 51 mL/kg of body weight per minute [SD, 8]). Growth hormone dosage (mean, 36 µg/kg per day [SD, 21]) and treatment duration (mean, 20 days [SD, 18] for studies giving growth hormone for >1 day) varied. Lean body mass increased in growth hormone recipients compared with participants who did not receive growth hormone (increase, 2.1 kg [95% CI, 1.3 to 2.9 kg]), but strength and exercise capacity did not appear to improve. Lactate levels during exercise were statistically significantly higher in 2 of 3 studies that evaluated this outcome. Growth hormone–treated participants more frequently experienced soft tissue edema and fatigue than did those not treated with growth hormone.
Limitations: Few studies evaluated athletic performance. Growth hormone protocols in the studies may not reflect real-world doses and regimens.
Conclusion: Claims that growth hormone enhances physical performance are not supported by the scientific literature. Although the limited available evidence suggests that growth hormone increases lean body mass, it may not improve strength; in addition, it may worsen exercise capacity and increase adverse events. More research is needed to conclusively determine the effects of growth hormone on athletic performance.
Author and Article Information
From Santa Clara Valley Medical Center, San Jose, California; Stanford University, Stanford, California; and Veterans Affairs Palo Alto Health Care System, Palo Alto, California
Acknowledgment: The authors thank Rikke Ogawa, MLIS, and Christopher Stave, MLS, Information Services Librarians, Lane Medical Library, Stanford University, for their assistance with the literature searches. They also thank Arthur Weltman, PhD, University of Virginia, for his insight and expertise in growth hormone and exercise physiology. Ms. Ogawa, Mr. Stave, and Dr. Weltman did not receive compensation for their contributions.
Grant Support: In part or fully by the Agency for Healthcare Research and Quality (National Research Service Award, grant no. HS000028-19), the Department of Veteran Affairs, Stanford University Medical Center, Stanford University, Genentech, Inc. (fellowship stipend), the National Science Foundation, and the Evidence-Based Medicine Center of Excellence of Pfizer.
Potential Financial Conflicts of Interest: Consultancies: A.M. Garber (Blue Cross and Blue Shield Association), A.R. Hoffman (Genentech, Teva, LG Life Sciences, Ambrx). Honoraria: A.R. Hoffman (Genentech). Stock ownership or options (other than mutual funds): A.R. Hoffman (Ambrx). Expert testimony: A.R. Hoffman (U.S. Attorney, regarding off-label GH use). Grants received: A.R. Hoffman (Genentech, Pfizer).
Requests for Single Reprints: Hau Liu, MD, MBA, MPH, Santa Clara Valley Medical Center, 751 South Bascom Avenue, 4th Floor Medicine, San Jose, CA 95128; e-mail, hauliu{at}stanford.edu.
Current Author Addresses: Drs. Liu and Salpeter: Santa Clara Valley Medical Center, 751 South Bascom Avenue, San Jose, CA 95128.
Drs. Bravata, Bendavid, and Garber and Ms. Saynina: 117 Encina Commons, Stanford, CA 94305.
Dr. Olkin: Department of Statistics, Sequoia Hall, 390 Serra Mall, Stanford University, Stanford, CA 94305.
Dr. Friedlander: Stanford Center on Longevity, Encina Hall, East Wing–5th Floor, 616 Serra Street, Stanford, CA 94305.
Dr. Liu: Division of Pulmonary and Critical Care Medicine, Stanford University, 300 Pasteur Drive, Room H3143, Stanford, CA 94305.
Drs. Roberts and Hoffman: Division of Endocrinology and Metabolism, 300 Pasteur Drive, Stanford University, Stanford, CA 94305. Read all Rapid ResponsesREVIEW
Systematic Review: The Effects of Growth Hormone on Athletic Performance
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