Consensus Statement: PDF OnlyThe Male Athlete Triad—A Consensus Statement From the Female and Male Athlete Triad Coalition Part 1 Definition and Scientific BasisNattiv, Aurelia MD*; De Souza, Mary Jane PhD†; Koltun, Kristen J. PhD‡; Misra, Madhusmita MD, MPH§; Kussman, Andrea MD¶; Williams, Nancy I. ScD†; Barrack, Michelle T. PhD, RD‖; Kraus, Emily MD¶; Joy, Elizabeth MD, MPH**; Fredericson, Michael MD¶Author Information *Division of Sports Medicine and Non-Operative Orthopaedics, Departments of Family Medicine and Orthopaedic Surgery, University of California Los Angeles, Los Angeles, California; †Department of Kinesiology, Penn State University, University Park, Pennsylvania; ‡Department of Sports Medicine and Nutrition, University of Pittsburgh, Pittsburgh, Pennsylvania; §Division of Pediatric Endocrinology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts; ¶Department of Orthopaedic Surgery, Stanford University, Stanford, California; ‖Department of Family and Consumer Sciences, California State University, Long Beach, Long Beach, California; and **Intermountain Healthcare, Salt Lake City, Utah. Corresponding Author: Aurelia Nattiv, MD, UCLA-Santa Monica Medical Center and Orthopaedic Hospital, 1250 16th St, Suite #3142, Santa Monica, CA 90404 ([email protected]). The authors report no conflicts of interest. All authors have contributed substantially to the manuscript and have been involved in designing, drafting, and reviewing the manuscript, figure, and tables. K. J. Koltun, M. J. De Souza, and A. Kussman, in conjunction with A. Nattiv and M. Fredericson, were involved with the majority of editing. K. J. Koltun, M. J. De Souza, and A. Kussman were most involved with creating the tables. Received January 03, 2021 Accepted April 23, 2021 Clinical Journal of Sport Medicine: June 03, 2021 - Volume Publish Ahead of Print - Issue - doi: 10.1097/JSM.0000000000000946 Buy PAP Metrics Abstract The Male Athlete Triad is a syndrome of 3 interrelated conditions most common in adolescent and young adult male endurance and weight-class athletes and includes the clinically relevant outcomes of (1) energy deficiency/low energy availability (EA) with or without disordered eating/eating disorders, (2) functional hypothalamic hypogonadism, and (3) osteoporosis or low bone mineral density with or without bone stress injury (BSI). The causal role of low EA in the modulation of reproductive function and skeletal health in the male athlete reinforces the notion that skeletal health and reproductive outcomes are the primary clinical concerns. At present, the specific intermediate subclinical outcomes are less clearly defined in male athletes than those in female athletes and are represented as subtle alterations in the hypothalamic–pituitary–gonadal axis and increased risk for BSI. The degree of energy deficiency/low EA associated with such alterations remains unclear. However, available data suggest a more severe energy deficiency/low EA state is needed to affect reproductive and skeletal health in the Male Athlete Triad than in the Female Athlete Triad. Additional research is needed to further clarify and quantify this association. The Female and Male Athlete Triad Coalition Consensus Statements include evidence statements developed after a roundtable of experts held in conjunction with the American College of Sports Medicine 64th Annual Meeting in Denver, Colorado, in 2017 and are in 2 parts—Part I: Definition and Scientific Basis and Part 2: The Male Athlete Triad: Diagnosis, Treatment, and Return-to-Play. In this first article, we discuss the scientific evidence to support the Male Athlete Triad model. Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.