FEMALE ATHLETE TRIAD ERRORS AND MISUNDERSTANDINGS

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Dear Editor-in-Chief: Recent papers by Torsteit and Sundgot-Borgen (5,6) reporting a low incidence of the female athlete triad in Norwegian athletes similar to that in controls used definitions that caused the authors to greatly underestimate the incidence of the Triad in athletes and to overestimate the incidence in controls. In an effort to help prevent misinterpretation of these findings, we wish to draw attention to what we believe are methodological errors that have been overlooked. Torsteit and Sundgot-Borgen defined disordered eating more narrowly than the 1997 ACSM Position Stand, which included "inadvertently failing to balance energy expenditure with adequate energy intake" as a form of disordered eating. Not including such cases caused Torsteit and Sundgot-Borgen to selectively eliminate athletes. Meanwhile, since four of the five controls diagnosed with the Triad were more than 30% body fat, chronic energy deficiency may not have been the cause of their menstrual disorders. Torsteit and Sundgot-Borgen also defined short luteal phase (< 10 d), as short menstrual cycles (< 22 d), which are very rare. Endocrine measurements have revealed luteal phase defects and anovulation in almost 80% of regularly menstruating female athletes (2), who were not evaluated by Torsteit and Sundgot-Borgen. Finally, Torsteit and Sundgot-Borgen imposed quantitative criteria for low bone density that are not required for the diagnosis of osteoporosis in premenopausal women and adolescents (4). The predictable consequences of Torsteit and Sundgot-Borgen's methods should not cause MSSE® readers to forget that there are four reasons for "singling out the female athlete" in efforts to understand, prevent and treat the female athlete triad. First, the mammalian dependence of reproductive function on energy availability operates principally in females. Second, female athletes consume on average 30% less dietary energy per kilogram of body weight than do male athletes (1), which means that half are consuming even less. Third, dietary restriction is not necessary to induce reproductive disorders: exercise energy expenditure can be sufficient (7). And, fourth, when the energy availability of physically active women is low enough, either through dietary restriction alone, exercise energy expenditure alone, or through a combination of both, its suppressive influence on bone formation outweighs the stimulatory osteogenic influence of physical activity. Bone formation is impaired in exercising women when energy availability is reduced by more than 33% (3). Furthermore, misinterpretation of Torsteit and Sundgot-Borgen's observations should not lead MSSE® readers to ignore the hazards of exercising in an unhealthful manner. It is appropriate for ACSM to be concerned about the public health consequences of obesity and physical inactivity, but the College also has a long history of warning the public about such hazards as heat and cold illnesses during distance running and unhealthful weight loss in wrestlers. The ACSM Position Stand on the female athlete triad is in that responsible tradition. Nancy I. Williams, Sc.D., FACSM Department of Kinesiology Pennsylvania State University University Park, PA Mary Jane De Souza, Ph.D., FACSM Department of Exercise Science University of Toronto Toronto, Canada