The Female Athlete Triad: Are Elite Athletes at Increased Risk?

Description

... College of Sports Medicine http://www.acsm-msse.org ...... of athletes competing in weight-class sports (37%) and technical sports (30%) report use of ...

Sujets

• Sport

Informations

• Publié par: Sportif
• Nombre de lectures: 115
• Langue: Français

Extrait

Clinically Relevant

The Female Athlete at Increased Risk?

Triad:

Are

Elite

Athletes

1 1,2 MONICA KLUNGLAND TORSTVEIT and JORUNN SUNDGOTBORGEN 1 2 The Norwegian University of Sport and Physical Education, Oslo, NORWAY; and The Norwegian Olympic Training Centre, Oslo, NORWAY

ABSTRACT KLUNGLAND TORSTVEIT, M., and J. SUNDGOTBORGEN. The Female Athlete Triad: Are Elite Athletes at Increased Risk?Med. Sci. Sports Exerc., Vol. 37, No. 2, pp. 184 –193, 2005.Purpose:The aim of this study was to examine the percentage of elite athletes and controls at risk of the female athlete triad.Methods:A detailed questionnaire, which included questions regarding training and/or physical activity patterns, menstrual history, oral contraceptive use, weight history, eating patterns, dietary history, and the Body Dissatisfaction (BD) and Drive for Thinness (DT) subscales of the Eating Disorder Inventory (EDI), was prepared. The questionnaire was administered to the total population of female elite athletes in Norway representing the national teams at the junior or senior level, 13–39 yr of age (N938) and nonathlete controls in the same age group (N900). After exclusion, a total of 669 athletes (88%) and 607 controls (70%) completed the questionnaire satisfactorily.Results:A higher percentage of controls (69.2%) than athletes (60.4%) was classified as being at risk of the Triad (P0.01). A higher percentage of controls than athletes reported use of pathogenic weightcontrol methods and had high BD subscale scores (P0.001). However, more athletes reported menstrual dysfunction and stress fractures compared with controls (P0.05). A higher percentage of both athletes competing in leanness sports (70.1%) and the nonathlete control group (69.2%) was classified as being at risk of the Triad compared with athletes competing in nonleanness sports (55.3%) (P0.001). Furthermore, a higher percentage of athletes competing in aesthetic sports (66.4%) than ball game sports (52.6%) was classified as being at risk of the Triad (P0.001).Conclusions:More athletes competing in leanness sports and more nonathlete controls were classified as being at risk of the Triad compared with athletes competing in nonleanness sports.Key Words:EATING DISORDERS, DISORDERED EATING, AMENORRHEA, MENSTRUAL DYSFUNCTION, LOW BONE MASS, OSTEO POROSIS

serious syndrome comprising three interrelated A components— disordered eating, amenorrhea, and osteoporosis— has been termed the female athlete triad (the Triad) (21,33). It has been stated that all female athletes are potentially at risk of developing the Triad (19), but that athletes competing in sports in which leanness and/or a low body weight is considered important may be at increased risk of the Triad (19). However, a position state ment (21) claims that this syndrome occurs not only in elite athletes but also in nonathletes and in physically active girls and women who are not training or competing in a specific sport. It is unclear, however, to what extent girls and women

Address for correspondence: Monica Klungland Torstveit, The Norwegian University of Sport and Physical Education, PO Box 4014, Ullevaal Sta dion, 0806 Oslo, Norway; Email: [e-mail]. Submitted for publication October 2003. Accepted for publication July 2004.

01959131/05/37020184 MEDICINE & SCIENCE IN SPORTS & EXERCISE ® Copyright © 2005 by the American College of Sports Medicine DOI: 10.1249/01.MSS.0000152677.60545.3A

184

engaged in physical activity at different levels are at risk of the Triad. The prevalence of disordered eating and eating disorders in young female athletes has been reported to be higher in athletes than in nonathletes, and particularly in athletes competing in sports that emphasize leanness or a low body weight (4,5,27,29). Furthermore, it has been reported that amenorrhea is more prevalent in the athletic population (3– 66%) than in the general female population (2–5%) (20). Few prevalence studies related to premature osteoporosis in young athletes and nonathletes have been published. Two studies have reported a prevalence of osteoporosis of 10 – 13% in small groups of amenorrheic distance runners (22,23), whereas two other studies did not find any females with osteoporosis in their samples (15,34). Each of the three disorders of the Triad alone may result in serious medical health consequences. The appearance of all three disorders of the female athlete triad increases the potential for considerable morbidity and even a higher rate of mortality. Because the Triad is frequently denied, not recognized, and underreported, proper screening for a num ber of symptoms and risk factors has been recommended (21). Because disordered eating (24) and most likely also menstrual dysfunction and osteoporosis are assumed to oc

RISK OF THE FEMALE ATHLETE TRIAD

cur on a continuum, early detection and identification of females with atrisk behavior associated with these three components may actually prevent further development and worsening of Triad symptoms. Therefore, identification of atrisk factors is essential in the evaluation of the Triad. Furthermore, little is known about the prevalence of symp toms and risk factors of the Triad in elite athletes and nonathlete controls. Therefore, the purpose of this study was to examine the percentage of elite athletes and nonathlete controls at risk of the Triad.

METHODS Participants The total population of female elite athletes in Norway, 13–39 yr of age (N938) and nonathlete controls in the same age group (N900) were invited to participate in the study. Permission to undertake the study was provided by the Norwegian Olympic Committee and the Norwegian Confederation of Sports, the Data Inspectorate, and the Regional Committee for Medical Research Ethics. The sec retary general of each sport federation and the head of the health care team for each of the national teams received detailed written information about the procedures and aims of the study. In addition, all secretaries general were asked to return a list containing the names, ages, and addresses of all eligible athletes in their federation competing for na tional teams. Lists were obtained from all secretaries gen eral. All participants received an information letter and had to complete a written consent form. Parents of responders younger than 18 yr old had the opportunity to refuse par ticipation on behalf of their child, whereas written parental consent was required for responders younger than 16 yr. In this study, an elite athlete was defined as one who qualified for the national team at the junior or senior level or who was a member of a recruiting squad for that team. The athletes had to be 13–39 yr old. Exclusion criteria included pregnancy with a subsequent plan to discontinue the athletic career after delivery, severe injury that had prevented the athlete from training for more than 3 months, or participa tion in two different sport groups. The athletes represented 66 different sports/events. For parts of the analysis, these sports/events were divided into different sport groups. The classification of sports/events has been developed and used by one of the authors (26). However, in this study, some additional sports/events were included, and it was therefore necessary to somewhat ex pand and revise the categories. Seven different sport groups were formed: technical (G ), endurance (G ), aesthetic (G ), 1 2 3 weightclass (G ), ball game (G ), power (G ), and anti 4 5 6 gravitation (G ) sports. This revised classification system is 7 used by the Norwegian Olympic Training Centre (Table 1). Furthermore, for parts of the analysis and in accordance with previous research (27), the seven different sport groups were divided into two groups: leanness sports and nonlean ness sports. Athletes competing in sports in which leanness and/or a specific weight were considered important (G , G , 2 3 Medicine & Science in Sports & Exercise 185 

G , and G ) were included in the leanness group. Athletes 4 7 competing in sports in which these factors were considered less important (G , G , and G ) were included in the non 1 5 6 leanness group. A randomly selected sample of controls (N900) rep resentative of the female Norwegian population in the same age group as the athletes was also included in the study. A Norwegian bureau of statistics (Ergo group), which keeps records of all citizens of Norway, was responsible for the random control sample selection. Every county in Norway was represented, and the sample’s age distribution and geo graphical distribution approximated that of the total Norwe gian women’s population 13–39 yr of age. The controls were not matched to the athletes because in this study we wanted to compare the total population of elite athletes with a sample of women from the general population in the same age range as the athletes. Exclusion criteria included severe illness, unfamiliarity with the Norwegian language leading to problems answering the questionnaire, and competition in sports for a junior or senior national team or its recruiting squad. Based on the latter criteria, our controls were clas sified as nonathlete controls.

Assessment Procedures Questionnaire.A questionnaire including a battery of assessment questions was sent to each of the 938 eligible athletes and 900 eligible controls. Thirtyone athletes did not receive the questionnaire because they were represent ing teams in other countries or were traveling. A total of 149 athletes were excluded from the study: 76 had ended their career, 35 did not compete at the national level, 15 were injured, 8 were pregnant and did not plan to continue their athletic careers after delivery, 5 were older than 39 yr of age, 9 did not complete the questionnaire satisfactorily, and 1 athlete competed in two different sport groups. In addition, 89 athletes of the remaining 758 (11.7%) did not respond for unknown reasons. The response rate of the total sample was 88.3%. Twentythree of the 900 eligible controls did not re ceive the questionnaire because of problems finding their addresses. In addition, 12 were excluded; nine did not understand the Norwegian language and three were se verely ill and were unable to fill in the questionnaire. Therefore, 865 controls were available for participation in the study. A total of 258 of the initial sample (29.8%) did not respond for unknown reasons, leaving 597 avail able for analysis (70.2%). In addition to questions regarding menstrual history, oral contraceptive use, and pregnancy, the Body Dissatisfaction (BD) and Drive for Thinness (DT) subscales of the Eating Disorder Inventory (EDI) (10) and questions regarding weight history, training history, training time and physical activity patterns, dietary history, nutritional habits, use of pathogenic weightcontrol methods, possible eating disor ders, and injury history were included on the questionnaire. Total training was defined as the total number of hours of training per week for the athletes (presented as a mean of the 186 Official Journal of the American College of Sports Medicine

training and competition period during the previous year). Amount of physical activity among the controls was defined as the total number of hours of physical activity per week including physical education lessons, recreational sports, and active daily living like walking. This value was calcu lated based on questions about type of physical activity, frequency, and duration during the previous year. For parts of the analysis, the athletes and controls were divided into quartiles based on their physical activity levels. In this study, primary amenorrhea was defined as the absence of menarche by the age of 16. Secondary amenor rhea was defined as the absence of three or more consecu tive menstrual cycles after menarche and outside pregnancy, and oligomenorrhea was defined as menstrual cycles of 35 d or more. A short menstrual cycle may reflect a short luteal phase, and luteal inadequacy may be the first stage in the development of amenorrhea (8). In this study, short luteal phase was defined as a menstrual cycle of less than 22 d. Primary amenorrhea, secondary amenorrhea, oligomenor rhea, and short luteal phase were all defined as menstrual dysfunction (MD). If current primary amenorrhea, second ary amenorrhea, oligomenorrhea, or short luteal phase or a history of primary amenorrhea and secondary amenorrhea was reported, the subject was diagnosed with MD. The purpose of the present study was to look at risk factors for the Triad components and not the prevalence of the end points of the Triadper se. Therefore, no blood samples, measurements of bone mineral density (BMD), or clinical interviews were conducted in the first part of this study. Selection criteria.The atrisk criteria used in this study (Table 2) were chosen based on the assumption that disordered eating (24) and the other components of the Triad occur on a continuum. Therefore, we found it important to include not only the end points of the Triad continuum— clinical eating disorders, amenorrhea, and osteoporosis— but to go beyond these three disorders and evaluate disor dered eating, signs of menstrual dysfunction, and stress fractures. Furthermore, pressure placed on females to achieve or maintain an unrealistically low body weight is considered the main reason for developing the Triad, and it has therefore been claimed that women who have significant weight, eating, and body image concerns may be at risk of the Triad (21). High scores on two of the eight subscales included on the EDI, DT, and BD, as well as use of patho genic weightcontrol methods, are also symptoms of disor dered eating and/or eating disorders and predict the devel

TABLE 2. Criteria for being classified as at risk of the female athlete triad: the subject had to meet to one or more of these criteria. Criteria BMI18.5 Pathogenic weightcontrol methods: use of diet pills, hungerrepressive pills, laxatives, diuretics, or vomiting to reduce weight EDIDT15 EDIBD14 Selfreported eating disorder (answer “yes” or “I don’t know”) Selfreported menstrual dysfunction (primary amenorrhea, secondary amenorrhea, oligomenorrhea, or short luteal phase) Selfreported stress fracture (answer “yes” or “I don’t know”)

http://www.acsmmsse.org

opment of eating disorders (27,29). The EDI has been found suitable for use as a screening instrument for eating disor ders in a nonclinical setting (10), and the two subscales EDI–DT and EDI–BD have been shown to be the only measures that predicted development of eating disorders (11). Furthermore, high EDI–DT and EDI–BD scores have also been used as selection criteria when investigating the prevalence of eating disorders in elite athletes (27). There fore, participants in this study were classified as at risk of developing eating disorders, and thus the Triad, if their score on the EDI–DT or EDI–BD subscale was at or above the mean score for known anorectics (10). The EDI–BD and EDI–DT subscales have previously been evaluated as reli able using Cronbach’s alpha values (range 0.74 – 0.90) (28). It has been claimed that a negative energy balance may be a key component in the development of the Triad (18). Unfortunately, measuring energy balance in both athletes and controls in this study was not possible. We chose to estimate energy balance indirectly by assuming that a very low body mass index (BMI) (32) may indicate energy de ficiency. Therefore, a BMI of18.5 was identified as an atrisk criterion for the Triad. Irregular or absent menstruation is clearly associated with disordered eating and low bone mass (6,27). In fact, it has been reported that missing even single menstrual cycles at intervals of several months may lead to reduced bone mass (7). Therefore, the presence of any of the menstrual disor ders (amenorrhea, oligomenorrhea, and short luteal phase) was included as an atrisk criterion for the development of the Triad. Furthermore, because stress fractures have been associated with disordered eating and amenorrhea (2), self reported stress fracture was also included as an atrisk criterion for the Triad. For parts of the analysis, the participants were divided into three different age groups: 13–19, 20 –29, and 30 –39 yr of age.

Statistical Analysis All analyses were performed using SPSS software, ver sion 11.0 (SPSS, Evanston, IL). Results are expressed as

TABLE 3. Anthropometric data presented for each sport group and controls.

NAge (yr) Technical (G ) 90 22.5 (5.7) 1 Endurance (G ) 113 22.3 (6.3) 2 c Aaesthetic (G ) 65 17.3 (4.6) 3 f Weightclass (G ) 35 24.3 (5.6) 4 Ball game (G ) 308 21.0 (4.6) 5 Power (G ) 40 21.5 (3.8) 6 Antigravitation (G ) 18 21.4 (5.4) 7 i Athletes, total 669 21.3 (5.3) Controls 607 27.3 (8.0) The values are given as means (SD). a Pand0.001 compared with G , G , and G P0.002 compared with G . 1 5 6 4 b P0.001 compared with G , G , G , and G . 1 4 5 6 c P0.001 compared with all other sport groups. d Pand0.001 compared with G , G , G , G , and G P0.002 compared with G . 1 2 4 5 6 7 e P0.001 compared with G , G , G , and G andP0.002 compared with G . 1 4 5 6 2 f P0.001 compared with G . 5 g P0.001 compared with G . 3 h P0.001 compared with G . 5 i P0.001 compared with controls.

RISK OF THE FEMALE ATHLETE TRIAD

mean and SD. Comparisons between athletes and controls, between leanness and nonleanness sports, between the dif ferent age groups, and between the physical activity quar tiles were carried out using a twosample Student’sttest for continuous data and a chisquare test for categorical data. Fisher’s exact test was carried out when the cells had ex pected counts of5. Differences were considered statisti cally significant forPvalues5%. Comparisons between the sport groups were carried out using nonparametric tests (Kruskal–Wallis and Mann–Whitney) for continuous data and chisquare test for categorical data. All tests were two tailed. To prevent Type I error, the Bonferroni method of adjustment was used when describing differences between the sport groups. For these multiple comparisons, the sig nificance level was adjusted by dividing the conventional 0.05 level with the number ofttests (N21) per variable. Therefore, the actual significance level for each of these multiple comparisons was0.002. Only significant differ ences at or below this level are shown in the results. Binary logistic regression analysis was carried out to adjust for differences in age between athletes and controls.

RESULTS Characteristics of the Participants The athletes were younger than the controls and reported a lower BMI (P0.001). Athletes competing in aesthetic sports were younger with lower height and weight compared with all other sport groups (P0.002) (Table 3). No age differences between athletes competing in lean ness sports and nonleanness sports were found (21.16.2 yr and 21.44.8 yr, respectively). Athletes competing in leanness sports had a lower weight (57.28.1 kg) and BMI 2 (20.5) compared with athletes competing in2.4 kg∙m 2 nonleanness sports (64.37.9 kg and 22.12.2 kg∙m ) and controls (P0.001). Furthermore, athletes competing in nonleanness sports had lower weight and BMI compared with controls (P0.001). A total of 18% of the athletes had been ranked among the three best; 12% had been ranked from places 4 to 10 and

Weight (kg) 64.6 (9.2) a 58.4 (6.4) d 51.5 (7.4) 63.4 (8.6) 64.4 (7.8) 62.9 (5.8) h 58.3 (7.3) i 61.8 (8.7) 65.8 (12.9)

Height (cm) 169.5 (5.5) 168.6 (5.6) d 162.4 (6.8) 167.3 (6.2) g 170.8 (6.5) 168.9 (5.0) 168.9 (6.7) i 169.1 (6.6) 167.6 (6.0)

BMI 2 (kgm ) 22.4 (2.8) b 20.5 (1.8) e 19.5 (2.0) 22.8 (3.3) 22.0 (2.0) 22.1 (2.0) h 20.4 (1.5) i 21.6 (2.4) 23.4 (4.3)

Medicine & Science in Sports & Exercise 

187