The female athlete triad refers to the interrelated problems of disordered eating, amenorrhoea and osteoporosis as determined by the Task Force of the American College of Sports Medicine in 1992.
Those at risk of developing the triad are adolescents, women under stress and athletes (Talbott 1996, Otis & Goldingay 2000). In the athletic world, young female athletes appear to be most at risk as they are driven to excel in their chosen sport and pressured to fit a specific athletic image in order to achieve their goals. This puts them at risk of developing disordered eating patterns, which may lead to menstrual dysfunction and subsequent premature osteoporosis (Nattiv et al 1994, Thein & Thien 1996, Otis & Goldingay 2000). It is thought that the underlying cause of this problem is not exercising or participating in sports but rather the drive of girls and women to be unrealistically thin by restricting caloric intake in a misguided attempt to improve performance (Nattiv et al 1994, Otis & Goldingay 2000, Warren & Goodman 2003).
WHAT IS DISORDERED EATING?
Disordered eating, which includes skipping meals, eating less, vomiting, the use of laxatives and the use of diuretics, varies from mild to severe (Van de Loo & Johnson 1995, Thein & Thien 1996). Severe disordered eating can lead to the clinically recognised eating disorders of anorexia nervosa or bulimia nervosa (Johnson 1994, Sanborn et al 2000).
Sports where disordered eating is prevalent include gymnastics, dancing, figure skating, long distance running and where the athlete is judged by appearance or low body fat is seen as an advantage (Yurth 1995, Smith 1996, Thein & Thien 1996, Otis & Goldingay 2000, Byrne & McLean 2002,Sundgot-Borgen & Torstveit 2004).
As athletes with disordered eating tend to be secretive about their behaviour, friends, parents, coaches and physicians must remain alert, looking for changes in behaviour such as eating alone, making trips to the bathroom during or after meals, or the use of laxatives (Smith 1996). Symptoms may include fatigue, anaemia, depression, intolerance to cold, lanugo (down like hair that appears all over the body to act as insulation in the absence of body fat), eroded tooth enamel from vomiting, dry skin and hair loss (Yurth 1995, Smith 1996, Thein & Thien 1996).
WHAT IS AMENORRHOEA?
Amenorrhoea is a spectrum of menstrual irregularities which may be seen in female athletes, the three principal types observed being anovulation, luteal phase deficiency and athletic amenorrhoea (Otis 1992, Van de Loo & Johnson 1995, Talbott 1996).
Anovulation is characterised by low progesterone levels, although the levels of oestrogen are adequate, resulting in no ovulation (Otis 1992, Thein & Thein 1996). Luteal phase deficiency is a shortened luteal phase and insufficient progesterone (Otis 1992). The total menstrual cycle is usually of normal length making the deficiency difficult to detect.
Athletic amenorrhoea is classified as primary, whereby puberty is delayed and menses has not occurred, and secondary, whereby menstruation has stopped for 3 months, if cycles were regular, or 6 months, if irregular (Otis & Goldingay 2000, Warren & Goodman 2003).
Athletic amenorrhoea is thought to be hypothalamic-induced: production of the hypothalamic gonadotropin-releasing hormone (GnRH) is reduced, leading to a reduction of oestrogen and progesterone release from the ovaries (Wolman 1994, Wiggins & Wiggins 1997, Warren & Goodman 2003).
A decrease in GnRH levels has been linked with higher levels of cortisol in amenorrheic athletes (Kanaley et al 1992, Wiggins & Wiggins 1997, Francis-Cheung 1998). Although of possible short-term benefit, long term elevated levels of cortisol accentuates loss of calcium from the bone, leading to a possibility of osteoporosis (Kanaley et al 1992).
It is important to note that menstrual irregularities can also occur in the absence of an eating disorder (Manore 1999, Manore 2002). This may occur when demands for energy are high due to exercise, and the athlete may be energy deficient even though she may be consuming meals that would be considered normal for a healthy sedentary woman (Drinkwater 1996). This has been observed in vegetarian athletes (Otis 1992). Furthermore, menstrual irregularities can occur before any substantial weight loss or in the presence (versus absence) of body fat as the threshold for onset of menstrual disturbances varies from person to person and from sport to sport (Arena et al 1995, Yurth 1995,Thein & Thien 1996, Skierska et al 1996).
Athletic amenorrhoea is said to usually be reversible when the stresses responsible for its development are eliminated (Arena et al 1995). However, prolonged amenorrhoea may result in a shortfall in bone density, not necessarily restored after resumption of menses (Carbon 1994, Keen & Drinkwater 1997, Warren & Goodman 2003).
WHAT IS OSTEOPOROSIS?
Osteoporosis is a disease characterised by low bone mass, bone fragility and subsequent increase risk of non-traumatic fractures often associated with postmenopausal women (Heaney 1993, Wiggins & Wiggins 1997, Furia 1999). The diagnostic criterion for osteoporosis is bone mineral density (BMD) more than 2.5 standard deviation below the mean of young adults, as measured by dual energy x-ray absorptiometry. Osteopenia describes BMD between 1 and 2.5 standard deviation below the mean of young adults. As this condition is significantly more prevalent than osteoporosis, it is suggested that osteopenia, and not osteoporosis, should be among the criteria for defining the female athlete triad syndrome (Burke & Deakin 1994, Khan et al 2002).
Bone mass is accumulated in the first three decades of life although peak mass is thought to be reached around 18 to 20 years (Burke & Deakin 1994, Yurth 1995, Talbott 1996, Warren & Goodman 2003). The lack of oestrogen in young athletes with primary amenorrhoea puts them at risk of osteopenia as a consequence of inadequate bone formation (Heany 1993, Thein & Thien 1996, Warren & Goodman 2003).
Any athlete presenting with any one of the disorders should be screened for the others (Manore 1999). Treatment lies in prevention and requires a multidisciplinary approach which includes psychological support and a reduction in training (Smith 1996, Keen & Drinkwater 1997, Furia 1999, Otis & Goldingay 2000).
Nutritional education is relevant to coaches, athletes and family members. The disadvantages of inadequate eating should be emphasised:
- Most weight loss is due to loss of muscle tissue
- Low levels of lean body tissue makes training ineffectual
- Carbohydrate is essential for muscle glycogen stores
- Low energy intake depresses resting metabolic rate
- Eating orders may lead to amenorrhea and possibly osteopenia
(Burke & Deakin 1994)
Research has shown that nutrition may counteract or override the effects of an oestrogen deficiency on bone turnover (Zanker 1999). Women with anorexia nervosa have been seen to have a gradual increase in bone mineral density with feeding, even without resumption of menses (Zanker 1999).
Although studies differ on whether exercise alone is responsible for menstrual dysfunction, it is clear that athletes with an eating disorder, or not eating enough to meet energy demands, and following a strict exercise regime are at high risk of developing a menstrual disorder which may result in osteopenia.
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