The so-called ‘female athlete triad’ of disordered eating, menstrual irregularity and bone loss is increasingly recognised as a risk for sportswomen, particularly endurance athletes.

But an important new US study has revealed that the combination of eating and menstrual problems is no more detrimental to bone than either problem alone.

The subjects of this study were 91 competitive female distance runners aged 18-26. Disordered eating was assessed via the Eating Disorders Inventory (EDI), which measures attitudes to food and body size, menstrual irregularity was defined as anything from 0-9 periods a year, while bone mineral density (BMD) was measured by a technique called dual x-ray absorptiometry.

Key findings were as follows:

An elevated score on the EDI (highest quartile) was independently associated with oligomenorrhea (irregular periods) and amenorrhea (absent periods);
Oligo/amenorrheic women had lower BMD than normally menstruating runners at the spine (-5%), hip (-6%) and whole body (-3%);
Normally menstruating runners with elevated EDI scores had lower BMD than those with normal EDI scores at the spine (-11%), hip (-5%) and whole body (-5%);
Runners with a combination of oligo/amenorrhea and elevated EDI scores had no further reduction in BMD than those with only one of these risk factors.
The authors of the research point out that very few previous studies have actually measured menstruation, diet and BMD simultaneously, and that theirs is the first to attempt to establish the complex relationship between these three components of the female athlete triad.

A particularly interesting aspect of their findings was that, while the women with elevated EDI scores reported lower total energy intakes and lower percentage fat intakes than those with normal EDI scores, they tended to be heavier.

The researchers comment: ‘We would expect women with subclinical eating disorders to have lower weight and body fat, but this was not the case in our study. Possibly, heavier women are more prone to eating disorders because they are more dissatisfied with their natural body type.’

They speculate that some of the athletes with higher EDI scores might have had bulimic (binge-and-vomit) tendencies, which are less likely to produce weight loss than anorexia. Alternatively, the EDI scale may identify women in the early stages of an eating disorder but may miss women in the later stages, who have already lost weight. Or some of the thinnest women – those with menstrual problems but low EDI scores – may have been in denial about their eating problems.

Whatever the reason, the worrying conclusion is that the female athlete triad may be more of a hidden problem than has previously been appreciated, and not readily discernible by a doctor or coach.

The researchers conclude: ‘Because there is a high prevalence of [bone deficiency] in this population that may have serious life-long consequences, we recommend that all competitive women endurance athletes… receive screening for eating disorders and menstrual irregularity and education about the female athlete trial.’

Med Sci Sports Exerc, vol 35, no 5, pp711-719, 2003