Researchers call it the “female athlete triad:” the relationship between disordered eating, irregular periods, and osteoporosis in young women athletes. Some studies suggest that as many as two-thirds of these young women eat in ways that aren’t quite an eating disorder but are still harmful to their bodies. Very few studies have looked at all three parts of this triad at once.
These authors looked into this three-way relationship. They studied 91 competitive women distance runners between 18 and 26 years old. (All the runners were part of a larger study on the relationship between oral contraceptives and running.) All the young women competed in races, and they ran at least 40 miles a week during their peak training times. They filled out questionnaires about their eating habits and attitudes, their training schedule, and their menstrual history. They also went through tests of bone mineral density (BMD).
The data about running and menstruation supports other research:
About 36 percent of the runners had abnormal menstrual periods. They either menstruated infrequently or not at all.
Runners with high scores for disordered eating were more likely to have abnormal periods.
Runners with abnormal periods ran more miles per week than the runners with normal periods.The research also showed some interesting facts about BMD in young women runners:
Runners with abnormal periods were more likely to have low BMD, regardless of their weight or height. Low BMD was especially noticeable in the lumbar spine (the lower back). About six percent of the runners with abnormal periods had osteoporosis of the spine, and about 48 percent showed osteopenia (lower bone density, but not to the point of osteoporosis) in the spine. None of the runners with normal periods had osteoporosis, and only 26 percent had osteopenia of the spine.
Even runners with normal periods were more likely to have low BMD if they also showed disordered eating.
Disordered eating and abnormal menstruation were both equally bad for BMD. They didn’t seem to cause worse BMD when runners had both risk factors. The authors caution that further study is needed on this issue because this study was too small to draw any firm conclusions.The research also brought up questions that couldn’t be answered in this study:
Despite the high scores on the disordered eating questionnaire, none of the runners said they were dieting. The authors feel this means the eating restrictions were long-term rather than temporary attempts to lose weight.
Runners who started menstruating late were also more likely to have abnormal periods and low BMD. The authors don’t know if those factors are directly related, or if these runners had disordered eating even at a young age that contributed to these problems.
Runners with high scores of disordered eating tended to be heavier than runners with lower scores. The authors aren’t sure why. They suggest that the questionnaire may identify people in the early stages of an eating disorder, but not in the late stages, after they have lost weight.The authors stress that the relationships between the factors of the “female athlete triad” are complex. No one understands exactly how it works. It is thought that estrogen deficiency and metabolism play some role. And it is known that women who weigh very little are more likely to have low BMD. No matter what the causes, the authors recommend that all competitive women athletes be screened for eating disorders and menstrual irregularity, and that they be given information about the long-term consequences for their health.