Bone fractures are a well-documented complication of anorexia in adults, but little data is available on the risk in adolescents. A study published in the International Journal of Eating Disorders last summer looked at fractures in a sample of 418 females in a cross-sectional study. Results showed that the lifetime rate of fractures was 60% higher in those with anorexia vs controls. Also significant was the fact that the fractures were occurring without any reduction in bone mineral density on DXA scans.
This highlights the importance of early detection and treatment of the eating disorder, as nearly 1/3 of females with anorexia in this study had already suffered fractures. The window for accumulation of bone density closes during young adulthood, making the teenage years crucial for attaining maximum possible bone density. Once that period is over, women gradually lose bone density for the rest of their life as a normal part of the aging process. Hence, we want to gain as much density as possible to begin with, so that the loss over time has minimal impact.
Eating disorders can cause loss of bone density for several reasons, most of them hormonal, including low levels of estrogen and leptin (as a result of low calorie intake and loss of body fat), and elevated cortisol levels (a marker of physiological stress). The medicine for this is food. Restoring the body to a healthy nutritional state as quickly as possible will prevent further complications from the eating disorder.
It is also known that the risk of relapse is high with eating disorders, and that the sooner the ED is diagnosed and treated in adolescents, the better their prognosis. Those with multiple relapses and long periods of malnourishment are at highest risk of fractures, osteopenia and ultimately osteoporosis.
Faje et al. Fracture Risk and Areal Bone Mineral Density in Adolescent Females with Anorexia Nervosa. Int J Eat Disord 2014;47:5 458-466.