Anorexia increases risk of premenopausal osteoporosis, study finds

02/14/2011
A study recently conducted by an associate professor at Case Western Reserve University reiterated that an important but largely overlooked complication of eating disorders is early-onset osteoporosis.

Kathryn Teng, who is also the director of the Cleveland Clinic's office of Integration of Personalized Healthcare, said that it is likely that more than half of young women with anorexia nervosa will develop osteoporosis before menopause.

She cited a study published in the International Journal of Eating Disorders, which analyzed a group of young women with decade-long eating disorders and found that 75 percent had critically low bone density.



Teng's paper, which appears in the Cleveland Clinic Journal of Medicine, clarified which aspects of eating disorders may contribute to early-onset osteoporosis.



Anorexia occurs in about one in every 200 females in the U.S., according to the South Carolina Department of Mental Health. Women with anorexia have a severe aversion to weight gain, and typically weigh less than 85 percent of the body mass expected for their height.

According to Teng, anorexia occurs most commonly in teen girls between the ages of 11 and 14. She noted that approximately half an individual's bone mass develops during this period. Malnutrition may severely stunt bone growth, which can lead to a high risk of fracture.

The author estimated that a 10 percent decrease in bone growth at this age can triple the risk of later fracture.

Besides a general lack of nutrients, Teng emphasized that anorexia primarily causes premenopausal osteoporosis by scrambling hormone levels. Estrogen, androgen, insulin-like growth factor, osteoprotegerin, leptin, ghrelin and obestation are all hormones that are directly or indirectly linked to bone growth.

Anorexia can promote abnormal levels of all of these hormones, potentially leading to weakened bone. The author concluded that regaining weight and taking vitamin D are the most effective ways to mitigate bone loss caused by an eating disorder.

Other risk factors that increase the likelihood of osteoporosis include smoking, alcohol consumption, physical inactivity, corticosteroid use and amenorrhea, according to the International Osteoporosis Foundation.