Reprinted from Eating Disorders Review
September/October 2005 Volume 16, Number 5
©2005 Gürze Books
Osteoporosis is one of the most serious complications of anorexia nervosa, and some teenagers with AN may have permanent loss of bone mass. The process of losing bone density is still not clearly defined.
To chart changes in bone density, a team at Cambridge School of Clinical Medicine, Cambridge, UK, measured bone mineral density, total body composition and biochemical indices of bone turnover over 1 year in a group of 26 anorexic women 13 to 20 years of age (J.B. Bolton et all, Osteoporosis Int July 2005).
Weight and height increased but bone density did not
At the end of the year, the young women had a mean weight gain of 10 kg and there was a significant gain in height. Mean body mass index changed from 14.2 kg/m2 at baseline to 17.6 kg/m2. Despite the weight gain and growth, no significant increases were seen in bone density in the spine or proximal femur during the study.
At 3 months and again at 12 months, total body bone density was significantly higher than at baseline. In contrast, at 3 months, total body bone density was significantly lower than at baseline.
Serum osteocalcin and bone-specific alkaline phosphatase values increased significantly and remained higher than baseline values at all measurements. However, urinary N-telopeptide/creatinine excretion at 12 months was significantly lower than at baseline. At 6 months, mean serum-25-hydroxyvitamin D levels were significantly lower than baseline levels, but moved upward toward baseline after this. Serum parathyroid hormone levels significantly increased at all measurements compared to baseline.
Thus, although the women regained weight and also had an increase in height, bone mineral density did not increase over the year. Whether this loss of bone density can be corrected is not yet known, and the answer will require much longer-term studies, according to the authors.
