Q & A: Low Bone Density and Psychiatric Disorders

Q: I know that women with anorexia nervosa often have decreased bone density. Does this problem occur with any other psychiatric disorders? (L.L., Akron, Ohio)

A: This is an interesting question because several factors thought to contribute to osteopenia are present in psychiatric disorders other than eating disorders. Studies have shown, for example, that normal-weight, normally menstruating premenopausal women with depression and no known eating disorders have lower bone densities in the lumbar, femoral, and other skeletal regions than do age-matched controls. Although increased levels of serum cortisol have been thought to contribute to osteopenia in both anorexia nervosa and depression, in one recent study there were no significant differences in levels of serum cortisol between depressed women and controls. However, depressed women did have slightly lower levels of osteocalcin, a marker of bone growth activity (Yazici KM et al, Psychiatry Research 2003;117:271). Of note, smokers also have decreased bone mass and increased risk of fractures, and rates of smoking are known to be elevated in depressed individuals. Thus, it’s important to consider that both depression and smoking may contribute to osteopenia in patients with eating disorders as well.

—JY