IGF-1 and Bone Loss in Women With Anorexia Nervosa

Anorexia nervosa is an eating disorder that can cause thinning of the bones (a decrease in bone density). A significant decrease in bone density is called osteopenia or osteoporosis. Sometimes the loss of bone density can be severe enough to cause breaks and fractures of the bones. It is not known what causes the bones to thin in anorexia nervosa. Women who have this condition often have thin or weak bones that are more likely to break. They also have very low levels of a chemical called IGF-1 in their body. This chemical is very important for increasing bone growth in puberty and for maintaining healthy adult bones. The investigators would like to find out if giving rhIGF-1 followed by risedronate or risedronate alone can lead to an increase in bone formation, bone density, and bone strength in women with anorexia nervosa.