Low Bone Mass Is a Lasting Consequence of Anorexia Nervosa

Although only one in 10 Americans with eating disorders pursue care, US endocrinologists see many patients who suffer the long-term consequences of the conditions.

A new review published in Current Opinions in Endocrinology, Diabetes, and Obesity comprehensively examined anorexia nervosa — the third most common chronic disease among adolescents — and its long-lasting endocrine effects.

Even if an anorexic patient’s weight is restored to a healthy level, low bone mineral density (BMD) and other adverse outcomes often persist for years or decades as a result of the multiple neuroendocrine axis alterations that characterize anorexia nervosa, including acquired hypogonadotropic hypogonadism, growth hormone resistance with low insulin-like growth factor-1, relative hypercortisolemia, adipokine alterations, and gut peptides changes. Additionally, increased marrow adipose tissue (MAT) has been associated with BMD in other populations, and among women diagnosed with anorexia nervosa, increased MAT appears to affect osteoblast lineage differentiation and reduce BMD.

In terms of effective therapy for anorexic patients, gaining weight and returning to menstruation is the best plan to correct endocrine problems. While oral estrogen has not been found to effectively increase BMD in girls with anorexia nervosa — possibly due to some of its hepatic effects — transdermal estrogen has been shown to improve spine and hip BMD, though it rarely allows patients’ bones to catch up to their expected density.

In contrast, the bisphosphonates class of osteoporosis medications is rarely used in adolescents with anorexia nervosa because the drugs' mechanisms involve reducing bone turnover, which is already impaired in those patients. In addition, no long-term studies of bisphosphonates have been conducted in patients with anorexia, and the drugs’ effects in pregnancy are unknown.