Bone metabolism in patients with anorexia nervosa and amenorrhoea

Aim of this study is focusing on bone metabolism in AN patients with amenorrhoea and related estrogen deficiency effects.

AN patients were compared both with healthy females and with postmenopausal women (reference model for estrogen deficiency). The study sample included 81 females with AN. Laboratory tests [25-OH vitamin D, bone turnover markers, intact parathyroid hormone, sclerostin (SOST) and dickkopf-related protein (DKK1)] and dual energy X-ray absorptiometry (DXA) were taken into account.

AN patients had higher levels of C-terminal telopeptide of type I collagen (CTX) than both control groups. AN adolescents had CTX higher than AN young adults. In postmenopausal women, intact N-propeptide of type I collagen was higher if compared with each other group. In AN groups, Dickkopf-related protein 1 was significantly lower than the two control groups. No differences were found in sclerostin except in adolescents. In AN adolescents, DXA values at femoral sites were higher than in AN young adults and a positive correlation was found with body weight (p < 0.01) and with fat mass evaluated using DXA (p < 0.01).

AN women with amenorrhoea have an increased bone resorption like postmenopausal women but bone formation is depressed. The consequent remodeling uncoupling is considerably more severe than that occurring after menopause.