Context: Several studies assessed adiponectin levels in anorexia nervosa (AN) patients, however, data regarding the dynamics of changes in adiponectin levels during refeeding of these patients is limited and contradicting.

Objective: To assess adiponectin levels and the distribution of its different isoforms in AN patients, before and after long-term refeeding, and to relate them to alterations in body mass index (BMI), leptin, insulin sensitivity and additional endocrine parameters.

Design, setting and participants: Longitudinal controlled study. Thirty eight female adolescent malnourished AN inpatients, and thirteen control, young lean healthy women. Blood samples were obtained upon admission and thereafter at 1, 3, and 5 months (at target weight).

Main outcome measures: Changes in BMI, leptin, adiponectin, insulin sensitivity, and adiponectin multimeric forms.

Results: At admission, leptin levels of AN patients were significantly lower, while insulin sensitivity (assessed by HOMA-IR), adiponectin levels and the ratio of high molecular weight (HMW) adiponectin to total adiponectin were significantly higher compared with controls. During weight recovery, leptin levels and HOMA-IR increased significantly, while adiponectin and HMW adiponectin/total adiponectin ratio decreased significantly, to levels similar to controls. An initial increase in adiponectin levels was observed after one month of refeeding. There was no correlation between adiponectin and either thyroxin or cortisol levels.

Conclusions: our study demonstrates hyperadiponectinemia, increased adiponectin HMW isoform and increased insulin sensitivity in adolescent AN female patients and reversal of these findings with weight rehabilitation. We hypothesize that increased adiponectin levels may have a protective role in maintaining energy homeostasis during extreme malnourishment.