Amenorrhea after weight recover in anorexia nervosa: role of body composition and endocrine abnormalities

Abstract

Hypothalamic amenorrhea in anorexia nervosa often precedes weight loss and may persist after re-feeding and restoration of a stable normal weight.

Aim: To assess the rate of persistent amenorrhea in anorexia nervosa (AN) after re-feeding and the relations of this condition with body composition changes and other endocrine parameters.

Methods: A cohort of 250 female outpatients was studied to assess persistent amenorrhea prevalence after stable weight recovery. Among these, we selected 20 AN female patients (age 16.5-35), 10 with amenorrhea (group 1) and 10 with normal menses (group 2). We collected data such as age, age at menarche, age at onset of AN, actual body mass index (BMI) and at onset of AN, duration of disease. Physical activity has been evaluated as minute per day. The following data were obtained: prolactin, growth hormone, estradiol, luteinizing hormone, follicle stimulating hormone, thyroid stimulating hormone, free triiodothyronine, free thyroxine, free urinary cortisol, serum calcium and phosphates, urinary calcium, phosphaturia and alkaline phosphatase. Body composition was assessed with a dual energy x-ray absorptiometry (DEXA).

Results: Thirty-five patients (14%) over a cohort of 250 where still amenorrhoic after stable weight recovery. No significance was found in the evaluation of blood biochemical tests of the 2 groups. Free urinary cortisol was significantly higher in amenorrhoic patients (58.14+/-0.4 vs 15.91+/-9.5), p=0.02. The analysis of body composition has shown a percentage of fat of 22.23+/-5.32% in group 1 and of 26.03%+/-9.1% in group 2, respectively, showing no significant differences. Amenorrhoic patients carried on doing a significantly heavier physical activity than eumenorrhoic patients.

Conclusions: An adequate body composition and a well represented fat mass are certainly a necessary but not sufficient condition for the return of the menstrual cycle. Such menstrual cycle recovery would probably need other conditions at present being studied and evaluated to occur, such as secretory patterns of leptin and its correlations with adrenal function.