REDUCED SPINAL BONE-DENSITY IN YOUNG-WOMEN WITH AMENORRHEA

To assess the influence of diminished oestrogen production on bone density, we studied 23 amenorrhoeic women and 20 controls (age range 16-29 years) divided into four groups: group 1: 6 patients with idopathic hypogonadotrophic hypogonadism with primary amenorrhoea (IHH); group 2: 5 patients with delayed puberty owing to thalassaemia major (TM); group 3: 12 patients with secondary hypothalamic amenorrhoea (HA); group 4: 20 women with normal menses (controls). Secondary sexual characteristics had developed in all except the women with TM. Groups 1 and 2 had never menstruated and group 3 had been amenorrhoeic for 6 months to 3 years. The control group was studied during the follicular phase of the cycle. None of the patients were taking oestrogens at the time of observation. Plasma concentrations were determined for 17-beta-oestradiol (E2), deidroepiandrosterone sulphate (DHEA-S), cortisol (F), prolactin (PRL), thyroid hormones (T3 and T4), and gonadotrophins (LH and FSH). Spinal bone mineral density (BMD g/cm2) was assessed by dual photon absorbiometry. BMD (mean +/- 1SD) was reduced in the patients (group 2: 0.920 +/- 0.95; group 1: 0.980 +/- 0.94; and group 3: 1.037 +/- 0.75) as compared with the controls (1.290 +/- 0.95) (P < 0.01). In the three groups of patients, plasma E2 levels were lower than 50 pg/ml and were positively correlated with the BMD. As expected, plasma gonadotrophin levels were highly and significantly reduced (P < 0.01) in the patients, compared with that of the controls. These results suggest that reduced spinal BMD in hypogonadic women may be related to the lack of oestrogenic influence on bone metabolism. We conclude that decreased peak bone mass is a feature of amenorrhoea in young women. Early identification and treatment of these women is recommended.