Skeletal status and body composition in young women with functional hypothalamic amenorrhea

Functional hypothalamic amenorrhea (FHA) related to hypoestrogenism and hormonal status may influence skeletal homeostasis and body composition. The study aimed to evaluate hormones concentrations, body composition and bone strength in FHA cases.

Total body scans using DXA method (DPX-L, GE Lunar) were performed in a group of 27 women aged 21.8 years ± 3.9 with FHA related to weight loss. References of healthy control subjects were used to calculate Z-scores (age and gender matched), SD-scores (height and gender matched), and SDs-scores (weight and gender matched). Whole skeleton bone mineral content (TBBMC, g) and density (TBBMD, g/cm(2)), lumbar spine (L2-L4) bone mineral density (SBMD; g/cm(2)), lean body mass (LBM, g) and fat mass (FM, g) were investigated. Relative bone strength index was calculated as the TBBMC/LBM ratio. Serum follicle-stimulating hormone (FSH), luteinizing hormone (LH), estradiol, testosterone, and prolactin (PRL) concentrations were assayed to characterize hormonal profile of FHA cases.

Hormonal evaluation in patients with FHA revealed significantly decreased serum concentrations of gonadotropins and estradiol. Serum LH concentrations were 1.47 ± 0.89 mIU/ml, FSH 4.44 ± 1.94 mIU/ml. Estradiol concentrations in serum were 27.08 ± 13.10 pg/ml. As evidenced by Z-scores, FHA cases had decreased SBMD, TBBMD and TBBMC Z-scores of -1.23 ± 0.90 (p < 0.0001), -0.72 ± 0.86 (p < 0.001), and -0.90 ± 1.40 (p < 0.01), respectively. Reduced FM, LBM and FM/LBM ratio Z-scores of -1.80 ± 2.28 (p < 0.001), -0.59 ± 1.49 (p < 0.05) and -0.74 ± 1.55 (p < 0.05), but not TBBMC/LBM Z-score of -0.54 ± 2.14 (ns) were noted in FHA cases compared with healthy control cases. TBBMC, TBBMD, TBBMC/LBM when BH- or BW-matched were normal as evidenced by SD-scores and SDs-scores. SBMD remained reduced when BH-matched (SD-score = -0.40 ± 0.86; p < 0.05) whereas FM and FM/LBM were lower than expected in healthy, both compared to BH- and BW-dependent references. The length of amenorrhea in months negatively correlated with SBMD Z-score (R = -0.39, p < 0.05), and SD-scores for SBMD (R = -0.48), TBBMD (R = -0.43), TBBMC (R = -0.46) (all p < 0.05) and positively with SDs-scores for FM (R = 0.44, p < 0.05).

Patients with FHA were characterized by lower concentrations of serum FSH, LH and estradiol concentrations. Moreover, FHA cases had decreased FM and an imbalanced relationship between BW, FM, and LBM. Despite reduced BMD and BMC, bone strength was not significantly affected by FHA.