Low Areal Bone Mineral Density Values in Adolescents and Young Adult Turner Syndrome Patients Increase after Long-Term Transdermal Estradiol Therapy

Abstract

Objective: To study the effects of long-term estradiol therapy on areal bone mineral density (aBMD) values in young adult Turner syndrome patients. Methods: The effects of 2-year transdermal estradiol administration on lumbar, L2–L4, aBMD values were evaluated in 12 Turner syndrome patients, 15.41–21.85 years old, who had reached adult height and had low aBMD values. Puberty was induced in all at a chronological age above 12 years and menarche appeared between 13.82 and 15.40 years. The patients were on oral estrogen/gestagen therapy from then until the start of the study. Adhesive patches of 17-β-estradiol designed to be worn for 72 h and deliver 100 µg of estradiol per day, which results in a steady mean serum estradiol level of 75 pg/ml, were used for 21 days. From day 11 to day 21, 10 mg of oral didrogesterone were also added. Nutritional and physical activity habits were evaluated at the beginning, after 1 year and at the end of the study. Results: aBMD values significantly increased from 0.910 ± 0.065 to 1.005 ± 0.086 g/cm² (10.06 ± 3.37%) and the z-score from –2.38 ± 0.63 to –1.54 ± 0.71 (0.81 ± 0.30 z-score). No significant differences were observed in body mass index, calcium intake and physical activity habits at the start, during and at the end of the study. Conclusion: In summary, our results underline the importance of estrogens for bone mass peaking and suggest that this therapeutic protocol may be useful in the therapy of Turner syndrome patients with low bone mass.