Fracture risk and bone mineral density in Turner syndrome.

Bone health is a major lifelong concern in caring for women and girls with Turner syndrome (TS). There is an approximately 25% increase in fracture risk most of which is related to medium or high impact trauma. The long bones, especially of the forearm are predominantly affected. This fact may be due to a selective cortical bone deficiency in TS which is unrelated to hypogonadism. In addition, lack of adequate estrogen replacement can lead to trabecular bone deficiency and increase in vertebral compression fractures after age 45. Evaluation of bone density by dual X-ray absorptiometry (DEXA) is important, however, it should be used judiciously in TS in view of its inherent tendency to underestimate the bone density of people with short stature. Bone size-independent methods, such as QCT or volumetric transformation of DEXA data should be used in individuals shorter than 150 cm. Achieving optimal bone density is of critical importance for fracture prevention in TS, and should be pursued by timely introduction of hormone replacement therapy, adequate dose of estrogens during the young adult life, optimal calcium and vitamin D intake and regular physical exercise. In addition, other measures to prevent fall and trauma should be considered, including optimizing hearing and vision, avoiding contact sports and exercise to improve coordination.