Objective: Osteopenia in Turner's syndrome is well recognized. This study is aimed to elucidate whether this is an intrinsic feature of the disorder, or is a non-specific feature resulting from oestrogen deficiency.
Design: Comparison of bone mineral density and fracture rate in Turner's patients and in 46,XX women with equivalent oestrogen deprivation from other causes.
Subjects: One hundred and twenty women in the reproductive age range (16-45 years): 40 with Turner's syndrome, 40 with other forms of primary amenorrhoea, and 40 healthy controls matched to patients for duration of oestrogen usage.
Measurements: Measurement of bone mineral density in the lumbar spine (and femoral neck in some subjects) by dual-energy X-ray absorptiometry, and reported history of fracture.
Results: Vertebral bone mineral density was similar in women with Turner's syndrome (mean 0.84, SD 0.11 g/cm2) and those with other causes of primary amenorrhoea (mean 0.81, SD 0.11 g/cm2; P = 0.26). Both groups had severe osteopenia compared with healthy controls (mean 1.06, SD 0.09 g/cm2, P < 0.0005, confirmed after correction for height and weight). Fractures had been sustained by 45% (10/22) of Turner's patients for whom information was available, a high frequency compared with controls (P = 0.014); half of these were at 'osteoporotic' sites of fracture (wrist, vertebra, femoral neck).
Conclusion: Osteopenia in Turner's syndrome is not an intrinsic feature specific to this disorder, but results from extreme oestrogen deprivation. Early treatment with oestrogen is therefore recommended.