Bone mineral density and fractures in Turner syndrome

Purpose To determine whether women with Turner syndrome who were treated with estrogen were more likely to have osteoporosis and fractures. Methods Areal bone density at the lumbar spine and femoral neck was measured in 40 adult women with Turner syndrome and 43 age-matched healthy women using dual-energy X-ray absorptiometry. Histories of estrogen treatment and fractures were obtained by structured personal interviews. Results Mean (± SD) areal bone density was significantly lower at the lumbar spine (0.87 ± 0.11 g/cm2 vs. 0.98 ± 0.10 g/cm2, P<0.001) and femoral neck (0.68 ± 0.07 g/ cm2 vs. 0.83 ± 0.08 g/cm2, P<0.001) in women with Turner syndrome than in controls. The diagnostic criterion for osteoporosis (T-score <−2.5) was met by 8 women with Turner syndrome (20%) with scores at the lumbar spine and by 3 (8%) with scores at the femoral neck. All women diagnosed with osteoporosis were less than 150 cm in height. Areal bone density correlated significantly with height (lumbar spine: R2 = 0.3, P<0.001; femoral neck: R2 = 0.4, P<0.001). Adjustments for skeletal size reduced the differences between the groups as well as the number of women diagnosed with osteoporosis (e.g., from 8 to 2 women based on lumbar spine scores). The prevalence and type of fractures were similar in the two groups. Conclusion The prevalence of osteoporosis and bone fractures is not increased significantly in women with Turner syndrome who are treated with standard estrogen therapy. Women less than 150 cm in height are likely to be misdiagnosed with osteoporosis when areal bone density is measured, unless adjustments for body size are made.