The effects of growth hormone treatment on bone mineral density and body composition in girls with Turner syndrome

Background: Many girls with Turner syndrome (TS) are treated with GH to increase adult height. In addition to promoting longitudinal bone growth, GH has effects on bone and body composition. Objective: The objective was to determine how GH treatment affects bone mineral density (BMD) and body composition in girls with TS. Method: In a cross-sectional study, we compared measures of body composition and BMD by dual energy x-ray absorptiometry, and phalangeal cortical thickness by hand radiography in 28 girls with TS who had never received GH and 39 girls who were treated with GH for at least 1 yr. All girls were participants in a National Institutes of Health (NIH) Clinical Research Center (CRC) protocol between 2001 and 2006. Results: The two groups were similar in age (12.3 yr, SD 2.9), bone age (11.5 yr, SD 2.6), and weight (42.8 kg, SD 16.6); but the GH-treated group was taller (134 vs. 137 cm, P = 0.001). The average duration of GH treatment was 4.2 (SD 3.2) yr (range 1-14 yr). After adjustment for size and bone age, there were no significant differences in BMD at L1-L4, 1/3 radius or cortical bone thickness measured at the second metacarpal. However, lean body mass percent was higher (P < 0.001), whereas body fat percent was lower (P < 0.001) in the GH-treated group. These effects were independent of estrogen exposure and were still apparent in girls that had finished GH treatment at least 1 yr previously. Conclusions: Although GH treatment has little effect on cortical or trabecular BMD in girls with TS, it is associated with increased lean body mass and reduced adiposity.