ESPE Abstracts

Background: Childhood onset growth hormone deficiency (CO-GHD) may contribute to low bone mass and alterations of body composition. However, the mechanisms by which CO-GHD effects bone health are not yet clearly defined.

Objective and hypotheses: To evaluate musculoskeletal health in CO-GHD subjects at initial evaluation and retesting after final height.

Method: A cross-sectional study of assessing bone health and body composition by imaging (DXA and pQCT), muscle strength by mechanography, and biochemical assessment in children undergoing GH stimulation tests for short stature (total – 25, GH deficiency – 15, median age (range) 10.9 years (5.6–16.0)) and biochemical revaluation at final height after GH therapy (total – 11, GH deficiency – 7, age 16.7 years (14.9-18.6)).

Results: After adjusting for age, height, and bone area, GH deficient subjects did not differ in bone and body composition parameters (as measured by DXA and pQCT) from those who had normal GH levels at initial evaluation and retesting after final height. When assessing muscle strength by mechanograph, the median of maximum-force in naive GHD was significantly lower than normal subjects (0.5 kN (0.3, 2.8) vs 2.7 kN (2.2, 3.3) respectively, P=0.03). This was proportional to their tibia muscle cross sectional area. There were no differences in bone profiles and bone formation markers between all studied groups. However, the bone resorption marker, C-terminal telopeptide (CTX) was significantly higher in naive GHD vs the normal in the first time assessment group (2.0 ng/ml (1.4, 3.9) vs 1.6 ng/ml (0.9, 2.8), respectively, P=0.02). A positive correlation was found between CTX and parathyroid hormone (PTH) at time of initial evaluation (r=0.46, P=0.02) and retesting (r=0.77, P=0.02).

Conclusion: Subjects with CO-GHD have normal bone mass and body composition at initial evaluation and retesting at final height. However, significant lower muscle force and higher CTX was found in naive GHD compared to the normal. Our results suggest that muscle force and PTH are important determinants of bone health in subjects with CO-GHD. However, a large-scale study is required to verify our findings.