Relation Between Secretory Status of Growth Hormone, Serum Concentration of Insulin-like Growth Factor I, and Insulin-like Growth Factor Binding Protein 3 with Bone Mineral Density in Postmenopausal Women

Although the decline in sex steroid levels, particularly estradiol, may be largely responsible for age-related bone loss and osteoporotic fractures in older women, the insulin-like growth factor (IGF) system may also play a key role. This study aimed at evaluating the relation between the secretory status of growth hormones (GH), insulin-like growth factor I (IGF-I) and In-sulin-like growth factor binding protein 3 (IGFBP3) and bone mineral density (BMD) in postmenopausal women. In a descriptive cross-sectional study, 150 postmenopausal healthy women were selected from among 1328 patients, referred to Tabriz Sina Hospital for bone densi-tometry, and divided into three groups according to their bone mineral density (BMD) (normal, os-teopenic and osteoporotic). The GH response to provocation by clonidine was assessed in all pa-tients. One hundred and fifty patients with a mean age of 65.6±6.6 years, were enrolled in this study. The impaired GH response to provocation by clonidine was significantly more common in the group with osteoporosis compared to their healthy and osteopenic counterparts (72% vs. 56% and 44%, respectively; p=0.018). Mean levels of serum IGF-I and IGFBP3 were not signifi-cantly different in healthy, osteopenic and os-teoporotic patients (55.4±20.7 μg/L, 57.5±21.7 μg/L, and 56.7±19.2 μg/L; p=0.880 and 2648.3±786.4 ng/ml, 2374.0±707.2 ng/ml, and 2613.5±1023.6 ng/ml; p=0.217, respectively). There was no strong cor-relation between the level of serum IGF-I or IGFBP3 and T-Score (r=-0.026, p=0.753 for IGF-1 and r=0.046, p=0.575 for IGFBP3). The results of this study showed that the defective release of GH is more prevalent in postmenopausal women suffering from osteoporosis; such a defect was not observed regarding serums of IGF1 and IGFBP3. Prescription of supplementary doses of synthetic GH might be beneficial in this population.