The effects of high serum growth hormone and IGF-1 levels on bone mineral density in acromegaly.

OBJECTIVE: Growth hormone (GH) and insulin-like growth factor-1 (IGF-1) play a major role in bone homeostasis. In this study, we aimed to assess bone mineral density (BMD) in active acromegaly.

MATERIALS AND METHODS: A total of 29 patients with active acromegaly (age 46.10 ± 13.27 years; body mass index [BMI]: 29.51 ± 4.91 kg/m(2)) and 42 healthy individuals matched for age and BMI (age: 40.35 ± 11.74 years; BMI: 28.18 ± 7.35 kg/m(2)) were included in the study. BMD was measured by DXA.

RESULTS: The mean levels of GH and IGF-1 were found to be 12.61 ± 11.34 ng/ml and 676.47 ± 316.19 ng/ml in acromegaly, respectively, while the mean levels of GH and IGF-1 were found to be 0.59 ± 0.81 ng/ml (p = 0.0001) and 178.17 ± 57.11 ng/ml (p = 0.0001) in the control group, respectively. Only total hip t‑score was determined to be significantly lower in acromegaly compared to the control group (p = 0.037). No significant differences were found between the other parameters in DXA and only a positive correlation was found between IGF-1 levels and L1-L4 BMD (r = 0.259, p = 0.029).

CONCLUSIONS: Although GH and IGF-1 levels were increased in acromegalic patients, no significant difference was found in terms of vertebral BMD. Only hip t‑scores were found to be lower in acromegalic patients, but this low hip t‑score did not reach the osteopenic level. The positive correlation between IGF-1 and lumbar vertebral BMD suggested a more prominent effect of IGF-1 on BMD compared to GH.