Bone mineral density and parameters of bone metabolism in patients with acromegaly

Abstract

To assess the effect of chronically elevated plasma growth hormone (GH) levels on bone metabolism and bone mineral density (BMD), 16 patients (10 females and 6 males) with a mean age of 49.1 +/- 13.2 years (range 33-68) with active acromegaly were studied and compared to a control group of 16 sex- and age-matched subjects. BMD of the lumbar spine and two different sites of the proximal femur were measured by dual-energy x-ray absorptiometry (Norland XR-26). In the acromegalic patients the mean plasma GH concentration was 30.1 +/- 11.1 micrograms/liter, and the mean plasma somatomedin C (SMC) concentration was 6.5 +/- 1.5 U/liter. Mean serum osteocalcin (OC) levels (14.3 +/- 1.1 versus 7.2 +/- 0.4 ng/ml, p < 0.001) as well as the urinary hydroxyproline excretion (OHP; 8.8 +/- 1.4 versus 2.7 +/- 0.3 mg, p < 0.0001) were significantly higher in the acromegalic patients than in the control subjects. In the acromegalic patients BMD was significantly elevated in the two examined regions of the proximal femur, that is, the femoral neck (1.06 +/- 0.05 versus 0.86 +/- 0.03 g/cm2, p < 0.05) and Ward's triangle (0.92 +/- 0.06 versus 0.76 +/- 0.03 g/cm2, p < 0.02), whereas the BMD of the lumbar spine was not significantly different from that of control subjects. Among the patients with acromegaly a significant positive correlation between serum OC concentrations, on the one hand, and urinary OHP excretion (r = 0.7, p < 0.004) as well as BMD in the proximal femur (r = 0.64, p < 0.007), on the other hand, could be observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Bone Properties in Patients with Acromegaly: Quantitative Ultrasound of the Heel

“…Increased bone turnover has previously been documented in patients with acromegaly (21,22,23). Moreover, growth hormone treatment in elderly osteoporotic women has been shown to increase both bone resorption and bone formation markers (24).…”

Pituitary disorders and osteoporosis

“…In some studies BMD was reported to be increased or within the reference ranges, while in other papers it was decreased [17,26,[34][35][36][37]. Conflicting data on bone mineral density might be related to gonadal status, different skeletal sites being measured, various techniques employed, subject's gender, age, and activity of the disease [28,36,38].…”

“…It is well known that in patients with acromegaly bone turnover is increased [28,29,35]. A specific marker of bone formation, osteocalcin, is elevated in subjects with active disease [28,29,35,40,43].…”

“…A specific marker of bone formation, osteocalcin, is elevated in subjects with active disease [28,29,35,40,43]. Indicators of bone resorption such as urinary hydroxyproline/creatinine, urinary type I collagen cross-linked N-telopeptide, and serum C-terminal collagen type I cross-links are in higher concentrations than in controls [28,29,35,40,43]. Additionally, serum calcium and phosphate values and 24-hour urinary calcium are elevated in patients with active disease [27,29,34,35,41].…”

“…Indicators of bone resorption such as urinary hydroxyproline/creatinine, urinary type I collagen cross-linked N-telopeptide, and serum C-terminal collagen type I cross-links are in higher concentrations than in controls [28,29,35,40,43]. Additionally, serum calcium and phosphate values and 24-hour urinary calcium are elevated in patients with active disease [27,29,34,35,41]. Rise in serum calcium levels may be caused by increased intestinal calcium absorption, while high serum phosphate levels may be due to GH-mediated increased intestinal and renal absorption [27].…”