Primary hyperparathyroidism (PHP) and growth hormone deficiency (GHD) are both associated with alterations of bone metabolism.
GH secretion is frequently impaired in PHP patients; thus GH/IGF-I system alterations could be involved in the pathogenesis of osteoporosis.
In the present study 50 post-menopausal women with PHP were evaluated by GH response to GH-releasing hormone (GHRH)+arginine (ARG) test and femoral neck bone mineral density (BMD, g/cm2) by dual energy X-ray absorptiometry. BMI, serum ionised calcium, PTH and markers of bone remodelling (serum osteocalcin (OC), serum bone-specific alkaline phosphatase (B-AP), serum cross-laps (S-CTX) were evaluated as well.
Same data were collected in a group of 60 age-matched controls.
No difference was found between the two groups regarding age, age at menopause, BMI, serum ionised calcium, PTH and IGF-I concentrations.
GH secretion was reduced (mean GH response to GHRH+arg test: 8.8±4.2 μg/liter) in 34 patients and normal (28.7±11.8 μg/liter) in the remaining 16 (P<0.05), in the control group peak GH was 33.8±10.9 μg/liter.
Osteoporosis (T-score <−2.5) and osteopenia (T-score >−2.5 and <−1) were found in 73.5% and 17.6% of GHD patients, in 37.5% and 43.7% of patients with normal GH secretion and 3.1% and 27% of controls.
The prevalence of osteoporosis in GHD group was significantly different with respect to patients with normal GH secretion (P=0.02) and to controls (P=0.02).
T-score was not correlated with ionised calcium, nor with age, age at menopause or BMI, but was correlated with PTH serum levels in both groups and T-score was correlated with markers of bone remodelling only in GHD patients.
In conclusion, impairment of GH secretion could be involved as a pathogenetic factor in bone metabolism alterations of PHP.