Association between calcium-regulating hormones, 25(OH)D, IGF-I, and BMD in elderly women who were not estrogen or bisphosphonate users.

Objective(s): Secondary hyperparathyroidism is a frequent condition in elderly women, and represents a risk factor for increased bone resorption. Measurement of BMD is currently considered of diagnostic value to predict an individual long-term fracture risk, and BMD values correlate with several demographics and anthropometric parameters, and with markers of bone metabolism and calcium-regulating hormones. The aim of this study was to evaluate the relationship between BMD, BMI, PTH, vitamin D (25(OH)D), and IGF-I in elderly women. Material & Methods: A group of 31 postmenopausal women over age 65 (median 68 years, range 65-74) who were not bisphosphonates, estrogen, calcium or vitamin D users, and had no history of fracture, were enclosed in the study. The following parameters have been recorded: age, age at menarche and menopause, weight, height, BMI (kg/m2), systolic and diastolic blood pressure. Lumbar spine (L2-L4) BMD (g/cm2) using DXA, serum albumin, calcium, PTH (ng/L), 25(OH)D (nmol/L), and IGF-I (μg/L) were measured in all patients. Results: The main results are reported in the Table. There were no hypertensive patients, and both s-albumin and s-calcium were within the normal range (41-47 g/L, and 2.10-2.55 mmol/L, respectively). There was an inverse correlation between age and both 25(OH)D (R=-0.50, p=0.020) and IGF-I (R=-0.7, p<0.0001), and between BMD and PTH (R=-0.48, p=0.027). Moreover, a significant relationship between IGF-I and both BMD (R=0.64, p=0.0016) and PTH (R=0.48, p= 0.026) was found, while IGF-I did not correlate with 25(OH)D (R=0.16, p=0.47) and BMI (R=-0.89, p=0.70). Age at menarche and menopause were independent parameters (p=NS). Conclusion(s): In this group of elderly women there was a strong relationship of osteoporosis (expressed as BMD values) to calcium-regulating hormones, such as PTH and IGFI, while BMI and 25(OH)D seem to be independent of bone mineralization status.