To assess the association among serum insulinlike growth factor I (IGF-I) concentrations, bone mineral density (BMD), and biochemical markers of bone turnover in a large group of postmenopausal women from the general population.
As an extension of a larger epidemiological study, the Iranian Multicentral Osteoporosis Study, a total of 406 healthy postmenopausal women (age, 59.0 ± 7.6 years) were randomly selected from 13 clusters in Bushehr Port. IGF-I, serum CrossLaps, degradation products of C-terminal telopeptides of type I collagen, and osteocalcin were measured by highly specific enzyme-linked immunosorbent assay. BMD was determined for the lumbar spine (L2-4) and proximal femur using dual-energy x-ray absorptiometry.
The mean (± SD) serum IGF-I concentration for all postmenopausal women was 183.35 ± 65.60 ng/mL. In age-adjusted analyses, there was no correlation between IGF-I and BMD at the lumbar spine and femoral neck. Compared with women in the lowest quartile of IGF-I, women in the highest quartile had a significantly greater means of osteocalcin (P = 0.04) and alkaline phosphatase (P = 0.01). Analysis by quartiles of IGF-I did not reveal an association with serum CrossLaps.
Circulating IGF-I is associated with biochemical markers of bone formation, but there is no relationship among IGF-I, degradation products of C-terminal telopeptides of type I collagen, and BMD in postmenopausal women. Clearly more work will be needed before serum IGF-I can be used in clinical practice as a risk predictor for postmenopause-associated loss of bone mass.
In a large group of postmenopausal women, this study found that circulating insulinlike growth factor I-related with biochemical markers of bone formation, but there was no relationship between insulinlike growth factor I, degradation products of C-terminal telopeptides of type I collagen, and bone mineral density. More work will be needed before serum insulinlike growth factor I can be used in clinical practice as a useful clinical index of osteoporosis.
From the 1Department of Endocrine and Metabolic Diseases, The Persian Gulf Tropical Medicine Research Center, Bushehr University of Medical Sciences, Bushehr; and 2Tehran Endocrine Research Center, Tehran University of Medical Science, Tehran, Iran.
Received October 11, 2007; revised and accepted December 26, 2007.
Funding/support: This project was supported in joint by a grant from joint Ministry of Health, Tehran Endocrine Research Center, Tehran University of Medical Science, Tehran, Iran and Bushehr Province Research Committee.
Financial disclosure: None reported.
Address correspondence to: Iraj Nabipour, MD, Bushehr University of Medical Science, Moallem Street, PO Box 3631, Bushehr, I.R. Iran. E-mail: firstname.lastname@example.org