Associations of insulin-like growth factor-I and insulin-like growth factor binding protein-3 with bone quality in the general adult population

Summary

Objective

Growth hormone (GH) and its main mediator, insulin-like growth factor-I (IGF-I) play a significant role in bone metabolism. The relations between IGF-I and bone mineral density (BMD) or osteoporosis have been assessed in previous studies but whether the associations are sex-specific remains uncertain. Moreover, only few studies examined bone quality assessed by quantitative ultrasound (QUS). We aimed to investigate these associations in the general population of northeast Germany.

Design and Measurements

Data from 1759 men and 1784 women who participated in the baseline examination of the Study of Health in Pomerania (SHIP)-Trend were used. IGF-I and IGF-binding protein-3 (IGFBP-3) concentrations were measured on the IDS-iSYS multidiscipline automated analyzer (Immunodiagnostic Systems Limited). QUS measurements were performed at the heel (Achilles InSight, GE Healthcare). Sex-specific linear and multinomial logistic regression models adjusted for potential confounders were calculated.

Results

Linear regression analyses revealed significant positive associations between IGF-I and IGF-I/IGFBP-3 ratio, a marker for free IGF-I, with all QUS parameters in men. Among women, we found an inverse association between IGF-I and the QUS-based fracture risk but no association with any other QUS parameter. There was no association between IGFBP-3 and the QUS-based fracture risk.

Conclusions

Our data suggest an important role of IGF-I on bone quality in men. The observed association of IGF-I with the QUS-based stiffness index and QUS-based fracture risk in the present study might animate clinicians to refer patients with low IGF-I levels, particularly men, to a further evaluation of risk factors for osteoporosis and a detailed examination of the skeletal system.

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