The contribution of SHBG to the variation in HOMA-IR is not dependent on endogenous oestrogen or androgen levels in postmenopausal women
Article first published online: 11 SEP 2012
© 2011 Blackwell Publishing Ltd
Volume 77, Issue 4, pages 541–547, October 2012
How to Cite
Davis, S. R., Robinson, P. J., Moufarege, A. and Bell, R. J. (2012), The contribution of SHBG to the variation in HOMA-IR is not dependent on endogenous oestrogen or androgen levels in postmenopausal women. Clinical Endocrinology, 77: 541–547. doi: 10.1111/j.1365-2265.2011.04301.x
- Issue published online: 11 SEP 2012
- Article first published online: 11 SEP 2012
- Accepted manuscript online: 22 NOV 2011 07:55AM EST
- (Received 11 August 2011; returned for revision 7 September 2011; finally revised 7 November 2011; accepted 17 November 2011)
Objective Sex hormone-binding globulin (SHBG) is a robust predictor of insulin resistance. Whether this is independent of circulating sex steroid levels remains uncertain. The aim of this study was to investigate the determinants of SHBG in postmenopausal women and whether the relationship between SHBG and insulin resistance is independent of oestrogen and androgen levels.
Design A cross-sectional study of naturally and surgically menopausal women.
Participants Seven hundred and sixty three postmenopausal women not using any systemic hormone therapy, mean age 54·4 ± 5·8 years, recruited in the US, Canada, Australia, UK and Sweden between July 2004 and February 2005.
Measurements Relationships between log-transformed (ln) SHBG and ln homoeostasis model assessment for insulin resistance (HOMA-IR) were explored, taking into account age, body mass index (BMI), blood pressure (BP) and circulating oestradiol, oestrone, testosterone and dihydrotestosterone.
Results Taking into account age, race, years since menopause, menopause type, BMI, BP, prior postmenopausal hormone use and the sex steroids measured, 34·4% of the variation in SHBG could be explained by the model that included negative contributions by HOMA-IR, BMI and diastolic BP, and a positive contribution by total testosterone (P < 0·001). None of the sex steroids made independent contributions to HOMA-IR, which was best explained by the model that included BMI, SHBG, systolic BP and surgical menopause, with each variable being positively related to HOMA-IR (r2 = 0·3152, P = 0·03).
Conclusions The relationship between SHBG and HOMA-IR, as an estimate of insulin resistance, is not explained by endogenous oestrogen and androgen levels and is, at least in part, independent of BMI in postmenopausal women.