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Open Access Highly Accessed Research article

Low sex hormone-binding globulin is associated with hypertension: a cross-sectional study in a Swedish population

Bledar Daka1, Thord Rosen2, Per Anders Jansson3, Charlotte A Larsson4, Lennart Råstam4 and Ulf Lindblad1*

Author Affiliations

1 Department of Primary Health Care, Institute of Medicine, Gothenburg, Sweden

2 Department of Endocrinology, Gothenburg, Sweden

3 Department of Internal Medicine, University of Gothenburg, PO Box 454, Gothenburg SE-405 30, Sweden

4 Department of Clinical Sciences, Malmö, Social Medicine and Global Health, CRC 28-12, Lund University, Jan Waldenströms gata 35, Malmö 205 02, Sweden

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BMC Cardiovascular Disorders 2013, 13:30  doi:10.1186/1471-2261-13-30

Published: 18 April 2013

Abstract

Background

The aim of this study was to investigate the association of sex hormone-binding globulin (SHBG) and hypertension in a Swedish population.

Methods

The study is based on a random sample of a Swedish population of men and women aged 30–74 years (n=2,816). Total testosterone, oestradiol and SHBG were measured in 2,782 participants. Free androgen index was then calculated according to the formula FAI=100 × (Total testosterone)/SHBG. Hypertension was diagnosed according to JNC7.

Results

In men, but not in women, significant association between SHBG and both diastolic (diastolic blood pressure: β=−0.143 p<0.001) and systolic blood pressure (systolic blood pressure β=−0.114 p<0.001) was found. The association was still significant after adjusting for age, body mass index (BMI), homeostatic model assessment insulin resistance (HOMA-IR), triglycerides, high density lipoproteins (HDL) and C-reactive protein (CRP) (diastolic blood pressure: β=−0.113 p<0.001; systolic blood pressure β=−0.093 p=0.001). An inverse association was observed between SHBG and hypertension in both men (B=−0.024 p<0.001) and women (B=−0.022 p<0.001). The association was still significant in women older than 50 years after adjustments for age, BMI, physical activity, CRP and alcohol consumption (B=−0.014, p=0.008).

Conclusion

In conclusion, these results show a strong association between SHBG and blood pressure independent of major determinants of high blood pressure. This association might be addressed to direct effects of SHBG in endothelial cells through the receptor for SHBG. If this is confirmed by other observational and experimental studies, it might become a new field for the development of therapies for lowering blood pressure.

Keywords:
Sex hormone binding globulin (SHBG); Testosterone; Gender; Hypertension; BMI