Soluble ST2 is not independently associated with androgen and estrogen status in healthy males and females.

Background: Soluble ST2 (sST2) plasma concentrations are significantly higher in healthy men than in healthy women. The reason for the sex-specific difference of sST2 plasma concentrations is not established. The aim of this study was to evaluate the association of sST2 with sex-hormones in healthy males and females separately.

Methods: We recruited 528 consecutive blood donors and measured plasma concentrations of sST2 and several sex-hormones (i.e., total testosterone, estradiol, sex hormone-binding globulin, follicle-stimulating hormone, and luteinizing hormone). Of the 528 blood donors, 338 were male and 190 were female. For data analysis, we further divided the group of females into the subgroups of pre- and postmenopausal women using the age of 50 years as a proxy for menopause.

Results: In non-parametric Spearman's correlation analyses, we found a weak association between sST2 and total testosterone (r(s)+0.126, p=0.021) and also between sST2 and estradiol (r(s)+0.117, p=0.032) in males. In females <50 years of age (n=158) and ≥50 years of age (n=32), respectively, we did not detect any significant association between sST2 and sex-hormones. As a result of multiple linear regression analyses (calculated with log sST2 as dependent variable and log of age and all sex-hormones as explanatory variables), there was no independent association between sST2 and any of the sex-hormones neither in males nor in females.

Conclusions: In the present study cohort we did not find an independent association of sST2 with sex-hormones in healthy males and females. Therefore, the reason for the sex-specific difference of sST2 plasma concentrations still remains unclear.