Longitudinal changes over three years in sex steroid hormone levels in women aged 70years and over.

Abstract

Sex steroid levels in women vary with increasing age from the age of 70years (70+). Whether this reflects change within individuals with age or a survival advantage is not known. This study aimed to determine the stability of circulating sex steroids and SHBG over time in individual women aged 70+. A prospective cohort study. 400 women, aged 70+ not using any sex steroid, anti-androgen/oestrogen or glucocorticoid therapy. Sex steroid concentrations, measured by liquid chromatography-tandem mass spectrometry and sex hormone-binding globulin (SHBG) by immunoassay, in paired blood samples drawn 3years apart and analysed together. 400 women, median (IQR) age 78.0 (8.6)years, were included in the analysis. Mean testosterone concentrations were statistically significantly higher in follow-up samples compared with baseline. The change was modest (mean change 31pmol/L, 95% confidence interval (CI) 2.4-59.8; p=.034), and an increase was not observed in all women. There was a statistically significant decline in mean body mass index (mean change -0.4kg/m2 , 95% CI 0.6 to -0.3; p<.001) and a significant increase in the mean serum SHBG concentration (mean change 4.0 nmol/L, 95% CI 2.7-5.4; p<.001). The change observed in testosterone was not explained by the observed change in SHBG. There was no significant change in the mean oestrone or dehydroepiandrosterone concentration. Testosterone concentrations in women aged 70+ were more likely to increase than decrease. Whether increasing testosterone concentrations in older women confer a survival advantage needs investigation.