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

Objective: Sex steroid levels in women vary with increasing age from the age of 70 years (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+. Design: A prospective cohort study. Participants: 400 women, aged 70+ not using any sex steroid, anti-androgen/oestrogen or glucocorticoid therapy. Main outcome measurements: Sex steroid concentrations, measured by liquid chromatography-tandem mass spectrometry and sex hormone-binding globulin (SHBG) by immunoassay, in paired blood samples drawn 3 years apart and analysed together. Results: 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 31 pmol/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 −0.4 kg/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. Conclusions: 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.