Serum free and bioavailable rather than total testosterone is associated with the progression of non-alcoholic fatty liver disease in postmenopausal women: a prospective study

Background Sex steroid hormones may play vital roles in predisposing individuals to metabolic diseases. However, relationship between testosterone and progression of non-alcoholic fatty liver disease (NAFLD) in postmenopausal women remains unclear. Therefore, we conducted a community-based prospective cohort study, to investigate the associations between NAFLD progression and serum testosterone, as well as its fractions, in postmenopausal women. Methods A total of 1,705 postmenopausal women were included and analyzed after 5,269 person-years of follow-up. Serum total testosterone (TT) was measured by chemiluminescent immunoassay; concentrations and percentages (%) of free testosterone (cFT) and bioavailable testosterone (BioT) were calculated. Their relationships with NAFLD development or regression were investigated using logistic regression. Results Baseline concentrations and percentages of cFT and BioT, rather than TT levels, were significantly higher in non-NAFLD postmenopausal women who developed NAFLD after follow-up than in those who did not, while prominently lower in women with NAFLD regression than in those who had sustained NAFLD. Moreover, both higher concentrations and percentages of cFT and BioT were associated with the increased risk of NAFLD development; the fully adjusted ORs (95% CIs) for Q4 vs . Q1 of cFT were 2.35 (1.44–3.84) and 4.58 (2.67–7.86), and for BioT were 1.95 (1.21–3.14) and 3.13 (1.87–5.24). Meanwhile, they were associated with the decreased probability of NAFLD regression, the fully adjusted ORs (95% CIs) of cFT were 0.56 (0.33–0.95) and 0.23 (0.12–0.42), of BioT were 0.54 (0.31–0.91) and 0.22 (0.12–0.40). However, no significant association between TT levels and NAFLD progression was observed. Conclusions Serum concentrations and percentages of cFT and BioT are associated with the progression of NAFLD among postmenopausal women; they could be potential biomarkers for predicting NAFLD progression. Further studies in diverse populations and with a longer follow-up period are needed to verify whether our findings have broader implications.