Serum sex hormone and triglyceride‐glucose index in postmenopausal women: A population‐based study from NHANES

Abstract Objective The association between sex hormones and insulin resistance (IR) in postmenopausal women remains unclear. This study investigated the association between sex hormones and the triglyceride‐glucose index (TyG). Methods This cross‐sectional study used data from the National Health and Nutrition Examination Survey (NHANES) during the 2013–2016 cycles. The associations of log 2 ‐transformed estradiol, total testosterone, bioavailable testosterone, total testosterone‐to‐estradiol ratio, and sex hormone‐binding globulin (SHBG) with TyG were evaluated and verified by weighted linear regression, restricted cubic spline (RCS) analysis, subgroup analysis and sensitivity analysis. Results A total of 474 postmenopausal women with complete laboratory data for sex hormones and TyG calculation were included. After full adjustment for prespecified covariates, only SHBG showed an independent association with the TyG index when sex‐hormone indicators were modeled continuously: a log 2 ‐unit rise in SHBG predicted lower TyG ( β = −0.25, P < 0.001), whereas other sex hormones had no significant independent associations. When modeled as tertiles, SHBG remained negatively associated with TyG ( P for trend <0.001), while bioavailable testosterone showed a positive association ( P for trend = 0.020). RCS analyses confirmed a linear association for SHBG ( P overall <0.001, P nonlinear = 0.852) and a nonlinear association for bioavailable testosterone ( P overall = 0.008, P nonlinear = 0.010). Subgroup and sensitivity analyses further validated these findings across multiple covariates. Conclusion SHBG and bioavailable testosterone were associated with IR among postmenopausal women in this cross‐sectional study. Further prospective studies are warranted to validate these observations.