Associations between waist-to-height ratio and hormonal–metabolic profiles in midlife women: evidence from a population-based cross-sectional study

PURPOSE: Central adiposity increases during the menopausal transition, yet its hormonal signatures are not well defined. This study examined whether the waist-to-height ratio (WHtR) reflects coordinated variation in sex-steroid, thyroid, and metabolic pathways in midlife women, and evaluated the discriminative value of key endocrine markers for identifying elevated WHtR. METHODS: We conducted a population-based cross-sectional analysis of 17,379 women aged 40-60 years who underwent standardized WHtR measurement and serum assessment of sex-steroid hormones (estradiol, testosterone, progesterone, FSH, LH), thyroid hormones (free T4, free T3, TSH), and metabolic markers (lipid profile, HbA1c). Associations were tested using univariate correlations and multivariable regressions adjusted for age and BMI. Age-adjusted WHtR percentiles were estimated using quantile regression. Hormonal-metabolic clustering was mapped using correlation matrices. Logistic regression and ROC analyses evaluated the performance of estradiol, free T4, and their combination for identifying WHtR ≥ 0.50. RESULTS: WHtR values were in the healthy range for 68.4% of women, while 29.3% exceeded the ≥ 0.50 threshold. WHtR showed weak negative correlations with estradiol (r = -0.024, P = 0.0019) and free T4 (r = -0.017, P = 0.026), with small effect sizes, and these markers remained independently associated with WHtR after adjusting for age and BMI. ROC analyses demonstrated moderate discrimination by FT4 (AUC 0.67), compared with estradiol (AUC 0.61), with improved accuracy when combined (AUC 0.76). CONCLUSION: Lower estradiol and FT4 levels were associated with higher central adiposity in midlife women. WHtR showed weak, but significant associations with both hormones, yet the small effect sizes and low explanatory power render it clinically unsuitable for individual-level assessment.