Effect of body mass index on differences of sex hormone levels in postmenopausal women receiving low-dose hormone therapy
Irene Lambrinoudaki1, Eleni Armeni1, Demetrios Rizos2, Panagiotis Kofinakos1, George Kaparos2, Andreas Alexandrou3, Maria Creatsa1, Emanuel Logothetis2, Dimitra Papadimitriou1, Efstratios Tsakonas1 & Evangelia Kouskouni2
Objective: To investigate the effect of BMI on the absolute change from baseline levels in circulating sex hormone in postmenopausal women treated with oral continuous combined low dose HT for 6 months.
Design: The study recruited 36 postmenopausal women who received daily E2 1 mg/NETA 0.5 mg for 6 months. Hormonal assessment included measures of serum concentrations of FSH, LH, 17β-estradiol and free estrogen index (FEI), total and free testosterone (FAI), Δ4-Androstendione, SHBG and DHEA-S before treatment and after 6 months of treatment. We compared percental changes of hormone levels from baseline and mean absolute hormone concentrations between lean and overweight women.
Results: Lean subjects had statistically significant higher increments of FEI compared to overweight (lean women: 0.1±0.09 at baseline, and 0.3±0.1 at final levels, Δ=181%; overweight women: 0.2±0.1 at baseline, and 0.4±0.3 at final levels, Δ=87%, P=0.034). Mean 17β-estradiol increased in both groups at statistical significant levels (lean women: 22.4±12.0 pg/ml at baseline, and 45.9±20.7 pg/ml at final levels, Δ=105%, P=0.006; overweight women: 22.4±8.7 pg/ml at baseline 58.4±23.4 pg/ml at final levels, Δ=161%, P=0.0001; P(Δ%) between groups=0.619). Mean levels of FSH decreased significantly in both groups (lean women: Δ=−45%, P=0.0001; overweight women: Δ=39%, P=0.003; P(Δ%) between groups=0.661).
Conclusions: Concentrations of free estrogens increase more sharply in lean women being under treatment with oral low-dose HT. BMI did not influence the changes of total 17β-estradiol levels from baseline. This finding might in part explain the vulnerability of lean women under HT to develop breast cancer.