Background: A growing body of evidence reports implications of a direct extra-gonadal effect of follicle stimulating hormone (FSH), involving the development of obesity. The aim of this study was to evaluate the associations between traditional and local obesity indices and FSH concentrations in women after menopause.
Methods: We evaluated a total of 420 postmenopausal women in a cross-sectional design (age 55.6±6.5 years, BMI were 25.8±4.0 kg/m2, 8.01±6.7 years since menopause) with low insulin resistance (homeostasis model assessment of insulin resistance, HOMA-IR<5) We recorded anthropometric parameters and evaluated the body mass index (BMI). Indices of regional adiposity were sonographically assessed and included preperitoneal fat and subcutaneous fat). Fasting blood samples were obtained for biochemical and hormonal evaluation.
Results: Values of BMI and waist circumference exhibited an inverse association with increasing quartiles of FSH (BMI, FSH Q1 vs. Q2 vs. Q3 vs. Q4: 27.6±5.2 vs. 26±4.8 vs. 25.8±7.1 vs. 23.9±2.9; Waist, FSH Q1 vs. Q2 vs. Q3 vs. Q4: 93.2±2.4 vs. 87.6±4.4 vs. 85.4±1.8 vs. 80.89±2.8; ANOVA P-value for linear trend <0.001, both cases). Similarly, values of subcutaneous and preperitoneal fat exhibited a linear decrease with increasing quartiles of FSH (ANOVA P-value for linear trend <0.001). Multivariable stepwise linear regression analysis showed that preperitoneal fat measures were inversely associated with FSH levels (b coefficient= −0.130, P value=0.029), independently of traditional cardiovascular risk factors and circulating estrogen. The association between subcutaneous fat measures and FSH was lost following adjustment for circulating estrogen, implying a possible mediation effect of estrogen on this association.
Conclusions: Serum levels of FSH are inversely associated with markers of regional and total adiposity in postmenopausal women. The exact mechanism of this interaction remains to be elucidated in future studies.