17β-estradiol levels and oxidative balance in a population of pre-, peri-, and post-menopausal women

Background. The high incidence of various diseases observed in post-menopausal women has been widely associated to the decline of 17 beta-estradiol (E2) occurring in correspondence of menopausal transition. One of the mechanisms suggested to explain this link takes into account the ability of E2 to counteract oxidative stress (OS) which is believed to play an important role in several pathogenic processes. Aim. To investigate whether stages of women's life characterized by different levels of E2 influence OS. Subjects and methods. We conducted a cross-sectional study of OS markers in 159 women subdivided in 65 pre-menopausal, 36 peri-menopausal, and 58 post-menopausal classified according to the Staging of Reproductive Aging Workshop (STRAW) criteria. E2, follicle-stimulating hormone, and markers of OS including hydroperoxides, thiols, uric acid, total and residual antioxidant power, were assessed. Results. After adjustment for covariates, only total antioxidant power was significantly different according to menopausal status (p < 0.01), with lower value in pre- with respect peri-and post-menopausal women. No significant correlations between E2 levels and OS markers were detected. Conclusions. Endogen E2, and, consequently, its decline during menopausal transition, is not a determinant factor for OS.