Age related changes in indices of bone metabolism and oxidative stress in Postmenopausal women in Southern Nigeria

Background and Objectives: Oxidative stress (OS) associated with estrogen deficiency in menopause has been implicated in various complications of menopause. Some indices of OS, bone metabolism, and uric acid (UA) in postmenopausal women were assessed as possible predictors of gouty osteoarthritis. Materials and Methods: This case-control study enrolled 40 postmenopausal women and 60 premenopausal women as participants. The levels of reduced glutathione (GSH), nitric oxide (NO), total plasma peroxides (TPP), total antioxidant capacity (TAC), malondialdehyde (MDA), inorganic phosphate (Pi), total calcium (tCa), and UA were estimated by colorimetry, estradiol (E2) by ELISA and oxidative stress index (OSI) by calculation. Data were analyzed using t-test, correlation, and regression at P<0.05. Results: Postmenopausal women had higher UA, OSI and lipid peroxidation (higher MDA, TPP) with lower E2, tCa, and antioxidants (reduced GSH, NO, TAC) compared to premenopausal women studied (P<0.05). Aging correlated negatively with E2 (r=-0.273, P=0.006), TAC (r=-0.484, P=<0.001), GSH (r=-0.306, P=0.002), NO (r=-0.337, P=0.001), tCa (r=-0.571, P=<0.001) and positively with TPP (r=0.445, P=<0.001), OSI (r=0.454, P=<0.001), MDA (r=0.505, P=<0.001) and UA (r=0.441, P=<0.001) in all women studied irrespective of menopause status. There were no associations between UA, tCa, Pi, E2, and indices of oxidative stress (TPP, TAC, OSI, MDA, GSH, NO) with menopause (R2 =0.216, P=0.728). Conclusion: Elevated UA, lipid peroxidation and oxidative stress, and reduced tCa, E2, and antioxidants observed in postmenopausal women may be associated with aging and not the menopausal status suggesting that their assessment may be utilized in predicting women at increased risk of gouty osteoarthritis.