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BACKGROUND: Oxidative stress plays an essential role in bone health among postmenopausal women. This study aimed to compare the oxidative stress biomarkers among postmenopausal women aged 50-65 years with normal bone mineral density, osteopenia, and osteoporosis. METHODS: In this observational study, 120 women with normal bone mineral density, 82 with osteopenia, and 86 with osteoporosis were selected based on the densitometry data obtained from the dual-energy X-ray absorptiometry method. The serum total antioxidant capacity (TAC), superoxide dismutase (SOD) activity, and malondialdehyde (MDA) levels were measured using biochemical methods. A binary logistic regression model adjusted for confounders was used to estimate the risk of osteopenia and osteoporosis. The P-value of <0.05 was considered statistically significant. RESULTS: There were significant differences between the three groups in age, menopausal age, body mass index, and education (P<0.05). According to the binary logistic regression model, higher SOD activity and serum TAC levels were associated with a lower risk of osteoporosis (adjusted odds ratio [aOR], 0.991; 95% confidence intervals [CI], 0.986 to 0.996; and aOR, 0.373; 95% CI, 0.141 to 0.986, respectively). MDA was a significant risk factor for osteopenia in postmenopausal women (aOR, 1.702; 95% CI, 1.125 to 2.576). CONCLUSION: Higher SOD activity and serum TAC levels in the studied postmenopausal women were associated with a significantly lower risk of osteoporosis. Moreover, the risk of osteopenia increased significantly with higher serum MDA levels.
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OBJECTIVES: The present systematic review of literature was conducted to study the effect of Nigella sativa (N.S) on oxidative stress and inflammatory biomarkers. CONTENT: Different online databases such as Cochrane Central Register of Controlled Trials, MEDLINE (PubMed), Scopus, Web of Sciences, EMBASE, and Clininaltrial.gov for English articles and national databases of SID, Magiran, Irandoc, and Iranmedex for Persian articles, which were published until March; 2019 were scrutinized. All Randomised Controlled Trials (RCTs) and quasi-experimental studies that aimed to compare the impact of N.S along, with placebo or without supplementation, on inflammatory factors and oxidative stress were entered in the present study. SUMMARY: Finally, 11 RCTs covering 710 women and men, in total, were participated in the present meta-analysis. Significant differences were observed in Tumor Necrosis Factor alpha (TNF-α) (Weighted Mean Difference (WMD) =-2.15 pg/mL, 95% Confidence Interval (CI) =-3.22--1.09, I2=32%; 5 trials with 262 participants) superoxide dismutase (WMD=63.79 µ/gHb, 95% CI=6.84-120.75, I2=0%; 2 trials, with 88 participants), and total antioxidant capacity (WMD=0.34 mmol/L, 95% CI=0.04 to 0.63, I2=94%; 5 trials with 232 participants). Nevertheless, there was no significant difference in high sensitivity C-reactive protein (WMD=-0.98 mg/L, 95% CI=-1.98-0.03, I2=78%; 5 trials with 267 participants), Interleukin 6 (IL-6) (WMD=-0.25 pg/mL, 95% CI=-0.65 to 0.16, I2=0%; 2 trials with 134 participants), and malondialdehyde (WMD=-0.95 nmol/mL, 95% CI=-1.97-0.08, I2=68%; 4 trials with 179 participants). OUTLOOK: Generally speaking, N.S probably results in the improvement of superoxide dismutase serum levels, TNF-α, and total antioxidant capacity. Thus, further studies are required to fully assess its impacts on all oxidative stress and inflammatory biomarkers.