Oxidative stress as a risk factor for osteoporosis in elderly Mexicans as characterized by antioxidant enzymes

BACKGROUND Oxidative stress (OxS) has recently been linked with osteoporosis; however, we do not know the influence of OxS as an independent risk factor for this disease. METHODS We conducted a case-control study in 94 subjects > or =60 years of age, 50 healthy and 44 with osteoporosis. We measured total antioxidant status, plasma lipid peroxides, antioxidant activity of superoxide dismutase and glutathione peroxidase (GPx), and calculated the SOD/GPx ratio. Bone mineral density was obtained at the peripheral DXA in calcaneus using a portable Norland Apollo Densitometer. Osteoporosis was considered when subjects had a BMD of 2.5 standard deviations or more below the mean value for young adults. RESULTS GPx antioxidant activity was significantly lower in the group of subjects with osteoporosis in comparison with the group of healthy subjects (p < 0.01); in addition, the SOD/GPx ratio was significantly higher in the group of individuals with osteoporosis (p < 0.05). In logistic regression analysis, we found OxS to be an independent risk factor for osteoporosis (odds ratio [OR] = 2.79; 95% confidence interval [95% CI] = 1.08-7.23; p = 0.034). CONCLUSION Our findings suggest that OxS is an independent risk factor for osteoporosis linked to increase of SOD/GPx ratio.