Relación entre la obesidad central y el estrés oxidativo en mujeres premenopáusicas versus posmenopáusicas / Relationship between central obesity and oxidative stress in premenopausal versus postmenopausal women

INTRODUCCIÓN: los cambios endocrinológicos de la menopausia producen un incremento en la adiposidad central y el estrés oxidativo, por lo que podría inferirse que las mujeres posmenopáusicas obesas mostrarían un estrés oxidativo significativamente mayor que las mujeres premenopáusicas. OBJETIVO: evaluar la relación entre la obesidad central y el estrés oxidativo en mujeres premenopáusicas en comparación con posmenopáusicas utilizando diferentes índices. MÉTODOS: estudio transversal con 237 mujeres premenopáusicas y 255 posmenopáusicas (40-60 años). Como marcadores de estrés oxidativo se midieron los niveles de malondialdehído plasmático y ácido úrico sérico, las enzimas antioxidantes superóxido-dismutasa y glutatión-peroxidasa eritrocitarias, y la capacidad plasmática antioxidante total. También se obtuvieron el peso, la estatura y la circunferencia de cintura y cadera, con lo que se calcularon los índices de masa corporal (IMC), cintura-cadera (ICC) y cintura-talla (ICT). RESULTADOS: se observaron más de un 30 % de obesidad y un 50 % de sobrepeso en ambos grupos. Los niveles de malondialdehído y de ácido úrico son más altos en las mujeres con sobrepeso/obesidad en ambos grupos. El ICT tuvo una correlación positiva con el nivel de malondialdehído (r = 0,298, p < 0,0001) y ácido úrico (r = 0,263, p < 0,0001), y una negativa con la actividad de GPx (r = -0,148, p < 0,01). Con un valor de corte de ICT > 0,6, aumentan el malondiahldehído y el ácido úrico, sin importar el estado menopáusico. Los demás índices no mostraron ninguna relación. CONCLUSIÓN: nuestros hallazgos sugieren una asociación entre la obesidad central medida por el ICT y el aumento del estrés oxidativo, independientemente del estado menopáusico

BACKGROUND: endocrine changes in midlife women produce an increase in central obesity and oxidative stress, thus it is possible that obese postmenopausal women exhibit a higher oxidative stress than premenopausal women. OBJECTIVE: to evaluate the relationship between central obesity and oxidative stress in premenopausal compared with postmenopausal women using different indices. METHODS: this is a cross-sectional study that included 237 pre- and 255 post-menopausal women (40-60 years old). As oxidative stress markers we measured plasma malondialdehyde and serum uric acid levels, erythrocyte superoxide dismutase (SOD) and glutathione peroxidase (GPx), and total plasma antioxidant status. We also measured height, weight, and waist and hip circumferences, and we calculated body mass index (BMI), waist-to-hip ratio (WHR) and waist-to-height ratio (WHtR). RESULTS: we found over 30 % of women within the obesity range, whereas 50 % were placed in the overweight category in both groups. Plasma malondialdehyde and serum uric acid levels were higher in women with overweight or obesity than in women with normal weight regardless of menopausal status. We found a positive correlation between WHtR and malondialdehyde level (r = 0.298, p < 0.0001) and serum uric acid level (r = 0.263, p < 0.0001), and a negative correlation with erythrocyte GPx activity (r = -0.148, p < 0.01). If we use a WHtR > 0.6, malondialdehyde and uric acid levels increase regardless of menopausal status. The other indices measured did not show any relationship. CONCLUSION: our findings suggest that there is an association between central obesity, as measured with WHtR, and increased oxidative stress regardless of menopausal status

[Relationship between central obesity and oxidative stress in premenopausal versus postmenopausal women]. / Relación entre la obesidad central y el estrés oxidativo en mujeres premenopáusicas versus posmenopáusicas.

INTRODUCTION: Background: endocrine changes in midlife women produce an increase in central obesity and oxidative stress, thus it is possible that obese postmenopausal women exhibit a higher oxidative stress than premenopausal women. Objective: to evaluate the relationship between central obesity and oxidative stress in premenopausal compared with postmenopausal women using different indices. Methods: this is a cross-sectional study that included 237 pre- and 255 post-menopausal women (40-60 years old). As oxidative stress markers we measured plasma malondialdehyde and serum uric acid levels, erythrocyte superoxide dismutase (SOD) and glutathione peroxidase (GPx), and total plasma antioxidant status. We also measured height, weight, and waist and hip circumferences, and we calculated body mass index (BMI), waist-to-hip ratio (WHR) and waist-to-height ratio (WHtR). Results: we found over 30% of women within the obesity range, whereas 50% were placed in the overweight category in both groups. Plasma malondialdehyde and serum uric acid levels were higher in women with overweight or obesity than in women with normal weight regardless of menopausal status. We found a positive correlation between WHtR and malondialdehyde level (r = 0.298, p < 0.0001) and serum uric acid level (r = 0.263, p < 0.0001), and a negative correlation with erythrocyte GPx activity (r = -0.148, p < 0.01). If we use a WHtR > 0.6, malondialdehyde and uric acid levels increase regardless of menopausal status. The other indices measured did not show any relationship. Conclusion: our findings suggest that there is an association between central obesity, as measured with WHtR, and increased oxidative stress regardless of menopausal status.

INTRODUCCIÓN: Introducción: los cambios endocrinológicos de la menopausia producen un incremento en la adiposidad central y el estrés oxidativo, por lo que podría inferirse que las mujeres posmenopáusicas obesas mostrarían un estrés oxidativo significativamente mayor que las mujeres premenopáusicas. Objetivo: evaluar la relación entre la obesidad central y el estrés oxidativo en mujeres premenopáusicas en comparación con posmenopáusicas utilizando diferentes índices. Métodos: estudio transversal con 237 mujeres premenopáusicas y 255 posmenopáusicas (40-60 años). Como marcadores de estrés oxidativo se midieron los niveles de malondialdehído plasmático y ácido úrico sérico, las enzimas antioxidantes superóxido-dismutasa y glutatión-peroxidasa eritrocitarias, y la capacidad plasmática antioxidante total. También se obtuvieron el peso, la estatura y la circunferencia de cintura y cadera, con lo que se calcularon los índices de masa corporal (IMC), cintura-cadera (ICC) y cintura-talla (ICT). Resultados: se observaron más de un 30% de obesidad y un 50% de sobrepeso en ambos grupos. Los niveles de malondialdehído y de ácido úrico son más altos en las mujeres con sobrepeso/obesidad en ambos grupos. El ICT tuvo una correlación positiva con el nivel de malondialdehído (r = 0,298, p < 0,0001) y ácido úrico (r = 0,263, p < 0,0001), y una negativa con la actividad de GPx (r = -0,148, p < 0,01). Con un valor de corte de ICT > 0,6, aumentan el malondiahldehído y el ácido úrico, sin importar el estado menopáusico. Los demás índices no mostraron ninguna relación. Conclusión: nuestros hallazgos sugieren una asociación entre la obesidad central medida por el ICT y el aumento del estrés oxidativo, independientemente del estado menopáusico. Palabras clave.

Method to compare mu-tensile bond strength of a self-etching adhesive and mu-cohesive strength of adjacent dentin.

UNLABELLED: Laboratory results from tensile or micro-tensile testing of adhesive/restorative systems need a gold standard to make their interpretation possible. This can be done by comparing the mu-tensile bond strength (muTBS) of the tested adhesive(s) with the mu-tensile cohesive strength (muTCS) of the adjacent dentin, which is meant to be replaced by the restoration. OBJECTIVES: To test immediate muTBS of an adhesive/restorative system versus muTCS of the dentin adjacent to the bonded interface, in perfused specimens. METHODS: Enamel and roots of five-third sound molars were removed and teeth were perfused (30 cm distilled H2O) until after the bonding procedure was completed. Parallel grooves (1.5-mm widex 1.5-mm deep, separated by 1.5mm), were drilled in the exposed dentin, under water refrigeration. Teeth were restored (AdheSE/Filtek Z250). Specimens were sawn from grooves to test muTBS (n = 30) and from between grooves to test muTCS (n = 32) of dentin, adjacent to adhesive interfaces, both areas to be tested at the same relative depth. Areas to be studied were rounded (mean bonded surface area for both groups, BA = 0.68 mm2), and muTBS and muTCS were found. As not all BAs were identical, residuals of muTBS and muTCS values to the regression line relating BA and tensile test results (representing the null hypothesis, i.e. muTBS = muTCS) were compared using a non-parametric test. RESULTS: Difference in the means of residuals was not statistically significant (two tails p = 0.067). SIGNIFICANCE: mean muTBS of the tested adhesive was not different to mean muTCS of adjacent dentine. The null hypothesis was not rejected.