Systemic Oxidative Stress Is Increased in Postmenopausal Women and Independently Associates with Homocysteine Levels.

Oxidative stress plays a pivotal role in the pathogenesis of cardiovascular diseases (CVD). Postmenopausal women have an increased risk of developing CVD due to decreased estrogen availability, which is accompanied by increased oxidative stress. Serum free thiols (R-SH) provide a robust and powerful read-out of systemic oxidative stress. In this study, we aimed to establish serum levels of free thiols and explore associations between free thiols and demographic, clinical, and biochemical parameters related to obesity and the risk for developing CVD in both pre- and postmenopausal women. Serum free thiols were measured in a cohort consisting of healthy pre- (n = 223) and postmenopausal (n = 118) Omani women. Postmenopausal women had significantly lower levels of serum free thiols as compared to premenopausal women (762.9 ± 85.3 vs. 780 ± 80.9 µM, age-adjusted p < 0.001). Women's age was positively associated with serum free thiol levels in premenopausal women (ß = 0.36, p = 0.002), whereas an inverse association was observed in postmenopausal women (ß = -0.29, p = 0.002). Homocysteine levels were significantly inversely associated with serum free thiol levels in both pre- (ß = -0.19, p = 0.005) and postmenopausal (ß = -0.20, p = 0.032) women, independent from known cardiovascular risk factors. In this study, we show that postmenopausal women are affected by increased systemic oxidative stress, which independently associates with homocysteine levels.

Vitamin d status and anthropometric indices of an omani study population.

OBJECTIVES: Serum 25-hydroxyvitamin D [25(OH)D] concentrations reflect vitamin D status, with deficiency implicated as causative of many diseases. This study assessed vitamin D status and anthropometric indices in a sample of healthy Omanis. METHODS: Serum 25(OH)D concentrations were measured by high performance liquid chromatography in 206 healthy Omanis, aged 18-55 years (mean age: men 31.1, women 26.8) in Muscat, Oman. Of this number, 95% indicated that they had never taken vitamin D supplements. Findings were compared with published values for populations domiciled in more northerly latitudes. Classical procedures were used to determine global obesity (body mass index [BMI]), and central obesity determined by waist circumference, waist-to-hip ratio (WHR), and waist-to-height ratio. RESULTS: Women, as compared to men, had markedly lower concentrations of 25(OH)D. Applying the cut-off point of serum 25(OH)D levels at 50 nmol/L, the prevalence of vitamin D deficiency in the study population was 87.5%; this was higher than the rates reported for the British, and European-, Hispanic-, and African-Americans. At a BMI cut-point of ≥30 kg/m(2), the prevalence of obesity was 14.6%; this was lower than the rates reported for European-, Hispanic-, and African-Americans. Levels of 25(OH) D increased relative to age and obesity. WHR was the main predictor of 25(OH)D levels. CONCLUSION: The striking vitamin D deficiency seen in the study population, relative to more northerly populations, may be linked to sun avoidance, inadequate dietary vitamin D, and virtual non-intake of supplemental vitamin D. Age and male-gender determined the status of vitamin D and of obesity.