Correlation between percentage of fat mass and level of disease activity in rheumatoid arthritis.

Introduction: Controversies exist regarding the relationship between body fat and disease activity in patients with rheumatoid arthritis. The evaluation of the disease is critical for establishing treatment and prognosis. Fat mass could be a predictive factor for poor prognosis in rheumatoid arthritis because of its association with low- and high-grade inflammation. Objective: To evaluate the correlation between fat mass values and disease activity in patients with rheumatoid arthritis. Materials and methods: This was a cross-sectional study. Eighty female patients diagnosed with rheumatoid arthritis (American College of Rheumatology of 1987) were evaluated. For each one, the evaluation determined fat mass using bioelectrical impedance analysis and disease activity using the Disease Activity Score on 28 joints (DAS28). Results: The mean age was 59.11 ± 9.92 years, with an average disease duration of 14.13 ± 10.13 years; 85% of patients showed a high body fat percentage. Pearson's correlation between DAS28 values and fat mass was r = 0.035 (p = 0.76). Conclusion: The levels of DAS28 showed no correlation with fat mass percentage. Further studies are required to clarify the factors that can modify these levels.

The Effect of Visceral Abdominal Fat Volume on Oxidative Stress and Proinflammatory Cytokines in Subjects with Normal Weight, Overweight and Obesity.

PURPOSE: The increase of visceral abdominal fat (VAF) and oxidative stress (OS) are independent predictors for cardiovascular risk. This study aimed to determine the association of VAF with proinflammatory cytokines, oxidants, antioxidants, and oxidative damage to DNA in subjects with normal weight, overweight, and obesity. PATIENTS AND METHODS: A cross-sectional study that included 21 men and 71 women who attended for a medical check-up was conducted. Dual-energy X-ray absorptiometry (DXA) was used to measure the VAF volume. ELISA and colorimetric techniques were used for chemical analysis. RESULTS: Low activity of superoxide dismutase (SOD) was found in overweight and obese subjects compared to the normal weight group (p=0.005). In contrast, the activity of glutathione peroxidase (GPx) was higher in the overweight and obesity groups compared to the normal weight subjects (p=0.017). The total antioxidant capacity (TAC) was also increased in the overweight group compared to the normal weight group (p=0.04). According to the volume of VAF, the levels of tumor necrosis factor alfa and interleukin 6 showed no differences between subjects with normal and high VAF. Subjects with high VAF show higher levels of 8-isoprostans compared to normal VAF group (p=0.039). Less concentration of 8-oxoguanine-DNA-N-glycosylase-1 (hOGG1) was found in the high VAF group (p=0.032) compared to the normal VAF subjects. VAF was positively correlated with lipoperoxides (LPO) (r=0.27, p<0.05) and 8-isoprostanes (r=0.25, p<0.05). We also found correlations between oxidative stress markers and anthropometric ratios for intra-abdominal fat. The waist-hip ratio was positively correlated with LPO (r=0.30, p<0.05) and TAC (r=0.24, p<0.05). CONCLUSION: These findings suggest that the predominantly oxidative damage associated with VAF in overweight or obesity is lipoperoxidation and oxidative DNA damage. Alterations in endogenous antioxidant defenses may not be linked to the amount of VAF.