Oxidative stress increases continuously with BMI and age with unfavourable profiles in males.

Oxidative stress is a risk factor for chronic diseases and was previously shown to be independently associated with obesity. The authors investigated the relationship between body mass index (BMI), age and oxidative stress on 2190 subjects undergoing a health care examination. Total antioxidant status (TAS), total peroxides (TOC) and autoantibodies against oxidized LDL (oLAb) were used as oxidative stress biomarkers in addition to serum lipoproteins, bilirubin and uric acid. Gender-specific differences were observed for age, BMI, serum concentrations of bilirubin, low-density lipoprotein (LDL), uric acid and TAS, all of which were higher in males (p < 0.001), while high-density lipoprotein (HDL), HDL/LDL ratio and TOC were higher in females (p < 0.001). Total cholesterol (p < 0.05) and LDL were increased (p < 0.05), while HDL was decreased (p < 0.05) in overweight and obese subjects. This was accompanied by increased uric acid and TAS concentrations. Lowest oLAb titers were detected in obese subjects. In extremely obese subjects, increased TOC and decreased TAS were observed in spite of high uric acid levels. These results demonstrate that oxidative stress increases with increasing BMI and age, as a sequel to an impaired antioxidant status, the consumption of oLAbs, an increase of peroxides and uric acid and a disadvantaged lipid profile.