One-hour postload plasma glucose levels is associated with the production of hydrogen peroxide in abdominal obese men with normal glucose tolerance

To study the effects of acute hyperglycemia on oxidative stress during an oral glucose tolerance test (OGTT). This case-control study was conducted on 21 abdominal obese men (waist circumference ≥90 cm) and 21 normal-weight men (waist circumference <90 cm) aged 20~50 years with normal glucose tolerance (NGT). Cases and controls were matched for age. Blood samples were collected at fasting, 0.5, 1, 2 and 3-h postload, and assayed for glucose, insulin, hydrogen peroxide (H₂O₂) and malondialdehyde (MDA). On OGTT 0.5, 1 and 2-h plasma glucose values were higher in abdominal obese group than in normal-weight group (P < 0.05). The increase of glycemia during the OGTT was followed by a significant increase of H₂O₂ at 1-h (P < 0.05 versus baseline), which returned to baseline within 3-h in normal-weight subjects, but failed to do so at 2-h and 3-h in abdominal obese subjects (P < 0.05 versus baseline). MDA remained unchanged during OGTT. 1-h postload plasma glucose was positively correlated with fasting plasma H₂O₂ (r = 0.428, P = 0.005) and 3-h plasma H₂O₂ (r = 0.474, P = 0.002) during OGTT. In multiple regression analysis, 1-h postload plasma glucose maintained an independent association with fasting plasma H₂O₂ (β = 1.776, P = 0.006) and 3-h plasma H₂O₂ during OGTT (β = 2.720, P = 0.001). Hydrogen peroxide was elevated for longer periods of time postload in abdominal obese men. Elevated 1-h postload plasma glucose level is closely related with the change of hydrogen peroxide.