Comparison of serum ferritin and oxidative stress biomarkers between Japanese workers with and without metabolic syndrome

Objective Metabolic syndrome (MS) is closely associated to life-style and is characterized by central obesity causing severe diseases such as diabetes mellitus (DM) or atherosclerosis. This study investigates the role of oxidative stress and inflammation in MS. Subjects Total of 685 workers stratified by gender (293 men and 392 women) with a mean age of 41.2 ± 10.4 in different offices in a city in Japan. Methods Fasting blood and urine tests for MS, oxidative and/or inflammatory biomarker analysis and blood pressure (BP) measurement were performed. MS was defined on the basis of the Japanese criterion. Results Serum ferritin and urinary hydrogen peroxide (H2O2) levels were significantly higher in subjects with MS than those without. Ferritin was positively correlated with 8-hydroxy-2′-deoxyguanosine (8-OHdG) in all subjects and it was negatively correlated with 8-isoprostane and H2O2 in men. In addition, there was a significant positive correlation between ferritin and homeostasis model assessment (HOMA-R) in men. By using multiple regression analysis, ferritin was closely correlated with HOMA-R, γ-GT, 8-OHdG, smoking value and amount of alcohol ingestion in men, and it was correlated with 8-OHdG, γ-GT, HOMA-R in women under 50 years old. Conclusions Ferritin is a useful marker of MS including insulin resistance, reflecting the importance of oxidative stress as a cause of MS, especially in men.