Abdominal obesity exhibits distinct effect on inflammatory and anti-inflammatory proteins in apparently healthy Japanese men

BACKGROUND: Since visceral fat tissue is known to release various inflammatory and anti-inflammatory cytokines, abdominal obesity may play a key role in the inflammation associated with metabolic syndrome (MetS). However, few studies have determined precise relationships of abdominal obesity with inflammatory markers in MetS. To clarify the importance of abdominal obesity in sub-clinical inflammation, we examined the changes of inflammatory markers in clustering of MetS components with or without abdominal obesity. METHODS: Subjects consisted of 326 apparently healthy Japanese men (age: 30 to 59 years) who underwent health examination in the Osaka University Health Care Center. MetS components were assessed and serum levels of high sensitive C-reactive protein (hs-CRP), interleukin (IL)-6 and adiponectin were examined in all subjects. RESULTS: Subjects with abdominal obesity (waist circumference ≥ 85 cm) showed higher serum hs-CRP and IL-6 levels and a lower adiponectin level than those without abdominal obesity. Serum levels of hs-CRP and IL-6 significantly increased in association with clustering of MetS components in the subjects with abdominal obesity, but not in those without abdominal obesity. On the other hand, serum adiponectin level exhibited a little change with clustering of MetS components in the subjects with abdominal obesity. Significant negative correlation between adiponectin and hs-CRP was observed in the subjects with abdominal obesity, however this correlation was not detected in obese subjects defined by body mass index ≥ 25. CONCLUSION: Inflammatory status is not exaggerated by clustering of MetS components in the subjects without abdominal obesity. Abdominal obesity may exhibit distinct effect on inflammatory and anti-inflammatory proteins and modulate inflammatory network in MetS.