Background : Obesity is related to the development of vascular diseases and metabolic complications. Low grade inflammation is a key feature of central obesity, characterized by elevated plasma levels of C-reactive protein (CRP). We hypothesize that visceral adipose tissue contributes to systemic concentrations of CRP. Methods : In 2410 patients (1729 men and 681 women) with vascular diseases, subcutaneous and visceral fat masses were analyzed with ultrasonography. Metabolic parameters and CRP were measured in a fasting state. The association between fat measurements and plasma CRP was quantified using linear regression analysis. CRP levels were logarithmically transformed. Adjustments were made for age, smoking, type 2 diabetes mellitus, insulin resistance (HOMA-IR) and medication use. Results : Visceral fat was categorized into quartiles (Q) ranging from 3.2 to 7.8cm in Q1 (reference) to 11.019.8cm in Q4 in men and 2.76.0cm in Q1 (reference) to 9.017.4cm in Q4 in women. beta-coefficients gradually increased across the quartiles from 0.07 (0.010.13) in Q2 to 0.25 (0.190.31) in Q4 in men and 0.17 (0.070.26) in Q2 to 0.42 (0.320.52) in Q4 in women, indicating 0.25 and 0.42mg/l higher logarithmically transformed (log)CRP levels in Q4 compared to Q1 in respectively men and women. Per standard deviation increase of visceral fat, logCRP levels increased with 0.10mg/l (0.070.12) in men and with 0.11 (0.150.19) in women. Likewise, in separate analyses waist circumference and body mass index showed a positive, but weaker association with logCRP levels across quartiles (in men: beta 0.21 (0.150.27) in Q4 for waist circumference and beta 0.23 (0.170.30) in Q4 for body mass index; in women: beta 0.32 (0.220.42) in Q4 for waist circumference and beta 0.32 (0.220.42) in Q4 for body mass index). In men subcutaneous fat was not associated with logCRP (beta-coefficients relative to Q1: -0.01 (-0.07 to -0.05), -0.01 (-0.07 to -0.05) and 0.05 (-0.01 to -0.11) in Q2 to Q4 respectively). Conclusions : In conclusion, visceral fat thickness is the strongest contributor to the systemic CRP concentrations in patients with vascular diseases. (C) 2010 Elsevier Ireland Ltd. All rights reserved.