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 7.8 cm in Q1 (reference) to 11.0-19.8 cm in Q4 in men and 2.7-6.0 cm in Q1 (reference) to 9.0-17.4 cm in Q4 in women. beta-coefficients gradually increased across the quartiles from 0.07 (0.01-0.13) in Q2 to 0.25 (0.19-0.31) in Q4 in men and 0.17 (0.07-0.26) in Q2 to 0.42 (0.32-0.52) in Q4 in women, indicating 0.25 and 0.42 mg/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 0.10 mg/l (0.07-0.12) in men and with 0.11 (0.15-0.19) 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 (0.15-0.27) in Q4 for waist circumference and beta 0.23 (0.17-0.30) in Q4 for body mass index; in women: beta 0.32 (0.22-0.42) in Q4 for waist circumference and beta 0.32 (0.22-0.42) 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.
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