Background: Serum total bilirubin (TB) has been recognized as a potent endogenous antioxidant under physiological conditions, and serum high sensitive C reactive protein (hs-CRP) is the most commonly used marker which reflects activation of systemic inflammation in the body. The study investigated the association between these two indicators and further evaluated the anti-inflammatory effects of bilirubin and its clinical significance in impaired glucose tolerance (IGT) and type 2 diabetes mellitus (T2DM) individuals.
Methods: A group of 94 patients with T2DM, 68 persons with IGT, and 62 age and gender matched healthy control subjects were recruited. The serum TB, hs-CRP concentrations, carotid artery intima-media thickness (C-IMT), and other biochemical indicators were measured. The association between serum TB, hs-CRP concentrations, and C-IMT were investigated using Spearman's correlation test. The influence of analyzed parameters including the age, gender, serum TB, and hs-CRP, etc. in IGT and T2DM was assessed by binary logistic regression analyses.
Results: The serum TB level decreased significantly in patients of IGT and T2DM (p < 0.01) and serum hs-CRP concentrations were significantly increased in IGT and T2DM (p < 0.01) compared with healthy controls. Meanwhile, the serum TB levels was negatively correlated with serum hs-CRP (P < 0.05) and C-IMT (P < 0.05) in IGT and T2DM. Logistic regression analysis showed that the serum TB was a protective factor (OR = 0.852, P = 0.045) and serum hs-CRP was a risk factor (OR = 2.010, P = 0.006) for IGT and T2DM.
Conclusions: Lower serum TB is associated with enhancement of the inflammatory response in IGT and T2DM. The serum TB may play a crucial role in inflammatory by contributing to inhibit the inflammation effect.