Inverse association between adiponectin and C-reactive protein in substantially healthy Japanese men

Objective: An inverse association between adiponectin and C-reactive protein (CRP) has been shown in certain pathological states including obesity, diabetes, and coronary artery disease, which themselves might have confounded this association. This study investigated the association between adiponectin and CRP among substantially healthy subjects. Methods and results: A population of 2347 middle-aged Japanese men with no medical history of cardiovascular disease, cancer, diabetes, hypertension, or hyperlipidemia was evaluated. Those with some metabolic syndrome components from serological and anthropometric tests were excluded, leaving 714 men for analysis. Serum adiponectin and CRP were significantly correlated (r = -0.21, P < 0.001). After categorization into quartiles from the lowest to the highest adiponectin concentration (Q1 to Q4), the CRP level was found to be significantly higher in Q1 than in Q2, Q3 and Q4 (0.41 mg/L versus 0.30, 0.25 and 0.24 mg/L, P = 0.043, P < 0.001 and P < 0.001, respectively). These associations remained significant even after adjustment for covariates. Moreover, multiple linear regression analysis revealed that adiponectin contributed more strongly to CRP than other factors, including the index of insulin resistance. Conclusions: An inverse and strong association between adiponectin and CRP in substantially healthy subjects implies that decreased serum adiponectin might be fundamentally associated with the early stage of low-grade inflammation.