Hypoadiponectinemia is associated with blood pressure increase in obese insulin-resistant individuals

Abstract

Adiponectin is a major adipocytokine and has been considered as an independent risk factor for arterial hypertension. Most studies on the subject have been restricted to biracial (white-black) and Asian groups. The present report examined whether adiponectin affects blood pressure in a sample of untreated obese Brazilians of multiethnic origin. Fasting plasma adiponectin and serum insulin were determined by radioimmunoassay. Insulin resistance was estimated by homeostatic model assessment of insulin resistance (HOMA-IR). Blood pressure was recorded using Dinamap 1846 (Critikon, Tampa, FL). Adiponectin was significantly lower in obese hypertensive individuals than in obese normotensive ones. Blood pressure, insulin, and HOMA-IR were significantly higher in obese hypertensive than in obese normotensive individuals. Plasma adiponectin was negatively associated with waist-to-hip ratio, blood pressure, insulin, and HOMA-IR. The comparison of obese individuals who markedly differed in their HOMA-IR (> vs ≤2.71) showed that the association of adiponectin and blood pressure remained significant only in obese insulin-resistant individuals, whose adiponectin showed a positive association with high-density lipoprotein cholesterol. Stepwise regression analysis revealed that HOMA-IR, adiponectin, body mass index, and age independently affected the risk for increased systolic blood pressure, with HOMA-IR the strongest of them all. Finally, when patients were stratified into tertiles of HOMA-IR and further classified according to the 50th percentile of adiponectin (≤ vs >6. 5 μg/mL), a 3 × 2 analysis of variance showed an independent contribution of adiponectin in the variation of mean arterial pressure. These results support the notion that HOMA-IR and adiponectin independently predict blood pressure variation in obese insulin-resistant Brazilians.