Lower Total Fasting Plasma Adiponectin Concentrations Are Associated with Higher Metabolic Rates

Context: The possible role of adiponectin, a protein uniquely produced by the adipose tissue and significantly reduced in obesity and other insulin-resistant states, in the regulation of energy expenditure (EE) is still poorly understood. Objective: The objective of the study was to investigate the relationship between total fasting plasma adiponectin concentrations and the various components of EE measured in a metabolic chamber in Pima Indians and to test whether body fat distribution may have a role in this association. Design: This was a cross-sectional study. Setting: The study was an inpatient clinical research unit. Participants: Sixty nondiabetic Pima Indians (45 males and 15 females), aged 18–45 yr, spanning a wide range of adiposity (body mass index 19.6–46.2 kg/m2) participated in the study. Main Outcome Measures: Total fasting plasma adiponectin concentrations, EE (24-h respiratory chamber), insulin sensitivity (euglycemic-hyperisulinemic clamp), body composition (dual-energy x-ray absorptiometry), and body fat distribution (waist to thigh ratio) were the main outcome measures. Results: Total fasting plasma adiponectin concentrations are negatively associated with sleep EE adjusted for sex, age, fat-free mass, and fat mass. This correlation is still significant, although attenuated, after inclusion of insulin-stimulated glucose disposal among the regressors and further attenuated when adjusted also for waist to thigh ratio. Conclusions: The decrease in total fasting plasma adiponectin concentrations that accompanies fat accumulation may be a mechanism to prevent further weight gain by decreasing insulin sensitivity and increasing energy expenditure.