Total and high-molecular-weight adiponectin levels in relation to insulin resistance among overweight/obese adults

OBJECTIVE: To determine whether baseline levels or intervention-associated changes in total and high molecular weight (HMW) adiponectin levels were associated with insulin resistance after six months of behavioral treatment for weight loss. DESIGN: An ancillary study to a behavioral weight loss trial; the intervention was delivered in group sessions. METHODS: Participants included 143 overweight/obese adults with a mean BMI of 33.7 kg/m(2). The sample was 88% female, 67% white, and 44.2 ± 8.5 years old. Circulating adiponectin levels (total and HMW) and the homeostasis model assessment (HOMA) of insulin resistance were measured and evaluated. RESULTS: At baseline, there was significant inverse associations between total adiponectin and HOMA (p < 0.001) and between HMW adiponectin and HOMA (p < 0.001) independent of weight. At 6-mo, there was a 17% improvement in HOMA, 8% increase in total adiponectin, 17% increase in HMW adiponectin levels, and 8.72% weight loss (p’s for all< 0.001). There was also a significant inverse association between changes in total adiponectin and HOMA (p = 0.04) that was independent of baseline weight and weight loss. In contrast, the association between changes in HMW adiponectin and HOMA was attenuated after adjustment for weight loss. CONCLUSIONS: An increased level of total adiponectin was associated with improved insulin sensitivity, regardless of baseline weight and weight loss. However, baseline total and HMW adiponectin levels were more strongly associated with HOMA than changes in these measures at six months. HMW adiponectin level was not related more closely to insulin resistance than total adiponectin level.