These data are from the study described in the previous slide. Plasma glucose and insulin concentrations during an oral glucose tolerance test (the inset graphs show area under the plasma concentration-time curves) were broadly similar in lean subjects and in obese subjects with low intra-abdominal adiposity. The presence of obesity per se therefore did not appear to influence glycaemic status in these subjects.

In contrast, plasma glucose concentrations were significantly higher in obese subjects with high intra-abdominal adiposity, compared with the lean controls. While glucose levels generally differed little between obese subjects with high and low intra-abdominal adiposity, a markedly and significantly greater hyperinsulinaemia was required to maintain these glucose levels in the obese/high intra-abdominal adiposity group.

These results show that intra-abdominal adiposity is a more important cause of insulin resistance than obesity per se.