Fructosamine in Obese Normal Subjects and Type 2 Diabetes

The effect of various grades of obesity on serum fructosamine concentrations was studied in Type 2 diabetic (n = 105) and non‐diabetic (n = 128) subjects. In obese diabetic and non‐diabetic subjects (body mass index ≥ 30 kg m−2), the concentration of fructosamine was markedly lower than that obtained for lean diabetic and non‐diabetic subjects with similar glycaemic control. Stepwise multiple‐regression analysis showed that fructosamine was associated with glycaemic control (as indicated by fasting plasma glucose and glycated haemoglobin), fasting triglycerides, and body mass index in both diabetic and non‐diabetic subjects. In vitro studies showed marked decreases in both the extent of [14C]‐glucose incorporation into plasma proteins and fructosamine production by incubated sera of obese patients whether diabetic or non‐diabetic, with obese subjects with body mass index > 40 kg m−2 exhibiting the greatest decrease. In conclusion, serum fructosamine concentrations are shown to decrease in obese diabetic and non‐diabetic subjects with body mass index ≥ 30 kg m−2 giving rise to the underestimation of glycaemic control as indicated by fructosamine measurement. A change in the glycation reaction itself may be partly responsible for such decrease.