EFFECTS OF INSULIN ON BODY-COMPOSITION IN PATIENTS WITH INSULIN-DEPENDENT AND NON-INSULIN-DEPENDENT DIABETES

Insulin is used to control blood glucose but may have an adverse effec t on the amount and distribution of fat mass and other cardiovascular risk factors. To test this hypothesis the effect of insulin therapy on blood glucose, body composition, and lipid levels was measured during 6 months in 9 patients with newly diagnosed insulin-dependent (Type 1 ) diabetes mellitus (IDDM) and 15 patients with non-insulin dependent (Type 2) diabetes (NIDDM) and secondary failure of therapy with oral h ypoglycaemic agents. Both groups received similar daily doses of insul in (similar to 0.6 units kg(-1) day(-1)). Glycaemic control improved d uring 6 months treatment in both groups, although the reduction in HbA (1c) was greater in IDDM (5.2 +/- 0.7%) than in NIDDM (2.0 +/- 0.4%, p < 0.001). All parameters of the lipid profile improved in IDDM but no t in NIDDM. Body weight, lean mass, and fat mass, measured by dual ene rgy x-ray absorptiometry, increased at 1 month in IDDM but not in NIDD M. By 6 months, body weight had increased more in IDDM than NIDDM (9.1 +/- 1.2 vs 3.77 +/- 0.5 kg, p < 0.01). The increase in weight was pre dominantly lean mass in IDDM (60.4 +/- 9.3%) and fat mass in NIDDM (59 .9 +/- 8.4%). The increase in lean mass was greater in IDDM than NIDDM (5.6 +/- 1.1 vs 1.4 +/- 0.3 kg, p < 0.001). Fat mass increased by sim ilar increments in IDDM and NIDDM (3.4 +/- 0.8 vs 2.4 +/- 0.5 kg, p = ns) and was predominantly an increase in trunk fat (IDDM: 2.3 +/- 0.6 kg, NIDDM: 2.0 +/- 0.4 kg, p = ns). The central/peripheral fat mass ra tio prior to treatment was lower in IDDM than NIDDM (0.64 +/- 0.05 vs 1.09 +/- 0.09, p < 0.01) and then increased in IDDM by 0.32 +/- 0.15 ( p = 0.07) and in NIDDM by 0.22 +/- 0.06 (p < 0.001). In conclusion, in sulin therapy is associated with weight gain in both IDDM and NIDDM. I n the former, weight gain reflects increases in lean mass whereas in N IDDM it reflects an increase in trunk fat mass. It remains to be deter mined whether this trend to central obesity partly offsets other benef its of insulin therapy in NIDDM.