NIDDM IN THE ELDERLY

OBJECTIVE - We conducted this study to assess the metabolic alteration s in elderly patients with NIDDM. RESEARCH DESIGN AND METHODS - Health y lean (n = 15; age, 73 +/- 1 years; BMI, 23.8 +/- 0.5 kg/m(2)), and o bese (n = 10; age, 71 +/- 1 years; BMI, 28.9 +/- 1.2 kg/m(2)) control subjects and lean (n = 10; age, 75 +/- 2 years; BMI, 24.0 +/- 0.5 kg/m (2)) and obese (n = 23; age, 73 +/- 1 years; BMI, 29.9 +/- 0.7 kg/m(2) ) NIDDM patients underwent a 3-h glucose tolerance test, a 2-h hypergl ycemic glucose clamp study and a 3-h euglycemic glucose clamp study wi th tritiated glucose methodology to measure glucose production and dis posal rates. RESULTS - Waist-to-hip ratio (WHR) was greater in both le an and obese NIDDM patients than in control subjects. Insulin response s during the oral glucose tolerance test were similar in obese subject s (control subjects: 417 +/- 64 pmol/l; NIDDM patients: 392 +/- 47 pmo l/l) but were reduced in lean NIDDM patients (control subjects: 374 +/ - 34 pmol/l; NIDDM patients: 217 +/- 20 pmol/l, P < 0.01). Lean and ob ese NIDDM patients had absent first-phase insulin responses during the hyperglycemic clamp. Second-phase insulin responses were reduced in l ean (P < 0.01 vs, control subjects by analysis of variance) but not ob ese NIDDM patients. Hepatic glucose output was not increased in lean o r obese NIDDM patients. Steady-state (150-180 min) glucose disposal ra tes were 16% less in lean NIDDM patients (control subjects: 8.93 +/- 0 .37 mg . kg LBM (lean body mass)(-1). min(-1); NIDDM patients: 7.50 +/ - 0.28 mg . kg . LBM(-1). min(-1), P < 0.05) and 37% less in obese NID DM patients (control subjects: 8.17 +/- 0.38 mg . kg . LBM(-1). min(-1 ); NIDDM patients: 5.03 +/- 0.36 mg . kg LBM(-1). min(-1), P < 0.001). CONCLUSIONS - Lean elderly NIDDM patients have a profound impairment in glucose-induced insulin release but mild resistance to insulin-medi ated glucose disposal. Obese elderly NIDDM patients have adequate circ ulating insulin, but marked resistance to insulin-mediated glucose dis posal Hepatic glucose output is not increased in elderly NIDDM patient s.