Specific Relation Between Abdominal Obesity and Early-Phase Hyperglycemia Is Modulated by Hepatic Insulin Resistance in Healthy Older Women

OBJECTIVE: To describe the impact of abdominal obesity and hepatic insulin resistance on phase-specific glycemic responses in older women. RESEARCH DESIGN AND METHODS: We studied 23 healthy older women (60–88 years old). Abdominal obesity was defined by an abdominal circumference ≥95 cm. Plasma glucose and insulin were measured in response to a 3-h oral glucose tolerance test. Insulin suppression of hepatic glucose production was determined using in vivo clamp techniques. RESULTS: Despite identical prevailing insulin concentrations, glucose excursions 30 min postchallenge (but not later) were greater in women with abdominal obesity than in those without (162 ± 19 vs. 132 ± 16 mg/dl; P < 0.01). There was a strong correlation between hepatic glucose production suppression under low-dose insulin infusion and early-phase glucose excursions from the oral glucose tolerance test (r = −0.83; P < 0.001) in women with abdominal obesity, but not in women without (r = 0.44; P < 0.11). CONCLUSIONS: Abdominal obesity relates specifically to early-phase hyperglycemia via hepatic insulin resistance, even in healthy older women.