FASTING GALL-BLADDER VOLUME AND LITHOGENICITY IN RELATION TO GLUCOSE-TOLERANCE, TOTAL AND INTRAABDOMINAL FAT MASSES IN OBESE NONDIABETIC SUBJECTS

OBJECTIVE: To investigate whether total body fat mass or fat distribut ion and associated metabolic disturbances in glucose and lipid metabol ism influence the well known gallstone pathogenetic factors in obese s ubjects in order to explain why some obese subjects develop gallstones and some do not. DESIGN: Cross sectional study of gallstone pathogene tic factors, body composition, fat distribution, glucose and lipid met abolism. SUBJECTS: 57 healthy overweight subjects (aged 26-64 y, body mass index (BMI) 30-45 kg/m(2)). MEASUREMENTS: Total and intra-abdomin al fat masses were measured by dual X-ray absorptiometry and abdominal CT scanning, respectively. The lithogenic index was measured in aspir ated bile. The gallbladder volume was determined by ultrasound and the gallbladder ejection fraction% by dynamic cholescintigraphy. Plasma c holecystokinin (CCK) concentrations during a meal were measured with a specific radioimmunoassay. Insulin sensitivity was measured by the Mi nimal Model and glucose tolerance by an oral glucose tolerance test (O GTT). Serum lipid concentrations were measured by standard methods. RE SULTS: The gallbladder volume in the fasting state increased with incr easing intra-abdominal fat mass (P = 0.006) and was increased in subje cts with impaired glucose tolerance (41 vs 27 ml, P = 0.001). The lith ogenic index was > 1 in all subjects and correlated with total fat mas s (P = 0.04). CONCLUSION: Gallstone pathogenesis in obesity seems to b e influenced by the total body fat mass and its regional distribution possibly via mutual association with the glucose tolerance.