Contribution of intra-abdominal fat accumulation to the impairment of glucose and lipid metabolism in human obesity

Abstract

The causal relationship between intraabdominal visceral fat accumulation and metabolic disorders was analyzed in 46 obese subjects (15 males, 31 females) having 34.1 ± 5.5 of body mass index (BMI). The distribution of fat was determined by out CT scanning technique (Int J Obesity 7:437, 1983). The total cross-cut area, subcutaneous fat area, and intra-abdominal fat area was measured at the umbilical level. The fasting plasma glucose level, area under the plasma glucose concentration curve after oral glucose loading (plasma glucose area), fasting serum triglyceride level, and serum total cholesterol level were all significantly higher or otherwise greater in the group with intraabdominal visceral fat to subcutaneous fat ratio ( V S ratio ) of not less than 0.4 than in the group with a lower V S ratio, when either all or sex-matched obese subjects were examined, though BMI or the duration of obesity was not different between the two groups. The V S ratio was significantly correlated with the level of plasma glucose area ( r = 0.45, P < .001) under the curve of 75 g oral glucose tolerance test and also with the serum triglyceride ( r = 0.65, P < .001) and total cholesterol levels ( r = 0.61, P < .001). These relationships were also observed when examined in each sex separately and found to be significant after adjustment for BMI and age by multiple regression analyses. These results suggested that intraabdominal visceral fat, which is mainly composed of omental and mesenteric fat, may play a more important pathogenetic role or better reflect an underlying metabolic disorder than subcutaneous fat in the development of diabetes mellitus or hyperlipidemia. Based on the present investigations, we wish to propose two types of obesity: One is visceral type, characterized by a marked accumulation of fat in the abdominal cavity, and the other is subcutaneous type, characterized by an accumulation mainly in the subcutis. Thus, disturbances in glucose and lipid metabolism are considered greater in visceral type than in subcutaneous type.