Computed tomography-measured trunk fat and plasma lipoprotein levels in nonobese women

Abstract

The associations between total adiposity, adipose tissue distribution measured by computed axial tomography (CAT), regional variation in fat cell size, and plasma lipoprotein levels were studied in a sample of 22 premenopausal healthy nonobese women aged 34.6 ± 3.1 years (mean ± SD) (% body fat, 27.8 ± 5.8). In these nonobese women, no associations were found between total adiposity, adipose tissue distribution, and plasma triglyceride or very-low-density lipoprotein levels. However, total adiposity (as reflected by the body density-derived fat mass and by the adipose tissue volume measured by CAT), as well as the total trunk fat areas (measured at the abdominal and thoracic levels) were positively correlated with plasma low-density lipoprotein (LDL) cholesterol (.05 > P < .01) and LDL apolipoprotein (apo) B (.05 > P < .0005) levels. Because of these associations with LDL-C and LDL apo B levels, these body fatness indicators were negatively correlated with the HDL-cholesterol/LDL-cholesterol and HDL-apo A-I/LDL-apo B ratios. However, few significant associations were observed between the proportion of abdominal fat estimated by the waist/hip circumference ratio (WHR) and the lipoprotein-lipid profile ( r = .45 and r = .44, P < .05 with HDL triglyceride (TG) and LDL-apo B LDL -cholesterol ratio, respectively). Abdominal fat cell weight showed positive correlation with the LDL-apo B LDL -cholesterol ratio, ( r = .58, P < .005), and negative correlations with HDL-apo A-I ( r = −0.51, P < .05) and HDL 2-cholesterol levels ( r = −0.51; P < .05), as well as with HDL-apo A-I/LDL-apo B and HDL 2-cholesterol/HDL 3-cholesterol ratios ( r = −.53 and r = −.52, P < .01, respectively). No associations were observed between CAT-derived mid-thigh fat area, femoral fat-cell weight, and plasma lipoprotein levels. These results suggest that a subpopulation of women who are not obese and who have normal WHR values, but who are characterized by a preferential accumulation of fat in the trunk and by a relative enlargement of abdominal fat cells, might develop an altered and potentially atherogenic lipoprotein-lipid profile.