Objective: To investigate the distribution of body fat and analyze its characteristics and relationship with metabolic variables in obese Chinese.
Methods: In this observational, cross sectional study, the total body fat mass was measured using body mass index (BMI), and as an index of intra-abdominal fat accumulation, the ratio of the visceral (VA) to abdominal subcutaneous (SA) adipose area (VSR) was determined using a computed tomography (CT) scans made at the level of L4/L5 in 309 obese human subjects (male 88; female 221). Blood pressure (BP), fasting serum lipids such as triglycerides (TG), total cholesterol (TC), high density lipoprotein(HDL-c), low density lipoprotein (LDL-c), and serum uric acid (UA) were also determined.
Results: (1) There were no differences between the male and the female subjects in regard to age, BMI, SBP, LDL-c and HDL-c. SA was significantly greater in women, whereas VA and VSR were significantly greater in men; DBP, UA, TC and TG were significantly higher in men than in women. (2) In both men and women, VSR was significantly higher in obese Chinese than in obese European and Americans. Age, TG and LDL-c were higher in subjects with visceral fat obesity (VFO) than in those with subcutaneous fat obesity (SFO). In males, TC,UA were significantly higher in VFO than in SFO. (3) 57 paired cases of male and female subjects matched for VSR were studied, and significant higher levels of serum UA and TG were noted in the male than in the female subjects. (4) After being adjusted for age and BMI, the analyses of partial correlation showed that in both men and women, VSR was positively correlated with TG and LDL-c, and SA was negatively correlated with LDL-c. In men, VA was positively correlated with SBP, and SA was negatively correlated with TG. In women, VA was positively correlated with TG, LDL-c; SA was negatively with LDL-c, but it was positively correlated with HDL-c and UA. (5) Stepwise multiple regression analysis showed that SA, VA, VSR were independent predictor for TG and LDL-c, SBP, and TC respectively (adjusting R2=0.079, 0.193, 0.122, 0.072, P=0.005, 0.000, 0.001, 0.007, respectively) in males. In females. VSR was an independent predictor for TG and LDL-c (adjusting R2=0.024, 0.113, P=0.012, 0.000 respectively); both BMI and SA were important predictors for UA and HDL-c, and SA was an important predictor for SBP.
Conclusion: The above data suggest that in obese Chinese, the body fat distribution is characterized by central obesity, the cardiovascular risk factors are not only associated with general obesity but more closely associated with regional body fat distribution (VFO), and the relationships between regional body fat distribution and metabolic variables vary with gender.