Body mass index (weight/height2) or percentage body fat by bioelectrical impedance analysis: which variable better reflects serum lipid profile?

We present population data on percentage body fat (%BF) by bioelectrical impedance analysis (BIA) in 12,287 men and 6657 women aged 30-69 y. In addition, we examined relationships among BMI, %BF and serum lipids (total-cholesterol (TC), HDL-cholesterol (HDLC), TC/HDLC ratio, LDL-cholesterol (LDLC) and triglycerides (TG)) in order to determine whether body mass index (BMI, kg/m2) or %BF by BIA better reflected lipid metabolism. Women had larger %BF than men in all age groups. On the other hand, women aged < 60 y had smaller BMI than corresponding men. Regardless of age, BMI was obviously correlated with %BF (r = 0.743-0.924). As previously reported, high BMI and high %BF were strongly associated with high serum TC/HDLC ratio and TG, and low serum HDLC rather than high serum TC and LDLC. Compared with BMI, %BF by BIA was better correlated with the serum indices except for serum HDLC. These results were found in both sexes, and there was a trend in which younger subjects had stronger correlations among BMI, %BF and serum lipids. Consequently, %BF by BIA (an index of body composition) better reflects serum lipid profile than BMI.