Comparison of body composition with bioelectric impedance (BIA) and dual energy X-ray absorptiometry (DEXA) among Singapore Chinese

Abstract 

The purpose of the study was to determine the agreement of bioelectric impedance (BIA) with dual energy X-ray absorptiometry (DEXA) among Singapore Chinese adults. Hundred subjects [63 healthy males (age: 25.2±0.5 yrs; weight: 69.7±1.9kg; BMI: 22.8±0.4kgm⁻²) and 37 females (age: 22.9±0.3 yrs; weight: 51.8±0.8kg; BMI: 20.2±0.4kgm⁻²)] were selected and body fat percentage (%BF) was measured by DEXA and BIA. Paired t test and coefficient of correlation statistics were utilized to compare the relationship between %BF_BIA and %BF_DEXA. Bland and Altman plot was employed to investigate the agreement of %BF_BIA with %BF_DEXA. The limits of agreement between different methods were defined as mean (M; bias)±1.96SD of the difference between the methods (95% confidence interval; CI). %BF_BIA, when compared to %BF_DEXA, revealed non-significant underestimation of %BF in females (24.1%<24.4%, p>0.05) and significant overestimation in males (15.5%<17.7%, p<0.01). There was good absolute agreement between %BF_BIA and %BF_DEXA among the whole cohort (1.3±6.9%) as well as among both genders (male: 2.2±6.7%, female: −0.3±6.1%) due to small mean differences between both methods. However, wider limits of agreement were revealed for %BF_BIA among whole cohort and as well as on gender basis. The results indicate a good agreement between BIA and DEXA in measuring %BF among Singapore Chinese adults, but may not be a suitable method of measuring %BF for clinical purposes among this population due to wider limits of agreement.

Keywords: Body fat, Fat free mass, Bland and Altman plot, Bone mineral density