Assessment Of Total Body Fat Percentage From Regional Spine And Femur DXA Measurements

【Objective】Our study was designed to examine the correlation between the regional bodymeasurements [anteroposterior lumbar spine fat percentage (spine %fat) and proximalfemur fat percentage (femur %fat)] and the measurements from total body scan [totalbody fat percentage (TBF%), android fat percentage (android %fat) and gynoid fatpercentage (gynoid %fat)], as measured by dual-energy X-ray absorptiometry (DXA),among men and women in Guangzhou. The study also investigated whether regionalDXA measurements could be used to assess TBF%.【Methods】In total, 175 males and 597 females (age range: 20-87 yr) from Guangzhou wererecruited. Total body scan and regional scan were performed concurrently using DXA.The TBF%, android %fat and gynoid %fat were obtained from total body scan, and thefemur %fat and spine %fat from regional scan. Based on their body mass index (BMI),male and female subjects were subdivided into 4 groups. The relationship between DXAmeasurements was evaluated and prediction equations were established. A separate groupof subjects (mare: 28 and female: 33; age range: 22-84 yr) was used for cross-validation.【Results】For males and females, TBF% and android %fat were significantly correlated withspine %fat (r=0.89-0.94 in male and r=0.84-0.92 in female; p＜0.001); TBF% andgynoid %fat were significantly correlated with femur %fat (r=0.75-0.80 in male and r=0.75 in female; p＜0.001). For both genders, introduction of spine %fat, femur %fat,BMI and age provided good estimates of TBF%, android %fat, gynoid %fat and the ratioof android %fat to gynoid %fat (R2=0.63-0.90, p＜0.001); the accuracy of theprediction equations appeared to be high-to-moderate (R2=0.62-0.92, p＜0.001).【Conclusion】Spine %fat and femur %fat obtained from regional scan provide a good assessment of TBF%, android %fat and gynoid %fat. Our results provided a new method for assessingthe TBF% and regional fat distribution.