title: Predicting body composition using foot-to-foot bioelectrical impedance analysis in healthy Asian individuals.
abstract: BACKGROUND
  The objectives of this study were to develop a regression model for predicting fat-free mass (FFM) in a population of healthy Taiwanese individuals using standing foot-to-foot bioelectrical impedance analysis (BIA) and to test the model's performance in predicting FFM with different body fat percentages (BF%).
  
  
  METHODS
  We used dual-energy X-ray absorptiometry (DXA) to measure the FFM of 554 healthy Asian subjects (age, 16-75 y; body mass index, 15.8-43.1 kg/m(2)). We also evaluated the validity of the developed multivariate model using a double cross-validation technique and assessed the accuracy of the model in an all-subjects sample and subgroup samples with different body fat levels.
  
  
  RESULTS
  Predictors in the all-subjects multivariate model included height(2)/impedance, weight, year, and sex (FFM = 13.055 + 0.204 weight + 0.394 height(2)/Impedance - 0.136 age + 8.125 sex (sex: Female = 0, Male = 1), r(2) = 0.92, standard error of the estimate = 3.17 kg). The correlation coefficients between predictive FFM by BIA (FFMBIA) and DXA-measured FFM (FFMDXA) in female subjects with a total-subjects BF%DXA of <20 %, 20 %-30 %, 30 %-40 % and >40 % were r = 0.87, 0.90, 0.91, 0.89, and 0.94, respectively, with bias ± 2SD of 0.0 ± 3.0 kg, -2.6 ± 1.7 kg, -1.5 ± 2.8 kg, 0.5 ± 2.7 kg, and 2.0 ± 2.9 kg, respectively. The correlation coefficients between FFMBIA and FFMDXA in male subjects with a total-subjects BF%DXA of <10 %, 10 %-20 %, 20 %-30 %, and >30 % were r = 0.89, 0.89, 0.90, 0.93, and 0.91, respectively, with bias ± 2SD of 0.0 ± 3.2 kg, -2.3 ± 2.5 kg, -0.5 ± 3.2 kg, 0.4 ± 3.1 kg, and 2.1 ± 3.2 kg, respectively.
  
  
  CONCLUSIONS
  The standing foot-to-foot BIA method developed in this study can accurately predict FFM in healthy Asian individuals with different levels of body fat.
authors.affiliation: Center for General Education, I-Shou University, No.1 Sec. 1, Syuecheng Rd., Dashu Dist, Kaoshiung City, 84001, Taiwan. wucs@isu.edu.tw.
authors.forename: Chun-Shien
authors.initials: CS
authors.lastname: Wu
authors.affiliation: Department of Physical Education, National Taiwan Sport University, No. 16, Sec. 1, Shuang-Shih Road, Taichung City, 404, Taiwan. yu11.tw@yahoo.com.tw.
authors.forename: Yu-Yawn
authors.initials: YY
authors.lastname: Chen
authors.affiliation: Department of Radiology, Jen-Ai Hospital, No. 483, Don Long Road, Dali Dist, Taichung City, 412, Taiwan. bat911888@yahoo.com.tw.
authors.forename: Chih-Lin
authors.initials: CL
authors.lastname: Chuang
authors.affiliation: Department of Hotel, Restaurant, and Tourism Management, College of Business and Management, East Stroudsburg University of Pennsylvania, 200 Prospect St., East Stroudsburg, PA, 18301, USA. chiang1999@gmail.com.
authors.forename: Li-Ming
authors.initials: LM
authors.lastname: Chiang
authors.affiliation: Department of Exercise Science, College of Health Science, East Stroudsburg University of Pennsylvania, 200 Prospect St., East Stroudsburg, PA, 18301, USA. gdwyer@po-box.esu.edu.
authors.forename: Gregory B
authors.initials: GB
authors.lastname: Dwyer
authors.affiliation: Department of Applied Math, National Chung Hsing University, 250 Kuo Kuang Rd., Taichung City, 402, Taiwan. ylhsu@nchu.edu.tw.
authors.forename: Ying-Lin
authors.initials: YL
authors.lastname: Hsu
authors.affiliation: Department of Leisure, Recreation and Tourism Management, Tzu-Hui Institute of Technology, No. 367, Sanmin Rd., Nanjhou Hsian, Pingtung County, 926, Taiwan. justice8j@yahoo.com.tw.
authors.forename: Ai-Chun
authors.initials: AC
authors.lastname: Huang
authors.affiliation: Department of Physical Medicine and Rehabilitation, Taichung Hospital, Ministry of Health and Welfare, No. 199, Sec. 1, San-Min Road, Taichung City, 403, Taiwan. laipeter57@yahoo.com.tw.
authors.forename: Chung-Liang
authors.initials: CL
authors.lastname: Lai
authors.affiliation: Office of Physical Education and Sport, National Chung Hsing University, 250 Kuo Kuang Rd., Taichung City, 402, Taiwan. abaqus0927@yahoo.com.tw.|Research Center, Charder Electronic Co., LTD, No. 103, Guozhong Rd., Dali Dist., Taichung City, 412, Taiwan. abaqus0927@yahoo.com.tw.
authors.forename: Kuen-Chang
authors.initials: KC
authors.lastname: Hsieh
mesh_terms: D000273:Adipose Tissue / Q000502:physiology*; D000293:Adolescent; D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology*; D000886:Anthropometry / Q000379:methods*; D044466:Asian People; D001823:Body Composition / Q000502:physiology*; D001827:Body Height; D015992:Body Mass Index; D001835:Body Weight; D017097:Electric Impedance; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D015203:Reproducibility of Results; D012737:Sex Factors; D055815:Young Adult