title: Bodyfat percentage in girls increased steadily with age and percentile rank of body mass index.
abstract: BACKGROUND
  The purpose of the present study was to determine the body composition of elementary school children by bioelectrical impedance analysis (BIA) method with a subject in a standing position. The method is frequently used in Japan. The other aim was to evaluate the relationship between the body composition and percentile rank of the body mass index (BMI) in Japanese children.
  
  
  METHODS
  The number of subjects were 1042 children (530 boys and 512 girls aged from 6- to 12-years-old) from an elementary school. The bioelectrical impedance (BI) in the standing position was measured late in the morning before lunch. The fat percentage was derived from the body density according to the formula of Brozek et al. Each percentile value of BMI for each age and sex was determined from the frequency table of height and weight published by the Ministry of Education in Japan.
  
  
  RESULTS
  The fat percentage in both boys and girls was significantly correlated with the BMI, however, girls showed a closer linear relation than boys. The fat percentage in girls increased steadily with age and percent rank of the BMI. The fat percentage in boys was scattered in a wide range at each percentile rank of the BMI.
  
  
  CONCLUSIONS
  The fat percentage measured by the BIA in the standing position is closely associated with the percentile rank of the BMI in elementary school girls. For boys, it will be necessary to compare data among different types of BI measurement methods.
authors.affiliation: Department of Pediatrics, Faculty of Medicine, Kagoshima University, Sakuragaoka, Kagoshima and Noikura Hospital, Kagoshima, Japan.
authors.forename: Masao
authors.initials: M
authors.lastname: Yoshinaga
authors.forename: Atsushi
authors.initials: A
authors.lastname: Shimago
authors.forename: Yoshihide
authors.initials: Y
authors.lastname: Noikura
authors.forename: Sanae
authors.initials: S
authors.lastname: Kinou
authors.forename: Tsuruo
authors.initials: T
authors.lastname: Ohara
authors.forename: Koichiro
authors.initials: K
authors.lastname: Miyta
mesh_terms: D000273:Adipose Tissue; D000375:Aging; D001823:Body Composition; D015992:Body Mass Index; D002648:Child; D017097:Electric Impedance; D005260:Female; D006801:Humans; D008297:Male