Body composition of African American and white children: A 2-year follow-up of the BAROC study

Objective: To evaluate the 2-year changes in body composition of white and African American boys and girls. Research Methods and Procedures: A total of 114 boys and girls ages 12 to 1 4 years with equal sex and ethnic distribution between African American and white races participated in measurements of body composition using DXA, un derwater weighing (densitometry), skinfold thickness, corporal diameters, c ircumferences, isotope dilution ((H2O)-O-18), and bioelectric impedance. Results: Sixty-eight of the 114 children advanced from Tanner Stages 1 and 2 to Tanner Stages 3 to 5 over a 2-year period. More than 50% of the childr en were in the top 15th percentile according to normative data for body mas s index but not for triceps skinfold. All measures except for percentage of fat, density, and four of the six skinfolds increased significantly during the 2 years, with no differences between races, genders, or fat group. The boys who advanced in Tanner Stage reduced their percentage of fat and a nu mber of skinfolds and increased their lean body mass, but the girls did not . The percentage of water was significantly higher in the fatter children a nd declined significantly over 2 years. Most children remained in the same quartile of body fat, lean body mass, and bone mineral content over 2 years . Discussion: The data are consistent with the hypothesis that over 2 years, growth is the major determinant of changing body composition, with body-fat group and sexual maturation being additional variables.