Body Composition in Children (original) (raw)

2013, Pediatric Exercise Science

In his 1989 article "Body Composition in Children," Lohman wrote about the progress made during the 1980s in assessing body composition and the relation of body composition to health. He wrote, "The assessment of body composition in children has taken on greater significance because of the need to study the prevalence of obesity in children and youth, the need to better document the tracking and genetics of body fatness, the need to relate fat patterning in childhood and fat patterning in adults, and the need to assess changes in the prevalence of obesity over time in a given population" (69). In the present article, we revisit these issues, review progress over the past 25 years and suggest where research needs to go in the years ahead. A number of body composition studies in children before 1989 showed that Body Mass Index (BMI) had a larger error than skinfold thicknesses when predicting percent body fat (54,86). Studies since that time have elucidated the reasons why BMI is limited for estimating fatness, showing that variation in maturity, muscle mass, water content, bone mass and leg length all confound the relation of fatness to the ratio of weight-to-height squared, and contribute to the large prediction error (SE ± 5-7% fat) when estimating % fat for a given individual. Although skinfold thicknesses gave more accurate estimates of percent fat than BMI, often its errors were larger than desirable. We now know errors were inflated by the use of adult models to convert body density to percent fat which were unsuitable for children. Recognizing the problem, Lohman and colleagues developed a four-component approach to estimate body composition in children and adolescents using hydrostatic weighing, total body water by deuterium dilution, and body mineral content from forearm photon absorptiometry. That research showed that body density in children was significantly affected by variation in the water and mineral content of the fat-free body, especially in prepubescent children (67). Earlier work by Foman et al., (31) had shown similar developmental changes in the composition of fat-free body in children from birth to 10 years of age.