Adiposity and body mass indices in children: Benn's index and other weight for height indices as measures of relative adiposity.

OBJECTIVES

Several forms of weight for height or body mass index (BMI) are in widespread epidemiological and clinical use as measures of relative adiposity. The form derived by Benn for adults has been advocated for use in children and practical aspects of this proposition are considered.

METHODS

Height and weight data from 8492 Australian schoolchildren aged 7 to 15 were studied. A subsample of 2753 children aged 9, 12 and 15 years had skinfold thicknesses measured. The sum of four skinfolds and percentage body fat predicted from skinfolds were used as measures of adiposity.

RESULTS

Of the various forms of power type BMI examined, weight/(height)2 was most closely associated with adiposity in this sample. Benn's assumption of low correlation between height and adiposity (which holds in adults) was not satisfied in children.

CONCLUSIONS

Benn's index is not recommended for general use as a body mass index in children. However, Benn's relative weight has advantages as an indirect measure of adiposity which may be of value in epidemiological studies among children.