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December 1987

Early Attainment of Sex and Race Differences in Skeletal Mass

Author Affiliations

Center for Human Growth and Development University of Michigan Ann Arbor, MI 48109
The Children's Memorial Hospital Chicago, IL 60614

Am J Dis Child. 1987;141(12):1251-1252. doi:10.1001/archpedi.1987.04460120013009

Sir.—The study by Specker et al1 confirmed, through direct photon absorptiometry, what we previously learned about sex differences in the growth of the skeletal mass by measurement on roentgenograms (ie, "radiogrammetry"). Despite differences in biophysical measurements and in the bone sites surveyed (distal forearm vs second metacarpal), the trends are much the same. Though little boys are behind little girls in ossification timing and skeletal development, they have a larger bone mass, however it is measured. The two technical approaches are also parallel throughout the life cycle.2

In our work with many thousands of children, sex differences in bone size, cortical thickness, and cortical area are a consistent finding both for boys and for girls in a longitudinal growth program3 and for those studied in national surveys.4 This is also demonstrable in somewhat abridged form for 1163 white boys and girls who participated in the