Body fat and skinfold thicknesses: a dimensional analytic approach.
BACKGROUND
Body fat may be estimated from skinfold thickness measurements (Skfs), but current prediction equations are dimensionally inconsistent and do not properly allow for the influence of body size on fat mass.


OBJECTIVE
To find a dimensionally correct formula relating fat content to Skfs and body size.


METHODS
285 African children aged 9-11 years, with fat content measured by dual-energy X-ray absorptiometry, were studied. Because least-squares regression parameters can be a misleading guide to true functional relationships, the real data were compared with simulated data sets conforming to a dimensionally correct statistical model.


RESULTS
The data are consistent with functional relationships such that fat mass is proportional to Skfxheight(2). The mean ratio (fat mass)/(Skfxheight(2)) is 6% higher in the girls than in the boys.


CONCLUSIONS
Appropriately, Skfxheight(2) has the dimensions of fat mass/density. Height(2) has no obvious physical significance and a more meaningful expression might be 'heightxX', where X corresponds to some measure of body width or girth.


CONCLUSIONS
In formulae for predicting fat mass, multiplying Skfs by height(2) gives better estimates, especially for the tallest and shortest individuals. Fat mass, rather than percentage body fat (%BF), is best taken as the variable initially predicted.
Faculty of Biomedical and Life Sciences, Thomson Building, University of Glasgow, Glasgow, UK. R.F.Burton@bio.gla.ac.uk
Richard F
RF
Burton
Noël
N
Cameron
D000273:Adipose Tissue / Q000502:physiology*; D000886:Anthropometry / Q000379:methods*; D001827:Body Height / Q000502:physiology; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D012044:Regression Analysis; D012885:Skinfold Thickness