Body composition of neonates from fan beam dual energy X-ray absorptiometry measurement.
BACKGROUND
Fan beam dual energy x-ray absorptiometry (FB DXA) has recently been validated for the measurement of body composition in small subjects. This study represents the first report of body composition (bone mineral content, fat mass, and lean mass) in human neonates measured by FB DXA.


METHODS
FB DXA measurements were performed in 73 healthy singleton neonates with mean +/- SD birth weights 3354 +/- 316 g (range, 2720 to 3982 g) and gestational ages 39.5 +/- 1.2 weeks (range, 37 to 42 weeks). There were 26 white (11 male infants, 15 female infants), 42 African American (17 male infants, 25 female infants), and 5 Hispanic (4 male infants, 1 female infant) infants. The predictive ability of physiologic parameters to predict body composition measurements was determined with regression analysis.


RESULTS
The mean +/- SD for bone mineral content was 89.3 +/- 14.1 g, fat mass was 485 +/- 14.1 g, and lean mass was 2898 +/- 281.5 g. Weight was significantly correlated with all DXA measurements and was the single best predictor of body composition. Weight alone contributed 32% to 98% of the variance of the DXA measured parameters. Gender, race, and length were additional predictors that could be forced into a predictive equation for selected DXA dependent variables according to statistical significance. An independent gender effect was also demonstrated, with male infants having higher lean mass but lower fat mass.


CONCLUSIONS
Our data in human neonates demonstrated the ability of FB DXA to measure body composition. Body weight is the best physiologic predictor of overall body composition. There is also an independent gender effect on soft tissue body composition.
Hammami
Mouhanad
M
Department of Pediatrics, Wayne State University, Detroit, MI 48201, USA.
Koo
Winston W K
WW
Hockman
Elaine M
EM
D015502:Absorptiometry, Photon; D000273:Adipose Tissue / Q000502:physiology; D001724:Birth Weight / Q000502:physiology; D001823:Body Composition / Q000502:physiology*; D015519:Bone Density / Q000502:physiology; D005260:Female; D006801:Humans; D007229:Infant Welfare; D007231:Infant, Newborn / Q000378:metabolism*; D008297:Male; D011237:Predictive Value of Tests; D012016:Reference Values; D012737:Sex Factors