Body composition of preterm infants during infancy

Aims-To examine body composition in preterm infants. Methods-Body composition was measured by dual energy alpha-ray absorptiomet ry (DEXA) at hospital discharge, term, 12 weeks, and at 6 and 12 months cor rected age in 125 infants (birthweight less than or equal to 1750 g, gestat ional age less than or equal to 34 weeks). Results-Body weight derived by DEXA accurately predicted that determined by conventional scales. In both sexes lean mass (LM), fat mass (FM), %FM, bon e area (BA), bone mineral mass (BMM), and bone mineral density (BMD) increa sed rapidly during the study; significant changes were detectable between d ischarge and term. At 12 months, LM, BA, and BMM, but not FM, %FM, or BMD w ere greater in boys than in girls. Corrected for age, LM was less than thos e of the reference term infant; FM and %FM were similar; BMM was greater. C orrected for weight, LM was similar to those of the reference infant, while the FM and %FM of study infants were slightly greater. Conclusions-DEXA accurately measures body mass. Body composition in preterm boys and girls differs. Interpretation of DEXA values may depend on whethe r age or body weight are regarded as the appropriate reference.