Energy metabolism in infants with cystic fibrosis.
OBJECTIVE
To determine whether a defect in energy metabolism exists in infants with cystic fibrosis (CF).


METHODS
Unselected, newly-diagnosed subjects with CF (n = 46) and 24 healthy infants aged <20 weeks had measurements of resting energy expenditure (REE), total energy expenditure (TEE) (n = 25), and body composition. Metabolizable energy intake (MEI) was calculated. Genotype, energy intake, and pancreatic status was determined in all subjects with CF, and 24 underwent bronchial lavage.


RESULTS
At diagnosis, infants with CF detected by newborn screening had significant anthropometric deficits (mean [SD] z-weight = 0.5 [1.0], z-length = 0.7 [1.3]) associated with pancreatic insufficiency. Their REE, TEE, or MEI (absolute measurements, per unit body weight or fat-free mass) were not increased. No relationship between REE, TEE, or MEI and Delta F(508) genotype, and no proportional differences in individual components of MEI between subjects with CF and controls, or between subjects with CF who were homozygotes or compound heterozygotes for Delta F(508) were observed. REE and TEE were not correlated with bronchial infection or inflammation.


CONCLUSIONS
Growth impairment during the first weeks of life in infants with CF is associated with pancreatic insufficiency. However, there is no evidence for a defect of energy metabolism related to Delta F(508), and in infants with CF, minimal lung disease is unaccompanied by increased energy expenditure.
Bines
Julie E
JE
Department of Gastroenterology and Clinical Nutrition, Royal Children's Hospital, Parkville, Victoria, Australia.
Truby
Helen D
HD
Armstrong
David S
DS
Phelan
Peter D
PD
Grimwood
Keith
K
D000886:Anthropometry; D016022:Case-Control Studies; D003550:Cystic Fibrosis / Q000235:genetics / Q000378:metabolism*; D004734:Energy Metabolism; D005260:Female; D005838:Genotype; D006801:Humans; D007223:Infant; D008297:Male; D015999:Multivariate Analysis; D011446:Prospective Studies; D012044:Regression Analysis; D014739:Victoria