Increments in whole body bone mineral content associated with weight and length in pre-term and full-term infants during the first 6 months of life.
BACKGROUND
The objective of the present study was to assess bone mineral content (BMC) of the whole skeleton in pre-term and full-term healthy infants and the factors influencing BMC, such as bone area, birth weight, birth length, current weight, current length, gender, and gestational age.


METHODS
Forty-eight healthy full-term infants and 34 healthy premature infants fed predominantly with intact human milk were studied. BMC was measured monthly with dual energy X-ray absorptiometry (DEXA). At the same time, length and weight were measured and registered. Pre-term infants were studied at 60-day intervals.


RESULTS
For both full-term and pre-term infants, BMC increased during the first months of life. However, the values of pre-term infants never reached the values of full-term infants, even after correcting for age and weight. For both full-term and pre-term infants, BMC was significantly correlated at the second month with birth weight (r = 0.901), birth length (r = 0.860), gestational age (r = 0.803), bone area (r = 0.960), current weight (r = 0.920), and current length (r = 0.840, p <0.001 for all correlation coefficients). Multivariate analysis revealed that bone area was the most important factor in predicting BMC.


CONCLUSIONS
Pre-term children have lower BMC than full-term children. The main factor explaining this apparent osteopenia is bone area. Pre-term children have a higher daily mineralization rate than full-term children, but this catch-up mineralization is not enough to reach BMC levels seen in full-term children.
Avila-Díaz
M
M
Unidad de Investigación Médica en Nutrición Humana, Hospital de Pediatría, Centro Médico Nacional Siglo XXI (CMN-SXXI), Instituto Mexicano del Seguro Social (IMSS), Mexico City, Mexico.
Flores-Huerta
S
S
Martínez-Muñiz
I
I
Amato
D
D
D015502:Absorptiometry, Photon; D001724:Birth Weight; D001827:Body Height; D001835:Body Weight; D015519:Bone Density / Q000502:physiology*; D001846:Bone Development / Q000502:physiology*; D001851:Bone Diseases, Metabolic / Q000151:congenital*; D001942:Breast Feeding; D002118:Calcium / Q000032:analysis; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D007230:Infant, Low Birth Weight / Q000254:growth & development*; D007231:Infant, Newborn / Q000254:growth & development*; D007234:Infant, Premature / Q000254:growth & development*; D007700:Kinetics; D008297:Male; D008800:Mexico; D010012:Osteogenesis / Q000502:physiology*; D012016:Reference Values
D002118:Calcium