RESUMO
OBJECTIVE: The objective was to compare dual-energy x-ray absorptiometry-measured body composition between large (LGA) and appropriate (AGA) birth weight for gestational age neonates. STUDY DESIGN: LGA term infants (n = 47) with birth weights > or =4000 g were compared with 47 gestational age-matched AGA infants; 11 LGA infants were born to mothers with gestational (9) or pregestational diabetes (2). Dual-energy x-ray absorptiometry scans were performed at 1.8 +/- 1.0 days after birth. RESULTS: Body weight and length were the dominant predictors of body composition in LGA and AGA neonates. However, LGA neonates had significantly (P <.001, all comparisons) higher absolute amounts of total body fat, lean body mass, and bone mineral content and had significantly (P <.001, all comparisons) higher proportions of total body fat and bone mineral content but lower lean body mass as a percent of body weight. The changes for total body fat and lean body mass as a percent of body weight were greatest (P <.001) in LGA infants whose mothers had impaired glucose tolerance. CONCLUSION: LGA neonates have higher body fat and lower lean body mass than AGA infants. Impaired maternal glucose tolerance exaggerated these body composition changes.
Assuntos
Composição Corporal , Criança Pós-Termo , Absorciometria de Fóton , Antropometria , Peso ao Nascer , Estatura , Índice de Massa Corporal , Densidade Óssea , Humanos , Recém-NascidoRESUMO
OBJECTIVE: To determine whether prolonged feeding of preterm infant formula to preterm infants can accelerate recovery to normal plasma zinc levels without affecting plasma mineral homeostasis. DESIGN: Part of concurrent prospective feeding trials in a university hospital-based population. SUBJECTS AND INTERVENTION: Preterm infants (n = 33; birth weight, 1037 +/- 157 gm) were fed a preterm infant formula with higher concentrations of zinc, copper, calcium, magnesium, and potassium until 2 months past expected term, then a term infant formula. Term infants (n = 38; birth weight, 3318 +/- 401 gm) fed this term infant formula from birth were a reference group for comparison with study infants and with published values. Plasma mineral levels were analyzed by inductively coupled plasma atomic emission spectroscopy. RESULTS: Preterm infants fed a preterm infant formula after discharge from the hospital appeared to achieve normal plasma zinc concentrations by at least 2 months past term without adverse effects on mineral homeostasis.
Assuntos
Alimentos Fortificados/análise , Alimentos Infantis , Recém-Nascido Prematuro/sangue , Adolescente , Adulto , Cálcio/sangue , Cálcio/farmacocinética , Cobre/sangue , Cobre/farmacocinética , Espectroscopia de Ressonância de Spin Eletrônica , Feminino , Seguimentos , Hospitais Universitários , Humanos , Recém-Nascido , Estudos Longitudinais , Magnésio/sangue , Magnésio/farmacocinética , Masculino , Alta do Paciente , Potássio/sangue , Potássio/farmacocinética , Estudos Prospectivos , Fatores de Tempo , Zinco/sangue , Zinco/farmacocinéticaRESUMO
Seventy-one very low birth weight (less than or equal to 1500 gm) infants were studied to determine the sequential changes in serum vitamin D metabolite concentrations between infants with and without radiographically documented rickets, fractures, or both (R/F). Usual intake of vitamin D included 20 IU/kg/day from parenteral nutrition or 400 IU/day supplementation with enteral feeding. Radiographs of both forearms and serum samples were obtained at 3, 6, 9, and 12 months. Twenty-two infants had R/F. At 3 months, significantly lower mean (+/- SEM) serum phosphorus levels (4.5 +/- 0.4 vs 6.1 +/- 0.2 mg/dl), higher 1,25-dihydroxyvitamin D (1,25-[OH]2D) concentrations (96 +/- 5 vs 77 +/- 4 pg/ml), and higher free 1,25-(OH)2D index (1,25-[OH]2D:vitamin D binding protein ratio; 5.2 +/- 0.3 x 10(5) vs 4.0 +/- 0.2 x 10(5] were found in the R/F group. These values returned to normal and were similar between groups on subsequent measurements. Serum calcium, magnesium, and 25-hydroxyvitamin D (25-OHD) concentrations were normal and similar between groups. In both groups, serum vitamin D binding concentrations increased initially but remained stable and normal beyond 6 months. We conclude that in very low birth weight infants with R/F, the vitamin D status (as indicated by serum 25-OHD concentrations) is normal, and that lowered serum phosphorus levels, higher serum 1,25-(OH)2D levels, and a higher free 1,25-(OH)2D index support the thesis that mineral deficiency (especially of phosphorus) may be important in the pathogenesis of R/F in small preterm infants.
Assuntos
Calcifediol/sangue , Calcitriol/sangue , Fraturas Ósseas/sangue , Recém-Nascido de Baixo Peso/sangue , Raquitismo/sangue , Proteína de Ligação a Vitamina D/sangue , Nutrição Enteral , Fraturas Ósseas/complicações , Humanos , Recém-Nascido , Nutrição Parenteral , Estudos Prospectivos , Raquitismo/complicações , Vitamina D/administração & dosagemRESUMO
The response to aluminum loading from parenteral nutrition (PN) solutions was determined in 20 infants with gestational ages 29 to 41 weeks and birth weights 880 to 3630 gm. Mean duration of PN was 43 days (range 5 to 175 days). Ten infants received a high Al load (from an experimental high calcium- and phosphorus-containing PN solution, with a measured Al content of 306 +/- 26 micrograms/L (mean +/- SE), n = 11), for up to 6 weeks. Ten infants received a lower Al load (from standard Ca-P solutions, measured Al content 144 +/- 16 micrograms/L, n = 11). Five infants received PN with a low Al load for longer than 6 weeks. The mean urine Al/creatinine (Cr) ratio (micrograms/mg) increased threefold, from 0.3 +/- 0.09 to 0.97 +/- 0.17 during PN in the entire group (P less than 0.001), and was significantly higher in infants who received greater Al loading (P less than 0.001). There was no significant difference between preterm and term infants in the rate of change in urine Al/Cr during the study. Urine Al was calculated to account for less than 50% of Al load. During the study, serum Al concentrations ranged from 6 to 318 micrograms/L (median 37 micrograms/L, compared with the median 18 micrograms/L for normal infants and children). Serum Al concentrations were not significantly changed during the study, or between infants in high or lower Al loading groups. Vertebrae from autopsy of two infants who received the lower Al containing PN for 71 and 152 days, respectively, stained positive for Al at the bone mineralization front. Thus, currently used PN solutions are contaminated with Al, urine Al concentration is higher with higher Al loading, and is not different in term and preterm infants. We suggest that renal elimination of Al in infants is incomplete, as assessed by lower urine Al excretion versus load, elevated serum Al concentration, and bone deposition of Al.