RESUMO
To test the hypothesis that high-dose vitamin D2 supplementation would result in a lower incidence of radiographically detectable bone disease, we randomly assigned 40 very low birth weight infants to a control group who received vitamin D2 in a dosage of 400 IU/day and 41 to an experimental group who received a dosage of 2000 IU/day. After 6 weeks, radiographs from all infants were scored blindly for degree of radiographic bone disease, and serum osteocalcin and 25-hydroxyvitamin D levels were measured. Mean vitamin D intake was 360 +/- 141 (SD) IU/day in the control group and 2170 +/- 144 (SD) IU/day in the experimental group. Median 6-week serum 25-hydroxyvitamin D levels were 24 ng/ml (range 3 to 60 ng/ml) in the control group and 68 ng/ml (range 9 to 150 ng/ml) in the experimental group (p less than 0.001). Overall, 20% of the infants had evidence of moderate radiographic bone disease and only 2% were severely affected. The radiographic bone score (median = 2.5) and serum osteocalcin concentration (mean = 21.7 +/- 8.7 ng/ml) in the control subjects did not differ significantly from those in the experimental group (median bone score = 2.0; mean osteocalcin level = 24.1 +/- 7.9 ng/ml). Although there may be a subset of very low birth weight infants who would benefit from high doses of vitamin D, we conclude that no generalized clinical improvement can be attributed to this regimen alone.
Assuntos
Doenças Ósseas/tratamento farmacológico , Recém-Nascido de Baixo Peso , Vitamina D/uso terapêutico , Doenças Ósseas/diagnóstico por imagem , Doenças Ósseas/metabolismo , Calcifediol/sangue , Cálcio/metabolismo , Creatinina/metabolismo , Humanos , Recém-Nascido , Osteocalcina/sangue , Fosfatos/sangue , Radiografia , Distribuição AleatóriaRESUMO
To determine the predictive value of cranial ultrasonographic examination in high-risk preterm infants at different postnatal ages, we scanned 110 infants less than or equal to 32 weeks gestational age at 1, 2, 3, and 6 weeks postnatal ages and at 40 weeks postconceptional age (PCA). Cranial abnormalities detected by ultrasonography at each postnatal age of examination were classified as minor (periventricular superolateral echogenicity with or without intraventricular hemorrhage, grades 1 to 3) or major (cystic periventricular leukomalacia with or without intraventricular hemorrhage, grade 4) and correlated with neurodevelopmental outcome determined by 1 year of age. Major abnormalities detected by ultrasonography were present in four infants at 1 week, four at 2 weeks, eight at 3 weeks, and 11 infants at 6 weeks and 40 weeks PCA, respectively. Nineteen infants (17%) had moderate to severe functional handicaps defined as cerebral palsy, cognitive or visual deficit, or deafness. The positive and negative predictive values of ultrasound examinations, with regard to later neurodevelopmental outcome, improved with increasing postnatal age at examination and was best at 40 weeks PCA. Negative results of ultrasound study at 40 weeks PCA most correctly predicted satisfactory outcome. Although only 58% of moderately to severely handicapped infants were correctly identified by ultrasound examination at 40 weeks PCA, all infants with major ultrasonographic abnormalities at 40 weeks PCA had moderate or severe handicap. Our data demonstrate that the timing of cerebral ultrasonography is important in the prediction of later neurodevelopmental outcome in high-risk preterm infants.