Nutritional Status of Vitamin D and the Effect of Vitamin D Supplementation in Korean Breast-fed Infants

We investigated the vitamin D status and the effect of vitamin D supplementation in Korean breast-fed infants. The healthy term newborns were divided into 3 groups; A, formula-fed; B, breast-fed only; S, breast-fed with vitamin D supplementation. We measured serum concentrations of vitamin D (25OHD3), calcium (Ca), phosphorus (P), alkaline phosphatase (AP), intact parathyroid hormone (iPTH) and bone mineral density (BMD) at 6 and 12 months of age. Using questionnaires, average duration of sun-light exposure and dietary intake of vitamin D, Ca and P were obtained. At 6 and 12 months of age, 25OHD3 was significantly higher in group S than in group B (PS>B), but total intake of Ca and P were higher in group A than in group B and S (P<0.001). In conclusion, breast-fed infants show lower vitamin D status and bone mineralization than formula-fed infants. Vitamin D supplementation (200 IU/day) in breast-fed infants increases serum 25-OH vitamin D3, but not bone mineral density.

Several Problems of Growth Hormone Stimulation Test in Clinical Application / 대한소아내분비학회지

PURPOSE: We investigated properness of growth hormone stimulation test (GHST) to diagnose growth hormone deficiency (GHD) in comparison with clinical characteristics. METHODS: For twenty five GHD children classified by GHST criteria during the recent 5 years, clinical characteristics and laboratory findings were correlated retrospectively through medical records. RESULTS: Seventeen were idiopathic GHD and 8 were secondary GHD. 1) Among the idiopathic type, 8 had complete GHD (maximal stimulated GH 5, and <10 ng/mL). For this group, IGF-1, height SDS, and degree of delayed bone age were not correlated with maximal stimulated GH level, while the IGFBP-3 and growth velocity before GH treatment were significantly correlated (P<0.05). Growth velocity was significantly increased from 5.1 to 8.6 cm/yr during treatment (P<0.0001). 2) Variable results were obtained in 5 patients with multiple GHST. One idiopathic patient changed from non GHD to complete GHD during 5 years. One patient operated for craniopharyngioma showed from non to partial, then non GHD. Diffuse brain atrophy patient showed from partial to complete GHD. Two secondary form patients showed from non to partial GHD. 3) Three patients among idiopathic type showed growth velocity more than 5 cm/yr even without GH treatment. CONCLUSION: IGFBP-3 and growth velocity before treatment might be possible indicators to predict maximal stimulated GH level. In view of the variable results from multiple GHST, auxological and biological data should also be considered in diagnosis.

Late Detection of Thyroid Dysfunction in NICU Patients / 대한주산의학회잡지

OBJECTIVE: To evaluate the incidence, the time of detection, classification, and risk factors of thyroid dysfunction in very low birth weight (VLBW) and sick infants in order to help with the diagnosis and treatment of thyroid dysfunction in the neonatal intensive care unit (NICU). METHODS: We reviewed the medical records of 78 infants, who were admitted for more than 1 month in the NICU at Chungbuk National University Hospital from July 2004 through June 2006. In these infants, at least to 2 thyroid function tests were performed, a initial screening whthin 2 weeks of age and a repeated thyroid function test after 2 weeks of age. RESULTS: 1) The study infants were divided into 2 groups, VLBW (birth weight or =1,500 g). 2) In the VLBW groups (n=48), 24 infants (50%) showed thyroid dysfunction. Six infants (12.5%) were detected at initial screening test and all had transient hypothyroxinemia. The remaining 18 infants (37.5%) were detected at repeated tests, most commonly detected at 4~8 weeks of age (n=8). Their types of thyroid dysfunction were primary hypothyroidism (PH) with a delayed marked TSH rise (n=3), PH with a delayed mild TSH rise (n= 7), euthyroid sick syndrome (ESS, n=8), and central hypopituitary hypothyroidism (HH, n=1). 3) In the NVLBW groups (n=30), 11 infants (36.7%) showed thyroid dysfunction. Three infants (10%) were detected at initial screening test, while 8 (26.7%) were detected at repeated tests. Their types of thyroid dysfunction were PH (n=5), ESS (n=3), transient hyperthyrotropinemia (n=2), and HH (n=1). 4) Among 35 infants with thyroid dysfunction, 20 infants (57.1%) were treated with thyroxine. CONCLUSION: Thyroid dysfunction was very common in sick infants in the neonatal intensive care unit, especially in the very low birth weight infants. Often, they were not detected at the initial screening test, but detected at later repeated tests. The repeated thyroid function test need to be performed in infants at risk for late detection of thyroid dysfunction after 2~4 weeks of age.