Small for gestational age birth may increase airflow limitation in bronchopulmonary dysplasia.

OBJECTIVES: To determine significant indices for assessing the pulmonary function of infants according to bronchopulmonary dysplasia (BPD) severity and to evaluate whether small for gestational age (SGA) could affect pulmonary function in BPD. METHODS: We evaluated 117 preterm infants who had undergone tidal breathing flow-volume loop and multiple-breath washout analyses within 7 months after birth. We categorized preterm infants according to BPD severity into mild/moderate BPD (n = 86), severe BPD (n = 21), and without BPD (n = 10) and the presence of SGA or appropriate gestational age (AGA) using the Fenton growth chart. We evaluated nine healthy term infants as controls. RESULTS: The tidal breathing ratio (time to peak expiratory flow/expiratory time [tPEF /tE ]) was significantly lower in infants with severe BPD than in those with mild/moderate BPD. Lung clearance index (LCI) was not different based on BPD severity. In the correlation analysis after adjusting for gestational age and sex, tPEF /tE was correlated with the duration of mechanical ventilation (r = -0.347, P < .001) and the duration of oxygen supply (r = -0.248, P = .013) in infants with BPD. The proportion of "lower tPEF /tE ," defined as below the cut-off value, was greater in SGA infants (P = .017), while no significant difference was seen in the percentage of "higher LCI," defined as above the cut-off value between SGA and AGA infants. CONCLUSIONS: In infants with BPD, tPEF /tE could be a useful pulmonary index which shows lower values in severe BPD. The finding of SGA in infants with BPD could be associated with poor pulmonary function related to the tPEF /tE values.

Implementation of a Targeted Next-Generation Sequencing Panel for Constitutional Newborn Screening in High-Risk Neonates.

PURPOSE: Newborn screening (NBS) programs are important for appropriate management of susceptible neonates to prevent serious clinical problems. Neonates admitted to neonatal intensive care units (NICU) are at a potentially high risk of false-positive results, and repetitive NBS after total parenteral nutrition is completely off results in delayed diagnosis. Here, we present the usefulness of a targeted next-generation sequencing (TNGS) panel to complement NBS for early diagnosis in high-risk neonates. MATERIALS AND METHODS: The TNGS panel covered 198 genes associated with actionable genetic and metabolic diseases that are typically included in NBS programs in Korea using tandem mass spectrometry. The panel was applied to 48 infants admitted to the NICU of Severance Children's Hospital between May 2017 and September 2017. The infants were not selected for suspected metabolic disorders. RESULTS: A total of 13 variants classified as likely pathogenic or pathogenic were detected in 11 (22.9%) neonates, including six genes (DHCR7, PCBD1, GAA, ALDOB, ATP7B, and GBA) associated with metabolic diseases not covered in NBS. One of the 48 infants was diagnosed with an isobutyl-CoA dehydrogenase deficiency, and false positive results of tandem mass screening were confirmed in two infants using the TNGS panel. CONCLUSION: The implementation of TNGS in conjunction with conventional NBS can allow for better management of and earlier diagnosis in susceptible infants, thus preventing the development of critical conditions in these sick infants.

Genitopatellar Syndrome Secondary to De Novo KAT6B Mutation: The First Genetically Confirmed Case in South Korea.

Genitopatellar syndrome (GPS) is a rare disorder characterized by patellar hypoplasia, flexion contractures of the lower limbs, psychomotor retardation and genital and renal anomalies. We report the case of a female infant diagnosed with GPS to a KAT6B gene mutation, which was identified using whole exome sequencing.

The impact of a quality improvement effort in reducing admission hypothermia in preterm infants following delivery.

PURPOSE: Hypothermia at admission is associated with increased mortality and morbidity in preterm infants. We performed a quality improvement (QI) effort to determine the impact of a decrease in admission hypothermia in preterm infants. METHODS: The study enrolled very low birth weight (VLBW) infants born at Gangnam Severance Hospital between January 2013 and December 2016. This multidisciplinary QI effort included the use of occlusive wraps, warm blankets, and caps; the delivery room temperature was maintained above 23.0˚C, and a check-list was used for feedback. RESULTS: Among 259 preterm infants, the incidence of hypothermia (defined as body temperature <36.0˚C) decreased significantly from 68% to 41%, and the mean body temperature on neonatal intensive care unit admission increased significantly from 35.5˚C to 36.0˚C. In subgroup analysis of VLBW infants, admission hypothermia and neonatal outcomes were compared between the pre-QI (n=55) and post-QI groups (n=75). Body temperature on admission increased significantly from 35.4˚C to 35.9˚C and the number of infants with hypothermia decreased significantly from 71% to 45%. There were no cases of neonatal hyperthermia. The incidence of pulmonary hemorrhage was significantly decreased (P=0.017). Interaction analysis showed that birth weight and gestational age were not correlated with hypothermia following implementation of the protocol. CONCLUSION: Our study demonstrated a significant reduction in admission hypothermia following the introduction of a standardized protocol in our QI effort. This resulted in an effective reduction in the incidence of massive pulmonary hemorrhage.

Prediction of Postnatal Growth Failure among Very Low Birth Weight Infants.

Postnatal growth failure (PGF) in preterm infants remains an important clinical issue. In this study, we analysed the incidence of PGF among very low birth weight (VLBW) infants and evaluated the risk factors for PGF based on the data of 2799 VLBW infants obtained from the Korean Neonatal Network database from 2013 to 2014. PGF was defined as a decrease in weight Z score between birth and discharge of more than -1.28 using the Fenton growth charts. Risk factors were evaluated in relation to birth weight for gestational age, namely small (SGA) or appropriate (AGA) for gestational age, using propensity score matching used for between-group differences. The overall incidence of PGF was 45.5%, with a rate of 68.9% in the SGA group and 36.2% in the AGA group. PGF was negatively correlated with gestation and birth weight; additionally, PGF was associated with a higher incidence of co-morbidities. Predictors of PGF in the SGA group were respiratory distress syndrome and days to attain 100 mL/kg of enteral feeding. The only predictor of PGF in the AGA group was days to attain 100 mL/kg of enteral feeding. Early initiation and aggressive progression of enteral nutrition may decrease the incidence of PGF.

Effective Tidal Volume for Normocapnia in Very-Low-Birth-Weight Infants Using High-Frequency Oscillatory Ventilation.

PURPOSE: Removal of CO2 is much efficient during high-frequency oscillatory ventilation (HFOV) for preterm infants. However, an optimal carbon dioxide diffusion coefficient (DCO2) and tidal volume (VT) have not yet been established due to much individual variance. This study aimed to analyze DCO2 values, VT, and minute volume in very-low-birth-weight (VLBW) infants using HFOV and correlates with plasma CO2 (pCO2). MATERIALS AND METHODS: Daily respiratory mechanics and ventilator settings from twenty VLBW infants and their two hundred seventeen results of blood gas analysis were collected. Patients were treated with the Dräger Babylog VN500 ventilator (Drägerwerk Ag & Co.) in HFOV mode. The normocapnia was indicated as pCO2 ranging from 45 mm Hg to 55 mm Hg. RESULTS: The measured VT was 1.7 mL/kg, minute volume was 0.7 mL/kg, and DCO2 was 43.5 mL²/s. Mean results of the blood gas test were as follows: pH, 7.31; pCO2, 52.6 mm Hg; and SpO2, 90.5%. In normocapnic state, the mean VT was significantly higher than in hypercapnic state (2.1±0.5 mL/kg vs. 1.6±0.3 mL/kg), and the mean DCO2 showed significant difference (68.4±32.7 mL²/s vs. 32.4±15.7 mL²/s). The DCO2 was significantly correlated with the pCO2 (p=0.024). In the receiver operating curve analysis, the estimated optimal cut-off point to predict the remaining normocapnic status was a VT of 1.75 mL/kg (sensitivity 73%, specificity 80%). CONCLUSION: In VLBW infants treated with HFOV, VT of 1.75 mL/kg is recommended for maintaining proper ventilation.

Postdischarge growth assessment in very low birth weight infants.

PURPOSE: The goal of nutritional support for very-low-birth-weight (VLBW) infants from birth to term is to match the in utero growth rates; however, this is rarely achieved. METHODS: We evaluated postdischarge growth patterns and growth failure in 81 Korean VLBW infants through a retrospective study. Weight and height were measured and calculated based on age percentile distribution every 3 months until age 24 months. Growth failure was defined as weight and height below the 10th percentile at 24 months. For the subgroup analysis, small-for-gestational age (SGA) and extremely low birth weight (ELBW) infants were evaluated. The growth patterns based on the Korean, World Health Organization (WHO), or Centers for Disease Control and Prevention (CDC) standard were serially compared over time. RESULTS: At postconception age (PCA) 40 weeks, 47 (58%) and 45 infants (55%) showed growth failure in terms of weight and height, respectively. At PCA 24 months, 20 infants (24%) showed growth failure for weight and 14 (18%) for height. Growth failure rates were higher for the SGA infants than for the appropriate-weight-for-gestational age infants at PCA 24 months (P=0.045 for weight and P=0.038 for height). Growth failure rates were higher for the ELBW infants than for the non-ELBW infants at PCA 24 months (P<0.001 for weight and P=0.003 for height). Significant differences were found among the WHO, CDC, and Korean standards (P<0.001). CONCLUSION: Advancements in neonatal care have improved the catch-up growth of VLBW infants, but this is insufficient. Careful observation and aggressive interventions, especially in SGA and ELBW infants, are needed.

Experience and pharmacokinetics of Levetiracetam in Korean neonates with neonatal seizures.

PURPOSE: The aims of this study were to evaluate the safety and pharmacokinetics of levetiracetam (LEV) in neonates with seizures and to establish a population pharmacokinetics (PPK) model by using the software NONMEM. METHODS: A retrospective analysis of 18 neonatal patients with seizures, who were treated with LEV, including 151 serum samples, was performed. The mean loading dose was 20 mg/kg, followed by a mean maintenance dose of 29 mg/kg/day. RESULTS: Seventeen neonates (94%) had seizure cessation within 1 week and 16 (84%) remained seizure-free at 30 days under the LEV therapy. The mean serum concentration of LEV was 8.7 µg/mL. Eight samples (5%) were found above the therapeutic range. No serious adverse effects were detected. In the PPK analysis for Korean neonates, the half-life was 9.6 hours; clearance, 0.357 L/hr; and volume of distribution, 4.947 L, showing differences from those in adults. CONCLUSION: LEV is a safe and effective option for the treatment of neonatal seizures with careful therapeutic drug monitoring.

Abnormal neurodevelopmental outcomes are very likely in cases of bilateral neonatal arterial ischaemic stroke.

AIM: Neonatal arterial ischaemic stroke (AIS) is an important cause of severe neurological disability. This study aimed to analyse the clinical manifestations and outcomes of AIS patients. METHODS: We enrolled neonates with AIS admitted to Severance Children's Hospital and Gangnam Severance Hospital between 2008 and 2015. AIS was confirmed using magnetic resonance imaging (MRI). We retrospectively reviewed the clinical manifestations, MRI findings, electroencephalography (EEG) findings and neurodevelopmental outcomes. RESULTS: The study comprised 29 neonates (18 boys). The mean follow-up period was 15.4 months (range 6-44 months), and the mean age at diagnosis was 8.1 days. Seizure was the most common symptom (66%). Bilateral involvement was more common than unilateral involvement (52%). The middle cerebral artery was the most commonly identified territory (79%). Abnormal EEG findings were noted in 93% of the cases. Neurodevelopment was normal in 11 (38%) patients, while cerebral palsy and delayed development were noted in eight (28%) and six (21%) patients, respectively. Patients with bilateral involvement were very likely to have abnormal neurodevelopmental outcomes. CONCLUSION: Our study showed that abnormal neurodevelopmental outcomes were very likely after cases of neonatal AIS with bilateral involvement, and clinicians should consider early and more effective interventions in such cases.

A Case of Pulmonary Interstitial Emphysema Treated by Percutaneous Catheter Insertion in Extremely Low Birth Weight Infant.

The pulmonary interstitial emphysema (PIE) is a life-threatening illness in premature infants with mechanical ventilation. While most are managed conservatively, decompression would be necessary. Here, we report the first case of PIE treated by percutaneous catheter insertion in an extremely low birth weight (ELBW) infant in Korea. The patient, born with 660 g in 23+2 weeks of gestation, showed PIE in left lower lung on postnatal day 12. Percutaneous catheter insertion was performed on postnatal day 25. The size of PIE decreased, but didn't disappear completely. On postnatal day 42, we exchanged catheter and inserted additional catheter in pleural space. However, sudden desaturation and pneumothorax occurred on postnatal day 44. We changed catheter in pleural space, and pneumothorax and PIE improved. Finally, we successfully removed catheters, and weaned patient out. As in our case, percutaneous catheter insertion would be a useful option for ELBW infants with PIE.

Usefulness of serum cystatin C to determine the dose of vancomycin in neonate.

PURPOSE: The vancomycin dosage regimen is regularly modified according to the patient's glomerular filtration rate (GFR). In the present study, we aimed to assess the usefulness of serum cystatin C (Cys-C) concentration, compared with serum creatinine (SCr) concentration, for predicting vancomycin clearance (CLvcm) in neonates. METHODS: We retrospectively analyzed the laboratory data of 50 term neonates who were admitted to the neonatal intensive care unit and received intravenous vancomycin, and assessed the pharmacokinetic profiles. Creatinine clearance (CLcr) and GFR based on Cys-C (GFRcys-c) were estimated using the Schwartz and Larsson formulas, respectively. RESULTS: The mean CLvcm (±standard deviation) was 74.52±31.17 L/hr, the volume of distribution of vancomycin was 0.67±0.14 L, and vancomycin half-life was 9.16±17.42 hours. The SCr was 0.46±0.25 mg/dL and serum Cys-C was 1.43±0.34 mg/L. The peak and trough concentrations of vancomycin were 24.65±14.84 and 8.10±5.35 mcg/mL, respectively. The calculated GFR based on serum creatinine concentration (GFR-Cr) and GFRcys-c were 70.2±9.45 and 63.6±30.18 mL/min, respectively. The correlation constant for CLvcm and the reciprocal of Cys-C (0.479, P=0.001) was significantly higher than that for CLvcm and the reciprocal of SCr (0.286, P=0.044). GFRcys-c was strongly correlated with CLvcm (P=0.001), and the correlation constant was significantly higher than that for CLvcm and CLcr (0.496, P=0.001). Linear regression analysis showed that only GFRcys-c was independently and positively correlated with CLvcm (F=41.9, P<0.001). CONCLUSION: The use of serum Cys-C as a marker of CLvcm could be beneficial for more reliable predictions of serum vancomycin concentrations, particularly in neonates.

Initial Resuscitation at Delivery and Short Term Neonatal Outcomes in Very-Low-Birth-Weight Infants.

Survival of very-low-birth-weight infants (VLBWI) depends on professional perinatal management that begins at delivery. Korean Neonatal Network data on neonatal resuscitation management and initial care of VLBWI of less than 33 weeks gestation born from January 2013 to June 2014 were reviewed to investigate the current practice of neonatal resuscitation in Korea. Antenatal data, perinatal data, and short-term morbidities were analyzed. Out of 2,132 neonates, 91.7% needed resuscitation at birth, chest compression was performed on only 104 infants (5.4%) and epinephrine was administered to 80 infants (4.1%). Infants who received cardiac compression and/or epinephrine administration at birth (DR-CPR) were significantly more acidotic (P < 0.001) and hypothermic (P < 0.001) than those who only needed positive pressure ventilation (PPV). On logistic regression, DR-CPR resulted in greater early mortality of less than 7 days (OR, 5.64; 95% CI 3.25-9.77) increased intraventricular hemorrhage ≥ grade 3 (OR, 2.71; 95% CI 1.57-4.68), periventricular leukomalacia (OR, 2.94; 95% CI 1.72-5.01), and necrotizing enterocolitis (OR, 2.12; 95% CI 1.15-3.91) compared with those infants who needed only PPV. Meticulous and aggressive management of infants who needed DR-CPR at birth and quality improvement of the delivery room management will result in reduced morbidities and early death for the vulnerable VLBWI.

The efficacy and safety of Montelukast sodium in the prevention of bronchopulmonary dysplasia.

PURPOSE: The purpose of this study was to evaluate the efficacy and safety of Montelukast sodium in the prevention of bronchopulmonarydysplasia (BPD). METHODS: The Interventional study was designed as a multicenter, prospective, and randomized trial, with open labeled and parallel-experimental groups, 66 infants were enrolled and allocated to either the case group (n=30) or the control group (n=36) based on gestational age (GA). Infants in the case group were given Montelukast sodium (Singulair) based on their body weight (BW). Zero week was defined as the start time of the study. RESULTS: The incidence of moderate to severe BPD was not different between the groups (case group: 13 of 30 [43.3%] vs. control group: 19 of 36 [52.8%], P=0.912). Additionally, secondary outcomes such as ventilation index, mean airway pressure and resort to systemic steroids were not significantly different. There were no serious adverse drug reactions in either group, and furthermore the rate of occurrence of mild drug related-events were not significantly different (case group: 10 of 42 [23.8%] vs. control group: 6 of 48 (15.8%), P=0.414). CONCLUSION: Montelukast was not effective in reducing moderate or severe BPD. There were no significant adverse drug events associated with Montelukast treatment.

Imaging patterns of sonographic lenticulostriate vasculopathy and correlation with clinical and neurodevelopmental outcome.

PURPOSE: To evaluate the relationship between the imaging patterns of lenticulostriate vasculopathy (LSV) and clinical outcomes. METHODS: We performed cranial sonography (US) in 110 neonates and evaluated the patterns of visible lenticulostriate vessels with three grades: 0: no vessel seen; 1 (low grade): one or two thin branches seen; and 2 (high grade): more than three prominent branches seen. Color Doppler US was performed on these vessels to evaluate the presence of flow. Associated underlying diseases and the presence of neurodevelopmental delay on follow-up were reviewed retrospectively. RESULTS: There were 51 neonates with associated underlying diseases, including congenital heart diseases (CHD) (n = 34) and neonatal hypoxia (n = 13). Sonographic LSV was detected in 29.1% cases (22 low- and 10 high-grade cases). Doppler flow was not detected in three patients with CHD (p = 0.028). CHD (odds ratio [OR], 25.73; p < 0.001), neonatal hypoxia (OR, 7.00; p = 0.020), two underlying diseases (OR, 73.232; p < 0.001), high-grade LSV (OR, 16.29; p = 0.005), and absent color Doppler flow (OR, 40.80; p = 0.046) were significantly associated with neurodevelopmental delay in univariate analysis. In multivariate analysis, underlying diseases and absent color Doppler flow were associated with neurodevelopmental delay. Both high LSV grade (area under the receiver operating characteristic curves of 0.901; 95% confidence interval, 0.823-0.979) and absent color Doppler flow (area under the receiver operating characteristic curves of 0.874; 95% confidence interval, 0.803-0.945) had a high predictive power for neurodevelopmental delay. CONCLUSIONS: High-grade sonographic LSV and absent color Doppler flow on lenticulostriate vessels were significantly associated with neurodevelopmental delay.

Poly-cyclodextrin and poly-paclitaxel nano-assembly for anticancer therapy.

Effective anticancer therapy can be achieved by designing a targeted drug-delivery system with high stability during circulation and efficient uptake by the target tumour cancer cells. We report here a novel nano-assembled drug-delivery system, formed by multivalent host-guest interactions between a polymer-cyclodextrin conjugate and a polymer-paclitaxel conjugate. The multivalent inclusion complexes confer high stability to the nano-assembly, which efficiently delivers paclitaxel into the targeted cancer cells via both passive and active targeting mechanisms. The ester linkages between paclitaxel and the polymer backbone permit efficient release of paclitaxel within the cell by degradation. This novel targeted nano-assembly exhibits significant antitumour activity in a mouse tumour model. The strategy established in this study also provides knowledge for the development of advanced anticancer drug delivery.

Transient elastography and sonography for prediction of liver fibrosis in infants with biliary atresia.

OBJECTIVES: The purpose of this study was to assess the diagnostic performance of transient elastography and sonography for noninvasive evaluation of liver fibrosis in infants with biliary atresia. METHODS: Forty-seven infants with biliary atresia who underwent both transient elastography and sonography before surgery were included in this study. Two types of transient elastographic probes were used: an M probe, which is used for the general adult population; and an S probe, which is specific to children. Transient elastographic measurements and sonographic findings such as triangular cord thickness and hepatic artery and portal vein diameters were compared with the METAVIR histopathologic fibrosis scoring system. RESULTS: Only transient elastography (ρ = 0.63; P < .001) was significantly correlated with METAVIR fibrosis stages. The areas under the receiver operating characteristic curves for transient elastography were 0.86 and 0.96 for diagnosis of severe fibrosis and cirrhosis, respectively. The cutoff value of transient elastography for diagnosis of severe fibrosis was greater than 9.6 kPa, with sensitivity of 89.5% and specificity of 75%. The cutoff value of transient elastography for diagnosis of cirrhosis was greater than 18.1 kPa, with sensitivity of 100% and specificity of 90.5%. The success rate for the S probe (100%) was significantly higher than that for the M probe (77%; P < .001). CONCLUSIONS: Transient elastography may be a useful noninvasive method for diagnosis of severe fibrosis and cirrhosis and may help predict outcomes before surgery or invasive liver biopsy in infants with biliary atresia. The success rate of transient elastography in infants was improved by using the S probe.

Positive maternal C-reactive protein predicts neonatal sepsis.

PURPOSE: To evaluate the diagnostic performance of maternal inflammatory marker: C-reactive protein (CRP) in predicting early onset neonatal sepsis (that occurring within 72 hours after birth). MATERIALS AND METHODS: 126 low birth weight newborns (gestation 32±3.2 wk, birth weight 1887±623 g) and their mothers were included. Neonates were divided into sepsis group (n=51) including both proven (positive blood culture) and suspected (negative blood culture but with more than 3 abnormal clinical signs), and controls (n=75). Mothers were subgrouped into CRP positive ≥1.22 mg/dL (n=48) and CRP negative <1.22 mg/dL (n=78) group, determined by Receiver Operating Characteristic curves, and odds ratio was calculated for neonatal sepsis according to maternal condition. RESULTS: Maternal CRP was significantly higher in neonatal sepsis group than in control (3.55±2.69 vs. 0.48±0.31 mg/dL, p=0.0001). Maternal CRP (cutoff value >1.22 mg/dL) had sensitivity 71% and specificity 84% for predicting neonatal sepsis. Maternal CRP positive group had more neonatal sepsis than CRP negative group (71% vs. 29%, p<0.001). Odds ratio of neonatal sepsis in maternal CRP positive group versus CRP negative group was 10.68 (95% confidence interval: 4.313-26.428, p<0.001). CONCLUSION: The risk of early onset neonatal sepsis significantly increased in the case of positive maternal CRP (≥1.22 mg/dL). In newborn of CRP positive mother, the clinician may be alerted to earlier evaluation for possible neonatal infection prior to development of sepsis.

Nutritional outcomes in children with epidermolysis bullosa: the experiences of two centers in Korea.

PURPOSE: Epidermolysis bullosa (EB) is associated with variable risks of extracutaneous manifestations and death. Currently, there is limited information on the clinical course and prognosis of EB in Korea. This study analyzed the nutritional outcomes, clinical morbidity, and mortality of children with EB. MATERIALS AND METHODS: Thirty patients, admitted to Severance Hospital and Gangnam Severance Hospital, from January 2001 to December 2011, were retrospectively enrolled. All patients were diagnosed with EB classified by dermatologists. RESULTS: Among the 30 patients, 5 patients were diagnosed with EB simplex, four with junctional EB, and 21 with dystrophic EB. Wound infection occurred in 47% of the patients, and blood culture-proven sepsis was noted in 10% of the patients. Two (9.2%) patients had esophageal stricture and 11 (52.4%) of the dystrophic EB patients received reconstructive surgery due to distal extremity contracture. There were five mortalities caused by sepsis, failure to thrive, and severe metabolic acidosis with dehydration. According to nutrition and growth status, most of the infants (97%) were born as appropriate for gestational age. However, at last follow-up, 56% of the children were below the 3rd percentile in weight, and 50% were below the 3rd percentile in weight for height. Sixty percent of the children had a thrive index below -3. CONCLUSION: Postnatal growth failure is a serious problem in children with EB. Strategies to maximize nutritional support could alleviate growth failure in children with EB, and thus improve clinical outcomes.

Prevalence of 25-hydroxyvitamin D deficiency in Korean adolescents: association with age, season and parental vitamin D status.

OBJECTIVE: We aimed to assess the prevalence and associated factors of vitamin D deficiency in healthy adolescents and to determine parent-adolescent association in vitamin D status. DESIGN: A cross-sectional study. SETTING: Data from the Korean National Health and Nutrition Examination Survey (KNHANES) 2008-2009. Serum 25-hydroxyvitamin D (25(OH)D) levels were measured using 125I-labelled RIA kits. Vitamin D deficiency in adolescents was defined as 25(OH)D level <27·5 nmol/l, and 25(OH)D levels between 27·5 and <50 nmol/l were considered insufficient. For the parents, vitamin D deficiency was defined as 25(OH)D level <50 nmol/l. SUBJECTS: The study population consisted of 2062 adolescents (1095 boys, 967 girls; aged 10-18 years) and their parents (1005 fathers, 1341 mothers). RESULTS: Overall, 13·4% of adolescents (boys 11·7%, girls 15·4%) were 25(OH)D deficient, 54·7% were 25(OH)D insufficient. Prevalence of vitamin D deficiency increased with age (P < 0·0001). Parental vitamin D deficiency was more prevalent in vitamin D-deficient adolescents than in non-deficient adolescents (all P < 0·0001). In multivariate logistic regression analyses, predictors for vitamin D deficiency were senior high school students (OR = 3·45-4·33), winter/spring season (OR = 3·18-5·11/5·35-7·36) and parental vitamin D deficiency (OR = 1·78-4·88; all P < 0·05). CONCLUSIONS: Vitamin D insufficiency is prevalent among healthy Korean adolescents and the parent-offspring association warrants vitamin D screening for family members of deficient individuals.

Serological investigation of Ureaplasma urealyticum in Korean preterm infants.

PURPOSE: Ureaplasma colonization is related with perinatal complications in preterm infants. Little is known about the difference in virulence among various Ureaplasma urealyticum serovars. The aim of this study was to determine U. urealyticum serovars of preterm infants in order to assess whether any of the serovars were associated with bronchopulmonary dysplasia (BPD). METHODS: Three hundred forty-four preterm infants with a gestational age less than 34 weeks admitted to Gangnam Severance Hospital neonatal intensive care unit from July 2011 to December 2012 were included in this study. Tracheal and gastric aspirations were conducted on infants to confirm Ureaplasma colonization. Ureaplasma colonization was confirmed in 9% of infants, of these, serovars were determined by real-time polymerase chain reaction. RESULTS: A total of 31 infants (gestational age, 29.3±3.1 weeks; birth weight, 1,170±790 g) were U. urealyticum positive. The Ureaplasma positive group treated for more days with oxygen and ventilation than the negative group (P<0.05). Histologic chorioamnionitis and moderate to severe BPD were more frequent in the Ureaplasma positive group than in the negative group (P<0.05). U. urealyticum isolates were either found to be a mixture of multiple serovars (32%), serovar 9 alone or combined with other serovars (39%), serovar 11 (26%), 2 (13%), 8 (10%), 10 (13%), and 13 (25%). No individual serovars were significantly associated with moderate to severe BPD and chorioamnionitis. CONCLUSION: This is the first study to describe the distribution of U. urealyticum serovars from Korean preterm infants. Ureaplasma-colonized infants showed higher incidence of BPD and chorioamnionitis.