Comparative finite element analysis of mandibular posterior single zirconia and titanium implants: a 3-dimensional finite element analysis

PURPOSE@#Zirconia has exceptional biocompatibility and good mechanical properties in clinical situations. However, finite element analysis (FEA) studies on the biomechanical stability of two-piece zirconia implant systems are limited. Therefore, the aim of this study was to compare the biomechanical properties of the two-piece zirconia and titanium implants using FEA. @*MATERIALS AND METHODS@#Two groups of finite element (FE) models, the zirconia (Zircon) and titanium (Titan) models, were generated for the exam. Oblique (175 N) and vertical (175 N) loads were applied to the FE model generated for FEA simulation, and the stress levels and distributions were investigated. @*RESULTS@#In oblique loading, von Mises stress values were the highest in the abutment of the Zircon model. The von Mises stress values of the Titan model for the abutment screw and implant fixture were slightly higher than those of the Zircon model. Minimum principal stress in the cortical bone was higher in the Titan model than Zircon model under oblique and vertical loading. Under both vertical and oblique loads, stress concentrations in the implant components and bone occurred in the same area. Because the material itself has high stiffness and elastic modulus, the Zircon model exhibited a higher von Mises stress value in the abutments than the Titan model, but at a level lower than the fracture strength of the material. @*CONCLUSION@#Owing to the good esthetics and stress controllability of the Zircon model, it can be considered for clinical use.

Seasonal patterns and etiologies of croup in children during the period 2010–2015: A multicenter retrospective study

PURPOSE: Croup is known to have epidemics in seasonal and biennial trends, and to be strongly associated with epidemics of parainfluenza virus. However, seasonal and annual epidemics of croup have not been clearly reported in Korea. This study aimed to examine the seasonal/annual patterns and etiologies of childhood croup in Korea during a consecutive 6-year period. METHODS: Pediatric croup data were collected from 23 centers in Korea from 1 January 2010 to 31 December 2015. Electronic medical records, including multiplex reverse transcription polymerase chain reaction (RT-PCR) results, demographics and clinical information were cross-sectionally reviewed and analyzed. RESULTS: Overall, 2,598 childhood croup patients requiring hospitalization were identified during the study period. Among them, a total of 927 who underwent RT-PCR were included in the analysis. Males (61.5%) predominated, and most (63.0%) of them were younger than 2 years of age (median, 19 months; interquartile range, 11–31 months). Peak hospitalization occurred in 2010 and 2012 in even-numbered years, and parainfluenza virus (PIV, 39.7%) was the most common cause of childhood croup requiring hospitalization, followed by respiratory syncytial virus (14.9%), human rhinovirus (12.5%), Mycoplasma pneumonaie (10.6%), and human coronavirus (7.3%). CONCLUSION: It is concluded that croup hospitalization has a biennial pattern in even-numbered years. PIV may be the most common cause of childhood croup; however, croup epidemics could be attributed to other viruses.

ERRATUM: Comparison of Surgery Plus Chemotherapy and Palliative Chemotherapy Alone for Advanced Gastric Cancer with Krukenberg Tumor / Journal of the Korean Cancer Association, 대한암학회지

In this article, a grant number error was found in the Acknowledgments section.

Associates and Prognosis of Giant Left Atrium; Single Center Experience

BACKGROUND: Left atrial (LA) remodeling develops as a result of longstanding pressure overload. However, determinants and clinical outcome of excessive remodeling, so called giant left atrium (GLA), are not clear. METHODS: Clinical characteristics of patients with GLA (antero-posterior diameter higher than 65 mm), including echo-Doppler parameters, and follow-up clinical outcomes from a tertiary referral hospital were investigated. RESULTS: Among 68519 consecutive primary patients who underwent echocardiography over a period of 10 years, data from 163 GLA cases (0.24%) were analyzed. Main causes were significant rheumatic mitral stenosis (n = 58, 36%); other causes comprised significant rheumatic mitral regurgitation (MR; n = 10, 6%), mitral valve (MV) prolapse or congenital mitral valvular disease (MVD) (n = 20, 12%), and functional MR (n = 25, 15%). However, mild rheumatic MV disease (n = 4, 3%) or left ventricular (LV) systolic or diastolic dysfunction without significant MR (n = 46, 28%) were also causes of GLA. During median follow-up of 22 months, 42 cases (26%) underwent composite events. MV surgery was related to lower rate of composite events. In multivariate analysis, MV surgery, elevated pulmonary arterial systolic pressure, and increased LA volume index were independent predictors of future events (p < 0.05) regardless of underlying diseases or history of MV surgery. CONCLUSION: Although rheumatic MVD with atrial fibrillation is the main contributor to GLA, longstanding atrial fibrillation with LV dysfunction but without MVD also could be related to GLA. Even in GLA state, accurate measurement of LA volume is crucial for risk stratification for future events, regardless of underlying disease.

Clinical Study of Prevalence of Antibiotic Resistance of Escherichia coli in Urinary Tract Infection in Children: A 9-year Retrospective, Single Center Experience

PURPOSE: The aim of this study was to determine the prevalence of antibiotic susceptibility and resistance of Escherichia coli in urinary tract infections (UTIs) in children. METHODS: We retrospectively reviewed the clinical records of 212 inpatients aged 18 years or younger with UTIs treated at the Pediatric Department of Dongguk University Gyeongju Hospital between January 2008 and December 2016. For comparison, patients were divided into three groups according to age as follows: group 1, ≤1 month; group 2, >1 month to ≤12 months; and group 3, ≥13 months. The antibiotic resistance rates from January 2008 to December 2012 (study period 1) and from January 2013 to December 2016 (study period 2) were analyzed statistically by group. RESULTS: As the patient age increased, the antibiotic resistance rate to ampicillin (P=0.013), levofloxacin (P=0.050), piperacillin/tazobactam (TZP) (P<0.001), and trimethoprim/sulfamethoxazole (P=0.002) increased. The frequency of extended spectrum beta-lactamase producing E. coli showed a significant difference from 5 cases (4.6%) in study period 1 and 16 cases (15.8%) in study period 2 (P=0.007). The antibiotic resistance rate of E. coli was compared between the two time periods and we found that the antibiotic resistance rate to cefotaxime was significantly increased from 5.4% to 16.8% (P=0.008) and that to TZP was significantly decreased from 40.5% to 7.9% (P<0.001). CONCLUSION: Over the past 9 years, the resistance rate to cefotaxime has increased but the resistance rate to TZP has decreased. Thus, it is important to continue to investigate the antibiotic resistance rates of bacteria in the community.

Clinical Study of Prevalence of Antibiotic Resistance of Escherichia coli in Urinary Tract Infection in Children: A 9-year Retrospective, Single Center Experience

PURPOSE: The aim of this study was to determine the prevalence of antibiotic susceptibility and resistance of Escherichia coli in urinary tract infections (UTIs) in children. METHODS: We retrospectively reviewed the clinical records of 212 inpatients aged 18 years or younger with UTIs treated at the Pediatric Department of Dongguk University Gyeongju Hospital between January 2008 and December 2016. For comparison, patients were divided into three groups according to age as follows: group 1, ≤1 month; group 2, >1 month to ≤12 months; and group 3, ≥13 months. The antibiotic resistance rates from January 2008 to December 2012 (study period 1) and from January 2013 to December 2016 (study period 2) were analyzed statistically by group. RESULTS: As the patient age increased, the antibiotic resistance rate to ampicillin (P=0.013), levofloxacin (P=0.050), piperacillin/tazobactam (TZP) (P<0.001), and trimethoprim/sulfamethoxazole (P=0.002) increased. The frequency of extended spectrum beta-lactamase producing E. coli showed a significant difference from 5 cases (4.6%) in study period 1 and 16 cases (15.8%) in study period 2 (P=0.007). The antibiotic resistance rate of E. coli was compared between the two time periods and we found that the antibiotic resistance rate to cefotaxime was significantly increased from 5.4% to 16.8% (P=0.008) and that to TZP was significantly decreased from 40.5% to 7.9% (P<0.001). CONCLUSION: Over the past 9 years, the resistance rate to cefotaxime has increased but the resistance rate to TZP has decreased. Thus, it is important to continue to investigate the antibiotic resistance rates of bacteria in the community.

A Case of Primary Tracheal Schwannoma / 고신대학교의과대학학술지

Although benign nerve sheath tumors have been described, primary tracheal schwannomas are extremely rare. We report a case of primary tracheal schwannoma, a rare benign nerve sheath tumor in a 58-year-old man with atypical symptoms of chronic cough, sputum and dyspnea for 2 months. Chest computerized tomography showed a 1.7 cm polypoid lesion in posterior wall of mid trachea. The results of bronchoscopic biopsy and immuno-histo-chemical studies were consistent with schwannoma. A surgical treatment of tumor resection and tracheal reconstruction by end-to-end anastomosis was performed.

RSV Outbreak at a Single Postpartum Care Center in Gyeongsangbukdo / 대한주산의학회잡지

PURPOSE: We performed an analysis of the RSV outbreak in a postpartum center in Gyeongsangbukdo to provide preliminary data for health and hygiene management of postpartum care centers. METHODS: All of 22 newborns who were transferred to our hospital from a postpartum care center from December 2014 to January 2015 showed positive for RSV by viral culture and enrolled in the study group. To identify early symptoms in RSV infected newborn in the nursery 31 infants (1 month to 24 month of age) who were hospitalized in our hospital due to RSV infection during the same period were selected as control group and clinical symptoms were compared with the study group. A retrospective study was also performed on the newborns who were cared and not transferred to our hospital in the postpartum care center, as well as the facilities offered by the center. RESULTS: All of 22 neonatal patients who were transferred to our hospital had early symptoms of rhinorrhea and cough compared to control group. Rhinorrhea appeared 4.2±2.0 days before the admission, and cough occurred 1.0±1.1 days after rhinorrhea. The level of infection control specified by the law for general facilities relating to postpartum care centers was applied to the postpartum center, RSV infection was not controlled. Strict hand washing, individual equipment such as stethoscopes and exclusion of visitors with respiratory symptoms were done and infected neonates were segregated in separate air circulation system and cared by nurse-infant ratios from 1:1 to 1:2 depending on the needs of the individual neonates. Additional transmission was not observed after transfer to our hospital CONCLUSION: Neonates with cough and rhinorrhea were initial symptom for RSV infection in the postpartum center and should be evaluated for RSV infection during high risk season. Current guideline or support for infection control in postpartum center should be reevaluated for RSV infection control.

RSV Outbreak at a Single Postpartum Care Center in Gyeongsangbukdo / 대한주산의학회잡지

PURPOSE: We performed an analysis of the RSV outbreak in a postpartum center in Gyeongsangbukdo to provide preliminary data for health and hygiene management of postpartum care centers. METHODS: All of 22 newborns who were transferred to our hospital from a postpartum care center from December 2014 to January 2015 showed positive for RSV by viral culture and enrolled in the study group. To identify early symptoms in RSV infected newborn in the nursery 31 infants (1 month to 24 month of age) who were hospitalized in our hospital due to RSV infection during the same period were selected as control group and clinical symptoms were compared with the study group. A retrospective study was also performed on the newborns who were cared and not transferred to our hospital in the postpartum care center, as well as the facilities offered by the center. RESULTS: All of 22 neonatal patients who were transferred to our hospital had early symptoms of rhinorrhea and cough compared to control group. Rhinorrhea appeared 4.2±2.0 days before the admission, and cough occurred 1.0±1.1 days after rhinorrhea. The level of infection control specified by the law for general facilities relating to postpartum care centers was applied to the postpartum center, RSV infection was not controlled. Strict hand washing, individual equipment such as stethoscopes and exclusion of visitors with respiratory symptoms were done and infected neonates were segregated in separate air circulation system and cared by nurse-infant ratios from 1:1 to 1:2 depending on the needs of the individual neonates. Additional transmission was not observed after transfer to our hospital CONCLUSION: Neonates with cough and rhinorrhea were initial symptom for RSV infection in the postpartum center and should be evaluated for RSV infection during high risk season. Current guideline or support for infection control in postpartum center should be reevaluated for RSV infection control.

Comparison of Surgery Plus Chemotherapy and Palliative Chemotherapy Alone for Advanced Gastric Cancer with Krukenberg Tumor / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: This study was conducted to validate the survival benefit of metastasectomy plus chemotherapy over chemotherapy alone for treatment of Krukenberg tumors from gastric cancer and to identify prognostic factors for survival. MATERIALS AND METHODS: Clinical data from 216 patients with Krukenberg tumors from gastric cancer were collected. Patients were divided into two arms according to treatment modality: arm A, metastasectomy plus chemotherapy and arm B, chemotherapy alone. RESULTS: Overall survival (OS) was significantly increased in arm A relative to arm B for patients initially diagnosed with stage IV gastric cancer (18.0 months vs. 8.0 months; p < 0.001) and those with recurrent Krukenberg tumors (19.0 months vs. 9.0 months; p=0.002), respectively. Metastasectomy (hazard ratio [HR], 0.458; 95% confidence interval [CI], 0.287 to 0.732; p=0.001), signet-ring cell pathology (HR, 1.583; 95% CI, 1.057 to 2.371; p=0.026), and peritoneal carcinomatosis (HR, 3.081; 95% CI, 1.610 to 5.895; p=0.001) were significant prognostic factors for survival. CONCLUSION: Metastasectomy plus chemotherapy offers superior OS when compared to palliative chemotherapy alone in gastric cancer with Krukenberg tumor. Prolonged survival applies to all patients, regardless of gastric cancer stage. Metastasectomy, signet-ring cell pathology, and peritoneal carcinomatosis were prognostic factors for survival. Future prospective randomized trials are needed to confirm the optimal treatment strategy for Krukenberg tumors from gastric cancer.

Early Detection of Kawasaki Disease in Infants

BACKGROUND AND OBJECTIVES: This study aimed to investigate the clinical characteristics of infantile Kawasaki disease (KD), and to evaluate early diagnostic features of KD in febrile infants. SUBJECTS AND METHODS: We retrospectively reviewed the medical records of 64 KD patients from January 2010 to October 2014. There was an analysis of the clinical, laboratory data of the infants versus children groups. Furthermore, the clinical and laboratory data of infantile KD patients were compared with 16 infants who were admitted for other acute febrile diseases. RESULTS: A total of 64 patients with KD were identified; 20 (31.3%) were infants; 44 (68.8%) were >1 year old children. Incomplete KD was much more common in infants (n=13, 65.0%) than in children group (n=14, 31.8%) (p=0.013). The infants were characterized by significantly higher rates of inflammatory changes at the Bacille Calmett-Guerin (BCG) inoculation site (p<0.001), but lower rates of changes in the extremities (p=0.029) and cervical lymphadenopathy (p=0.006). The serum levels of platelet after 1 week (p=0.005), C-reactive protein (p=0.038), and N-terminal pro-brain natriuretic peptide (NT-proBNP) (p=0.026) were all significantly higher in the infants group. Comparing the infants with KD versus the other acute febrile diseases, there were significantly higher serum levels of erythrocyte sedimentation rate (p=0.002), C-reactive protein (p=0.046) and NT-proBNP (p=0.001) for the infants with KD group. CONCLUSION: BCGitis and higher levels of NT-proBNP can be helpful for early diagnosis of the incomplete KD in infants, and may be a good predictor of KD in acute febrile infants, when combined with other acute phase reactants.

An Epidemiological Survey on Serological Diagnosis of Legionnella Infection in Seoul, Korea

Serological investigation of antibodies to Legionella species in 1,802 sera collected in seoul was conducted with indirect fluorescent antibody assay (IFA). With an antibody titer of > or =1:128 to be positive, 17 (0.9%) of these sera were positive and 6 (35.3%) of positive sera showed cross-reactions between Legionella species. The number of sera with antibody titers of > or =1:128 to L. pneumophila serogroup 1, L. pneumophila serogroup 4, L. pneumophila serogroup 5, L. bozemanii, L. micdadei, L. anisa were 6 (35.3%), 3 (17.6%), 3 (17.6%), 2 (11.8%), 1 (5.9%), 2 (11.8%) respectively. Among 17 positive sera, 10 (58.8%) sera were from male and 7 (41.2%) from female. An average age of them was 68.9 (+/-15.3; 27~89). Except for one serum, 16 (94.1%) of positive sera were from those older than 50 years old. The result suggests that the aged over 50 years old should be more careful of Legionella infection.

Molecular Characterization of Norovirus and Rotavirus in Outbreak of Acute Gastroenteritis in Seoul

Norovirus and rotavirus are important causes of acute nonbacterial gastroenteritis in communities worldwide. Genotypes of norovirus and rotavirus in stool samples, which were collected from patients, was determined by RT-PCR and ELISA. A total 4,484 stool samples (461 outbreak cases) collected during January 2010-April 2013 were analyzed. Four hundred thirty eight of samples were positive for norovirus. Twelve samples were positive for Rotavirus. Norovirus genotypes identified were nine kinds of G I genotype (G I -1, G I -2, G I -3, G I -4, G I -6, G I -7, G I -9, G I -12, G I -13) and nine kinds of G II genotype(G II -2, G II -4, G II -5, G II -6, G II -7, G II -11, G II -12, G II -15, G II -16). Rotavirus genotypes were G2P[4]. The results might be useful information for evaluating the epidemiological status of viral diarrhea in Seoul, and providing a strategy to prevent human norovirus, rotavirus and other threats to public health in Korea.

Small Bowel Obstruction Caused by an Aberrant Congenital Band in a Child / 대한소아소화기영양학회지

Small bowel obstruction due to congenital band is not only rare in children, but also difficult to diagnose, because common symptoms such as vomiting and abdominal pain are observed in patients. In order to prevent a fatal result, an anomalous congenital band should be considered in the discriminative diagnosis of intestinal obstruction in children who have no previous experience of operation or intraperitoneal inflammation. This report presents a 4-year-old boy who was admitted with abdominal pain and nonbilious vomiting for a day. The initial suspicion was for acute gastroenteritis. However, after further investigation and performance of surgery, the intestinal obstruction associated with a congenital band was confirmed. No recurrence was observed during the 8-month follow-up period. Thus early confirmation based on radiologic study is a crucial factor for the diagnosis of small bowel obstruction caused by a congenital band.

Mutations in gyrA and parC Genes and Plasmid-Mediated Quinolone Resistance in Non-typhoid Salmonella Isolated from Pediatric Patients with Diarrhea in Seoul

A total of 91 non-typhoid Salmonella isolated from pediatric patients with diarrhea in Seoul from 2003 to 2009 was tested for antimicrobial susceptibility of nalidixic acid (NA). Forty strains of NA resistance or intermediate susceptible non-typhoid Salmonella were identified and their minimum inhibitory concentrations (MICs) of NA, ciprofloxacin (CIP), and norfloxacin (NOR) were determined. Of the 40 isolates, 26 were resistant to NA (MIC >256 microg/ml). Only one isolate was high-level resistant to CIP (12 microg/ml) and NOR (48 microg/ml). Mutations in gyrA and parC genes were studied by PCR and sequencing. All NA-resistant isolates carried point mutations in the gyrA quinolone resistance determining regions (QRDR) at codon 83 or 87 (MICs of NA, >256 microg/ml; MICs of CIP, 0.047~0.25 microg/ml; MICs of NOR, 0.38~1.5 microg/ml). A double change in GyrA was found in one Salmonella Enteritidis (MIC of CIP, 12 microg/ml; MIC of NOR, 48 microg/ml). In respect of the ParC protein, a single change at Thr57-->Ser was found in 3 isolates (MICs of NA, >256 microg/ml; MICs of CIP, 0.19~0.25 microg/ml; MICs of NOR, 1 microg/ml). At the same time, these strains changed from Ser83 to Tyr in the gyrA. The result of the investigation for the prevalence of plasmid-mediated quinolone resistance (PMQR) genes, 14 isolates harbored qnr gene among 40 isolates. All of 14 isolates showed decreased susceptibility at NA (MICs 4~16 microg/ml) and except one strain, all of qnr genes were identified as qnrB. Mutations in the gyrA gene and production of PMQR determinants were critical for quinolone resistance and decreased susceptibility to fluoroquinolone in these isolates.

Molecular Epidemiology of Legionella pneumophila Isolated from Bath Facilities of Public Establishments in Seoul

The genus Legionella is common in aquatic environments. Some species of Legionella are recognized as potential opportunistic pathogens for human, notably Legionella pneumophila that causes Legionellosis. During the summer season between June and August in 2010, we isolated 61 L. pneumophila from the bath facilities of public establishments of 25 wards in Seoul. The existence of 16S rRNA and mip gene of L. pneumophila was confirmed in the genome of the isolated strains by PCR. Among the 61 strains of L. pneumophila, thirty three isolates belong to serogroup 1 (54.1%), 13 isolates were serogroup 6 (21.3%), 9 isolates were serogroup 5 (14.8%), 3 isolates were serogroup 3 (4.9%), and 3 isolates were identified in serogroup 2 (4.9%). On pulsed-field gel electrophoresis (PFGE) analysis using SfiI, genetic types of L. pneumophila were classified into 8 (A to H) patterns by the band similarity with excess of 65%. Our results suggest the existence of serological and genetic diversity among the L. pneumophila isolates.

Transmission of Seasonal Outbreak of Childhood Enteroviral Aseptic Meningitis and Hand-foot-mouth Disease

This study was conducted to evaluate the modes of transmission of aseptic meningitis (AM) and hand-foot-mouth disease (HFMD) using a case-control and a case-crossover design. We recruited 205 childhood AM and 116 HFMD cases and 170 non-enteroviral disease controls from three general hospitals in Gyeongju, Pohang, and Seoul between May and August in both 2002 and 2003. For the case-crossover design, we established the hazard and non-hazard periods as week one and week four before admission, respectively. In the case-control design, drinking water that had not been boiled, not using a water purifier, changes in water quality, and contact with AM patients were significantly associated with the risk of AM (odds ratio [OR]=2.8, 2.9, 4.6, and 10.9, respectively), while drinking water that had not been boiled, having a non-water closet toilet, changes in water quality, and contact with HFMD patients were associated with risk of HFMD (OR=3.3, 2.8, 6.9, and 5.0, respectively). In the case-crossover design, many life-style variables such as contact with AM or HFMD patients, visiting a hospital, changes in water quality, presence of a skin wound, eating out, and going shopping were significantly associated with the risk of AM (OR=18.0, 7.0, 8.0, 2.2, 22.3, and 3.0, respectively) and HFMD (OR=9.0, 37.0, 11.0, 12.0, 37.0, and 5.0, respectively). Our findings suggest that person-to-person contact and contaminated water could be the principal modes of transmission of AM and HFMD.

Predictive factors for severe infection among febrile infants younger than three months of age / 소아과

PURPOSE: This study investigated the predictive factors for identifying infection-prone febrile infants younger than three months. METHODS: We conducted a retrospective study of 167 infants younger than three months with an axillary temperature >38degrees C who were hospitalized between 2006 and 2008. If they met any of the following criteria, positive blood culture, CSF WBC > or =11/mm3 or positive CSF culture, urinalysis WBC > or =6/HPF and positive urine culture, WBC > or =6/HPF on microscopic stool examination or positive stool culture, they were considered at high risk for severe infection. Infants with focal infection, respiratory infection or antibiotic administration prior to admission to the hospital were excluded. We evaluated the symptoms, physical examination findings, laboratory data, and the clinical course between the high risk and low risk groups for severe infection. RESULTS: The high-risk group included 77(46.1%) infants, and the most common diagnosis was urinary tract infection (51.9%). Factors, such as male sex, ESR and CRP were statistically different between the two groups. But, a multilinear regression analysis for severe infection showed that male and ESR factors are significant. CONCLUSION: We did not find the distinguishing symptoms and laboratory findings for identifying severe infection-prone febrile infants younger than three months. However, the high-risk group was male and ESR-dominated, and these can possibly be used as predictive factors for severe infection.

Phosphodiesterase 4D Gene and Risk of Noncardiogenic Ischemic Stroke in a Korean Population

Recently published studies from different populations provide apparently conflicting evidence on the association between the phosphodiesterase 4D (PDE4D) gene and ischemic stroke. The relationship between a representative PDE4D genotype and ischemic stroke was explored in a case-control study of 205 consecutive Korean patients with noncardiogenic ischemic stroke and 103 healthy controls who were neurologically and radiologically proven to be stroke-free. We selected and genotyped a PDE4D single nucleotide polymorphism (SNP 41, rs152312) as a candidate marker for susceptibility to ischemic stroke because SNP 41 has shown the most significant association with stroke in both a meta-analysis and the original Icelandic study of the PDE4D gene. No significant difference was observed between the cases and controls in the distribution of the PDE4D SNP 41 genotypes. The results from the adjusted conditional logistic regression analysis (adjusted for age, hypertension, diabetes and smoking status) showed no significant association between PDE4D SNP 41 genotypes and an increased risk of noncardiogenic ischemic stroke. The PDE4D gene is not a major risk factor for noncardiogenic ischemic stroke in a Korean population, which supports the recent evidence suggesting that the causative genetic variants of ischemic stroke may differ across populations.

Sleep Duration and Body Mass Index in Korean Children

OBJECTIVES: We conducted this study to investigate the relationship between sleep duration and body mass index (BMI), in Korean children. METHODS: We performed a cross-sectional analysis of data collected on 3,639 boys and girls (aged 7-12) in Daegu, Korea. The data included each child's age, sex, weight, height, extracurricular activities, bedtime, wake-up time, sleep latency, total sleep duration, parents' occupations, and parents' educational levels. The relationship between sleep duration and each variable was examined via analysis of variance (ANOVA). RESULTS: The analysis showed an association between short sleep duration and high BMI. Boys showed a graded inverse relationship between sleep duration and BMI. However, there was no significant corresponding result for girls. In the total sample, hours of computer use, time when the computer was turned off, time when the television was turned off, mother's bedtime, and hours of extracurricular activity were associated with longer sleep duration. No association was found between sleep duration and hours of watching television, child's wake-up time, or educational level of the parents. CONCLUSION: The results of this study show an inverse relationship between a child's sleep duration and BMI;thus, children with shorter sleep duration tend to have higher BMIs.