Geun-Yong Kwon

Inhalation Toxicity of Humidifier Disinfectants as a Risk Factor of Children's Interstitial Lung Disease in Korea: A Case-Control Study

Background The occurrence of numerous cases of interstitial lung disease in children (chILD) every spring in Korea starting in 2006 raised suspicion about a causal relationship with the use of humidifier disinfectants (HDs). The aim of this study was to evaluate the association between HD use and the risk of chILD. Methods This retrospective, 1∶3 matched case-control study consisted of 16 cases of chILD that had developed between 2010 and 2011. The three groups of parallel controls (patients with acute lobar pneumonia, asthma, and healthy children) were matched by age, gender, and index date. Indoor/outdoor environmental risk factors, including HD use, were investigated by asking the guardians to complete a questionnaire. Results The median age of the affected children (43.8% male) was 26 months (18.25–36.25). The chILD group did not differ significantly from the control groups with respect to socio-demographic and clinical variables. Indoor and outdoor environmental factors were not associated with a risk of chILD. However, the previous use of HDs (OR; 2.73. 95% CI; 1.41–5.90, P = 0.00) were independently associated with an increased risk. Conclusions This study showed that HDs, which are widely used in South Korea in the winter season, independently increased the risk of chILD in spring. Therefore, continuous monitoring and, if needed, changes in policy are essential to prevent and control pediatric diseases caused by toxic chemicals.

Emerging Pathogens and Vehicles of Food- and Water-borne Disease Outbreaks in Korea, 2007–2012

Objectives Food- and water-borne disease outbreaks (FBDOs) are an important public health problem worldwide. This study investigated the trends in FBDOs in Korea and established emerging causal pathogens and causal vehicles. Methods We analyzed FBDOs in Korea by year, location, causal pathogens, and causal vehicles from 2007 to 2012. Information was collected from the FBDOs database in the Korean Centers for Disease Control and Prevention. Results During 2007–2012, a total of 1794 FBDOs and 48,897 patients were reported. After 2007, FBDOs and patient numbers steadily decreased over the next 2 years and then plateaued until 2011. However, in 2012, FBDOs increased slightly accompanied by a large increase in the number of affected patients. Our results highlight the emergence of norovirus and pathogenic Escherichia coli other than enterohemorrhagic E. coli (EHEC) in schools in 2012. We found that pickled vegetables is an emerging causal vehicle responsible for this problem. Conclusion On the basis of this study we recommend intensified inspections of pickled vegetable manufacturers and the strengthening of laboratory surveillance of relevant pathogens.

Humidifier Disinfectants Are a Cause of Lung Injury among Adults in South Korea: A Community-Based Case-Control Study

Backgrounds An outbreak of lung injury among South Korean adults was examined in a hospital-based case-control study, and the suspected cause was exposure to humidifier disinfectant (HD). However, a case-control study with community-dwelling controls was needed to validate the previous study’s findings, and to confirm the exposure-response relationship between HD and lung injury. Methods Each case of lung injury was matched with four community-dwelling controls, according to age (±3 years), sex, residence, and history of childbirth since 2006 (for women). Environmental risk factors, which included type and use of humidifier and HD, were investigated using a structured questionnaire during August 2011. The exposure to HD was calculated for both cases and controls, and the corresponding risks of lung injury were compared. Results Among 28 eligible cases, 16 patients agreed to participate, and 60 matched controls were considered eligible for this study. The cases were more likely to have been exposed to HD (odds ratio: 116.1, 95% confidence interval: 6.5–2,063.7). All cases were exposed to HDs containing polyhexamethyleneguanidine phosphate, and the risk of lung injury increased with the cumulative exposure, duration of exposure, and exposure per day. Conclusions This study revealed a statistically significant exposure-response relationship between HD and lung injury. Therefore, continuous monitoring and stricter evaluation of environmental chemicals’ safety should be conducted.

Regional Distribution of Hepatitis C Virus Infection in the Republic of Korea, 2007-2011

Background/Aims In Korea, hepatitis C is included as an infectious disease in a sentinel surveillance system. Recently, a large variation in hepatitis C incidence between different regions in Korea has been noticed. The current study verified the nationwide distribution of hepatitis C infection for effective prevention and management. Methods We counted the number of hepatitis C patients who visited a hospital per county using the National Health Insurance database from 2007 to 2011. The age-adjusted prevalence ratio was used, and the age adjustment method was used as an indirect standardization method. Disease mapping and spatial analysis were conducted using a geographic information system. Results The annual prevalence of diagnosed hepatitis C was approximately 0.12% to 0.13% in Korea. The age-adjusted prevalence ratios in Busan, Jeonnam, and Gyeongnam were high (1.75, 1.4, and 1.3, respectively). The three regions in the southern coastal area of the Korean Peninsula were identified as a high-prevalence cluster (Moran’s index, 0.3636). Conclusions The present study showed that hepatitis C infection has very large regional variation, and there are several high-risk areas. Preventive measures focusing on these areas should be applied to block the transmission of hepatitis C and reduce the disease burden.

Epidemic intelligence service officers and field epidemiology training program in Korea.

Abstract Korea has adopted Epidemic Intelligence Service (EIS) officers through the Field Epidemiology Training Program (FETP) since 1999 for systematic control of emerging and re-emerging infectious diseases. Graduates of medical schools in Korea are selected and serve as public health doctors (PHDs) for their mandatory military service. The duration of service is 3 years and PHDs comprise general practitioners and specialists. Some PHDs are selected as EIS officers with 3 weeks basic FETP training and work for central and provincial public health authorities to conduct epidemiological investigations. The total number of EIS officers is 31 as of 2012. The Korea Centers for Disease Control and Prevention (KCDC) has 12 specialists, whereas specialists and each province has one or two EIS officers to administer local epidemiological investigations in 253 public health centers. The Korean EIS officers have successfully responded and prevented infectious diseases, but there is a unique limitation: the number of PHDs in Korea is decreasing and PHDs are not allowed to stay outside Korea, which makes it difficult to cope with overseas infectious diseases. Furthermore, after 3 years service, they quit and their experiences are not accumulated. KCDC has hired full-time EIS officers since 2012 to overcome this limitation.

Imported Melioidosis in South Korea: A Case Series with a Literature Review.

Objectives Melioidosis is a potentially fatal infectious disease caused by the environmental anaerobic Gram-negative bacillus Burkholderia pseudomallei. Melioidosis is endemic to areas of northern Australia and Southeast Asia. With increasing international travel and migration, imported cases of melioidosis are being reported regularly. Here, we summarize the 11 cases of melioidosis reported in South Korea from 2003 to 2014. Methods Tracing epidemiological investigations were performed on every patient reported to the National Surveillance System since 2011. A systematic literature search was performed to identify melioidosis cases that occurred prior to 2011. Results The overall fatality rate was 36.4%. All the patients had visited Southeast Asia where melioidosis is endemic. The stay in the endemic region ranged from 4 days to 20 years. Of the seven patients who developed initial symptoms after returning to South Korea, the time interval between returning to South Korea and symptom onset ranged from 1 day to 3 years. The remaining four patients developed symptoms during their stay in the endemic region and were diagnosed with melioidosis in South Korea. Seven (63.6%) patients possessed at least one risk factor, all of whom were diabetic. Pneumonia was the most frequent clinical manifestation, but the patients showed a wide spectrum of clinical features, including internal organ abscesses, a mycotic aneurysm of the aorta, and coinfection with tuberculosis. Conclusion An early diagnosis and initiation of the appropriate antibiotics can reduce the mortality of melioidosis. Consequently, increased awareness of the risk factors and clinical features of melioidosis is required.

Results of Tuberculosis Contact Investigation in Congregate Settings in Korea, 2013

Objectives This study aimed to check the status of the contact investigation in congregate settings to eradicate tuberculosis (TB) in the Republic of Korea. Methods The “Integrated System for Disease and Public Health Management” is used for care and follow-up for patients and contacts of TB. We downloaded data for contact investigations conducted from January to December 2013. Results A total of 1,200 contact investigations in congregate settings were carried out by 25 field investigators in 2013. We performed the status of contact investigation, TB, and LTBI rate by age, accept rate of LTBI treatment, and complete rate of LTBI treatment during 2013. A total of 1,547 index TB patients, 149,166 contacts, and 259 additional TB patients were found through the investigation. Kindergartens showed the highest LTBI rate, 19.8%, among educational facilities. The second highest was in elementary schools and the subtotal LTBI rate of educational facilities was 7.8%. Social welfare/correctional facilities and workplaces showed relatively high LTBI rates of 23.8% and 23.6%, respectively. By age, individuals >35 years showed the highest LTBI rate, followed by those aged 0–4 years, 30–34 years, and 5–9 years, with rates of 18.1%, 16.4%, and 15.4% respectively. When comparing the tuberculin skin test (TST) positive conversion ratio by facility, middle school and high school were relatively high compared to the others. The accept rate of LTBI treatment in the workplace was lowest at 63% and the complete rate in elementary schools was lowest at 76.5%. Conclusion TB contact investigation is considered as a meaningful strategy for preventing TB outbreaks in congregate settings and decreasing the prevalence of TB in young people. Results of this study could be used to establish the LTBI management policy.

Influence of congenital facial nerve palsy on craniofacial growth in craniofacial microsomia

Facial muscles are of major importance in human craniofacial growth and development. The purpose of our study was to investigate whether congenital facial nerve palsy influences craniofacial growth in craniofacial microsomia. Fifty-one patients with unilateral craniofacial microsomia and no history of craniofacial skeletal surgery whose radiographs were taken after craniofacial growth was complete were included in this study. These patients were divided into groups in which the facial nerve was involved or uninvolved. The authors evaluated a total of seven measurement items to analyze the midface and mandibular asymmetry. Twenty patients had facial nerve involvement, and 31 had no involvement. None of the measurement items revealed any significant differences between the facial nerve-involved group and the uninvolved group within the same modified Pruzansky grade. There was no correlation between the type of facial nerve involvement and the measurement items. In relationships among the measurement items within each group, maxillary asymmetry was indirectly correlated with mandibular asymmetry or midline deviation through the occlusal plane angle in the uninvolved groups. However, in the facial nerve-involved group, the relationships disappeared. When the correlations in the facial nerve-involved group were compared with those of the uninvolved group, the relationships in the uninvolved group appeared more significant than in the facial nerve-involved group. The loss of relationships between the upper and lower jaw in the facial nerve-involved group might have been caused by subtle changes, which occur in midfacial bones and in the mandible due to facial nerve palsy. The main limitation of our study is that aside from facial nerve palsy, craniofacial microsomia has many factors that can influence craniofacial growth, such as hypoplasia of the mandibular condyle and soft tissue deficiencies.

Dynamic reconstruction of the philtrum using coronal muscle splitting technique in microform cleft lip.

PurposeThe philtral column and dimple are especially important in patients with cleft lip. Recently, we have found that, at maximal puckering, the appearance of the philtrum worsens although the philtral column is well formed at rest. In this study, we explore the effectiveness of the coronal muscle splitting technique in a microform cleft lip through comparative analysis of the postoperative results between the control group (patients without coronal muscle splitting) and the study group (patients with coronal muscle splitting). MethodsPhiltral reconstruction was performed in 24 patients with microform cleft lip between March 2006 and March 2010. The philtrum was reconstructed in 12 patients using the coronal muscle splitting technique and in the other 12 patients without this technique.The convexity of the philtral column and the dimpling of the philtrum were evaluated at rest and at maximal puckering through digital photographs and videos taken preoperatively and postoperatively. In addition, we compared the postoperative results between the 2 groups using the paired t-test. ResultsPostoperative evaluation was done at 6 to 48 months (mean, 25 mo). There was no statistically significant difference in the shape of the philtral column and the philtral dimple between the 2 groups preoperatively (P > 0.05).Reconstruction of the philtral column in the study group rendered better results than in the control group at both rest and maximal puckering (P < 0.001 and P < 0.001). Reconstruction of the philtral dimple in the study group rendered better results than in the control group at both rest and maximal puckering (P = 0.018 and 0.035). ConclusionsThe coronal muscle splitting technique offers more esthetic and functional results in the formation of the philtral column and dimple both at rest and at maximal puckering than in the control group in cases of philtral reconstruction of the microform cleft lip.

The long-term changes of hard palatal bony cleft defects after palatoplasty in unilateral complete cleft lip and palate

There have been few long-term studies regarding the change of bony cleft defects in cleft lip and palate after palatoplasty. The purpose of this study was to evaluate the regenerated bone formed in bony cleft defects and the change in bony cleft width after palatoplasty using computed tomography (CT). Thirty non-syndromic unilateral complete cleft lip and palate patients were retrospectively reviewed. The patients underwent palatoplasty at an average age of 14.32 months. CT was performed at an average age of 9.8 years. The authors evaluated the regenerated bone volume ratio, remnant bony cleft area ratio and change in bony cleft width at the posterior nasal spine. The relative locations of the regenerated bone lesion and the bony cleft to the hard palate were measured. Regenerated bone was observed in all patients. The average regenerated bone volume ratio was 61.1%, and the largest regenerated bone was usually located in the anterior half of the hard palate. The average remnant bony cleft area ratio was 7.6%, and the widest bony cleft was usually located in the anterior 1/3 and the posterior 1/3. The remnant bony cleft and non-regenerated bone lesion were rarely located in the middle 1/3. The bony cleft width at the posterior nasal spine decreased significantly after palatoplasty. Hard palatal bony cleft defects after palatoplasty were decreased by regenerated bone, and possibly by the contracting force of the scar at the midline of the hard palate, and the continuous pressure of the surrounding tissues.