Ho Kim

Seoul National University, Sŏul, Seoul, South Korea

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Publications (120)300.87 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: This paper describes the background, aim, and design of a prospective birth-cohort study in Korea called the COhort for Childhood Origin of Asthma and allergic diseases (COCOA). COCOA objectives are to investigate the individual and interactive effects of genetics, perinatal environment, maternal lifestyle, and psychosocial stress of mother and child on pediatric susceptibility to allergic diseases.Methods/design: The participants in COCOA represents a Korean inner-city population. Recruitment started on 19 November, 2007 and will continue until 31 December, 2015. Recruitment is performed at five medical centers and eight public-health centers for antenatal care located in Seoul. Participating mother-baby pairs are followed from before birth to adolescents. COCOA investigates whether the following five environmental variables contribute causally to the development and natural course of allergic diseases: (1) perinatal indoor factors (i.e. house-dust mite, bacterial endotoxin, tobacco smoking, and particulate matters 2.5 and 10), (2) perinatal outdoor pollutants, (3) maternal prenatal psychosocial stress and the child's neurodevelopment, (4) perinatal nutrition, and (5) perinatal microbiome. Cord blood and blood samples from the child are used to assess whether the child's genes and epigenetic changes influence allergic-disease susceptibility. Thus, COCOA aims to investigate the contributions of genetics, epigenetics, and various environmental factors in early life to allergic-disease susceptibility in later life. How these variables interact to shape allergic-disease susceptibility is also a key aim.The COCOA data collection schedule includes 11 routine standardized follow-up assessments of all children at 6 months and every year until 10 years of age, regardless of allergic-disease development. The mothers will complete multiple questionnaires to assess the baseline characteristics, the child's exposure to environmental factors, maternal pre- and post-natal psychological stress, and the child's neurodevelopment, nutritional status, and development of allergic and respiratory illnesses. The child's microbiome, genes, epigenetics, plasma cytokine levels, and neuropsychological status, the microbiome of the residence, and the levels of indoor and outdoor pollutants are measured by standard procedures.
    BMC Pulmonary Medicine 07/2014; 14(1):109. · 2.76 Impact Factor
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    ABSTRACT: Although traffic accidents are associated with weather, the influence of temperature on injuries from traffic accidents has not been evaluated sufficiently. The objective of this study was to evaluate the effect of temperature, especially cold temperatures, on injuries from traffic accidents in Seoul, Korea. We also explored the relationship of temperature with different types of traffic accident.
    Environmental research. 05/2014; 132C:290-296.
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    ABSTRACT: The purpose of this study was to analyze the initial changes in salivary mutans streptococci levels after orthodontic treatment with fixed appliances. Our subjects consisted of 58 adults. Whole saliva and simplified oral hygiene index values were obtained at 4 time points: at debonding (T1), 1 week after debonding (T2), 5 weeks after debonding (T3), and 13 weeks after debonding (T4). Repeated measures analysis of variance was used to determine the time-related differences in salivary bacterial levels and the simplified oral hygiene index values among the 4 time points after quantifying the salivary levels of Streptococcus mutans, Streptococcus sobrinus, and total bacteria with real-time polymerase chain reaction. Simplified oral hygiene index values and total bacteria significantly decreased, but salivary mutans streptococci levels significantly increased after orthodontic treatment. The amounts of total bacteria in saliva significantly decreased at T3 (T1, T2 > T3, T4), and the simplified oral hygiene index values decreased at T2 (T1 > T2, T3, T4). However, salivary S mutans and S sobrinus significantly increased at T3 and T4, respectively (T1, T2 < T3 < T4). Furthermore, the proportion of mutans streptococci to total bacteria significantly increased at T4 (T1, T2, T3 < T4). This study suggests that careful hygienic procedures are needed to reduce the risk for dental caries after orthodontic treatment, despite overall improved oral hygiene status.
    American journal of orthodontics and dentofacial orthopedics: official publication of the American Association of Orthodontists, its constituent societies, and the American Board of Orthodontics 05/2014; 145(5):603-609. · 1.33 Impact Factor
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    ABSTRACT: While exposure to ambient fine particles <2.5 μm in aerodynamic diameter (PM2.5) has well-established health effects, there is limited quantitative evidence that links specific sources of PM2.5 with those effects. This study was designed to examine the risks of exposure to chemical species and source-specific PM2.5 mass on mortality in Seoul, Korea, a highly populated city. We compare daily mortality counts with PM2.5 chemical speciation data collected every 3 days, as well as nine sources of PM2.5 mass resolved by a positive matrix factorization receptor model, from March 2003 through November 2007. A Poisson generalized linear model incorporating natural splines was used to evaluate associations of PM2.5 chemical species and sources with mortality. PM2.5 mass and several chemical species were associated with mortality. Organic carbon, elemental carbon, and lead were associated with mortality outcomes when using multipollutant models adjusted for other chemical species levels. Source-apportioned PM2.5 derived from mobile sources (ie, gasoline and diesel emissions) and biomass burning was associated with respiratory mortality and cardiovascular mortality, respectively. There were moderate associations of industry and of roadway emissions with cardiovascular mortality. Local combustion sources may be particularly important contributors to PM2.5, leading to adverse health effects.
    Epidemiology (Cambridge, Mass.) 05/2014; 25(3):379-88. · 5.51 Impact Factor
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    ABSTRACT: In our previous longitudinal study, we found that exposure to current levels of ambient total fungal spores was related to a reduction of childhood lung function. However, the biological properties of various taxa of fungal spores varied greatly, as well as their health effects. In this study, we aimed to determine whether any specific fungal spores were responsible for observed changes in lung function. Measurement of lung function was conducted for 100 elementary and middle-school students on 5-10 occasions from October 2007 to November 2009 in New Taipei City, Taiwan. During the week of each lung function measurement, continuous daily concentrations of fungal spores were measured from Sunday to Saturday. The counts of fungal spores belonging to specific taxa were identified. A mixed-effect model with repeated measurements was used to analyze the association of lung function and exposure to each specific taxon of fungal spores. Forward stepwise regression was applied to determine which specific fungal spores were the most closely related to lung function changes. The non-linear relationship was examined using a generalized additive model. The piecewise linear regression was then applied to determine the threshold value. A total of 824 measurements were obtained from 100 participants. Among all the species of fungal spores, only Cladosporium spores were found to be negatively associated with forced vital capacity (FVC) and forced expiratory volume in one second (FEV1) one day later. This association was stronger than the one between the total spore counts and lung function. The threshold of exposure where lung function effect became observable was approximately 1500spores/m(3). This study showed that ambient Cladosporium was most strongly associated with the observed lung function changes among schoolchildren. Replication of these preliminary findings in other geographic areas with different populations would be warranted.
    Science of The Total Environment 03/2014; 481C:370-376. · 3.26 Impact Factor
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    ABSTRACT: Asian dust storms (ADS) have affected several Asian countries and have been a major concern due to adverse effects on public health. The occurrence of ADS differs in each country based on geographical features and distance from the storms' origin. Many studies have reported significant associations between ADS and morbidity. However, regarding the association between ADS and mortality, only a few studies have found statistically significant ADS effects in Korea, Taiwan and Japan. Accordingly, this study aimed to examine the effects of ADS on daily mortality in three Asian cities (Seoul, South Korea; Taipei, Taiwan; and Kitakyushu, Japan) and to explore the differences in the extent of effects in each city. We performed time-series analyses using a generalized additive model (GAM) with Quasi-Poisson regressions. Deaths due to accidents or external causes were excluded. We used a dummy variable as an indicator of ADS and considered lag effects of ADS. Stratified analyses by disease and age and sensitivity analyses controlling for NO2, SO2, and PM10 were also conducted respectively. Additionally, influenza epidemics were adjusted for considering seasonal patterns, and a meta-analysis was performed. We reported results as excess mortality by percentage due to Asian dust storms. We found significant excess mortality in Seoul and Kitakyushu as follows. In Seoul, ADS showed adverse effects on mortality under 65 years old (lag 2: 4.44%, lag 3: 5%, lag 4: 4.39%). In Kitakyushu, ADS had adverse effects on respiratory mortality (lag 2: 18.82%). Contradictory to results in Seoul and Kitakyushu, ADS seemed to have a protective effect in Taipei: total non-accidental mortality (lag 0: -2.77%, lag 1: -3.24%), mortality over 65 years old (lag 0: -3.35%, lag 1: -3.29%) and respiratory mortality (lag 0: -10.62%, lag 1: -9.67%). Sensitivity analyses showed similar findings as the main results. Our findings suggest that ADS may affect mortality in several Asian cities, and that a dust storm warning system could help protect people from dust storms.
    Atmospheric Environment. 01/2014; 89:309–317.
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    ABSTRACT: Objective Although traffic accidents are associated with weather, the influence of temperature on injuries from traffic accidents has not been evaluated sufficiently. The objective of this study was to evaluate the effect of temperature, especially cold temperatures, on injuries from traffic accidents in Seoul, Korea. We also explored the relationship of temperature with different types of traffic accident. Methods The daily frequencies of injuries from traffic accidents in Seoul were summarized from the integrated database established by the Korea Road Traffic Authority. Weather data included temperature, barometric pressure, rainfall, snow, and fog from May 2007 to December 2011. The qualitative relationship between daily mean temperature and injuries from traffic accidents was evaluated using a generalized additive model with Poisson distribution. Further analysis was performed using piecewise linear regression if graph the showed non-linearity with threshold. Results The incidence of injuries was 216 per 100,000 person–months in Seoul. The effect of temperature on injuries from traffic accidents was minimal during spring and summer. However, injuries showed a more striking relationship with temperature in winter than in other seasons. In winter, the number of injuries increased as the temperature decreased to <0 °C. The injuries increased by 2.1% per 1 °C decrease under the threshold of the daily average temperature −5.7 °C, which is 10-fold greater than the effect of temperature above the threshold. Some groups were more susceptible to injuries, such as young and male drivers, according to the types of traffic accident when the temperature decreased to below the freezing temperature. Conclusions The incidence of injuries increased sharply when the temperature decreased below freezing temperature in winter. Temperature can be effectively used to inform high risk of road traffic injuries, thus helping to prevent road traffic injuries.
    Environmental Research. 01/2014; 132:290–296.
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    ABSTRACT: Introduction The purpose of this study was to analyze the initial changes in salivary mutans streptococci levels after orthodontic treatment with fixed appliances. Methods Our subjects consisted of 58 adults. Whole saliva and simplified oral hygiene index values were obtained at 4 time points: at debonding (T1), 1 week after debonding (T2), 5 weeks after debonding (T3), and 13 weeks after debonding (T4). Repeated measures analysis of variance was used to determine the time-related differences in salivary bacterial levels and the simplified oral hygiene index values among the 4 time points after quantifying the salivary levels of Streptococcus mutans, Streptococcus sobrinus, and total bacteria with real-time polymerase chain reaction. Results Simplified oral hygiene index values and total bacteria significantly decreased, but salivary mutans streptococci levels significantly increased after orthodontic treatment. The amounts of total bacteria in saliva significantly decreased at T3 (T1, T2 > T3, T4), and the simplified oral hygiene index values decreased at T2 (T1 > T2, T3, T4). However, salivary S mutans and S sobrinus significantly increased at T3 and T4, respectively (T1, T2 < T3 < T4). Furthermore, the proportion of mutans streptococci to total bacteria significantly increased at T4 (T1, T2, T3 < T4). Conclusions This study suggests that careful hygienic procedures are needed to reduce the risk for dental caries after orthodontic treatment, despite overall improved oral hygiene status.
    American Journal of Orthodontics and Dentofacial Orthopedics. 01/2014; 145(5):603–609.
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    ABSTRACT: Background In our previous longitudinal study, we found that exposure to current levels of ambient total fungal spores was related to a reduction of childhood lung function. However, the biological properties of various taxa of fungal spores varied greatly, as well as their health effects. In this study, we aimed to determine whether any specific fungal spores were responsible for observed changes in lung function. Methods Measurement of lung function was conducted for 100 elementary and middle-school students on 5–10 occasions from October 2007 to November 2009 in New Taipei City, Taiwan. During the week of each lung function measurement, continuous daily concentrations of fungal spores were measured from Sunday to Saturday. The counts of fungal spores belonging to specific taxa were identified. A mixed-effect model with repeated measurements was used to analyze the association of lung function and exposure to each specific taxon of fungal spores. Forward stepwise regression was applied to determine which specific fungal spores were the most closely related to lung function changes. The non-linear relationship was examined using a generalized additive model. The piecewise linear regression was then applied to determine the threshold value. Results A total of 824 measurements were obtained from 100 participants. Among all the species of fungal spores, only Cladosporium spores were found to be negatively associated with forced vital capacity (FVC) and forced expiratory volume in one second (FEV1) one day later. This association was stronger than the one between the total spore counts and lung function. The threshold of exposure where lung function effect became observable was approximately 1500 spores/m3. Conclusion This study showed that ambient Cladosporium was most strongly associated with the observed lung function changes among schoolchildren. Replication of these preliminary findings in other geographic areas with different populations would be warranted.
    Science of The Total Environment 01/2014; 481:370–376. · 3.26 Impact Factor
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    ABSTRACT: The adverse effects of dust storms on health have been a major issue in several countries. A substantial number of studies have found significant associations between dust storms and morbidity such as emergency visits and hospitalizations. However, the results of the studies on the association between dust storms and mortality are inconsistent. In Korea, no study has found statistically significant effect of Asian dust storms on daily mortality. Thus, this study aims to explore the effect of Asian dust storms on daily mortality in Korea during 2001-2009. All analyses were confined to non-accidental mortality. We used generalized additive model with Quasi-Poisson regressions. We considered the lag effect of dust storms up to 7 days and performed subgroup analyses by disease, sex and age. Current day's temperature, relative humidity, barometric pressure, day of the week, season and time trends were controlled for in a basic model. SO2, NO2 and PM10 levels were also added in the further analyses. Meta-analysis was applied for seven metropolitan cities in Korea to estimate the pooled effects of Asian dust storms. We reported results as excessive mortality by percentage due to Asian dust storms. We found significant positive associations between Asian dust storms and mortality at lag 0 (cardiovascular: 2.91%; 95% CI: 0.13, 5.77, male: 2.74%; 95% CI: 0.74, 4.77 and <65 years: 2.52%; 95% CI: 0.06, 5.04), at lag 2 (male 2.4%; 95% CI: 0.43, 4.4 and <65 years: 2.49%; 95% CI: 0.07, 4.97), at lag 3 (total non-accidental: 1.57%; 95% CI: 0.11, 3.06, male: 2.24%; 95% CI: 0.28, 4.25 and <65 years: 2.43%; 95% CI: 0.01, 4.91) and at lag 5 (cardiovascular: 3.7%; 95% CI: 0.93, 6.54 and male: 2.04%, 95 CI: 0.08, 4.04) in the model which adjusted for NO2 additionally. Other models showed similar significant results except the PM10-adjusted model. This is the first study to show the significant relationship between Asian dust storms and mortality in Korea and to present a pooled effect estimate by meta-analysis of multiple cities in a country. Asian dust storms could significantly affect daily mortality in Korea.
    Atmospheric Environment 11/2013; · 3.11 Impact Factor
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    ABSTRACT: Little evidence has been provided on the effects of the programme on public perceptions of heat waves and health behaviours. This study aimed to: (1) evaluate the impact of a heat wave warning system on public awareness of and responses to heat wave risk, (2) identify the factors affecting public awareness of heat wave risk, and (3) investigate whether public awareness of heat wave warnings contributes to increased health-protective behaviours. Using a stratified random sampling design, the residents of Seoul, the capital of South Korea, were surveyed via telephone. Data were collected in two campaigns. The total sample size was 2400 adults. Statistically significant changes were detected in the awareness of heat wave warnings and in the practice of health-protective behaviours. Awareness of heat wave warnings was an important factor in health-protective behaviours to reduce the risk of heat wave (odds ratio (OR), 1.50; 95% confidence interval (CI) 1.13–1.99). This study encourages future investigations of the role of public awareness of heat wave warnings in reducing risk behaviours using better analytical frameworks.
    Meteorological Applications 10/2013; · 1.32 Impact Factor
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    ABSTRACT: Antihypertensive medication treatment is one effective management strategy to prevent cardiovascular disease (CVD) and mortality. However, little research has been conducted on the rates of antihypertensive medication adherence and the effect of antihypertensive medication adherence on health outcomes in South Korea. We searched the Korean National Health Insurance Claims Database for records from 2003 to 2007. Patients in this study were 18 years of age or older and they were diagnosed with hypertension and newly prescribed antihypertensive medication in 2003. Adherence to antihypertensive medication was estimated as the medication possession ratio (MPR). Multivariate Cox regression was used to evaluate the association between medication adherence and adverse health outcomes after adjusting for patient demographics and clinical characteristics. Our study population consisted of 40 408 patients with a mean age of 51 years. Among the patients, 50.3% were men, 4.0% had Medicaid health insurance, 17.8% had diabetes, 20.9% had dyslipidemia and 42.4% were adherent (MPR 80%). Nonadherent patients (MPR<80%) were younger and more likely to have Medicaid health insurance; they had lower rates of diabetes and dyslipidemia compared with adherent patients. In the Cox multivariate analysis, nonadherence increased the risk of all adverse health outcomes, including all-cause mortality and hospitalization for CVD (hazard ratio: 1.57, confidence interval: 1.40-1.76). In conclusion, our study indicates that medication adherence is important for reducing hospitalization due to CVD and mortality.Hypertension Research advance online publication, 22 August 2013; doi:10.1038/hr.2013.85.
    Hypertension Research 08/2013; · 2.79 Impact Factor
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    ABSTRACT: We previously developed a model for projection of heat-related mortality attributable to climate change. The objective of this paper is to improve the fit and precision of and examine the robustness of the model. We obtained daily data for number of deaths and maximum temperature from respective governmental organizations of Japan, Korea, Taiwan, the USA, and European countries. For future projection, we used the Bergen climate model 2 (BCM2) general circulation model, the Special Report on Emissions Scenarios (SRES) A1B socioeconomic scenario, and the mortality projection for the 65+-year-old age group developed by the World Health Organization (WHO). The heat-related excess mortality was defined as follows: The temperature-mortality relation forms a V-shaped curve, and the temperature at which mortality becomes lowest is called the optimum temperature (OT). The difference in mortality between the OT and a temperature beyond the OT is the excess mortality. To develop the model for projection, we used Japanese 47-prefecture data from 1972 to 2008. Using a distributed lag nonlinear model (two-dimensional nonparametric regression of temperature and its lag effect), we included the lag effect of temperature up to 15 days, and created a risk function curve on which the projection is based. As an example, we perform a future projection using the above-mentioned risk function. In the projection, we used 1961-1990 temperature as the baseline, and temperatures in the 2030s and 2050s were projected using the BCM2 global circulation model, SRES A1B scenario, and WHO-provided annual mortality. Here, we used the "counterfactual method" to evaluate the climate change impact; For example, baseline temperature and 2030 mortality were used to determine the baseline excess, and compared with the 2030 excess, for which we used 2030 temperature and 2030 mortality. In terms of adaptation to warmer climate, we assumed 0 % adaptation when the OT as of the current climate is used and 100 % adaptation when the OT as of the future climate is used. The midpoint of the OTs of the two types of adaptation was set to be the OT for 50 % adaptation. We calculated heat-related excess mortality for 2030 and 2050. Our new model is considered to be better fit, and more precise and robust compared with the previous model.
    Environmental Health and Preventive Medicine 08/2013;
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    ABSTRACT: Mercury (Hg) is a nonessential and toxic metal that is widely distributed in the environment. This study was performed to estimate the representative blood Hg level, to determine the contributing factors to Hg exposure, and to analyze the association of blood Hg with metabolic syndrome in Korean adults. Mercury exposure is assessed by total Hg concentration in blood. A total of 2,114 healthy adults who have not been exposed to Hg occupationally were sampled by the multistaged, sex-, and age-stratified probability method. Information was collected regarding the subjects' demographic characteristics, lifestyles, and past medical history. The participants then underwent physical examination and blood sampling. The geometric mean concentration of Hg in whole blood was 3.90 μg/L, which was significantly influenced by sex, age, smoking, alcoholic consumption, residence area, and seafood intake after adjustment for confounders. Significant increases in body mass index, waist circumference, diastolic blood pressure, total cholesterol, and triglyceride were observed according to the blood Hg levels after adjustment for covariates. Also, Hg exposure was significantly associated with metabolic syndrome and their components such as obesity and increased fasting glucose. The blood Hg level in Korean adults is higher than that in USA and other Western countries, while it is similar to or lower than that in other Asian countries. The blood Hg level is influenced by sociodemographic factors and individual lifestyles including dietary habits. Furthermore, blood Hg is associated with metabolic syndrome, in which Hg exposure may play a role as a possible risk factor for cardiovascular diseases.
    International Archives of Occupational and Environmental Health 07/2013; · 2.10 Impact Factor
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    ABSTRACT: Lung cancer in never-smokers ranks as the seventh most common cause of cancer death worldwide, and the incidence of lung cancer in non-smoking Korean women appears to be steadily increasing. To identify the effect of genetic polymorphisms on lung cancer risk in non-smoking Korean women, we conducted a genome-wide association study of Korean female non-smokers with lung cancer. We analyzed 440,794 genotype data of 285 cases and 1,455 controls, and nineteen SNPs were associated with lung cancer development (P < 0.001). For external validation, nineteen SNPs were replicated in another sample set composed of 293 cases and 495 controls, and only rs10187911 on 2p16.3 was significantly associated with lung cancer development (dominant model, OR of TG or GG, 1.58, P = 0.025). We confirmed this SNP again in another replication set composed of 546 cases and 744 controls (recessive model, OR of GG, 1.32, P = 0.027). OR and P value in combined set were 1.37 and < 0.001 in additive model, 1.51 and < 0.001 in dominant model, and 1.54 and < 0.001 in recessive model. The effect of this SNP was found to be consistent only in adenocarcinoma patients (1.36 and < 0.001 in additive model, 1.49 and < 0.001 in dominant model, and 1.54 and < 0.001 in recessive model). Furthermore, after imputation with HapMap data, we found regional significance near rs10187911, and five SNPs showed P value less than that of rs10187911 (rs12478012, rs4377361, rs13005521, rs12475464, and rs7564130). Therefore, we concluded that a region on chromosome 2 is significantly associated with lung cancer risk in Korean non-smoking women.
    Journal of Korean medical science 06/2013; 28(6):840-7. · 0.84 Impact Factor
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    ABSTRACT: PURPOSE: The purpose of this study was to assess gender differences in dentofacial characteristics of adult patients according to temporomandibular joint (TMJ) disc displacement (DD) status. MATERIALS AND METHODS: The sample consisted of 293 adult patients (80 male and 213 female). Male and female patients were divided into 3 groups based on magnetic resonance images of bilateral TMJs: bilateral normal disc position (BN), bilateral DD with reduction (DDR), and bilateral DD without reduction (DDNR). Seventeen variables from lateral cephalograms were analyzed by 2-way analysis of variance to identify differences in dentofacial morphologies with respect to gender and TMJ DD status. RESULTS: Patients with TMJ DD had short ramus height, short mandibular body length, and backward positioning of the ramus and mandible. These dentofacial characteristics became more severe as TMJ DD progressed to DDNR. In addition, dentofacial characteristics associated with TMJ DD were not significantly different between men and women except for effective mandibular length (Articulare to pogonion). Effective mandibular length even tended to decrease as TMJ DD progressed, but male patients showed a larger difference in effective mandibular length between BN and DDR than female patients. CONCLUSIONS: This study's findings suggest that dentofacial morphology is strongly associated with TMJ DD status and that skeletal Class II hyperdivergent pattern with a short ramus and mandible may be a potential indicator of TMJ DD regardless of gender.
    Journal of oral and maxillofacial surgery: official journal of the American Association of Oral and Maxillofacial Surgeons 02/2013; · 1.58 Impact Factor
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    ABSTRACT: The aim of this study was to evaluate the role of polymorphisms of renin-angiotensin system (RAS) genes in modulating outdoor temperature-related blood pressure (BP) responses. Data for RAS gene polymorphisms, BP and outdoor temperature were collected from 4903 subjects from February 2003 to August 2004. Generalized additive and linear models were used to determine whether genetic variants of RAS affected the interplay between outdoor temperature and BP. Outdoor temperature (°C) was inversely associated with systolic BP and diastolic BP. These inverse relationships were stronger in subjects with ACE DD, AGT TT and AGTR1 AA genotypes. In contrast, significant positive temperature-dependent BP responses were found at temperatures above 21.4 °C in subjects with the AGTR1 C allele, but not at temperatures below 21.4 °C. Our findings suggest that subjects with ACE DD, AGT TT or AGTR1 AA genotypes are susceptible to cold temperature-induced BP increase, whereas subjects with AGTR1 C allele have a high risk of BP elevation when exposed to hot temperatures.Hypertension Research advance online publication, 7 February 2013; doi:10.1038/hr.2012.218.
    Hypertension Research 02/2013; · 2.79 Impact Factor
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    ABSTRACT: Anemia and vitamin D deficiency are both important health issues; however, the nature of the association between vitamin D and either hemoglobin or anemia remains unresolved in the general population. Data on 11,206 adults were obtained from the fifth Korean National Health and Nutritional Examination Survey. A generalized additive model was used to examine the threshold level for relationship between serum 25-hydroxyvitamin D [25(OH)D] and hemoglobin levels. A multivariate logistic regression for anemia was conducted according to 25(OH)D quintiles. All analyses were stratified according to sex and menstrual status. The generalized additive model confirmed a threshold 25(OH)D level of 26.4 ng/mL (male, 27.4 ng/mL; premenopausal females, 11.8 ng/mL; postmenopausal females, 13.4 ng/mL). The threshold level affected the pattern of association between 25(OH)D and anemia risk: the odds ratio of the 1(st) quintile but not the 2(nd), 3(rd), and 4(th) quintiles were significantly different from the 5(th) quintile in both premenopausal and postmenopausal females, however there was no obvious trend in males. This population-based study demonstrated a non-linear relationship with a threshold effect between serum 25(OH)D and hemoglobin levels in females. Further interventional studies are warranted to determine whether the appropriate level of hemoglobin can be achieved by the correction of vitamin D deficiency.
    PLoS ONE 01/2013; 8(8):e72605. · 3.73 Impact Factor
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    ABSTRACT: The timing of referral to a nephrologist may influence the outcome of chronic kidney disease patients, but its impact has not been evaluated thoroughly. The results of a recent study showing an association between early referral and patient survival are still being debated. A total of 1028 patients newly diagnosed as end-stage renal disease (ESRD) from July 2008 to October 2011 were enrolled. Early referral (ER) was defined as patients meeting with a nephrologist more than a year before dialysis and dialysis education were provided, and all others were considered late referral (LR). The relationship of referral pattern with mortality in ESRD patients was explored using a Cox proportional hazards regression models. Time from referral to dialysis was significantly longer in 599 ER patients than in 429 LR patients (62.3±58.9 versus 2.9±3.4 months, P<0.001). Emergency HD using a temporary vascular catheter was required in 485 (47.2%) out of all patients and in 262 (43.7%) of ER compared with 223 (52.0%) of LR (P = 0.009). After 2 years of follow-up, the survival rate in ER was better than that in LR (hazard ratio [HR] 2.38, 95% confidence interval [CI] 1.27-4.45, P = 0.007). In patients with diabetes nephropathy, patient survival was also significantly higher in ER than in LR (HR 4.74, 95% CI 1.73-13.00, P = 0.002). With increasing age, HR also increased. Timely referral to a nephrologist in the predialytic stage is associated with reduced mortality.
    PLoS ONE 01/2013; 8(1):e55323. · 3.73 Impact Factor
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    ABSTRACT: Several studies for health impacts of natural disasters have not been comprehensive with respect to disaster type and areas, nor quantitative. The aim of our study is to quantitatively examine the associations between disasters and human health in South Korea. This study considered "special disasters" that occurred from 2003 to 2009 in seven metropolitan cities and nine provinces in South Korea. First, we completed health impact counts in both disaster periods and reference periods. We then calculated the rate ratios between health impact counts in these two periods. Mortality is estimated to be higher in the case of typhoons, whereas morbidity is estimated to be higher in heavy rain disasters. The difference in health impacts of typhoons and heavy rain may be explained by the difference in meteorological exposure patterns. Consequentially, we suggest the development of properly adaptive plans against the influence of future natural disasters on human health.
    International Journal of Environmental Health Research 10/2012; · 1.20 Impact Factor

Publication Stats

1k Citations
300.87 Total Impact Points

Institutions

  • 2004–2014
    • Seoul National University
      • • Graduate School of Public Health
      • • Department of Dentistry
      • • School of Public Health
      • • Institute of Health and Environment
      • • Cancer Research Institute
      Sŏul, Seoul, South Korea
  • 2005–2012
    • Seoul National University Hospital
      • • Department of Surgery
      • • Department of Family Medicine
      Sŏul, Seoul, South Korea
  • 2011
    • Virginia Polytechnic Institute and State University
      • Department of Statistics
      Blacksburg, VA, United States
    • Ulsan University Hospital
      Urusan, Ulsan, South Korea
  • 2007–2009
    • University of Washington Seattle
      • Department of Environmental and Occupational Health Sciences
      Seattle, WA, United States
    • Ewha Womans University
      • Department of Preventive Medicine
      Sŏul, Seoul, South Korea
  • 2003–2009
    • Hanyang University
      • Department of Preventive Medicine
      Ansan, Gyeonggi, South Korea
    • Inha University Hospital
      Sinhyeon, South Gyeongsang, South Korea
  • 2008
    • MEDIPOST Biomedical Research Institute
      Sŏul, Seoul, South Korea