Jae-Yeon Jang

Biological exposure indices of organic solvents for Korean workers.

SummaryBiological exposure indices (BEIs) of toluene, perchloroethylene (PCE) and methyl ethyl ketone (MEK) for Korean workers were studied respectively. Exposure in workplace to organic solvents were measured by personal sampling. Blood toluene, blood PCE, urinary trichloroacetic acid and urinary MEK were determined by headspace GC. Urinary hippuric acid was determined by HPLC and corrected for creatinine. BEIs for Korean workers were calculated with the levels of the determinants corresponding to permissible exposure limits in Korea which were the same with TLV of ACGIH. Blood toluene level of 2.2 mg/l and urinary hippuric acid level of 1.7 g/g creatinine corresponded to exposure of 100 ppm toluene. Blood PCE concentration of 1.6 mg/l and urinary trichloroacetic acid concentration of 2.9 mg/l corresponded to exposure to 50 ppm PCE. Urinary MEK concentration of 1.4 mg/l corresponded to exposure to 200 ppm of MEK. In conclusion, BEIs for Korean workers determined in this study were different to ACGIHs BEI as urinary determinants were lower and blood determinants were higher than ACGIHs BEI.

Correlations Between Climate Change-Related Infectious Diseases and Meteorological Factors in Korea

OBJECTIVES Infectious diseases are known to be affected by climate change. We investigated if the infectious diseases were related to meteorological factors in Korea. METHODS Scrub typhus, hemorrhagic fever with renal syndrome (HFRS), leptospirosis, malaria and Vibrio vulnificus sepsis among the National Notifiable Infectious Diseases were selected as the climate change-related infectious diseases. Temperature, relative humidity and precipitation were used as meteorological factors. The study period was from 2001 through 2008. We examined the seasonality of the diseases and those correlations with meteorological factors. We also analyzed the correlations between the incidences of the diseases during the outbreak periods and monthly meteorological factors in the hyper-endemic regions. RESULTS All of the investigated diseases showed strong seasonality; malaria and V. vulnificus sepsis were prevalent in summer and scrub typhus, HFRS and leptospirosis were prevalent in the autumn. There were significant correlations between the monthly numbers of cases and all the meteorological factors for malaria and V. vulnificus sepsis, but there were no correlation for the other diseases. However, the incidence of scrub typhus in hyper-endemic region during the outbreak period was positively correlated with temperature and humidity during the summer. The incidences of HFRS and leptospirosis had positive correlations with precipitation in November and temperature and humidity in February, respectively. V. vulnificus sepsis showed positive correlations with precipitation in April/May/July. CONCLUSIONS In Korea, the incidences of the infectious diseases were correlated with meteorological factors, and this implies that the incidences could be influenced by climate change.

Investigation on Health Effects of an Abandoned Metal Mine

To investigate potential health risks associated with exposure to metals from an abandoned metal mine, the authors studied people living near an abandoned mine (n=102) and control groups (n=149). Levels of cadmium, copper, arsenic, lead, and zinc were measured in the air, soil, drinking water, and agricultural products. To assess individual exposure, biomarkers of each metal in blood and urine were measured. β2-microglobulin, α1-microglobulin, and N-acetyl-beta-glucosaminidase and bone mineral density were measured. Surface soil in the study area showed 2-10 times higher levels of metals compared to that of the control area. Metal concentrations in the groundwater and air did not show any notable differences between groups. Mean concentrations of cadmium and copper in rice and barley from the study area were significantly higher than those of the control area (p<0.05). Geometric means of blood and urine cadmium in the study area were 2.9 µg/L and 1.5 µg/g Cr, respectively, significantly higher than those in the control area (p<0.05). There were no differences in the levels of urinary markers of early kidney dysfunction and bone mineral density. The authors conclude that the residents near the abandoned mine were exposed to higher levels of metals through various routes.

Quantitative Exposure Assessment for Shipyard Workers Exposed to Hand-Transmitted Vibration From a Variety of Vibration Tools

The quantitative exposure to vibration for shipyard workers who have used several kinds of vibratory tools was studied. The dose-response relationship between lifetime exposure dose and hand-arm vibration syndrome also was studied. The study included 344 workers who were exposed to vibration in one shipyard and 53 unexposed workers in the same company. Vibration measurements were made on several vibratory tools according to the international standard, ISO 5349. The actual exposure times for the vibratory tools were measured. Questionnaires for demographics, exposure to vibration, and confounding factors were completed. A lifetime vibration dose was calculated for each worker using job categories, usage pattern of vibratory tools, and the measured vibration acceleration magnitude. Each worker was asked about vascular and neurological symptoms, and symptoms were classified according to the Stockholm workshop scale. The prevalence of vascular and sensorineural symptoms for workers exposed to vibration was 22.7 and 78.2%, which were significantly higher than 0 and 34.0% obtained in the nonexposed workers, respectively. The prevalence and severity of the hand-arm vibration syndrome was increased with an increased lifetime vibration dose. The lifetime vibration dose showed a significant association with both vascular and sensorineural symptoms. In conclusion, the lifetime vibration dose was a useful parameter for quantitative exposure assessment and showed a dose-response relationship between exposure and symptoms when adjusted for confounding factors.

Psychological Distress in Young Adult Males with Atopic Dermatitis: A Cross-Sectional Study

Abstract The relationship between atopic dermatitis (AD) and psychological distress has been well established for children and adolescents. However, it is unclear whether this relationship exists in young adults. This study aimed to assess the relationship between AD and psychological distress in young male adults in South Korea. A cross-sectional study was conducted using regional conscription data from 2008 to 2012. A dermatologist diagnosed AD based on historical and clinical features, and determined severity using the eczema area and severity index. A psychiatrist used medical records, an interview, and a psychological test to examine psychological distress (depression, anxiety, and somatization). The relationship between psychological distress and AD was assessed by multivariate logistic regression analyses. Among the 120,508 conscripts, 1517 (1.2%) presented with AD. The odds of having each type of psychological distress were significantly greater for individuals with AD compared with those without AD. The adjusted odds ratios for depression, anxiety, and somatization were 1.79 (95% CI 1.40–2.29), 1.38 (95% CI 1.08–1.76), and 1.75 (95% CI 1.40–2.20), respectively. Moderate-to-severe AD was significantly related to depression and somatization to a greater extent compared with mild AD. Depression, anxiety, and somatization are strongly and independently associated with AD in young adult males. Early treatment of skin inflammation might modify the risk of psychiatric problems. Prospective cohort studies are needed to verify causal relationships.

Simulation of Toluene in Venous Blood with a Physiologically Based Pharmacokinetic Model: Its Application to Biological Exposure Index Development

Abstract The recent reduction of the threshold limit value of the American Conference of Governmental Industrial Hygienists for toluene to 50 ppm called for a redefinition of the corresponding biological exposure indices (BEIs). The simulation model used in this study consists of seven compartments representing the different tissues. All simulations were done for a standard man (170 cm, 70 kg) exposed in standard working conditions (8 hours/day with a 1-hour break, 5 days/week). The comparison of the simulation results for several biological indicators with measurements in workers showed good agreement. The effects of confounding factors, such as exposure fluctuation, physical work load after exposure, and air contamination at the sampling site were also simulated. According to fluctuations of the exposure level within the exposure day, there were big differences in the venous blood toluene concentrations at the end of shift, but no difference in the venous blood toluene concentrations the next morning. T...

Impact of meteorological variation on hospital visits of patients with tree pollen allergy

BackgroundClimate change could affect allergic diseases, especially due to pollen. However, there has been no epidemiologic study to demonstrate the relationship between meteorological factors, pollen, and allergic patients. We aimed to investigate the association between meteorological variations and hospital visits of patients with tree pollen allergy.MethodsThe study subjects were adult patients who received skin prick tests between April and July from 1999 to 2008. We reviewed the medical records for the test results of 4,715 patients. Patients with tree pollen allergy were defined as those sensitized to more than 1 of 12 tree pollen allergens. We used monthly means of airborne tree pollen counts and meteorological factors: maximum/average/minimum temperature, relative humidity, and precipitation. We analyzed the correlations between meteorological variations, tree pollen counts, and the patient numbers. Multivariable logistic regression analyses were used to investigate the associations between meteorological factors and hospital visits of patients.ResultsThe minimum temperature in March was significantly and positively correlated with tree pollen counts in March/April and patient numbers from April through July. Pollen counts in March/April were also correlated with patient numbers from April through July. After adjusting for confounders, including air pollutants, there was a positive association between the minimum temperature in March and hospital visits of patients with tree pollen allergy from April to July(odds ratio, 1.14; 95% CI 1.03 to 1.25).ConclusionsHigher temperatures could increase tree pollen counts, affecting the symptoms of patients with tree pollen allergy, thereby increasing the number of patients visiting hospitals.

Causes of death and demographic characteristics of victims of meteorological disasters in Korea from 1990 to 2008

BackgroundMeteorological disasters are an important component when considering climate change issues that impact morbidity and mortality rates. However, there are few epidemiological studies assessing the causes and characteristics of deaths from meteorological disasters. The present study aimed to analyze the causes of death associated with meteorological disasters in Korea, as well as demographic and geographic vulnerabilities and their changing trends, to establish effective measures for the adaptation to meteorological disasters.MethodsDeaths associated with meteorological disasters were examined from 2,045 cases in Victim Survey Reports prepared by 16 local governments from 1990 to 2008. Specific causes of death were categorized as drowning, structural collapse, electrocution, lightning, fall, collision, landslide, avalanche, deterioration of disease by disaster, and others. Death rates were analyzed according to the meteorological type, specific causes of death, and demographic and geographic characteristics.ResultsDrowning (60.3%) caused the greatest number of deaths in total, followed by landslide (19.7%) and structural collapse (10.1%). However, the causes of deaths differed between disaster types. The meteorological disaster associated with the greatest number of deaths has changed from flood to typhoon. Factors that raised vulnerability included living in coastal provinces (11.3 times higher than inland metropolitan), male gender (1.9 times higher than female), and older age.ConclusionsEpidemiological analyses of the causes of death and vulnerability associated with meteorological disasters can provide the necessary information for establishing future adaptation measures against climate change. A more comprehensive system for assessing disaster epidemiology needs to be established.

Dependency on Smartphone Use and its Association with Anxiety in Korea

Objective. South Korea has the highest rate of smartphone ownership worldwide, which is a potential concern given that smartphone dependency may have deleterious effects on health. We investigated the relationship between smartphone dependency and anxiety. Methods. Participants included 1,236 smartphone-using students (725 men and 511 women) from six universities in Suwon, South Korea. Participants completed measures of smartphone use, smartphone dependency, anxiety, and general characteristics (i.e., demographic, health-related, and socioeconomic characteristics). To measure smartphone dependency and anxiety, we used questionnaires of Yangs test developed from Youngs Internet Addiction Test and Zungs Self-Rating Anxiety Scale. We used multiple logistic regression to determine the association between smartphone dependency and anxiety after adjusting for relevant factors. Results. On a scale from 25 to 100, with higher scores on the smartphone dependency test indicating greater dependency, women were significantly more dependent on smartphones than were men (mean smartphone dependency score: 50.7 vs. 56.0 for men and women, respectively, p<0.001). However, the amount of time spent using smartphones and the purpose of smartphone use affected smartphone dependency in both men and women. Particularly, when daily use time increased, smartphone dependency showed an increasing trend. Compared with times of use <2 hours vs. ≥6 hours, men scored 46.2 and 56.0 on the smartphone dependency test, while women scored 48.0 and 60.4, respectively (p<0.001). Finally, for both men and women, increases in smartphone dependency were associated with increased anxiety scores. With each one-point increase in smartphone dependency score, the risk of abnormal anxiety in men and women increased by 10.1% and 9.2%, respectively (p<0.001). Conclusion. Among this group of university students in South Korea, smartphone dependency appeared to be associated with increased anxiety. Standards for smartphone use might help prevent deleterious health effects.

General Factors of the Korean Exposure Factors Handbook

Risk assessment considers the situations and characteristics of the exposure environment and host. Various physiological variables of the human body reflects the characteristics of the population that can directly influence risk exposure. Therefore, identification of exposure factors based on the Korean population is required for appropriate risk assessment. It is expected that a handbook about general exposure factors will be used by professionals in many fields as well as the risk assessors of the health department. The process of developing the exposure factors handbook for the Korean population will be introduced in this article, with a specific focus on the general exposure factors including life expectancy, body weight, surface area, inhalation rates, amount of water intake, and soil ingestion targeting the Korean population. The researchers used national databases including the Life Table and the 2005 Time Use Survey from the National Statistical Office. The anthropometric study of size in Korea used the resources provided by the Korean Agency for Technology and Standards. In addition, direct measurement and questionnaire surveys of representative samples were performed to calculate the inhalation rate, drinking water intake, and soil ingestion.