A set of exposure factors that reflects the characteristics of individual behavior capable of influencing exposure is essential for risk and exposure assessment. In 2007, the Korean Exposure Factors Handbook was, therefore, issued, driven by the need to develop reliable exposure factors representing the Korean population. The purpose of this study was to overview the development process of the Korean Exposure Factors Handbook and major recommended exposure values for the Korean population to allow information exchanges and comparison of recommended values among nations. The researchers reviewed the domestic data that could be used in the development of exposure factors, confirmed a knowledge gap, and set a priority of development by phases. A methodology to measure exposure factors was established to develop measuring techniques and test their validity. Data were processed or a survey was conducted according to the availability of data. The study thus produced recommended values for 24 exposure factors grouped by general exposure factors, food ingestion factors, and activity factors by setting up a database of exposure factors and carrying out statistical analysis. The study has significantly contributed to reducing the potential uncertainty of the risk and exposure assessment derived by the application of foreign data or research findings lacking representativeness or grounds by developing a set of exposure factors reflecting the characteristics of the Korean people. It will be necessary to conduct revisions in light of the changing statistical values of national data and the exposure factors based on Korean characteristics.
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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.
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The purpose of this study was to establish food ingestion factors needed to assess exposure to contaminants through food ingestion. The study reclassified the raw data of the Korean National Health and Nutrition Examination Survey in 2001 into 12 subcategories including grain products, meat products, fish and shellfish, and vegetables for international comparability of exposure evaluation. The criteria for food intake calculation were unified according to the characteristics of food groups, and recommended values for food ingestion factors were calculated through moisture correction and recategorization of cooked, processed, and mixed foods for each group. The average intake rate for grain and grain products was 6.25 g/kg-d per capita and the men's intake rate was approximately 8% higher than that of the women. The average intake rate of meat and meat products was 1.62 g/kg-d per capita and the men's intake rate was 30% higher than that of the women, on average. The average intake rate of fish and shellfish was 1.53 g/kg-d per capita, and the age groups of 1 to 2 and 3 to 6 recorded higher capita intake rates than other age groups, 2.62 g/kg-d and 2.25 g/kg-d, respectively. The average intake rate of vegetables was 6.47 g/kg-d per capita, with the age group of 1 to 2 recording the highest per capita intake rate of 9.79 g/kg-d and that of 13 to 19 recording the lowest mean. The study also offers recommended values for food ingestion factors of other food groups by gender, age, and region. The food ingestion exposure factors will need future updates in consideration of ongoing changes in food consumption behavior.
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Exposure factors based on the Korean population are required for making appropriate risk assessment. It is expected that handbooks for exposure factors will be applied in many fields, as well as by health department risk assessors. The present article describes the development of an exposure factors handbook that specifically focuses on human activities in situations involving the possible risk of exposure to environmental contaminants. We define majour exposure factors that represent behavioral patterns for risk assessment, including time spent on routine activities, in different places, on using transportation, and engaged in activities related to water contact including swimming, bathing and washing. Duration of residence and employment are also defined. National survey data were used to identify recommended levels of exposure factors in terms of time spent on routine activities and period of residence and employment. An online survey was conducted with 2073 subjects who were selected using a stratified random sampling method in order to develop a list of exposure factors for the time spent in different places and in performing water-related activities. We provide the statistical distribution of the variables, and report reference levels of average exposure based on the reliable data in our exposure factors handbook.
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To evaluate the association between fracture risk and levothyroxine use in elderly women with hypothyroidism, according to previous osteoporosis history.
We conducted a cohort study from the Korean Health Insurance Review and Assessment Service claims database from January 2005 to June 2006. The study population comprised women aged ≥65 years who had been diagnosed with hypothyroidism and prescribed levothyroxine monotherapy. We excluded patients who met any of the following criteria: previous fracture history, hyperthyroidism, thyroid cancer, or pituitary disorder; low levothyroxine adherence; or a follow-up period <90 days. We categorized the daily levothyroxine doses into 4 groups: ≤50 µg/d, 51 to 100 µg/d, 101 to 150 µg/d, and >150 µg/d. The hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated with the Cox proportional hazard model, and subgroup analyses were performed according to the osteoporosis history and osteoporosis-specific drug prescription status.
Among 11 155 cohort participants, 35.6% had previous histories of osteoporosis. The adjusted HR of fracture for the >150 µg/d group, compared with the 51 to 100 µg/d group, was 1.56 (95% CI, 1.03 to 2.37) in osteoporosis subgroup. In the highly probable osteoporosis subgroup, restricted to patients who were concurrently prescribed osteoporosis-specific drugs, the adjusted HR of fracture for the >150 µg/d group, compared with the 51 to 100 µg/d group, was 1.93 (95% CI, 1.14 to 3.26).
While further studies are needed, physicians should be concerned about potential levothyroxine overtreatment in elderly osteoporosis patients.
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The purpose of this study was to investigate the current status of and problems with the Safe Community Programs in Gangbuk-gu, one of the 25 districts of the capital city of Korea.
The study subjects were 396 individuals who were involved in Safe Community Programs between 2009 and 2011. We examined the effectiveness and willingness of respondents to participate as a safety leader of the Safe Community Program with a questionnaire. We examined the injury death rates of Gangbuk-gu by using of the death certificate data of Korea's National Statistical Office. Descriptive statistics and chi-squared tests were used.
The effectiveness of programs did not differ but active participation differed significantly among subjects (
This study suggests that the lack of active participation may be a major problem of Safe Community Programs in Gangbuk-gu. Therefore, Safe Community Programs should be expanded to the entire district of Gangbuk-gu and more active participation programs should be developed.
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We established a Wistar rat model of asthma caused by toluene diisocyanate (TDI) exposure, and investigated the relationship between TDI exposure concentrations and respiratory hypersensitivity, airway inflammation, and cytokine secretions in animals, to better understand the mechanism of TDI induced occupational asthma.
Wistar rats were exposed to two different concentrations of TDI vapor four hours a day for five consecutive days. Bronchoalveolar lavage (BAL) was performed, and differential leucocytes from the BAL fluid were analyzed. Lung histopathological examination was carried out to investigate the inflammatory status in the airways. Production of cytokines interleukin (IL)-4 and IL-5 productions in the BAL fluid
The TDI-exposed rats exhibited greater airway hypersensitivity symptoms than the control rats. The BAL differential cell count and lung histopathological examination demonstrated that inflammation reactions were present in both the central and peripheral airways, characterized with marked infiltration of eosinophils in the TDI-exposed rats. The cytokine assay showed that IL-4 and IL-5 were predominantly produced in the BAL fluid
These findings imply that TDI exposure concentrations may greatly affect the occurrence and extent of inflammatory events and that Th2 type cytokines may play an important role in the immunopathogenesis of TDI-induced occupational respiratory hypersensitivity.
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Physical activity behavior begins to decline during adolescence and continues to decrease throughout young adulthood. This study aims to explain factors that influence physical activity behavior in a sample of female adolescents using a health promotion model framework.
This cross-sectional survey was used to explore physical activity behavior among a sample of female adolescents. Participants completed measures of physical activity, perceived self-efficacy, self-esteem, social support, perceived barriers, and perceived affect. Interactions among the variables were examined using path analysis within a covariance modeling framework.
The final model accounted for an R2 value of 0.52 for physical activity and offered a good model-data fit. The results indicated that physical activity was predicted by self-esteem (β=0.46,
The findings of this study showed that the health promotion model was useful to predict physical activity behavior among the Iranian female adolescents. Information related to the predictors of physical activity behavior will help researchers plan more tailored culturally relevant health promotion interventions for this population.
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