Measuring the Environmental Burden of Disease in South Korea: A Population-Based Study.

BACKGROUND: This study attempted to measure the environmental burden of disease by examining mortality and disability rates in South Korea, permitting international comparisons. METHODS: Disability-adjusted life years (DALY) was used to analyze data from public records. Years of life lost (YLL) and years lost to disability (YLD) were measured in terms of incidence rate and number of deaths. Attributable risks were based on those for WHO Western Pacific Regions. For air pollution, attributable risk was calculated using local PM10 levels and relative risk. RESULTS: The total Korean environmental burden of disease was 17.98 per 1000 persons and the most serious risk factor was air pollution, at 6.89 per 1000 persons. Occupation was the second highest contributing factor, at 3.29 per 1000 persons, followed by indoor air pollution at 2.91 per 1000 persons. The DALY of air-pollution (indoor and outdoor) was 9.80 per 1000 persons, accounting for more than half of the total environmental burden of disease. The burden of chronic obstructive pulmonary disease, lung cancer, and asthma were 4.07, 3.16, and 1.96 per 1000 persons, respectively. CONCLUSIONS: Respiratory illnesses comprised most of the disease burden, the majority of which was linked to air pollution. The present results are important as they could be used to make evidence-based decisions regarding the management of diseases and environmental-risk factors.

Utilization of health insurance data in an environmental epidemiology.

OBJECTIVES: In South Korea, health insurance data are used as material for the health insurance of national whole subject. In general, health insurance data could be useful for estimating prevalence or incidence rate that is representative of the actual value in a population. The purpose of this study was to apply the concept of episode of care (EoC) in the utilization of health insurance data in the field of environmental epidemiology and to propose an improved methodology through an uncertainty assessment of disease course and outcome. METHODS: In this study, we introduced the concept of EoC as a methodology to utilize health insurance data in the field of environmental epidemiology. The characterization analysis of the course and outcome of applying the EoC concept to health insurance data was performed through an uncertainty assessment. RESULTS: The EoC concept in this study was applied to heat stroke (International Classification of Disease, 10th revision, code T67). In the comparison of results between before and after applying the EoC concept, we observed a reduction in the deviation of daily claims after applying the EoC concept. After that, we categorized context, model, and input uncertainty and characterized these uncertainties in three dimensions by using uncertainty typology. CONCLUSIONS: This study is the first to show the process of constructing episode data for environmental epidemiological studies by using health insurance data. Our results will help in obtaining representative results for the processing of health insurance data in environmental epidemiological research. Furthermore, these results could be used in the processing of health insurance data in the future.

Applying policy and health effects of air pollution in South Korea: focus on ambient air quality standards.

OBJECTIVES: South Korea's air quality standards are insufficient in terms of establishing a procedure for their management. The current system lacks a proper decision-making process and prior evidence is not considered. The purpose of this study is to propose a measure for establishing atmospheric environmental standards in South Korea that will take into consideration the health of its residents. METHODS: In this paper, the National Ambient Air Quality Standards (NAAQS) of the US was examined in order to suggest ways, which consider health effects, to establish air quality standards in South Korea. Up-to-date research on the health effects of air pollution was then reviewed, and tools were proposed to utilize the key results. This was done in an effort to ensure the reliability of the standards with regard to public health. RESULTS: This study showed that scientific research on the health effects of air pollution and the methodology used in the research have contributed significantly to establishing air quality standards. However, as the standards are legally binding, the procedure should take into account the effects on other sectors. Realistically speaking, it is impossible to establish standards that protect an entire population from air pollution. Instead, it is necessary to find a balance between what should be done and what can be done. CONCLUSIONS: Therefore, establishing air quality standards should be done as part of an evidence-based policy that identifies the health effects of air pollution and takes into consideration political, economic, and social contexts.

Exposure characteristics of familial cases of lung injury associated with the use of humidifier disinfectants.

BACKGROUND: This study describes 17 families with 38 lung injury patients (14 males, 24 females; 22 preschool-age children less than six years of age and 16 individuals of 13-50 years) who used disinfectant added to humidifiers in the home. METHODS: Clinical examination and humidifier disinfectant-use histories were taken, and a thorough home investigation was performed to assess exposure to humidifier disinfectant. RESULTS: Nine of the patients (three pregnant females, six preschool-age children) died soon after they first developed lung damage. Six (16%) were pregnant females and 22 (58%) were preschool-aged children younger than six years. The patients used humidifier disinfectant products containing either polyhexamethylene guanidine phosphate (PHMG, n = 36) or oligo(2-(2-ethoxy)ethoxyethyl guanidinium chloride (PGH, n = 2). Twenty-six patients (68%) used the brand "Oxy"®, which contains PHMG. Of the ten patients with fatal lung injury, nine were found to have used PHMG. CONCLUSIONS: Our findings suggest that the use of humidifier disinfectant products containing either PGH or PHMG can cause lung injury, especially in preschool-age children younger than six years and pregnant women.

Changes in the association between summer temperature and mortality in Seoul, South Korea.

The health impact of climate change depends on various conditions at any given time and place, as well as on the person. Temporal variations in the relationship between high temperature and mortality need to be explored in depth to explain how changes in the level of exposure and public health interventions modify the temperature-mortality relationship. We examined changes in the relationship between human mortality and temperature in Seoul, which has the highest population in South Korea, considering the change in population structure from 1993-2009. Poisson regression models were used to estimate short-term temperature-related mortality impacts. Temperature-related risks were divided into two "time periods" of approximately equal length (1993 and 1995-2000, and 2001-2009), and were also examined according to early summer and late summer. Temperature-related mortality in summer over the past 17 years has declined. These decreasing patterns were stronger for cardiovascular disease-related mortality than for all non-accidental deaths. The novel finding is that declines in temperature-related mortality were particularly noteworthy in late summer. Our results indicate that temperature-related mortality is decreasing in Seoul, particularly during late summer and, to a lesser extent, during early summer. This information would be useful for detailed public health preparedness for hot weather.

Impacts of typhoon and heavy rain disasters on mortality and infectious diarrhea hospitalization in South Korea.

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.

Policy Directions Addressing the Public Health Impact of Climate Change in South Korea: The Climate-change Health Adaptation and Mitigation Program.

Climate change, caused by global warming, is increasingly recognized as a major threat to mankind's survival. Climate change concurrently has both direct and modifying influences on environmental, social, and public health systems undermining human health as a whole. Environmental health policy-makers need to make use of political and technological alternatives to address these ramifying effects. The objective of this paper is to review public health policy in Korea, as well as internationally, particularly as it relates to climate change health adaptation and mitigation programs (such as C-CHAMP of Korea), in order to assess and elicit directions for a robust environmental health policy that is adaptive to the health impacts of climate change. In Korea, comprehensive measures to prevent or mitigate overall health effects are limited, and the diffusion of responsibility among various government departments makes consistency in policy execution very difficult. This paper proposes integration, synergy, and utilization as the three core principles of policy direction for the assessment and adaptation to the health impacts of climate change. For specific action plans, we suggest policy making based on scientifically integrated health impact assessments and the prioritization of environmental factors in climate change; the development of practical and technological tools that support policy decisions by making their political implementation more efficient; and customized policy development that deals with the vulnerability of local communities.

Serum concentrations of major perfluorinated compounds among the general population in Korea: dietary sources and potential impact on thyroid hormones.

Perfluorinated compounds (PFCs) have been frequently detected in both the environment and biota, and have become a growing concern. However, information is limited on the potential sources and human health implications of such exposure. We evaluated the exposure levels of 13 major PFCs among a population (n=633, >12 years of age) in a mid-sized city of Korea, and investigated for their potential dietary sources and the impact on thyroid hormone concentrations. For this purpose, we collected blood samples from a general population in Siheung, Korea and measured for 13 PFCs, total thyroxine (T4), and thyroid stimulating hormone (TSH). In addition, a questionnaire survey on diet was conducted. Perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorohexane sulfonic acid (PFHxS), and perfluorononanoic acid (PFNA) were detected in relatively greater concentrations than the other 9 PFCs in the blood serum. Males tend to have greater concentrations than females for most PFCs, and the concentrations were elevated as age increased up to 50s. Body mass index (BMI) was also shown to influence the serum concentrations of several PFCs. After adjustment for age, sex, and BMI, the consumption of vegetable, potato, fish/shellfish, and popcorn was identified to be significantly related with concentrations of major PFCs in blood. Among the studied PFCs, the concentrations of perfluorotridecanoic acid (PFTrDA) were negatively correlated with total T4, and positively with TSH levels, especially among females. The result of this study will provide information useful for developing public health and safety management measures for PFCs.

Distributed lag effects in the relationship between temperature and mortality in three major cities in South Korea.

In many cases, the effect of an environmental exposure event is not restricted to the period when it occurs. Understanding the extent to which high-temperature exposure hastens the occurrence of health outcomes is a key to interpreting public health risks correctly and developing appropriate intervention programs related to heat. We explored distributed lag effects in the relationship between high temperature and mortality in summer (June-August) in Seoul, Daegu, and Incheon, South Korea, from 1991 to 2008. A Poisson regression model adapted for time-series data was used to estimate short-term heat-related mortality impacts. To examine the distributed lag effects, we fitted a constrained distributed lag model that included lagged exposure variables as covariates, applying a function of days of lag according to B-spline bases. The effects on mortality caused by high-temperature exposure continued for about 5 days, and slight deficit effects after the initial mortality increases were observed, even if not initially apparent. Thirty days after high-temperature exposure, the cumulative effects were still high in Seoul and Incheon. This study shows a pattern of distributed lag effects of high-temperature exposure that the single-day model could not identify. Our results confirm that summer high temperature has an effect on mortality, not advancing the date of adverse events by a few days. Ultimately, it suggests that public health programs be amended to allow for differential high-temperature effects spread over multiple days.

Effect of previous-winter mortality on the association between summer temperature and mortality in South Korea.

BACKGROUND: It has recently been postulated that low mortality levels in the previous winter may increase the proportion of vulnerable individuals in the pool of people at risk of heat-related death during the summer months. OBJECTIVES: We explored the sensitivity of heat-related mortality in summer (June-August) to mortality in the previous winter (December-February) in Seoul, Daegu, and Incheon in South Korea, from 1992 through 2007, excluding the summer of 1994. METHODS: Poisson regression models adapted for time-series data were used to estimate associations between a 1 °C increase in average summer temperature (on the same day and the previous day) above thresholds specific for city, age, and cause of death, and daily mortality counts. Effects were estimated separately for summers preceded by winters with low and high mortality, with adjustment for secular trends. RESULTS: Temperatures above city-specific thresholds were associated with increased mortality in all three cities. Associations were stronger in summers preceded by winters with low versus high mortality levels for all nonaccidental deaths and, to a lesser extent, among persons ≥ 65 years of age. Effect modification by previous-winter mortality was not evident when we restricted deaths to cardiovascular disease outcomes in Seoul. CONCLUSIONS: Our results suggest that low winter all-cause mortality leads to higher mortality during the next summer. Evidence of a relation between increased summer heat-related mortality and previous wintertime deaths has the potential to inform public health efforts to mitigate effects of hot weather.

Relationship between winter temperature and mortality in Seoul, South Korea, from 1994 to 2006.

In South Korea, the mortality increases with temperature above a certain threshold during the warm season. In contrast, despite the common burden of cold weather, little is known about the effects of low temperatures on mortality. We evaluated the relationship between low temperatures and mortality in winter (December-February) in Seoul, South Korea, from 1994 to 2006. Data were obtained from government agencies. After adjusting for trends in time, day of the week, holidays, and relative humidity, we explored the associations between mortality and various cold indicators of winter in Seoul, South Korea. First, we fitted nonparametric smoothing regression models to check the shape of associations and then fitted threshold models (including two different slopes in a model) to estimate the thresholds and the effects of low temperatures using the Akaike Information Criterion (AIC). The graphical associations between cardiorespiratory, cardiovascular, and all causes of mortality and the cold wave index (CWI=T(min, previous day)-T(min, current day)) were observed. We confirmed the threshold according to a lag structure and after that, estimated the effects of CWI below the threshold, respectively. The effects of the daytime CWI lagged by 0-2 days were the strongest among those of the daytime CWI lagged by 0-6 days. The most significant mortality outcomes were cardiovascular-related. Although we could not consider respiratory-related mortality, the effect of CWI on cardiovascular-related mortality below a certain threshold was greater than cardiorespiratory-related or all cause-related mortality. In addition, the association between mortality and CWI was more immediate and vulnerable in an elderly subgroup (> or =65 years old) than in a younger subgroup (0-64 years old). Our results suggest that public health programs should be considered to alleviate not only the effect of sudden change in winter temperature on mortality.

The weather watch/warning system for stroke and asthma in South Korea.

Weather watch/warning systems have been established for human health outcomes. Our study aims to develop and demonstrate a weather watch/warning system for asthma and stroke within the whole of South Korea, using a stratified regression approach. We converted claim-based health insurance data covering almost all medical claims for the only health insurance system in Korea for asthma and stroke from 1996-2003 into personalized disease episode data, and combined them with meteorological data. We utilized a step-wise regression method using factors extracted from the meteorological data to develop stratified models for six (stroke) and nine (asthma) regional and day-of-week strata. Validation studies showed that the actual number of hospitalizations in 2003 increased according to the three-leveled predictions (levels I, II, and III) from the model based on the 1996-2002 data. This system is accessible via the internet (http://industry.kma.go.kr/APP/sub_APP15_H01.htm) at the Korean Meteorological Administration website.

High temperature, heat index, and mortality in 6 major cities in South Korea.

The authors conducted a time-series analysis to estimate the acute effects of high temperature in 6 cities in Korea and to compare thresholds of temperature on daily mortality among the cities. They examined the association between total mortality and the daily mean temperature and heat index during the summers in Korea from 1994 to 2003. The threshold temperature was estimated to be between 27.0 degrees C and 29.7 degrees C for 4 cities. For a daily mean temperature increase of 1 degrees C above the thresholds in Seoul, Daegu, Incheon, and Gwangju, estimated percentage increases in daily mortality were 16.3 (95% confidence interval [CI] = 14.2-18.4), 9.10 (CI = 5.12-13.2), 7.01 (CI = 4.42-9.66), and 6.73 (CI = 2.47-11.2), respectively. These city-specific threshold temperatures and the magnitude of the effects of hot temperature indicate that any analysis of the impact of climate change should take into account regional differences.