Comparison of Long Term Follow-up Chest CT Imaging in Adult and Pediatric Patients with Humidifier Disinfectant-related Lung Injury

Background@#To compare the chest computed tomography (CT) images of children and adults in families with clusters of humidifier disinfectant-related lung injury (HDLI) after cessation of exposure to humidifier disinfectant (HD). @*Methods@#We reviewed medical records of 19 families with 43 patients (21 adults, 22 children) among families, which had at least one adult and one child with HDLI. Each family was exposed to the same HD exposure environment. @*Results@#In adults, centrilobular nodules were predominant (95.2%) in chronic HDLI findings after cessation of exposure to HD, however, in children, normal pattern was most prevalent on chest CT (45.5%), followed by centrilobular nodule (36.4%), bizarre lung cysts (36.4%), and reticulation (13.6%). @*Conclusion@#Unlike the known chronic HDLI finding of adults, centrilobular nodules were only present in 36.4% of children. The frequency of bizarre lung cysts were significantly greater in children than that in adults after cessation of similar exposure to HD. Thus, bizarre lung cysts may be useful as another novel finding of chronic HDLI in children who have no history of pulmonary infection or other perinatal disorder such as hyaline membrane disease or other interstitial lung disease.

The relationship between precarious employment and subjective well-being in Korean wage workers through the Cantril ladder Scale

Background@#The global labor market is moving towards increasing job instability. Relatively few studies have examined the relationship between precarious employment and subjective well-being using quantitative scales. We evaluated the association between wage workers' employment status and their subjective well-being through the Cantril ladder scale using Korean Welfare Panel Survey data (KOWEPS). @*Methods@#This study used KOWEPS data. A total of 4,423 wage workers were divided into permanently employed workers, temporarily employed workers and daily employed workers.The relationship between precarious employment and subjective well-being was analyzed by multiple linear regression adjusted for potential confounding factors. @*Results@#The more unstable the employment status, the lower the subjective well-being, which can be expressed by the Cantril ladder scale. The mean score of both temporarily employed and daily employed workers were statistically significantly lower (B = −0.454, p < 0.001; B = −0.994, p < 0.001, respectively) than permanently employed workers. This appeared to be the same when occupational and sociodemographic factors were adjusted (B = −0.153, p = 0.002 for temporarily employed, B = −0.610, p < 0.001 for daily employed). @*Conclusions@#The more unstable the employment status, the lower the subjective well-being score according to the Cantril ladder scale.

Longitudinal associations between occupational stress and depressive symptoms

Background@#Most of the studies that have examined the association between the sub-factors of occupational stress and depressive symptoms have used cross-sectional data. However, our study has longitudinally measured the occupational stress and depressive symptoms of Korean workers of a semiconductor manufacturing company across six years to intending to investigate the associations between the sub-factors of occupational stress and depressive symptoms using longitudinal data. @*Methods@#Data collected from the workers of a semiconductor manufacturing company.Out of 1,013 recruited workers, 405 (40.0%) completed the survey questionnaires at 3 and 6-year follow-ups. Occupational stress was measured using a shorter version of the Korean Occupational Stress Scale (KOSS), whereas depressive symptoms were assessed using the Korean version of the Center for Epidemiological Studies-Depressive Symptoms Scale (CES-D). The data of male and female participants independently analyzed. Longitudinal associations were analyzed using panel data analysis with fixed effects. @*Results@#In panel data analysis with fixed effects, job insecurity (B = 0.048, p-value = 0.004) was associated with depressive symptoms among male workers. In female workers, inadequate social support (B = 0.080, p-value < 0.001), job insecurity (B = 0.039, p-value = 0.004), lack of reward (B = 0.059, p-value = 0.004) and discomfort in occupational climate (B = 0.074, p-value < 0.001) were associated with depressive symptoms among female workers. @*Conclusions@#Temporal changes in the sub-factors of occupational stress were associated with changes in depressive symptoms within the same period. There was a gender difference in occupational stress sub-factors related to depressive symptoms.

The relationship between precarious employment and subjective well-being in Korean wage workers through the Cantril ladder Scale

Background@#The global labor market is moving towards increasing job instability. Relatively few studies have examined the relationship between precarious employment and subjective well-being using quantitative scales. We evaluated the association between wage workers' employment status and their subjective well-being through the Cantril ladder scale using Korean Welfare Panel Survey data (KOWEPS). @*Methods@#This study used KOWEPS data. A total of 4,423 wage workers were divided into permanently employed workers, temporarily employed workers and daily employed workers.The relationship between precarious employment and subjective well-being was analyzed by multiple linear regression adjusted for potential confounding factors. @*Results@#The more unstable the employment status, the lower the subjective well-being, which can be expressed by the Cantril ladder scale. The mean score of both temporarily employed and daily employed workers were statistically significantly lower (B = −0.454, p < 0.001; B = −0.994, p < 0.001, respectively) than permanently employed workers. This appeared to be the same when occupational and sociodemographic factors were adjusted (B = −0.153, p = 0.002 for temporarily employed, B = −0.610, p < 0.001 for daily employed). @*Conclusions@#The more unstable the employment status, the lower the subjective well-being score according to the Cantril ladder scale.

Longitudinal associations between occupational stress and depressive symptoms

Background@#Most of the studies that have examined the association between the sub-factors of occupational stress and depressive symptoms have used cross-sectional data. However, our study has longitudinally measured the occupational stress and depressive symptoms of Korean workers of a semiconductor manufacturing company across six years to intending to investigate the associations between the sub-factors of occupational stress and depressive symptoms using longitudinal data. @*Methods@#Data collected from the workers of a semiconductor manufacturing company.Out of 1,013 recruited workers, 405 (40.0%) completed the survey questionnaires at 3 and 6-year follow-ups. Occupational stress was measured using a shorter version of the Korean Occupational Stress Scale (KOSS), whereas depressive symptoms were assessed using the Korean version of the Center for Epidemiological Studies-Depressive Symptoms Scale (CES-D). The data of male and female participants independently analyzed. Longitudinal associations were analyzed using panel data analysis with fixed effects. @*Results@#In panel data analysis with fixed effects, job insecurity (B = 0.048, p-value = 0.004) was associated with depressive symptoms among male workers. In female workers, inadequate social support (B = 0.080, p-value < 0.001), job insecurity (B = 0.039, p-value = 0.004), lack of reward (B = 0.059, p-value = 0.004) and discomfort in occupational climate (B = 0.074, p-value < 0.001) were associated with depressive symptoms among female workers. @*Conclusions@#Temporal changes in the sub-factors of occupational stress were associated with changes in depressive symptoms within the same period. There was a gender difference in occupational stress sub-factors related to depressive symptoms.

Relationship between occupational sunlight exposure and the incidence of renal cancer

BACKGROUND: The risk factors for renal cancer include smoking, obesity, hypertension, and exposure to trichloroethylene. Recent studies have shown that low sunlight exposure increases the risk of developing a range of cancers, including renal cancer. Given that most of the daytime is spent at work, a lack of occupational sunlight exposure can be a risk factor for renal cancer. Therefore, this study examined the relationship between occupational sunlight exposure and the incidence of renal cancer. METHODS: This was a university hospital-based case-control study on renal cancer. Of the 706 newly diagnosed patients with renal cell carcinoma (RCC), 633 cases were selected; 73 who had no occupational history were excluded. In addition, 633 controls were selected from the general population after 1:1 matching with respect to sex, age (within 5 years), and residential area (constituency-level). Information on sunlight exposure by the occupational group was referred to data from France. To estimate the association between occupational sunlight exposure and the RCC risk, the odds ratios (ORs) were calculated using conditional logistic regression analysis. RESULTS: Sunlight exposure was divided into quartiles and the risk of RCC was analyzed. The adjusted OR of RCC (OR: 0.664, 95% confidence interval: 0.449–0.983) was significantly lower for the Q4 group than Q1 group but the Q2 and Q3 groups did not show significant results. The risk of RCC tended to decrease with increasing exposure to sunlight (p for trend < 0.028). CONCLUSIONS: Higher occupational sunlight exposure reduces the risk of RCC.

Satisfaction with life and the risk of occupational injury

BACKGROUND: Occupational injuries increase burden on society as well as personal health. Low satisfaction with life may not only increases the risk of occupational injuries directly, but also influences other factors that increase the risk of occupational injury. Along with previous studies on the risk of occupational injury, we sought to explore the relationship between satisfaction with life and occupational injury. METHODS: The study participants were 6234workers health screened at a university hospital in Incheon. Information on occupational injury and satisfaction with life scale (SWLS) was obtained in a self-report format. Participants were allocated to one of four SWLS groups; the dissatisfied group, the slightly dissatisfied group, the slightly satisfied group, and the satisfied group. The analysis was performed using the chi-square test primarily and by logistic regression adjusted for potential confounders. RESULTS: In men, the un-adjusted and adjusted odds ratios (ORs) of low satisfaction with life (SWLS< 20) were 1.98(CI1.55–2.53) and 1.81(CI 1.41–2.32), respectively. When the SWLS were divided into four groups, the adjusted ORs of the slightly satisfied (20–25), slightly dissatisfied(15–19), and dissatisfied(≤14) groups were 1.21, 1.72, and 2.70, respectively. That is ORs tended to increase linearly with decreasing SWLS score (p for trend < 0.001). In women, this relation was of borderline significance at best. When subjects were dichotomized based on SWLS scores, for males, the cured and adjusted RRs of occupational injury in the low satisfaction with life group were1.91 (95% CI: 1.50–2.42) and 1.66 (95% CI: 1.30–2.13), and for females, the adjusted-RR was marginally significant (1.67; 95% CI: 0.93–2.99). When subjects were divided into four groups by SWLS scores, adjusted RRs tended to increase linearly with decreasing SWLS score for males (slightly satisfied: 1.18, 95% CI: 0.77–1.82; slightly dissatisfied: 1.65, 95% CI: 1.08–2.52; dissatisfied: 2.22, 95% CI: 1.44–3.42; p for trend < 0.001) and for females (slightly satisfied: 1.17, 95% CI: 0.42–3.30; slightly dissatisfied: 1.56, 95% CI: 0.56–4.36; dissatisfied: 2.38, 95% CI: 0.84–6.74; p for trend = 0.040). CONCLUSIONS: This study suggests that the risk of occupational injury was higher in workers not satisfied with life, and indicates attention to satisfaction with life may promote the health of workers.

Combined approaches using adverse outcome pathways and big data to find potential diseasesassociated with humidifier disinfectant

According to previous survey, about two million of people were expected to suffer from toxic effects due to humidifier disinfectant (HD), regardless of healing or not. Extremely small group are recognized as HDs’ victims. Up to now, previous research tried to focus on interstitial fibrosis on terminal bronchiole because it is specific finding, compared with other diseases. To figure out overall effects from HDs, we recommend adverse outcome pathways (AOPs) as new approach. Reactive oxygen species (ROS) generation, decreased T-cell and pro-inflammatory cytokine release from macrophage could be key events between the exposure to HDs and diseases. ROS generation, decreased cell and pro-inflammatory cytokine release from macrophage could be cause of interstitial fibrosis, pneumonia and many other diseases such as asthma, allergic rhinitis, allergic dermatitis, fetal death, premature baby, autoimmune disease, hepatic toxicity, renal toxicity, cancer, and so on. We predict potential disease candidate by AOPs. We can validate the real risk of the adverse outcome by epidemiologic and toxicologic study using big data such as National Health Insurance data and AOPs knowledge base. Application of these kinds of new methods can find the potential disease list from the exposure to HD.

Humidifier disinfectant-associated specific diseases should be called together as “humidifier disinfectant syndrome”

Humidifier disinfectant (HD) damage was terrible chemical damage caused by household goods that happened in only South Korea, but still very little is known in HD damage. Up to now, previous research tried to focus on interstitial fibrosis on terminal bronchioles and alveoli because it is a specific finding, compared with other diseases. To figure out whole effects from HDs, much epidemiologic and toxicologic research is underway. HDs were shown to give rise to typical toxicologic effects on various target organs, such as skin, conjunctiva, naval mucosa, bronchial mucosa, alveoli and so on, which shared common toxicological responses. On a specific target, specific toxicologic effects existed. Diverse diseases along exposure pathways can occur at the same time with a common toxicologic mechanism and cause of HDs, which can be called as HD syndrome. To gain stronger scientific evidence about it, further epidemiological and toxicological studies should be applied.

Combined approaches using adverse outcome pathways and big data to find potential diseases associated with humidifier disinfectant

According to previous survey, about two million of people were expected to suffer from toxic effects due to humidifier disinfectant (HD), regardless of healing or not. Extremely small group are recognized as HDs’ victims. Up to now, previous research tried to focus on interstitial fibrosis on terminal bronchiole because it is specific finding, compared with other diseases. To figure out overall effects from HDs, we recommend adverse outcome pathways (AOPs) as new approach. Reactive oxygen species (ROS) generation, decreased T-cell and pro-inflammatory cytokine release from macrophage could be key events between the exposure to HDs and diseases. ROS generation, decreased cell and pro-inflammatory cytokine release from macrophage could be cause of interstitial fibrosis, pneumonia and many other diseases such as asthma, allergic rhinitis, allergic dermatitis, fetal death, premature baby, autoimmune disease, hepatic toxicity, renal toxicity, cancer, and so on. We predict potential disease candidate by AOPs. We can validate the real risk of the adverse outcome by epidemiologic and toxicologic study using big data such as National Health Insurance data and AOPs knowledge base. Application of these kinds of new methods can find the potential disease list from the exposure to HD.

Lung Cancer Risk and Residential Exposure to Air Pollution: A Korean Population-Based Case-Control Study

PURPOSE: To investigate the association between long-term exposure to ambient air pollution and lung cancer incidence in Koreans. MATERIALS AND METHODS: This was a population-based case-control study covering 908 lung cancer patients and 908 controls selected from a random sample of people within each Korean province and matched according to age, sex, and smoking status. We developed land-use regression models to estimate annual residential exposure to particulate matter (PM₁₀) and nitrogen dioxide (NO₂) over a 20-year exposure period. Logistic regression was used to estimate odds ratios (ORs) and their corresponding 95% confidence intervals (CI). RESULTS: Increases in lung cancer incidence (expressed as adjusted OR) were 1.09 (95% CI: 0.96−1.23) with a ten-unit increase in PM₁₀ (µg/m³) and 1.10 (95% CI: 1.00−1.22) with a ten-unit increase in NO₂ (ppb). Tendencies for stronger associations between air pollution and lung cancer incidence were noted among never smokers, among those with low fruit consumption, and among those with a higher education level. Air pollution was more strongly associated with squamous cell and small cell carcinomas than with adenocarcinoma of the lung. CONCLUSION: This study provides evidence that PM₁₀ and NO₂ contribute to lung cancer incidence in Korea.

Public-health impact of outdoor air pollution for 2nd air pollution management policy in Seoul metropolitan area, Korea

OBJECTIVES: Air pollution contributes to mortality and morbidity. We estimated the impact of outdoor air pollution on public health in Seoul metropolitan area, Korea. Attributable cases of morbidity and mortality were estimated. METHODS: Epidemiology-based exposure-response functions for a 10 microg/m3 increase in particulate matter (PM(2.5) and PM(10)) were used to quantify the effects of air pollution. Cases attributable to air pollution were estimated for mortality (adults > or = 30 years), respiratory and cardiovascular hospital admissions (all ages), chronic bronchitis (all ages), and acute bronchitis episodes (< or =18 years). Environmental exposure (PM(2.5) and PM(10)) was modeled for each 3 km x 3 km. RESULTS: In 2010, air pollution caused 15.9% of total mortality or approximately 15,346 attributable cases per year. Particulate air pollution also accounted for: 12,511 hospitalized cases of respiratory disease; 20,490 new cases of chronic bronchitis (adults); 278,346 episodes of acute bronchitis (children). After performing the 2nd Seoul metropolitan air pollution management plan, the reducible death number associated with air pollution is 14,915 cases per year in 2024. We can reduce 57.9% of death associated with air pollution. CONCLUSION: This assessment estimates the public-health impacts of current patterns of air pollution. Although individual health risks of air pollution are relatively small, the public-health consequences are remarkable. Particulate air pollution remains a key target for public-health action in the Seoul metropolitan area. Our results, which have also been used for economic valuation, should guide decisions on the assessment of environmental health-policy options.

A meta-analysis of exposure to particulate matter and adverse birth outcomes

OBJECTIVES: The objective of this study was to conduct a systematic review to provide summarized evidence on the association between maternal exposure to particulate air pollution and birth weight (BW) and preterm birth (PTB) after taking into consideration the potential confounding effect of maternal smoking. METHODS: We systematically searched all published cohort and case-control studies examining BW and PTB association with particulate matter (PM, less than or equal to 2.5μm and 10.0 μm in diameter, PM₂.₅ and PM₁₀, respectively) from PubMed and Web of Science, from January 1980 to April 2015. We extracted coefficients for continuous BW and odds ratio (OR) for PTB from each individual study, and meta-analysis was used to combine the coefficient and OR of individual studies. The methodological quality of individual study was assessed using a standard protocol proposed by Downs and Black. Forty-four studies met the inclusion criteria. RESULTS: In random effects meta-analyses, BW as a continuous outcome was negativelyassociated with 10 μg/m³ increase in PM₁₀ (-10.31 g; 95% confidence interval [CI], -13.57 to -3.13 g; I-squared=0%, p=.947) and PM₂.₅ (-22.17 g; 95% CI, -37.93 to -6.41 g; I-squared=92.3%, p<0.001) exposure during entire pregnancy, adjusted for maternal smoking. A significantly increased risk of PTB per 10 μg/m³ increase in PM₁₀ (OR, 1.23; 95% CI, 1.04 to 1.41; I-squared=0%, p=0.977) and PM2.5 (OR, 1.14; 95% CI, 1.06 to 1.22; I-squared=92.5%, p<0.001) exposure during entire pregnancy was observed. Effect size of change in BW per 10 μg/m³ increase in PM tended to report stronger associations after adjustment for maternal smoking. CONCLUSIONS: While this systematic review supports an adverse impact of maternal exposure to particulate air pollution on birth outcomes, variation in effects by exposure period and sources of heterogeneity between studies should be further explored.

A meta-analysis of exposure to particulate matter and adverse birth outcomes

OBJECTIVES: The objective of this study was to conduct a systematic review to provide summarized evidence on the association between maternal exposure to particulate air pollution and birth weight (BW) and preterm birth (PTB) after taking into consideration the potential confounding effect of maternal smoking. METHODS: We systematically searched all published cohort and case-control studies examining BW and PTB association with particulate matter (PM, less than or equal to 2.5μm and 10.0 μm in diameter, PM₂.₅ and PM₁₀, respectively) from PubMed and Web of Science, from January 1980 to April 2015. We extracted coefficients for continuous BW and odds ratio (OR) for PTB from each individual study, and meta-analysis was used to combine the coefficient and OR of individual studies. The methodological quality of individual study was assessed using a standard protocol proposed by Downs and Black. Forty-four studies met the inclusion criteria. RESULTS: In random effects meta-analyses, BW as a continuous outcome was negativelyassociated with 10 μg/m³ increase in PM₁₀ (-10.31 g; 95% confidence interval [CI], -13.57 to -3.13 g; I-squared=0%, p=.947) and PM₂.₅ (-22.17 g; 95% CI, -37.93 to -6.41 g; I-squared=92.3%, p<0.001) exposure during entire pregnancy, adjusted for maternal smoking. A significantly increased risk of PTB per 10 μg/m³ increase in PM₁₀ (OR, 1.23; 95% CI, 1.04 to 1.41; I-squared=0%, p=0.977) and PM2.5 (OR, 1.14; 95% CI, 1.06 to 1.22; I-squared=92.5%, p<0.001) exposure during entire pregnancy was observed. Effect size of change in BW per 10 μg/m³ increase in PM tended to report stronger associations after adjustment for maternal smoking. CONCLUSIONS: While this systematic review supports an adverse impact of maternal exposure to particulate air pollution on birth outcomes, variation in effects by exposure period and sources of heterogeneity between studies should be further explored.

Computation of geographic variables for air pollution prediction models in South Korea

Recent cohort studies have relied on exposure prediction models to estimate individual-level air pollution concentrations because individual air pollution measurements are not available for cohort locations. For such prediction models, geographic variables related to pollution sources are important inputs. We demonstrated the computation process of geographic variables mostly recorded in 2010 at regulatory air pollution monitoring sites in South Korea. On the basis of previous studies, we finalized a list of 313 geographic variables related to air pollution sources in eight categories including traffic, demographic characteristics, land use, transportation facilities, physical geography, emissions, vegetation, and altitude. We then obtained data from different sources such as the Statistics Geographic Information Service and Korean Transport Database. After integrating all available data to a single database by matching coordinate systems and converting non-spatial data to spatial data, we computed geographic variables at 294 regulatory monitoring sites in South Korea. The data integration and variable computation were performed by using ArcGIS version 10.2 (ESRI Inc., Redlands, CA, USA). For traffic, we computed the distances to the nearest roads and the sums of road lengths within different sizes of circular buffers. In addition, we calculated the numbers of residents, households, housing buildings, companies, and employees within the buffers. The percentages of areas for different types of land use compared to total areas were calculated within the buffers. For transportation facilities and physical geography, we computed the distances to the closest public transportation depots and the boundary lines. The vegetation index and altitude were estimated at a given location by using satellite data. The summary statistics of geographic variables in Seoul across monitoring sites showed different patterns between urban background and urban roadside sites. This study provided practical knowledge on the computation process of geographic variables in South Korea, which will improve air pollution prediction models and contribute to subsequent health analyses.

Computation of geographic variables for air pollution prediction models in South Korea

Recent cohort studies have relied on exposure prediction models to estimate individual-level air pollution concentrations because individual air pollution measurements are not available for cohort locations. For such prediction models, geographic variables related to pollution sources are important inputs. We demonstrated the computation process of geographic variables mostly recorded in 2010 at regulatory air pollution monitoring sites in South Korea. On the basis of previous studies, we finalized a list of 313 geographic variables related to air pollution sources in eight categories including traffic, demographic characteristics, land use, transportation facilities, physical geography, emissions, vegetation, and altitude. We then obtained data from different sources such as the Statistics Geographic Information Service and Korean Transport Database. After integrating all available data to a single database by matching coordinate systems and converting non-spatial data to spatial data, we computed geographic variables at 294 regulatory monitoring sites in South Korea. The data integration and variable computation were performed by using ArcGIS version 10.2 (ESRI Inc., Redlands, CA, USA). For traffic, we computed the distances to the nearest roads and the sums of road lengths within different sizes of circular buffers. In addition, we calculated the numbers of residents, households, housing buildings, companies, and employees within the buffers. The percentages of areas for different types of land use compared to total areas were calculated within the buffers. For transportation facilities and physical geography, we computed the distances to the closest public transportation depots and the boundary lines. The vegetation index and altitude were estimated at a given location by using satellite data. The summary statistics of geographic variables in Seoul across monitoring sites showed different patterns between urban background and urban roadside sites. This study provided practical knowledge on the computation process of geographic variables in South Korea, which will improve air pollution prediction models and contribute to subsequent health analyses.

Effect of Traffic-Related Air Pollution on Allergic Disease: Results of the Children's Health and Environmental Research

PURPOSE: This study evaluated the relationship of living near to main roads to allergic diseases, airway hyperresponsiveness (AHR), allergic sensitization, and lung function in Korean children. METHODS: A total of 5,443 children aged 6-14 years from 33 elementary schools in 10 cities during 2005-2006 were included in a baseline survey of the Children's Health and Environmental Research. We assessed association of traffic-related air pollution (TAP) exposure with the distance to the nearest main road, total road length of main roads and the proportion of the main road area within the 200-m home area. RESULTS: Positive exposure-response relationships were found between the length of the main road within the 200-m home area and lifetime wheeze (adjusted prevalence ratio [PR] for comparison of the longest to the shortest length categories=1.24; 95% CIs, 1.04-1.47; P for trend=0.022) and diagnosed asthma (PR=1.42; 95% CIs, 1.08-1.86; P for trend=0.011). Living less than 75 m from the main road was significantly associated with lifetime allergic rhinitis (AR), past-year AR symptoms, diagnosed AR, and treated AR. The distance to the main road (P for trend=0.001), the length of the main road (P for trend=0.041), and the proportion of the main road area (P for trend=0.006) had an exposure-response relationship with allergic sensitization. A strong inverse association was observed between residential proximity to the main load and lung function, especially FEV1, FEV1/FVC, and FEF25-75. The length of the main road and the proportion of the main road area were associated with reduced FEV1 in schoolchildren. CONCLUSIONS: The results of this study suggest that exposure to traffic-related air pollution may be associated with increased risk of asthma, AR, and allergic sensitization, and with reduced lung function in schoolchildren.

Increase of diesel car raises health risk in spite of recent development in engine technology

Diesel exhaust particles (DEP) contain elemental carbon, organic compounds including Polyaromatic hydrocarbons (PAHs), metals, and other trace compounds. Diesel exhaust is complex mixture of thousands of chemicals. Over forty air contaminants are recognized as toxicants, such as carcinogens. Most diesel exhaust particles have aerodynamic diameters falling within a range of 0.1 to 0.25 microm. DEP was classified as a definite human carcinogen (group 1) by the International Agency for Research on Cancer at 2012 based on recently sufficient epidemiological evidence for lung cancer. Significant decreases in DEP and other diesel exhaust constituents will not be evident immediately, and outworn diesel car having longer mileage still threatens health of people in spite of recent remarkable development in diesel engine technology. Policy change in South Korea, such as introduction of diesel taxi, may raise health risk of air pollution in metropolitan area with these limitations of diesel engine. To protect people against DEP in South Korea, progressive strategies are needed, including disallowance of diesel taxi, more strict regulation of diesel engine emission, obligatory diesel particulate filter attachment in outworn diesel car, and close monitoring about health effects of DEP.

The relationship between working condition factors and well-being

OBJECTIVES: Working conditions can exert influence on the physical, mental, and even social health of workers. Well-being is an appropriate index for the evaluation of a person's overall health. This paper investigated the association between various working conditions and worker's well-being. METHODS: Data from 10,019 interviews were collected from the second wave of the Korean Working Conditions Survey (2010) conducted by the Korea Occupational Safety and Health Agency between June and October 2010. The data from 5,995 employed workers were examined in this study. Well-being was measured through the WHO Five Well-Being Index (1998 version). Sociodemographic and working conditions were analyzed. Adjusted odds ratios for well-being were calculated with adjusted sociodemographic factors, working condition factors, or both. RESULTS: Workers' well-being was significantly higher when they were satisfied with their working conditions (OR = 1.656, 95% CI = 1.454-1.885), when their actual working hours were the same as their anticipated working hours (OR = 1.366, 95% CI: 1.120-1.666) or exceeding less than 10 hours (OR = 1.245, 95% CI: 1.004-1.543), and when their employment was stable (OR = 1.269, 95% CI: 1.098-1.467). CONCLUSIONS: This study supports the association between working condition factors and well-being in workers.

Work-relatedness of lung cancer by smoking and histologic type in Korea

OBJECTIVES: This study investigated the distribution of causative agents related to occupational lung cancer, their relationships with work, and associations between work-relatedness and the histologic type of lung cancer. METHODS: We used data from the occupational surveillance system in Korea in 2013. In addition, data from 1,404 participants diagnosed with lung cancer were collected through interviews. We included the patients' longest-held job in the analysis. Work-relatedness was categorized as "definite," "probable," "possible," "suspicious," "none," or "undetermined." RESULTS: Among the subjects, 69.3% were men and 30.7% were women. Regarding smoking status, current smokers were the most prevalent (35.5%), followed by non-smokers (32.3%), ex-smokers (32.2%). Regarding the causative agents of lung cancer, asbestos (1.0%) and crystalline silica (0.9%) were the most common in definite work-related cases, while non-arsenical insecticide (2.8%) was the most common in probable cases followed by diesel engine exhaust (1.9%) and asbestos (1.0%). Regarding histologic type, adenocarcinoma was the most common (41.7%), followed by squamous cell carcinoma (21.2%). Among current smokers, squamous cell carcinoma was the most common among definite and probable cases (13.4%), while non-small cell lung cancer was the least common (7.1%). Among non-smokers, squamous cell carcinoma was the most common (21.4%), while the least common was adenocarcinoma (1.6%). CONCLUSIONS: Approximately, 9.5% of all lung cancer cases in Korea are occupational-related lung cancer. Well-known substances associated with lung cancer, such as crystalline silica, asbestos, and diesel engine exhaust, are of particular concern. However, the histologic types of lung cancer related to smoking were inconsistent with previous studies when work-relatedness was taken into account. Future studies are required to clarify the incidence of occupational lung cancer in agricultural workers exposed to non-arsenical insecticides and the associations between work-relatedness and the histologic type of lung cancer.