Widening Social Inequalities in Cancer Mortality of Children Under 5 Years in Korea

Background@#To investigate the effect of parental social class on cancer mortality in children under 5 in Korea, two birth cohorts were constructed by linking national birth data to under-5 death data from the Statistics Korea for 1995–1999 (3,323,613 births) and 2010–2014 (2,297,876 births). @*Methods@#The Cox proportional hazards model adjusted for covariates was used in this study. @*Results@#Social inequalities of under-5 cancer mortality risk in paternal education and paternal employment status were greater in 2010–2014 than in 1995–1999. The gap of hazard ratio (HR) of under-5 cancer mortality between lower (high school or below) and higher (university or higher) paternal education increased from 1.23 (95% confidence interval, 1.041.46) in 1995–1999 to 1.45 (1.11–1.97) in 2010–2014; the gap of HR between parents engaged in manual work and non-manual work increased from 1.32 (1.12–1.56) in 1995–1999 to 1.45 (1.12–1.89) in 2010–2014 for fathers, and from 1.18 (0.7–1.98) to 1.69 (1.03–2.79) for mothers. When the parental social class was lower, the risk of under-5 cancer mortality was higher in not only adverse but normal births. @*Conclusion@#Social inequalities must be addressed to reduce the disparity in cancer mortality of children under 5 years old.

Association between organizational justice and depressive symptoms among securities company workers

BACKGROUND: The organizational justice model can evaluate job stressor from decision-making process, attitude of managerial or senior staff toward their junior workers, and unfair resource distribution. Stress from organizational injustice could be harmful to workers' mental health. The purpose of this study is to explore the association between organizational justice and depressive symptoms in a securities company. METHODS: To estimate organizational justice, a translated Moorman's organizational justice evaluation questionnaire (Korean) was employed. Cronbach's α coefficient was estimated to assess the internal consistency of the translated questionnaire. To assess depressive symptoms, the Center for Epidemiologic Studies Depression (CES-D) scale was used. The link between the sub-concepts of the organizational justice model and depressive symptoms was assessed utilizing multiple logistic regression models. RESULTS: The risk of depressive symptoms was significantly higher among workers with higher levels of all subcategory of organizational injustice. In the full adjusted model odds ratio (OR) of higher level of procedural injustice 2.79 (95% confidence interval [CI], 1.58–4.90), OR of the higher level of relational injustice 4.25 (95% CI, 2.66–6.78), OR of higher level of distributional injustice 4.53 (95% CI, 2.63–7.83) respectively. Cronbach's α coefficient of the Korean version was 0.93 for procedural justice, 0.93 for relational justice, and 0.95 for distributive justice. CONCLUSIONS: A higher level of organizational injustice was linked to higher prevalence of depressive symptoms among workers in a company of financial industry.

Association of discrimination and presenteeism with cardiovascular disease: the Fourth Korean Working Conditions Survey

BACKGROUND: Discrimination is a representative social determinant of health. Presenteeism is defined as presenting to work despite of illness and is an indicator of group health. We investigated the association of discrimination and presenteeism with cardiovascular disease using Korean data. METHODS: This study used the fourth Korea Working Conditions Survey (2014) data of 27,662 wage workers (employees). Presenteeism and discrimination related to age, sex, education, birth region, and employment type were ascertained. Self-reported cardiovascular disease was also assessed using the survey questionnaire. General and occupational characteristics found to be significant in univariate analyses were entered into a multivariate logistic regression analysis of the association of discrimination and presenteeism with cardiovascular disease. We also calculated the odds ratios of multiple discriminations and/or presenteeism for cardiovascular disease. RESULTS: In the univariate analyses, sex, age, education, monthly income, employment type, occupation, hours worked per week, workplace scale, and shift work were significantly associated with cardiovascular disease. A multivariate logistic regression analysis adjusted for general and occupational characteristics showed that discrimination and presenteeism were significantly associated with cardiovascular disease. Finally, the association with cardiovascular disease was strongest when both multiple discriminations and presenteeism were present. CONCLUSIONS: Discrimination and presenteeism are associated with cardiovascular disease, and this association was stronger in the presence of multiple types of discrimination and presenteeism.

Health effects of environmental pollution in population living near industrial complex areas in Korea

Several epidemiological studies have reported an association between environmental pollution and various health conditions in individuals residing in industrial complexes. To evaluate the effects of pollution from industrial complex on human health, we performed a pooled analysis of environmental epidemiologic monitoring data for residents living near national industrial complexes in Korea. The respiratory and allergic symptoms and the prevalence of acute and chronic diseases, including cancer, were used as the outcome variables for health effects. Multiple logistic regression analysis was used to analyze the relationship between exposure to pollution from industrial complexes and health conditions. After adjusting for age, sex, smoking status, occupational exposure, level of education, and body mass index, the residents near the industrial complexes were found to have more respiratory symptoms, such as cough (odds ratio [OR], 1.18; 95% confidence interval [CI], 1.06 to 1.31) and sputum production (OR, 1.13; 95% CI, 1.03 to 1.24), and symptoms of atopic dermatitis (OR, 1.10; 95% CI, 1.01 to 1.20). Among residents of the industrial complexes, the prevalence of acute eye disorders was approximately 40% higher (OR, 1.39; 95% CI, 1.04 to 1.84) and the prevalence of lung and uterine cancer was 3.45 times and 1.88 times higher, respectively, than those among residents of the control area. This study showed that residents living in the vicinity of industrial complexes have a high risk of acute and chronic diseases including respiratory and allergic conditions. These results can be used as basic objective data for developing health management measures for individuals residing near industrial complexes.

Health effects of environmental pollution in population living near industrial complex areas in Korea

Several epidemiological studies have reported an association between environmental pollution and various health conditions in individuals residing in industrial complexes. To evaluate the effects of pollution from industrial complex on human health, we performed a pooled analysis of environmental epidemiologic monitoring data for residents living near national industrial complexes in Korea. The respiratory and allergic symptoms and the prevalence of acute and chronic diseases, including cancer, were used as the outcome variables for health effects. Multiple logistic regression analysis was used to analyze the relationship between exposure to pollution from industrial complexes and health conditions. After adjusting for age, sex, smoking status, occupational exposure, level of education, and body mass index, the residents near the industrial complexes were found to have more respiratory symptoms, such as cough (odds ratio [OR], 1.18; 95% confidence interval [CI], 1.06 to 1.31) and sputum production (OR, 1.13; 95% CI, 1.03 to 1.24), and symptoms of atopic dermatitis (OR, 1.10; 95% CI, 1.01 to 1.20). Among residents of the industrial complexes, the prevalence of acute eye disorders was approximately 40% higher (OR, 1.39; 95% CI, 1.04 to 1.84) and the prevalence of lung and uterine cancer was 3.45 times and 1.88 times higher, respectively, than those among residents of the control area. This study showed that residents living in the vicinity of industrial complexes have a high risk of acute and chronic diseases including respiratory and allergic conditions. These results can be used as basic objective data for developing health management measures for individuals residing near industrial complexes.

Association between working time quality and self-perceived health: analysis of the 3rd Korean working conditions survey (2011)

BACKGROUND: Self-perceived health, a subjective assessment of one's health condition, is an important health indicator at the level of quality of life. In this study, working time quality refer to job factors with qualitative aspects of working time. This study was conducted to investigate the association between working time quality and self-perceived health in paid workers in Korea. METHODS: In this study, 35,902 paid workers were analyzed based on the 3rd Korean working conditions survey. For independent variables, working time quality (working at night, working in the evenings, working on Sundays, working on Saturdays, and working more than 10 h a day) were set as major job-related variables. Other occupational characteristics were divided into 6 groups and general characteristics were divided into 6 groups, and univariate analysis was conducted with self-perceived health, a dependent variable. Variables that had significance in the univariate analysis were used for multivariate logistic regression analysis. RESULTS: In the univariate analysis using Chi-square test, variables showing significance in self-perceived health were age, income, education, occupation, employment type, work hours per week, and shift work. Working time quality showed a significant association with self-perceived health. After adjusting for these variables using logistic regression analysis, working at night, working in the evening, working on Sundays, and working more than 10 h a day showed significant association with self-perceived health. CONCLUSIONS: This study showed a statistically significant association between working time quality of employees with self-perceived health.

IgA nephropathy in a laboratory worker that progressed to end-stage renal disease: a case report

BACKGROUND: IgA nephropathy (IgAN) is the most common form of glomerulonephritis, a principal cause of end-stage renal disease (ESRD) worldwide. The mechanisms of onset and progression of IgAN have not been fully revealed, and epidemiologic studies have yielded diverging opinions as to the role of occupational exposure to organic solvents in the initiation or worsening of IgAN. As the authors encountered a laboratory worker with IgAN that progressed to ESRD, we present a case report of IgAN progression due to dichloromethane exposure along with a review of literature. CASE PRESENTATION: A 41-year-old male laboratory worker began to experience gross painless hematuria after two years of occupational exposure to toluene. Although clinical follow-up was initiated under the impression of IgAN based on clinical findings, the patient continued to work for four more years in the same laboratory, during which he was in charge of laboratory analysis with direct exposure to a high concentration of dichloromethane without proper protective equipment. During that time, his renal function rapidly worsened and finally progressed to ESRD 10 years after the first clinical symptoms. The result of exposure assessment through reenactment of his work exceeded the occupational exposure limit for dichloromethane to a considerable degree. CONCLUSIONS: The causal association between occupational solvent exposure and IgAN is still unclear; therefore, this case report could be used as a basis to support the relevance of occupational solvent exposure to IgAN and/or its progression. Early intervention as well as close monitoring of laboratory workers exposed to various organic solvents is important to prevent or delay the progression of glomerulonephritis to ESRD in the occupational setting.

The association of relational and organizational job stress factors with sleep disorder: analysis of the 3rd Korean working conditions survey (2011)

BACKGROUND: Sleep disorder is a disease that causes reduction in quality of life and work efficiency of workers. This study was performed to investigate the relationship between job-related stress factor and sleep disorder among wageworkers in Korea. METHODS: This study was based on analysis of the 3rd Korean working conditions survey. We analyzed 35,902 workers whose employment status is wageworker. We classified the job-related stress factor into 12 sections. Logistic regression was performed to estimate the relationship between job-related stress factor and sleep disorder and Odds ratio and 95 % CI were calculated using the SPSS version 23.0 program. RESULTS: Many categories of Job-related stress factor were correlated with sleep disorder (8 of 12 for women, 10 of 12 for men). The results of the regression analysis, corrected for general and occupational characteristics, indicated that sleep disorder was significantly correlated with the following categories of job-related stress: discrimination experience (OR 3.37, 95 % CI = 2.49 ~ 4.56 in women, OR 1.96, 95 % CI = 1.53 ~ 2.51 in men), direct customer confrontation (OR 2.72, 95 % CI = 1.91 ~ 3.86 in women, OR 1.99, 95 % CI = 1.45 ~ 2.72 in men), emotional stress (OR 2.01, 95 % CI = 1.30 ~ 3.09 in men), work dissatisfaction (detailed) (OR 1.99, 95 % CI = 1.36 ~ 2.93 in men), work dissatisfaction (overall) (OR 2.30, 95 % CI = 1.66 ~ 3.20 in women, OR 2.40, 95 % CI = 1.88 ~ 3.08 in men), expression of opinion difficulty (OR 0.66, 95 % CI = 0.48 ~ 0.92 in women, OR 0.57, 95 % CI = 0.45 ~ 0.73 in men). CONCLUSION: A number of studies have reported that stress affects sleep disorder. In this study, many factors suspected to increase the risk of sleep disorder were added to previously known job stress factors. In particular, this study found a strong correlation between work-associated sleep disorder and relational and organizational job stress factors. Sleep disorder may lead to large decreases in workers’ quality of life and work efficiency. Awareness and interventions are therefore required to reduce workplace stress; additional research of this topic is also required. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s40557-016-0131-2) contains supplementary material, which is available to authorized users.

Humidifier disinfectants, unfinished stories

Once released into the air, humidifier disinfectants became tiny nano-size particles, and resulted in chemical bronchoalveolitis. Families had lost their most beloved members, and even some of them became broken. Based on an estimate of two million potential victims who had experienced adverse effects from the use of humidifier disinfectants, we can say that what we have observed was only the tip of the iceberg. Problems of entire airways, as well as other systemic effects, should be examined, as we know these nano-size particles can irritate cell membranes and migrate into systemic circulation. The story of humidifier disinfectant is not finished yet.

Inhalation Lung Injury Associated with Humidifier Disinfectants in Adults

We recently established a novel disease entity presented as progressive respiratory failure associated with the inhalation of humidifier disinfectants. In April 2011, we encountered a series of peripartum patients with complaints of respiratory distress of unknown etiology, which was an uncommon phenomenon. Accordingly, we created a multidisciplinary team comprising intensivists, radiologists, pathologists, epidemiologists, and the Korea Centers for Disease Control and Prevention (KCDC). Further, we defined the disease entity and performed a case-control study, epidemiologic investigation, and animal study to determine the etiology. The study findings indicated that the lung injury outbreak was related to the inhalation of humidifier disinfectants and showed that household chemical inhalation can cause severe respiratory failure. Following the withdrawal of humidifier disinfectants from the Korean market in 2012, no such cases were reported. This tragic event is a warning that appropriate safety regulations and monitoring for potential toxic household chemicals are critical to protect public health.

Rebuttal to Authors' Reply, Re: Cancer Risk in Adult Residents Near Nuclear Power Plants in Korea: A Cohort Study of 1992-2010

No abstract available.

Effect of Long Working Hours on Self-reported Hypertension among Middle-aged and Older Wage Workers

OBJECTIVES: Many studies have reported an association between overwork and hypertension. However, research on the health effects of long working hours has yielded inconclusive results. The objective of this study was to identify an association between overtime work and hypertension in wage workers 45 years and over of age using prospective data. METHODS: Wage workers in Korea aged 45 years and over were selected for inclusion in this study from among 10,254 subjects from the Korean Longitudinal Study of Ageing. Workers with baseline hypertension and those with other major diseases were excluded. In the end, a total of 1,079 subjects were included. A Cox proportional hazards model was used to calculate hazard ratios and adjust for baseline characteristics such as sex, age, education, income, occupation, form of employment, body mass index, alcohol habit, smoking habit, regular exercise, and number of working days per week. Additional models were used to calculate hazard ratios after gender stratification. RESULTS: Among the 1,079 subjects, 85 workers were diagnosed with hypertension during 3974.2 person-months. The average number of working hours per week for all subjects was 47.68. The proportion of overtime workers was 61.0% (cutoff, 40 h per week). Compared with those working 40 h and less per week, the hazard ratio of subjects in the final model, which adjusted for all selected variables, working 41-50 h per week was 2.20 (95% confidence interval [CI], 1.19-4.06), that of subjects working 51-60 h per week was 2.40 (95% CI, 1.07-5.39), and that of subjects working 61 h and over per week was 2.87 (95% CI, 1.33-6.20). In gender stratification models, the hazard ratio of the females tended to be higher than that of the males. CONCLUSION: As the number of working hours per week increased, the hazard ratio for diagnosis of hypertension significantly increased. This result suggests a positive association between overtime work and the risk of hypertension.

Re: Cancer Risk in Adult Residents Near Nuclear Power Plants in Korea: A Cohort Study of 1992-2010

No abstract available.

Social Inequality in Birth Outcomes in Korea, 1995-2008

Social inequality in adverse birth outcomes has been demonstrated in several countries. The present study examined the separate and joint effects of parental education and work in order to investigate the causal pathways of social class effects on adverse birth outcomes in Korea. The occurrence of low birth weight, preterm births, and intrauterine growth retardation was examined among 7,766,065 births in Korea from 1995 to 2008. The effect of social inequality, as represented by parental education and work, was examined against adverse birth outcomes using multivariate logistic regression after controlling for other covariates. Parental education had the most significant and greatest effect on all three adverse outcomes, followed by parental work and employment, which had lesser effects. For adverse birth outcomes, the gap between educational levels increased steadily in Korea from 1995 to 2008. Throughout the analysis, the effect of maternal manual work on adverse birth outcomes was apparent in the study results. Given this evidence of social inequality in education and employment, social interventions should aim at more in-depth and distal determinants of health.

Corrigendum: Necessity for a National Carcinogen List in Korea, Based on International Harmonization

This article was initially published on the Environmental Health and Toxicology 2013;28:e2013008, with a misspelled name of the 7th coauthor.

Necessity for a National Carcinogen List in Korea, Based on International Harmonization

Cancer has been the leading cause of death in Korea for the last 30 years. Cancer patients' 5-year survival rate between 2005 and 2009 was 62.0%, representing a highly advanced standard of care, as much as developed countries in the EU and the US. The Korean government formulated its first 10-year plan for cancer control in 1996 and has been carrying out a second 10-year plan for cancer control since 2006. But despite the Korean government's efforts, the cancer burden in Korea continues to increase. Many separate laws have gone into effect concerning the management of carcinogen exposure. However, there are no integrated regulatory laws or management systems against carcinogen exposure in Korea. Dead zones remain where carcinogen exposure cannot be controlled properly in Korea. In this paper, we suggest the need to establish a national carcinogen list based on international harmonization as a prerequisite for a paradigm shift in cancer control policy from treatment to primary prevention.

The Magnitude of Mortality from Ischemic Heart Disease Attributed to Occupational Factors in Korea: Attributable Fraction Estimation Using Meta-analysis

OBJECTIVES: Ischemic heart disease (IHD) is a major cause of death in Korea and known to result from several occupational factors. This study attempted to estimate the current magnitude of IHD mortality due to occupational factors in Korea. METHODS: After selecting occupational risk factors by literature investigation, we calculated attributable fractions (AFs) from relative risks and exposure data for each factor. Relative risks were estimated using meta-analysis based on published research. Exposure data were collected from the 2006 Survey of Korean Working Conditions. Finally, we estimated 2006 occupation-related IHD mortality. RESULTS: For the factors considered, we estimated the following relative risks: noise 1.06, environmental tobacco smoke 1.19 (men) and 1.22 (women), shift work 1.12, and low job control 1.15 (men) and 1.08 (women). Combined AFs of those factors in the IHD were estimated at 9.29% (0.3-18.51%) in men and 5.78% (-7.05-19.15%) in women. Based on these fractions, Korea's 2006 death toll from occupational IHD between the age of 15 and 69 was calculated at 353 in men (total 3,804) and 72 in women (total 1,246). CONCLUSION: We estimated occupational IHD mortality of Korea with updated data and more relevant evidence. Despite the efforts to obtain reliable estimates, there were many assumptions and limitations that must be overcome. Future research based on more precise design and reliable evidence is required for more accurate estimates.

Factors Associated with Unmet Needs for Medical Care among Island Inhabitants in Korea / 農村醫學 地域保健

OBJECTIVE: Korea has 3,170 islands with about 188,000 inhabitants. These inhabitants' needs for health services might go unmet because of geographic isolation, slimmer availability of health services, and higher proportion of the elderly compared with the mainland population. Unmet health service needs might result in serious health problems for these island residents. Therefore, the purpose of this study was to investigate their unmet health service needs and related factors from population of Nowha island. METHODS: The survey was conducted from July 30 to August 1 by trained interviewers. Target population were residents in Nohwa island and the sampling method was incomplete quota sampling. General characteristics, socioeconomic status, utilization of health service, and unmet medical service needs were investigated. First univariate and then multivariate logistic analyses were done for the statistical analysis. RESULTS: 324 residents were surveyed and the proportion of unmet health services needs was 26.5%. People living alone and of female sex had increased health services needs based on univariable analysis. From the multivariate analysis, those living alone increased the health services needs. Self-determined low socioeconomic status and medical aid increased the proportion of unmet medical needs, but these were not statistically significant. CONCLUSION: In Nowha island, those who are elder, and of lower socioeconomic status had much higher unmet medical needs. The results suggest the need for more social support by qualified health services to solve this unmet medical needs problem.

The Distribution of Intraocular Pressure and Its Association With Metabolic Syndrome in a Community / 예방의학회지

OBJECTIVES: The current study was performed to assess the distribution of intraocular pressure (IOP) and its association with metabolic syndrome (MS) in a community. METHODS: We measured IOP and MS components from 446 adults, age 20 or more years old, who reside in a community in Kyunggi Province, South Korea. We compared the level of IOP according to the number of metabolic abnormalities and between normal and abnormal metabolic components. Linear regression analyses were used to determine the relationship between IOP and metabolic components. RESULTS: No significant difference in IOP (mean +/- SE) was found between men (12.24 +/- 2.42) and women (12.55 +/- 2.41 mmHg, p > 0.1), while IOP of men tended to decrease as age increased (p for trend < 0.01). After adjusting for age, IOP of subjects with abdominal obesity in men and high blood pressure in women were significantly higher than those without abdominal obesity or high blood pressure (p < 0.05). Female subjects with MS showed significantly higher IOP than those without MS. Participants with more metabolic disturbances tended to have a greater IOP elevation with a linear trend after adjusting for age and sex. In the univariate regression analysis, age and waist circumference were significantly associated with IOP in men, but systolic and diastolic blood pressure were associated with IOP in women. In final multiple regression model, age, systolic blood pressure, and triglyceride were associated with IOP in women, and age in men. CONCLUSIONS: These findings suggest that MS and its components may be important determinants of elevated IOP.

Depressive Symptoms of Workplace Violence Exposed Subjects in Korea / 대한산업의학회지

OBJECTIVES: This study was conducted to evaluate the association between workplace violence and depression METHODS: In total, 2236 employees who were providing services at hotels, casinos and amusement halls were used in this study. A structured questionnaire was used to assess exposures to violence, which was classified into physical violence, verbal violence, sexual harassment and bullying together with jobs and sociodemographic factors. Depressive symptoms were assessed using the Korean Beck depression inventory-II (BDI-II). Those with total BDI-II score over 22 points were defined as people with depression. RESULTS: Prevalence of depression among subjects exposed to any violence was higher than those who were not exposed to violence. After adjusting covariates, the odds ratio of depression was 2.47 (95% CI;1.13~5.39) for sexually harassed male subjects (n=72, 4.90%), 3.22 (95% CI; 1.51~6.87) for bullied male subjects (n=570, 38.83%), and 2.57 (95% CI; 1.52~4.32) for bullied female subjects (n=447, 58.20%). CONCLUSIONS: The results of this study suggest that depression can be an important psychological issue to those exposed to workplace violence in Korea. First of all, acknowledgement of the problem should be made in the workplace. Exalting public awareness and transforming work ethics and culture is cardinal to making this a social rather than an individual problem.