The association between low blood lead levels and the prevalence of prehypertension among nonhypertensive adults in Korea.

OBJECTIVES: Low-level lead exposure has been associated with increases in blood pressure (BP) and impairment of the cardiovascular system. Prehypertension is not categorized as a disease currently; however, individuals with untreated prehypertension are known to be at increased risk of progression to hypertension and mortality caused by cardiovascular disease. We investigated the association between blood lead levels below the threshold for the harmful effects of lead and the prevalence of prehypertension in Korean adults. METHODS: A total of 8,493 participants (3,945 men and 4,548 women) were included in the current analysis, using data from the fourth, fifth, and sixth Korean National Health and Nutrition Examination Survey (KNHANES) in 2007-2013. Blood analysis, self-report questionnaires, and physical examinations were used to assess blood lead levels, BP, and medical history. Odds ratios (OR) and 95% confidence intervals (95% CI) for prehypertension were calculated using multiple logistic regression models. RESULTS: Compared to the first quartile (Q1) blood lead level (0.206-1.539 µg/dl), the ORs (95% CI) were 1.24 (1.04-1.48) in Q2, (1.540-2.056 µg/dl), 1.27 (1.06-1.52) in Q3, (2.057-2.716 µg/dl), and 1.30 (1.07-1.60) in Q4 (2.717-24.532 µg/dl) for the prevalence of prehypertension after adjusting for age, sex, morbidity status, socioeconomic status, and health behavioral variables. CONCLUSIONS: Our large, cross-sectional, nationwide study revealed that blood lead levels below the threshold for the harmful effects of lead were significantly associated with prehypertension. Am. J. Hum. Biol. 28:729-735, 2016. © 2016 Wiley Periodicals, Inc.

Metabolic outcomes of workers according to the International Standard Classification of Occupations in Korea.

BACKGROUND: Occupation influences the risk for developing chronic metabolic diseases. METHODS: We compared the prevalence of MetS by International Standard Classification of Occupations using the nationally representative data in Korea (KNHANES). We enrolled 16,763 workers (9,175 males; 7,588 females) who had measurements for the National Cholesterol Education Program criteria III and other variables. OR and 95%CIs for MetS and its components were estimated according to occupation using the multiple logistic regression models. RESULTS: The occupational groups with the highest age-standardized prevalence of MetS were lower skilled white-collar men (31.1 ± 2.4%) and green-collar women (24.2 ± 2.9%). Compared with the unskilled male blue-collar group, which had the lowest prevalence of MetS, the OR (95%CIs) of MetS in men were 1.77 (1.45-2.15) in higher skilled white-collar, 1.82 (1.47-2.26) in lower-skilled white-collar, 1.63 (1.32-2.01) in pink-collar and 1.37 (1.13-1.66) in skilled blue-collar workers in final logistic regression model. CONCLUSIONS: MetS and its components vary by occupational category and gender in ways that may guide health interventions. Am. J. Ind. Med. 59:685-694, 2016. © 2016 Wiley Periodicals, Inc.

Concealing Emotions at Work Is Associated with Allergic Rhinitis in Korea.

Concealing emotions at work can cause considerable psychological stress. While there is extensive research on the adverse health effects of concealing emotions and the association between allergic diseases and stress, research has not yet investigated whether concealing emotions at work is associated with allergic rhinitis. Allergic rhinitis is a common disease in many industrialized countries, and its prevalence is increasing. Thus, our aim was to determine the strength of this association using data from three years (2007-2009) of the 4th Korean National Health and Nutrition Examination Survey. Participants (aged 20-64) were 8,345 individuals who were economically active and who had completed the questionnaire items on concealing emotions at work. Odds ratio (OR) and 95% confidence intervals (95% CIs) were calculated for allergic rhinitis using logistic regression models. Among all participants, 3,140 subjects (37.6%) reported concealing their emotions at work: 1,661 men and 1,479 women. The OR (95% CIs) for allergic rhinitis among those who concealed emotions at work versus those who did not was 1.318 (1.148-1.512). Stratified by sex, the OR (95% CIs) was 1.307 (1.078-1.585) among men and 1.346 (1.105-1.639) among women. Thus, individuals who concealed their emotions at work were significantly more likely to have a diagnosis of AR in comparison to those who did not. Because concealing emotions at work has adverse health effects, labor policies that aim to reduce this practice are needed.

The Perceived Socioeconomic Status Is an Important Factor of Health Recovery for Victims of Occupational Accidents in Korea.

We aimed to examine whether there is a correlation between the health recovery of industrial accident victims and their perceived socioeconomic status. Data were obtained from the first Panel Study of Worker's Compensation Insurance, which included 2,000 participants. We performed multivariate regression analysis and determined the odds ratios for participants with a subjectively lower socioeconomic status and for those with a subjectively lower middle socioeconomic status using 95% confidence intervals. An additional multivariate regression analysis yielded the odds ratios for participants with a subjectively lower socioeconomic status and those with a subjectively upper middle socioeconomic class using 95% confidence intervals. Of all participants, 299 reported a full recovery, whereas 1,701 did not. We examined the odds ratio (95% confidence intervals) for participants' health recovery according to their subjective socioeconomic status while controlling for sex, age, education, tobacco use, alcohol use, subjective state of health prior to the accident, chronic disease, employment duration, recovery period, accident type, disability status, disability rating, and economic participation. The odds of recovery in participants with a subjectively lower middle socioeconomic status were 1.707 times greater (1.264-2.305) than that of those with a subjectively lower socioeconomic status. Similarly, the odds of recovery in participants with a subjectively upper middle socioeconomic status were 3.124 times greater (1.795-5.438) than that of those with a subjectively lower socioeconomic status. Our findings indicate that participants' perceived socioeconomic disparities extend to disparities in their health status. The reinforcement of welfare measures is greatly needed to temper these disparities.

Workplace Violence Experienced by Substitute (Daeri) Drivers and Its Relationship to Depression in Korea.

Workplace violence is related to various health effects including mental illness such as anxiety or depression. In this study, the relationship between the experience of workplace violence and depression in substitute drivers in Korea, namely, daeri drivers, was investigated. To assess workplace violence, questions regarding types and frequency of the experience of violence over the past year were asked to the daeri drivers. In order to assess the risk of depression, the Center for Epidemiological Studies Depression Scale was used. Odds ratios with 95% confidence intervals of depression were estimated using multiple logistic regression analysis. All of the daeri drivers had experienced instance of verbal violence while driving and 66 of the drivers (34.1%) had been in such a situation more than once in the past quarter of a year. Sixty-eight daeri drivers (42.2%) had experienced certain type of physical violence over the past year. Compared to daeri drivers who had experienced workplace verbal violence less than 4 times and who had not experienced workplace physical violence over the past year, higher odds ratio was observed in daeri drivers who had experienced workplace verbal violence or physical violence, more than 4 times and more than one time respectively, after adjustment. Experience of verbal or physical type of workplace violence over the past year increased the risk of depression in the daeri drivers. Because violence against drivers can compromise the safety of the driver, the customer, and all the passengers, it is imperative that the safety and health of daeri drivers be highlighted.

The association between blood cadmium level and airflow obstruction in Korean men.

BACKGROUND: Most humans are exposed to environmental contaminants via inhalation. Various toxic inhalants cause lung damage with pathologic changes to the airway system. Lung function decline is an important cause of morbidity and mortality worldwide. AIM: To consider the potential burden of cadmium on pulmonary disease, this study examined the relationship between blood cadmium levels and airflow obstruction in a Korean general population. SUBJECTS AND METHODS: Data from the Korean National Health and Nutrition Examination Surveys from 2008-2011 were used. Male participants were selected who were older than 40 years, who had completed a reliable pulmonary function test and for who measurements of blood cadmium levels were available (n = 1974). The pulmonary function tests were undertaken and airflow obstruction was defined when forced vital capacity/forced expiratory volume in 1 second ratio < 0.7. RESULTS: In an age-adjusted logistic regression model, blood cadmium levels correlated with the risk of obstructive airflow pattern in total participants as well as in smokers or never smokers. Further adjustment for BMI, current occupation and educational level did not attenuate these associations among total participants, smokers and never smokers (OR = 2.53, 95% CI = 1.83-3.50 in total; OR = 2.17, 95% CI = 1.55-3.02 in smokers; OR = 3.71, 95% CI = 1.48-9.33 in never smokers). CONCLUSIONS: In conclusion, blood cadmium level was associated with airflow obstruction independently of smoking history and that association was still significant in never smokers. Careful attention is needed for the general population who are potentially exposed to cadmium.

Association between occupational clusters and allergic rhinitis in the Korean population: analysis of the Korean National Health and Nutrition Examination Survey data.

OBJECTIVES: This study aimed to investigate the association between occupational clusters and allergic rhinitis (AR). METHODS: The study was based on data from the Korean National Health and Nutrition Examination Survey (KNHANES: 2007-2015). This study included 46,965 individuals: 20,491 men and 26,474 women. AR was defined as having been diagnosed by a physician. Occupations were classified according to occupational characteristics and skill levels into white (chief executives, senior officials, legislators, managers, professionals, and technicians), pink (clerks, clerical support workers, services and sales workers), blue (craft and related trades workers, drivers, plant and machine operators, assemblers, elementary occupation workers), and green (skilled agricultural, forestry, and fishery workers) categories. We calculated the odds ratios (ORs) and 95% confidence intervals (CIs) of AR according to the occupational clusters by using the chi-squared test and logistic regression. RESULTS: In the study population, 10.7% of the men and 13.5% of the women had AR. The prevalence of AR was highest among white-collar workers, followed by pink, blue, and green-collar workers. Compared to green-collar workers, among men the adjusted ORs of the blue, pink, and white-collar workers were 2.00 (95% CI 1.58-2.53), 2.46 (95% CI 1.91-3.15), and 2.78 (95% CI 2.20-3.51), respectively; and among women were 2.45 (95% CI 1.99-3.02), 2.64 (95% CI 2.15-3.25), and 3.63 (95% CI 2.96-4.47), respectively. CONCLUSIONS: This study suggests that AR prevalence is significantly associated with occupational clusters.

Relationship between Long Working Hours and Suicidal Thoughts: Nationwide Data from the 4th and 5th Korean National Health and Nutrition Examination Survey.

BACKGROUND: Long working hours are a worldwide problem and may increase the risk of various health issues. However, the health effects of long working hours on suicidal thoughts have not been frequently studied. Our goal was to investigate the relationship between long working hours and suicidal thoughts in the rapidly developing country of Korea. METHODS: Data from 12,076 participants (7,164 men, 4,912 women) from the 4th and 5th Korean National Health and Nutrition Examination Surveys were used for the current analysis. Multivariate logistic regression models were used to estimate odds ratios and 95% confidence intervals for suicidal thoughts. Combined effects of long working hours and lower socioeconomic status or sleep disturbance were also estimated. RESULTS: Compared to groups who worked less than 52 hours per week, odds ratios (95% confidence intervals) for suicidal thoughts in groups who worked 60 hours or more per week were 1.36 (1.09-1.70) for males and 1.38 (1.11-1.72) for females, even after controlling for household income, marital status, history of hypertension or diabetes mellitus, health-related behaviors, and past two weeks' experience of injury, intoxication, or acute or chronic diseases, as well as type of work. The combined effects of long working hours with lower socioeconomic status, or with sleep disturbance, were also significantly higher compared to participants who worked less than 52 hours per week with higher socioeconomic status, or with 6-8 hours of nighttime sleep. CONCLUSION: In this study, long working hours were linked to suicidal thoughts for both genders. Additionally, the odds of those suicidal thoughts were higher for lower socioeconomic groups. To prevent adverse psychological health problems such as suicidal thoughts, a strategy regarding long working hours should be investigated.

A case of multiple myeloma in a poultry worker.

BACKGROUND: Livestock breeders including poultry workers are exposed to various agricultural chemicals including pesticides and/or organic solvents. Multiple myeloma is a rare disease in Korea, and few reports have investigated the influence of occupational exposures on multiple myeloma occurrence. CASE PRESENTATION: A 61-year-old male poultry farm worker presented with bone pain and generalized weakness. A bone marrow biopsy was performed, and he was diagnosed with multiple myeloma. The patient had worked in a poultry farm for 16 years and was exposed to various pesticides and organic solvents such as formaldehyde without any proper personal protective equipment. Results of the work reenactment revealed that the concentration of formaldehyde (17.53 ppm) greatly exceeded the time-weighted average (0.5 ppm) and short-term exposure limit (1.0 ppm) suggested in the Korean Industrial Safety and Health Act. CONCLUSIONS: This case report suggests that poultry workers may be exposed to high levels of various hazardous chemicals including pesticides and/or organic solvents. Numerous previous studies have suggested an association between multiple myeloma and exposure to agricultural chemicals; thus, multiple myeloma in this patient might have resulted from the prolonged, high exposure to these chemicals.

Occupational noise annoyance linked to depressive symptoms and suicidal ideation: a result from nationwide survey of Korea.

BACKGROUND: Noise, or undesirable sound, is one of the most common environmental stressors, and it can cause various health effects. Beyond the auditory consequences of occupational noise exposure, extra-auditory effects such as psychological problems have also been found. The aim of the current study is to elucidate the association between occupational noise annoyance and psychological symptoms, including symptoms of depression and suicidal ideation. METHODS: A total of 10,020 participants (5,410 men and 4,610 women) were included in the current analysis, using data from the fourth Korean National Health and Nutrition Examination Survey (KNHANES). Self-report questionnaires were used to assess noise annoyance levels, depressive symptoms, and suicidal ideation. Odds ratios (ORs) and 95% confidence intervals (95% CIs) for psychosocial symptoms were calculated using multiple logistic regression models. RESULTS: Compared to the no noise annoyance group, ORs (95% CI) of the severe annoyance groups were 1.58 (1.12-2.23) and 1.76 (1.29-2.40) in men and 1.49 (1.05-2.11) and 1.41 (1.01-1.97) in women for depressive symptoms and suicidal ideation, respectively. The ORs (95% CI) for severe noise annoyance in those with less than five hours of sleep were 2.95 (1.46-5.96) and 2.05 (1.01-4.16) in men and women, respectively, compared with those with no noise annoyance and a sleep time of more than five hours. CONCLUSION: Our study shows that occupational noise annoyance is significantly related to mental health, including depressive symptoms and suicidal ideation after controlling for individual and socio-demographic characteristics even with gender stratification. However, prospective studies with quantified noise exposure assessment were needed to elucidate the causality on the association between noise annoyance and psychological symptoms.

The association between concealing emotions at work and medical utilization in Korea.

OBJECTIVES: We aimed to investigate the association between concealing emotions at work and medical utilization. METHODS: Data from the 2007-2009 4th Korea National Health and Nutrition Examination Survey (KNHANES IV) was used, 7,094 participants (3,837 males, 3,257 females) aged between 20 and 54 who were economically active and completed all necessary questionnaire items were included. Odds ratios (ORs) and 95% confidence intervals (95% CI) for differences in hospitalization, outpatient visits, and pharmaceutical drug use between those who concealed their emotions and those who did not were investigated using logistic regression models with and without gender stratification. RESULTS: Among those who concealed their emotions (n = 2,763), 47.4% were females, and 50.1% had chronic disease. In addition, 9.7% of the concealing emotions group had been hospitalized within the last year, 24.8% had been outpatients in the last two weeks, and 28.3% had used pharmaceutical drugs in the last two weeks. All ORs represent the odds of belonging to the concealing emotions group over the non-concealing emotions group. After adjustment for individual, occupational, socioeconomic and disease factors, the adjusted ORs (95% CI) in hospitalization are 1.29 (1.08 ~ 1.53) in the total population, 1.25 (0.98 ~ 1.60) in males and 1.30 (1.02 ~ 1.66) in females, in outpatient visits are 1.15 (1.02 ~ 1.29) in the total population, 1.05 (0.88 ~ 1.24) in males and 1.25 (1.06 ~ 1.47) in females and in pharmaceutical drug use are 1.12 (1.01 ~ 1.25) in the total population, 1.08 (0.92 ~ 1.27) in males and 1.14 (0.98 ~ 1.33) in females. CONCLUSIONS: Those who concealed their emotions at work were more likely to use medical services. Moreover, the health effects of concealing emotions at work might be more detrimental in women than in men.

The effect of work characteristics on dermatologic symptoms in hairdressers.

OBJECTIVES: Hairdressers in Korea perform various tasks and are exposed to health risk factors such as chemical substances or prolonged duration of wet work. The objective of this study is to provide descriptive statistics on the demographics and work characteristics of hairdressers in Korea and to identify work-related risk factors for dermatologic symptoms in hairdressers. METHODS: 1,054 hairdressers were selected and analyzed for this study. Independent variables were exposure to chemical substances, the training status of the hairdressers, and the main tasks required of them, and the dependent variable was the incidence of dermatologic symptoms. The relationships between work characteristics and dermatologic symptoms were evaluated by estimating odds ratios using multiple logistic regression analysis. RESULTS: Among the 1,054 study subjects, 212 hairdressers (20.1%) complained of dermatologic symptoms, and the symptoms were more prevalent in younger, unmarried or highly educated hairdressers. The main tasks that comprise the majority of the wet work were strictly determined by training status, since 96.5% of staff hairdressers identified washing as their main task, while only 1.5% and 2.0% of master and designer hairdressers, respectively, identified this as their main task. Multiple logistic regressions was performed to estimate odds ratios. While exposure to hairdressing chemicals showed no significant effect on the odds ratio for the incidence of dermatologic symptoms, higher odds ratios of dermatologic symptoms were shown in staff hairdressers (2.70, 95% CI: 1.32 - 5.51) and in hairdressers who perform washing as their main task (2.03, 95% CI: 1.22 - 3.37), after adjusting for general and work characteristics. CONCLUSIONS: This study showed that the training status and main tasks of hairdressers are closely related to each other and that the training status and main tasks of hairdressers are related to the incidence of dermatologic symptoms. This suggests that in the future, regulations on working conditions and health management guidelines for hairdressers should be established.

Working hours and cardiovascular disease in Korean workers: a case-control study.

OBJECTIVES: Long working hours can negatively impact a worker's health. The objective of this study was to examine the association between working hours and cardiovascular diseases (CVDs) and compare the degree of risk based on CVD subtypes in Korean workers. METHODS: This study was a case-control study of the patients registered in the Occupational Cardiovascular Diseases Surveillance 2010. The cases included 348 patients diagnosed with a CVD (123 cerebral infarction, 69 intracerebral hemorrhage, 57 subarachnoid hemorrhage, 99 acute myocardial infarction). Controls were 769 participants with no history of CVDs matched for gender, age, type of occupation, and region. Participants' working hours in the previous week and the average working hours over the past three months were assessed to examine short-term and long-term effects. RESULTS: After adjusting for confounding factors, the odds ratios (ORs) for CVDs in the short-term were 2.66 (95% Confidence interval (CI) :1.78-3.99) for working ≤40 hours, 1.85 (95% CI: 1.22-2.81) for working 50.1-60 hours and 4.23 (95% CI: 2.81-6.39) for working >60 hours compared with the 40.1-50-hour working group. The ORs in the long-term were 2.90 (95% CI: 1.86-4.52) for working ≤40 hours, 1.73 (95% CI: 1.03-2.90) for working 48.1-52 hours and 3.46 (95% CI: 2.38-5.03) for working >52 hours compared with the 40.1-48-hour working group. CONCLUSIONS: Long working hours are related to an increased risk of CVDs, and the degree of risk differs based on CVD subtype. Short working hours are also related to an increased risk for CVDs. More prospective studies targeting specific disease risks are required.