Factors Related to Subjective Well-being in Workers Who Interact with Angry Clients.

BACKGROUND: Among workers who interact with angry clients, there is limited information about the characteristics of workers who are most vulnerable to mental health problems. Thus, we determined the association of multiple demographic, socioeconomic, and modifiable work-related psychosocial factors with the subjective well-being of workers who interact with angry clients. METHODS: This was a secondary analysis of data from the fifth Korean Working Conditions Survey, conducted in 2017. The study focused on workers who interacted with angry clients during 25% or more of their work time. Multiple logistic regression was used to determine odds ratios (ORs) and 95% confidence intervals for the association of multiple factors with self-reported subjective well-being after adjustment for demographic, socioeconomic, and modifiable psychosocial factors. RESULTS: Overall, 9.6% of men and 7.4% of women who interacted with angry clients reported poor subjective well-being. Poor well-being was significantly more likely to be reported by men who worked 40 hours or more per week (aOR, 3.97-5.37) and by men who were daily workers (aOR, 2.21). Poor subjective well-being had a significantly positive association with exposure to adverse social behaviors by clients (men: aOR, 1.54, women: aOR, 1.58), and significantly negative associations with unskilled manual work (women only: aOR, 0.30), job satisfaction (men: aOR, 0.70, women: aOR, 0.52), and good social climate (men: aOR, 0.70, women: aOR, 0.44). CONCLUSION: Workers who interact with angry clients were widely distributed over non-manual labor and manual labor, but not limited to service and sales job. We identified modifiable factors that affect the subjective well-being of workers who interact with angry clients. We suggest that employers provide protection to prevent adverse social behaviors by clients, and also make an effort to establish a good social climate at the workplace.

Factors Related to Physical and Mental Health in Workers With Different Categories of Employment.

INTRODUCTION: We examined a large representative sample of workers in South Korea to compare the subjective well-being and musculoskeletal symptoms of those with standard employment and those with non-standard employment (temporary, daily, and part-time work). METHODS: This was a secondary analysis of data from the fifth Korean Working Condition Survey, conducted in 2017. RESULTS: Female part-time workers who had temporary and daily jobs were more likely to have poor subjective well-being, whereas female regular workers with part-time jobs were less likely to have poor subjective well-being than regular workers with full-time jobs. Daily workers of both sex with full-time jobs were more likely to have musculoskeletal pain than regular workers. CONCLUSION: Our characterization of workers with precarious employment indicated that several modifiable factors affected the subjective well-being and musculoskeletal symptoms of these workers.

Comparison of occupational health problems of employees and self-employed individuals who work in different fields.

We used a representative sample of the working population of Korea to compare the occupational health problems of employees and self-employed individuals who performed different types of work. The Korean Working Conditions Survey (KWCS) of 2014 was used to compare the working conditions and occupational safety and health (OSH) issues of employees and self-employed individuals performing different types of work. Relative to paid employees, self-employed individuals were older, more likely to perceive their health as bad, and had less education, longer working hours, more exposure to workplace ergonomic hazards, more musculoskeletal problems, and poorer mental well-being. Relative to those performing "mental work" or "emotional work", individuals performing "physical work" were more vulnerable to OSH problems. In conclusion, self-employed individuals in the sample were more vulnerable to OSH problems.

The history of occupational health in South Korea.

South Korea has experienced rapid economic development over a 60-year period, since the 1960s, rising up from the ruins of the 1950-1953 Korean War. During this short period, South Korea experienced a wide range of occupational safety and health (OSH) problems, similar to that experienced in most developed countries about 100-200 years previously. In response, the South Korean government established a national OSH services system that is on par with most developed countries. In recent years, South Korea now faces a new collection of OSH challenges, such as mental health issues, microenterprise issues, precarious workers, and the promotion of work ability in a rapidly changing socioeconomic structure. This study evaluates the establishment of South Korea's OSH services system, including the socio-politico-economic contexts that have had a profound influence on the system during each historical period.

Validity of self-reported concentration and memory problems: Relationship with neuropsychological assessment and depression.

BACKGROUND: This study investigated the validity of self-reported concentration and memory problems (CMP) in residents environmentally exposed to manganese (Mn). METHOD: Self-report of CMP from a health questionnaire (HQ) and the Symptom Checklist-90-Revised (SCL-90-R) was compared to neuropsychological assessment (Trails A&B; Digit Span; Digit Symbol; Similarities; Auditory Consonant Trigrams, ACT; NAB Memory; Rey-Osterrieth, Rey-O, Delayed). Participants included 146 residents from Ohio exposed to air-Mn, with a modeled average concentration of 0.55 µg m-3 (range = 0.01-4.58). RESULTS: Residents were primarily White (94.5%), aged 30-64 years (M = 51.24), with a minimum of 10 years of residence (range = 10-64). Ninety-four (65.3%) participants reported concentration problems, and 107 residents (73.3%) reported memory problems. More participants endorsed CMP on the SCL-90-R than on the HQ. The prevalence of self-reported CMP was higher for women than for men (88.4% vs. 68.3%). Point-biserial and Pearson's correlations between self-reported CMP and neuropsychological test scores were nonsignificant and weak for both the HQ (rpb = -.20 to rpb = .04) and the SCL-90-R (r = -.12 to r = .007). Greater levels of depression, anxiety, and female sex predicted having more self-reported CMP on both the HQ and the SCL-90-R. Air-Mn and blood-Mn were not associated with self-reported CMP. Residential distance from the Mn source accounted for a small proportion of variance (sr2 = .04), although depression remained the largest predictor (sr2 = .21). CONCLUSION: These results indicate that self-report of CMP in Mn-exposed residents appear to be invalid when compared to neuropsychological test scores. The participants' misperception of having CMP is associated with less education and higher levels of depression. Neuropsychological assessment is recommended to attain valid results.

Multiple assessment methods of prenatal exposure to radio frequency radiation from telecommunication in the Mothers and Children's Environmental Health (MOCEH) study.

OBJECTIVES: To evaluate prenatal exposure to radiofrequency radiation (RFR) from telecommunication using a mobile phone questionnaire, operator data logs of mobile phone use and a personal exposure meter (PEM). MATERIAL AND METHODS: The study included 1228 mother-infants pairs from the Mothers and Children's Environmental Health (MOCEH) study - a multicenter prospective cohort study ongoing since 2006, in which participants were enrolled at ≤ 20 weeks of pregnancy, with a follow-up of a child birth and growth to assess the association between prenatal environmental exposure and children's health. The questionnaire included the average calling frequency per day and the average calling time per day. An EME Spy 100 PEM was used to measure RFR among 269 pregnant women from November 2007 to August 2010. The operators' log data were obtained from 21 participants. The Spearman's correlation test was performed to evaluate correlation coefficient and 95% confidence intervals between the mobile phone use information from the questionnaire, operators' log data, and data recorded by the PEM. RESULTS: The operators' log data and information from the self-reported questionnaire showed significantly high correlations in the average calling frequency per day (ρ = 0.6, p = 0.004) and average calling time per day (ρ = 0.5, p = 0.02). The correlation between information on the mobile phone use in the self-reported questionnaire and exposure index recorded by the PEM was poor. But correlation between the information of the operators' log data and exposure index for transmission of mobile communication was significantly high: correlation coefficient (p-value) was 0.44 (0.07) for calling frequency per day, and it was 0.49 (0.04) for calling time per day. CONCLUSIONS: The questionnaire information on the mobile phone use showed moderate to high quality. Using multiple methods for exposure assessment might be better than using only one method. Int J Occup Med Environ Health 2016;29(6):959-972.

Maternal Stress and Depressive Symptoms and Infant Development at Six Months: the Mothers and Children's Environmental Health (MOCEH) Prospective Study.

Our objective is to evaluate the relationships between prenatal maternal stress and depressive symptoms, respectively, and infant neurodevelopment at 6 months, adjusted for heavy metals and oxidative stress. This research is a part of a multi-center birth cohort study in South Korea. Information on stress and depressive symptoms was collected during the first trimester using Psychosocial Well-Being Index Short Form (PWI-SF) and Center for Epidemiological Studies Depression Scale (CES-D). The Korean Bayley Scales of Infant Development-II assessment (BSID-II), which includes the standardized mental development index (MDI) and psychomotor developmental index (PDI), and Korean Ages & Stages Questionnaires (K-ASQ) were applied to infants at six months of age. A higher index score indicates better development. Among 641 babies, 320 were female (50%). Maternal PWI ≥ 29 (vs. PWI ≤ 18) during early pregnancy was associated with a decrease in MDI scores of 5.37 points (P = 0.02) after adjusting for socioeconomic factors. Maternal CES-D ≥ 26 (vs. CES-D ≤ 10) during early pregnancy was associated with a decrease in MDI scores of 8.18 points (P = 0.01). The associations remained significant even after adjustment for lead, cadmium, and MDA levels (P < 0.05). However, no association was found between maternal PWI/CES-D and PDI score. No interaction was observed between stress and lead exposure. We found an inverse association between prenatal maternal stress and depressive symptoms, and MDI scores in 6-month-old infants after adjustment for prenatal lead exposure, which is known to affect cognitive function negatively.

Maternal iron intake at mid-pregnancy is associated with reduced fetal growth: results from Mothers and Children's Environmental Health (MOCEH) study.

BACKGROUND: Iron supplementation is a common recommendation for pregnant women to prevent iron deficiency during pregnancy. There is an increasing concern about excessive iron consumption as a general iron prophylaxis by pregnant women without any due consideration about their dietary iron intake or iron status. Our present study investigated the association between total iron intake from diet and supplements and fetal growth in 337 pregnant women at mid-pregnancy in South Korea. METHODS: Iron intake from diet and supplements was examined by a 24-hour recall method. Subjects were divided into three groups based on tertiles of total iron intake levels. Fetal biometry was assessed by ultrasonography at mid-pregnancy. RESULTS: About 99% of the non-supplement users had iron intake below the recommended nutrient intake (RNI) for pregnant women (24 mg), whereas 64.9% of supplement users had iron intake above the upper level (UL) (45 mg). In the babies of mothers in the third tertile of iron intake (>17.04 mg), biparietal diameter, abdominal circumference, and femur length were lower by 0.41 cm (P =0.019), 0.41 cm (P = 0.027), and 0.07 cm (P = 0.051), respectively, than the babies of mothers in the second tertile of iron intake (11.49 ~ 17.04 mg). CONCLUSION: These results suggest that excessive maternal iron intake at mid-pregnancy is associated with reduced fetal growth. Iron supplementation for pregnant women should be individualized according to their iron status. Appropriate diet education is needed for pregnant women so that they can consume adequate amounts of iron from food and supplements.

Effects of menopause on blood manganese levels in women: analysis of 2008-2009 Korean National Health and Nutrition Examination Survey data.

INTRODUCTION: We present data from the Korean National Health and Nutrition Examination Survey 2008-2009 on the association between blood manganese (Mn) levels and menopausal status in women. METHODS: The present analysis was restricted to female participants who completed the health examination survey, including blood Mn measurements (n=1826). Menopausal status was categorized into pre- and post-menopausal. Multivariable linear regression analyses were performed to determine whether menopausal status or serum ferritin were significant predictors of blood Mn level and to investigate whether menopausal status modifies the association between blood Mn and serum ferritin after adjusting for covariates. RESULTS: The geometric means (GMs) of blood Mn in the low and low-normal serum ferritin groups were significantly higher than the GM of blood Mn in the normal group. The GM of blood Mn in premenopausal women was significantly higher than in postmenopausal women Multivariable linear regression analyses showed that both serum ferritin and menopausal status were predictors of blood Mn, after adjusting for various covariates, and menopausal status acted as a modifier of the effect of ferritin on blood Mn levels. Blood Mn levels were 11.0% and 22.7% lower in premenopausal women when serum ferritin increased from 10 µg/dL to 60 and 100 µg/dL, respectively, but the decrease in blood Mn based on the increase in serum ferritin was minimal in postmenopausal women. DISCUSSION: To our knowledge, this is the first report that menopausal status was a predictor of blood Mn level after adjusting for serum ferritin. In conclusion, the present study showed that both serum ferritin and menopausal status were predictors of blood Mn, after adjusting for various covariates, and menopausal status acted as a modifier of the effect of ferritin on blood Mn levels.

Assessment of polybrominated diphenyl ethers (PBDEs) in serum from the Korean general population.

In 2009 and 2010, 720 serum samples were collected from non-occupationally exposed study participants at four Korean locations and monitored for the presence of 27 polybrominated diphenyl ether (PBDE) congeners. The median concentrations of Σ(27)PBDEs (the sum of 27 congeners) and Σ(3-7)PBDEs (the sum of tri- to hepta-BDE congeners) were 6.04 and 4.97 ng/g lipid, respectively. The most abundant congener detected in serum samples was BDE-153, followed by BDE-47 and BDE-99. The median value of Σ(3-7)PBDEs was similar to the median values observed in Asia and Europe, but much lower than that observed in North America. Some significant differences, based on geographic region and sex, were observed. We also observed a positive increase of BDE-153 with regard to age. In addition, we estimated the daily exposure to PBDEs from previously published reports of PBDE concentrations in food and dust, and determined the individual contributions of a variety of sources.

A comparison of the recognition of overwork-related cardiovascular disease in Japan, Korea, and Taiwan.

In Japan, Korea, and Taiwan, cerebrovascular and cardiovascular diseases (CVDs) caused by overwork are recognized by government as work-related. These three countries are the only countries in the world that officially recognize CVDs caused by psychosocial factors (e.g., overwork) as work-related cerebrovascular and cardiovascular diseases (WR-CVDs), and compensate employees accordingly. The present study compared the similarities and differences among the recognition of overwork-related CVDs in Japan, Korea, and Taiwan. The criteria by which WR-CVDs are identified are very similar in the three countries. However, in the interval surveyed (1996-2009), Korea had a remarkably larger number of recognized WR-CVD patients than did Japan or Taiwan. Recognition of occupational diseases is influenced by various factors, including socio-cultural values, the nature of occupational health care schemes, the extent of the social security umbrella, national health insurance policy, and scientific evidence. Our results show that social factors may be very different among the three countries studied, although the recognition criteria for WR-CVDs are quite similar.

The recognition of occupational diseases attributed to heavy workloads: experiences in Japan, Korea, and Taiwan.

OBJECTIVE: Health problems caused by long working hours and work stress have gained growing concerns in Japan, Korea, and Taiwan. In all the three countries, cardiovascular, cerebrovascular, and mental disorders attributed to heavy workloads or stressful work events are considered compensable occupational diseases by workers' compensation systems. This study compared the trends of such cases and correlated the trends with changes in working hours during the period from 1980 to 2010. METHODS: Data on occupational diseases were obtained from official statistics of the workers' compensation systems. Information on working hours was obtained from official statistics and national surveys of employees. RESULTS: While occupational cardiovascular, cerebrovascular, and mental disorders attributed to work stress were increasingly compensated in all the three countries, the averaged working hours and the percentage of employees with long working hours had been in decline discordantly. CONCLUSION: Findings of this study suggested that reducing working hours alone is unlikely to reduce the problems of work stress. There is an urgent need to monitor and regulate a wider range of psychosocial work hazards. Especially, precarious employment and its associated health risks should be targeted for effective prevention of stress-related health problems in the workplace.

The Mothers and Children's Environmental Health (MOCEH) study.

The MOCEH study is a prospective hospital- and community-based cohort study designed to collect information related to environmental exposures (chemical, biological, nutritional, physical, and psychosocial) during pregnancy and childhood and to examine how exposure to environmental pollutants affects growth, development, and disease. The MOCEH network includes one coordinating center, four local centers responsible for recruiting pregnant women, and four evaluation centers (a nutrition center, bio-repository center, neurocognitive development center, and environment assessment center). At the local centers, trained nurses interview the participants to gather information regarding their demographic and socioeconomic characteristics, complications related to the current gestation period, health behaviors and environmental factors. These centers also collect samples of blood, placenta, urine, and breast milk. Environmental hygienists measure each participant's level of exposure to indoor and outdoor pollutants during the pre- and postnatal periods. The participants are followed up through delivery and until the child is 5 years of age. The MOCEH study plans to recruit 1,500 pregnant women between 2006 and 2010 and to perform follow-up studies on their children. We expect this study to provide evidence to support the hypothesis that the gestational environment has an effect on the development of diseases during adulthood. We also expect the study results to enable evaluation of latency and age-specific susceptibility to exposure to hazardous environmental pollutants, evaluation of growth retardation focused on environmental and genetic risk factors, selection of target environmental diseases in children, development of an environmental health index, and establishment of a national policy for improving the health of pregnant women and their children.

A retrospective cohort study of Parkinson's disease in Korean shipbuilders.

OBJECTIVE: We performed a retrospective cohort study in South Korea to clarify the role of occupational exposure, especially to welding, in the etiology of Parkinson's disease (PD). METHODS: We constructed a database of subjects classified into an exposure group (blue-collar workers) and a non-exposure group (white-collar workers) in two shipbuilding companies. Jobs of blue-collar workers were categorized into the first group of welding, the second group of fitting, grinding and finishing, cutting, and the other group. To determine new cases of PD during the follow-up period (1992-2003), we used the physician billing claims database of the National Health Insurance Corporation. For the detected PD patients in the physician billing claims database, a neurologist in our research team confirmed the appropriateness of each diagnosis by reviewing medical charts. Based on the review, we confirmed the numbers of new cases of PD and calculated the relative risk (RR) and the 95% confidence intervals (CI) by Cox regression analysis. RESULTS: In a backward selection procedure, 'age' was a significant independent variable but exposure was not. Furthermore, the RR in welders (high exposure group) was also insignificant and less than that in others (very low exposure group). CONCLUSION: This longitudinal study of shipbuilding workers supports our previous case-control studies suggesting that exposure to manganese does not increase the risk of PD.

Quantitative assessment of bone marrow cellularity by magnetic resonance imaging in workers with long-term exposure to solvents.

This study was conducted to develop a noninvasive method of bone marrow cellularity evaluation in solvent-exposed painters. Six painters with hypocellular marrow and 132 referents were examined using magnetic resonance imaging (MRI). Full examination of the peripheral blood and bone marrow biopsy was done on each patient. Signal indices were calculated from the signal intensities measured at the vertebral bodies from T12 to S1 and on the paraspinal muscles on both the T1- and the T2-weighted image (T1WI and T2WI). Bone marrow cellularities of the painters were between 20.3% and 33.6%. Signal indices at T1WI were greater in the hypocellular marrow cases compared to those of the referents (p<0.05, p<0.01) and were significantly higher in older women compared with men (p<0.05). After adjusting for age and gender, the signal index of cases at S1 of T1WI was higher than that of the referents by 0.364. Five of the six cases had signal index at S1 of T1WI higher than the mean +1 standard deviation for the same age group and gender. MRI signal indices can be used as a useful indicator of bone marrow cellularity in a high-risk population after adequate adjustment.