Infantile allergic diseases: a cohort study prenatal fish intake and mercury exposure context.

BACKGROUND: Allergic diseases (ADs) have been increasingly reported in infants and children over the last decade. Diet, especially the inclusion of fish intake, may help to lower the risk of ADs. However, fish also, can bioaccumulate environmental contaminants such as mercury. Hence, our study aims to determine what effects the type and frequency of fish intake have on ADs in six-month-old infants, independently and jointly with mercury exposure. METHODS: This study is part of the prospective birth cohort: Mothers and Children's Environmental Health (MOCEH) study in South Korea. Data was collected on prenatal fish intake, prenatal mercury concentration and ADs for infants aged six months for 590 eligible mother-infant pairs. Logistic regression analysis was conducted to evaluate the risk of prenatal fish intake and mercury concentration on ADs in infants. Finally, interaction between fish intake and mercury concentration affecting ADs in infants was evaluated. Hazard ratios of prenatal fish intake on ADs in 6 month old infants were calculated by prenatal mercury exposure. RESULTS: Logistic regression analysis showed that white fish (OR: 0.53; 95% CI 0.30-0.94; P < 0.05) intake frequency, once a week significantly decreased the risk of ADs in infants. Stratification analysis showed that consuming white fish once a week significantly reduced the hazard of ADs (HR: 0.44; 95% CI 0.21-0.92; P < 0.05) in infants in the high-mercury (≥ 50th percentile) exposure group. CONCLUSION: The result indicates that prenatal white fish intake at least once a week reduces the risk of ADs in infants, especially in the group with high prenatal mercury exposure.

Factors affecting work-related non-fatal injuries among aged workers in South Korea.

Introduction: The objective of this paper is to investigate whether an aging workforce is associated with an increase in work-related non-fatal injuries and to explore the underlying reasons for this potential increase. Methods: Aged workers were defined as those who were at least 55-years-old. Work-related non-fatal injuries were assessed in aged and young workers who were registered with the workers' compensation system from 2017 to 2021 of South Korea. Results: The mean estimated rate of work-related non-fatal injuries of aged workers (0.88/100) was about 2.5-times higher than that of younger workers (0.35/100). Most work-related non-fatal injuries in the older adults were in individuals working in the "construction sector" (36.0%), those with "elementary occupations (unskilled workers)" (45.0%), and those with employment status of "daily worker" (44.0%). "Trip & slip" (28.7%) and "falling" (19.6%) were more frequent types of work-related non-fatal injuries in aged workers relative to young workers. The category of "buildings, structures, and surfaces" was a more frequent cause of work-related non-fatal injuries in aged workers than young workers. Discussion: The incidence of non-fatal work-related injuries is higher among aged workers compared to their younger counterparts. The increased occurrence of aged workers participating in precarious employment and jobs, along with the greater physical vulnerability, is likely the cause of their higher rate of work-related non-fatal injuries.

Cooking oil fume exposure and Lung-RADS distribution among school cafeteria workers of South Korea.

Background: Cooking oil fumes (COFs) from cooking with hot oil may contribute to the pathogenesis of lung cancer. Since 2021, occupational lung cancer for individual cafeteria workers has been recognized in South Korea. In this study, we aimed to identify the distribution of lung-imaging reporting and data system (Lung-RADS) among cafeteria workers and to determine factors related to Lung-RADS distribution. Methods: We included 203 female participants who underwent low-dose computed tomography (LDCT) screening at a university hospital and examined the following variables: age, smoking status, second-hand smoke, height, weight, and years of service, mask use, cooking time, heat source, and ventilation. We divided all participants into culinary and non-culinary workers. Binomial logistic regression was conducted to determine the risk factors on LDCT of Category ≥ 3, separately for the overall group and the culinary group. Results: In this study, Lung-RADS-positive occurred in 17 (8.4%) individuals, all of whom were culinary workers. Binary logistic regression analyses were performed and no variables were found to have a significant impact on Lung-RADS results. In the subgroup analysis, the Lung-RADS-positive, and -negative groups differed only in ventilation. Binary logistic regression showed that the adjusted odds ratio (aOR) of the Lung-RADS-positive group for inappropriate ventilation at the workplace was 14.89 (95% confidence interval [CI]: 3.296-67.231) compared to appropriate ventilation as the reference, and the aOR for electric appliances at home was 4.59 (95% CI: 1.061-19.890) using liquid fuel as the reference. Conclusions: The rate of Lung-RADS-positive was significantly higher among culinary workers who performed actual cooking tasks than among nonculinary workers. In addition, appropriate ventilation at the workplace made the LDCT results differ. More research is needed to identify factors that might influence LDCT findings among culinary workers, including those in other occupations.

Decrease in Weekly Working Hours of Korean Workers From 2010 to 2020 According to Employment Status and Industrial Sector.

BACKGROUND: The present study examined changes in the working hours of Korean workers from 2010 to 2020 according to employment status and industrial sector. METHODS: This was a secondary analysis of data from the third (2010), fourth (2014), fifth (2017) and sixth (2020) Korean Working Conditions Surveys, which were conducted by the Korea Occupational Safety and Health Agency. RESULTS: During the past 10 years, workers classified as employees, self-employed, or employers experienced clear declines in average weekly working hours and in the percentages of individuals who worked more than 48 hours per week. During 2020, the largest proportion of employees (52.8%) had 40-hour work weeks, whereas the largest proportions of self-employed individuals (26.8%) and employers (25.1%) had very long work weeks (≥ 60 h/week). Also during 2020, individuals who were self-employed or employers in the sectors of 'Accommodation and food service' had the longest weekly work hours, whereas employees in the sector of 'Transportation' had the longest weekly work hours. All three groups (employees, self-employed, and employers) in all 21 industrial sectors experienced declines in average weekly working hours from 2017 to 2020. CONCLUSION: From 2010 to 2020, employees, self-employed individuals, and employers experienced clear declines in average weekly working hours, and in the percentages of individuals with long weekly working hours. However, there were also differences in the weekly working hours of those who had different employment status and who worked in different industrial sectors. The implementation of the 40-hour work-week and the 52-hour maximum work-week in Korea reduced excessive work hours by individuals who had different employment status and who worked in different industrial sectors, and probably improved worker quality-of-life. We recommend extension of these regulations to workplaces with fewer than 5 employees.

The effect of residential greenness during pregnancy on infant neurodevelopment using propensity score weighting: A prospective mother-infant paired cohort study.

BACKGROUND: While prior studies have suggested an association between green spaces and infant neurodevelopment, the causal effect of green space exposure during pregnancy has not been fully investigated. This study aimed to identify with causal inference the effect of exposure to residential greenness during pregnancy on infants' mental-psychomotor development and the role of maternal education in modifying this association. METHODS: We prospectively collected data of pregnant women and their infants from Mothers and Children Environmental Health cohort study. Based on residential addresses, we compiled information on the percent of green space using different buffer distances (100 m, 300 m, and 500 m) and air pollution (PM2.5). Infant neurodevelopment was measured at 6 months of age using the Korean Bayley Scales of Infant Development II Mental Developmental Index (MDI) and Psychomotor Developmental Index (PDI). Generalized propensity scores (GPSs) were estimated from machine-learning (ML) algorithms. We deduced causal inference through GPS adjustment and weighting approaches. Further analyses confirmed whether the association was altered by maternal academic background. RESULTS: A total of 845 mother-infant pairs from the cohort study were included. We found that exposure to green spaces was robustly associated with infants' mental development. For example, an increase in % green space within 300 m increased the MDI by 14.32 (95 % confidence interval [CI], 3.44-25.2) in the weighting approach. Additionally, the association was even more noticeable for mothers with college degrees or above: an increase in % green space within 300 m increased the MDI by 23.69 (95 % CI, 8.53-38.85) and the PDI by 22.45 (95 % CI, 2.58-42.33) in the weighting approach. This association did not appear in mothers without college degrees. CONCLUSION: Exposure to green spaces during pregnancy showed a beneficial relationship with infant mental development. Maternal academic background could modify the impact of green space exposure on infant neurodevelopment.

Effect of PM concentration on anemia blood indicators reduced by air purifiers.

Housewives perform daily household chores, which directly expose them to indoor particulate matter (PM). Indoor PM exposure is a potential factor that increases systemic inflammation and affects hematopoietic action. This study investigated the decrease in indoor PM concentration by air purifiers on indicators of anemia, such as hemoglobin, mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), and mean corpuscular hemoglobin concentration (MCHC). We analyzed the data of 40 housewives who were subjected to an air purifier intervention in Seoul and Ulsan, Republic of Korea. Indoor exposure levels of PM2.5 and PM10 were analyzed with sensor adjusted and gravimetric measurement. We also investigated the same anemia indicators before and after the installation of an air purifier for three months (short-term: one month, long-term: three months). Statistical analysis was performed by a multiple linear model and a linear mixed model. The indoor PM exposure levels and air purifier use were related to anemia indicators (hemoglobin and MCHC). The increase in indoor PM2.5 level was associated with a decrease in MCHC (ß: 0.034, P = 0.031) and hemoglobin (ß: 0.013, P = 0.04). The decrease in indoor PM2.5 concentration by air purifier was associated with an increase in MCHC (ß: 0.204, P = 0.087) and hemoglobin (ß: 0.190, P = 0.039). In particular, after air purifier intervention, the amounts of MCHC and hemoglobin significantly increased. Our results suggest that indoor air purifier use could decrease indoor PM level and the risk of anemia to housewives. Because the effect on anemia is subacute, it was confirmed three months after air purifier operation. In conclusion, anemia indicators can be improved by PM reduction management.

Association of paternal cadmium and other heavy metal exposure to birth outcomes using propensity score matching.

BACKGROUND: Human exposure to cadmium has various effects on health, especially on male reproductive organs. Although it is widely known that prenatal maternal cadmium exposure can affect birth outcomes, the effect of paternal exposure to cadmium remains unclear. OBJECTIVES: This study aimed to evaluate the effect of paternal cadmium exposure on fetal growth by considering maternal cadmium exposure and exposure to other heavy metals, namely mercury and lead. METHODS: The Mothers and Children's Environmental Health (MOCEH) study is a prospective birth cohort study in Korea. Overall, 1313 families (father-mother-child triple) without child abnormalities and who completed paternal whole blood cadmium assessments were included in this study. Families were divided into two subgroups based on the blood sampling periods, namely early and late pregnancy. Subjects were selected as follows: one family triple with a high level of paternal cadmium and two triples with low levels of paternal cadmium, using the method of propensity score matching. And linear regression analyses were performed. RESULTS: The group with high paternal cadmium exposure (80% or more; 1.93 µg/L) had lower birth weight infants compared to the group with low cadmium concentrations (ß(se) = -0.21(0.10); p-value = 0.0283). After stratification by infant sex, prenatal paternal cadmium exposure significantly reduced the birth weight of females in subgroups of different sampling times, namely early pregnancy (ß(se) = -0.52 (0.22); p-value = 0.0170) and late pregnancy (ß(se) = -0.43 (0.18); p-value = 0.0160). Finally, after performing propensity score matching in the early pregnancy measurement group, it was found that the prenatal exposure of father to cadmium significantly reduced birth weight in females (ß(se) = -0.72(0.25); p-value = 0.0047). CONCLUSION: This study assessed the effect of paternal cadmium exposure on birth outcomes in family units consisting of a father, mother, and child. Prenatal paternal cadmium exposure negatively affected birth weight, especially that of female, considering covariates and other heavy metals exposure, namely mercury and lead.

Reduced Diffusing Capacity in Humidifier Disinfectant-Associated Asthma Versus Typical Asthma: A Retrospective Case Control Study.

BACKGROUND: Humidifier disinfectant-related lung injury (HDLI) is a severe form of toxic inhalational pulmonary parenchymal damage found in residents of South Korea previously exposed to specific guanidine-based compounds present in humidifier disinfectants (HD). HD-associated asthma (HDA), which is similar to irritant-induced asthma, has been recognized in victims with asthma-like symptoms and is probably caused by airway injury. In this study, diffusing capacity of the lung for carbon monoxide (DLCO) in individuals with HDA was compared to that in individuals with pre-existing asthma without HD exposure. METHODS: We retrospectively compared data, including DLCO values, of 70 patients with HDA with that of 79 patients having pre-existing asthma without any known exposure to HD (controls). Multiple linear regression analysis and logistic regression analysis were performed to confirm the association between HD exposure and DLCO after controlling for confounding factors. The correlation between DLCO and several indicators related to HD exposure was evaluated in patients with HDA. RESULT: The mean DLCO was significantly lower in the HDA group than in the control group (81.9% vs. 88.6%; P = 0.021). The mean DLCO of asthma patients with definite HD exposure was significantly lower than that of asthma patients with lesser exposure (P for trend = 0.002). In multivariable regression models, DLCO in the HDA group decreased by 5.8%, and patients with HDA were 2.1-fold more likely to have a lower DLCO than the controls. Pathway analysis showed that exposure to HD directly affected DLCO values and indirectly affected its measurement through a decrease in the forced vital capacity (FVC). Correlation analysis indicated a significant inverse correlation between DLCO% and cumulative HD exposure time. CONCLUSION: DLCO was lower in patients with HDA than in asthma patients without HD exposure, and decreased FVC partially mediated this effect. Therefore, monitoring the DLCO may be useful for early diagnosis of HDA in patients with asthma symptoms and history of HD exposure.

Prenatal Exposure to Traffic-Related Air Pollution and the DNA Methylation in Cord Blood Cells: MOCEH Study.

Particulate matter with a diameter of ≤10 µm (PM10) and nitrogen dioxide (NO2) affect the DNA methylation in the fetus, but epigenetic studies regarding prenatal exposure to air pollution in Asia are lacking. Therefore, this study aimed to assess whether there is any association between the ambient concentrations of PM10 and NO2 and CpG methylation in the cord blood DNA by using a Korean birth cohort. The concentrations of the air pollutants were incorporated into the final LUR model by using the maternal address data. The methylation level was determined using HumanMethylationEPIC BeadChip and a linear regression analysis model. A multipollutant model including both PM10 and NO2 and models with single pollutants were used for each trimester exposure. The number of differentially methylated positions was the largest for midpregnancy exposure in both the single pollutant models and the multipollutant regression analysis. Additionally, gene-set analysis regarding midpregnancy exposure revealed four gene ontology terms (cellular response to staurosporine, positive regulation of cytoskeleton organization, neurotransmitter transport, and execution phase of apoptosis). In conclusion, these findings show an association between prenatal PM10 and NO2 exposure and DNA methylation in several CpG sites in cord blood cells, especially for midpregnancy exposure.

Acute lung injury in a worker after inhalation of ethylene phosphorodifluoridite.

Ethylene phosphorodifluoridite (C2H4F4O2P2) (CAS No. 3965-00-2) is a colorless corrosive fuming liquid that is used as a stabilizer in the electrolyte of rechargeable batteries. There are no previous reports of toxic effects following exposure to this compound. A 28-year-old male complained of respiratory distress after accidental inhalation of ethylene phosphorodifluoridite for 30 min. The patient developed acute lung injury with noncardiogenic pulmonary edema and was treated with supportive management. The patient fully recovered and was discharged after 7 days without any significant sequelae. The patient's symptoms were attributed to non-cardiogenic pulmonary edema caused by ethylene phosphorodifluoridite exposure. The case study showed that ethylene phosphorodifluoridite should be added to the list of chemicals that can cause acute lung injury. Int J Occup Med Environ Health. 2022;35(3):361-6.

Pre- and postnatal exposure to multiple ambient air pollutants and child behavioral problems at five years of age.

Ambient air pollution is emerging as a risk factor for adverse neurological symptoms and early childhood diseases. This study aimed to evaluate the association between pre- and postnatal exposure to air pollutants and childhood behavior by using MOCEH prospective birth cohort data. In total, 353 mother-child pairs at birth, who completed child behavioral assessments using the Korean version of the Child Behavior Checklist at five years of age, were included in the study. Multivariate linear regression (MLR) for single pollutant and Bayesian kernel machine regression (BKMR) for multiple pollutants were conducted. MLR analysis showed that air pollutant exposures during the first trimester were significantly associated with the internalizing problems score after adjusting for covariates. The estimates were 0.19 (0.05-0.32) per 1 µg/m3 increase in PM2.5, 0.13 (0.04-0.22) per 1 µg/m3 increase in PM10, and 0.20 (0.02-0.37) per 1 ppb increase in NO2. The BKMR model analysis revealed that the overall effects of multiple air pollutants during the first trimester of pregnancy and 0-6 months of the infantile period were significantly associated with behavioral problems. Boys showed a stronger associations than girls. Taken together, these results showed that the first trimester of pregnancy and 0-6 months of the infantile period were important for air pollutant exposure because exposure at these periods was associated with behavioral problems in 5-year-old children. Future efforts are required to control air pollution levels and reduce the health burden of vulnerable populations, including pregnant women and children.

Cardiovascular age of workers with different employment categories.

INTRODUCTION: We compared the cardiovascular age (an indicator of cardiovascular disease risk) in workers with different employment status after adjustment for demographic and socioeconomic factors. METHODS: This cross-sectional study used data collected from 2007 to 2017 for the Korea National Health and Nutrition Examination Survey (KNHANES). Study participants were placed into different employment categories based on employment status and work schedule: regular full-time, regular part-time, temporary full-time, temporary part-time, daily full-time, and daily part-time. RESULTS: Analysis of women indicated that regular part-time, temporary full-time, temporary part-time, daily full-time, and daily part-time workers were more likely to have an older cardiovascular age (OR = 1.180, 1.238, 1.297, 1.493, and 1.408, respectively) after adjustment for age, marriage, education, income, residence, region, and drinking status. Analysis of men indicated employment status was unrelated to cardiovascular age. CONCLUSION: Female nonstandard Korean workers were more likely to have an increased cardiovascular age. However, most of these workers, especially daily workers, are not currently protected by the Occupational Safety and Health Act (OSHA) of Korea. Collaboration or networking with community-based health care services in Korea is essential to better manage the health of these vulnerable female workers.

Direct and Indirect Effects of Indoor Particulate Matter on Blood Indicators Related to Anemia.

Exposure to indoor particulate matter (PM) is a potential risk factor that increases systemic inflammation and affects erythropoiesis. This study investigated the association between exposure to indoor PM and blood indicators related to anemia (BIRA) in housewives. Indoor PM and blood folate status are important factors in the risk of anemia. This was a housewife cohort study; we recruited 284 housewives in Seoul and Ulsan, Republic of Korea. Indoor exposure to PM2.5 and PM10 was measured by gravimetric analysis and sensors. We investigated the BIRA, such as hemoglobin (Hb), hematocrit, mean corpuscular volume (MCV), mean corpuscular Hb (MCH), and mean corpuscular Hb concentration (MCHC). Statistical analysis was performed by multiple linear regression model and mediation analysis. The association between BIRA and PM was assessed by multiple linear regression models fitted by mediation analyses. The increase in the level of indoor PM2.5 was associated with a decrease in MCV (Beta coefficient (B): -0.069, Standard error (SE): 0.022) and MCH (B: -0.019, SE: 0.009) in gravimetric measurements. The increase in the level of indoor PM2.5 was associated with a decrease in Hb (B: -0.024, SE: 0.011), hematocrit (B: -0.059, SE: 0.033), and MCV (B: -0.081, SE: 0.037) and MCH (B: -0.037, SE: 0.012) in sensor measurements (PM2.5-Lag10). Further, we identified a serum folate-mediated PM effect. The indoor PM exposure was significantly associated with decreased Hb, MCV, and MCH in housewives. Taken together, our data show that exposure to indoor PM is a risk factor for anemia in housewives. Blood folate concentration can be a mediating factor in the effect of indoor PM on BIRA. Therefore, folate intake should be recommended to prevent anemia in housewives. Moreover, indoor PM exposure should be managed.

Association between prenatal polycyclic aromatic hydrocarbons and infantile allergic diseases modified by maternal glutathione S-transferase polymorphisms: results from the MOCEH birth cohort.

BACKGROUND: Prenatal exposure to polycyclic aromatic hydrocarbons (PAH) has been linked to allergic disease onset. Variations in the glutathione S-transferase (GST) gene family can impact the progression of allergic diseases. We sought to examine the association between prenatal PAH exposure and infantile allergic diseases in 6-month-old infants, and how maternal glutathione S-transferase M1 (GSTM1) or T1 (GSTT1) polymorphism affects the association between prenatal PAH exposure and allergic diseases in the Mothers and Children's Environmental Health (MOCEH) study. METHODS: The study sample comprised 349 infants and their mothers from the MOCEH study, for whom 1-hydroxypyrene (1-OHP) and 2-naphthol were measured in both the early period of pregnancy and late period of pregnancy. An infant was deemed to be affected by an allergic disease if diagnosed with or if developed at least one of the allergic diseases. A logistic regression analysis was performed to study the association between urinary 1-OHP and 2-naphthol levels during pregnancy and allergic diseases in 6-month-old infants. Furthermore, analyses stratified by maternal GSTM1 or GSTT1 present/null polymorphisms were performed. RESULTS: The risk of allergic diseases in 6-month-old infants was significantly increased in accordance with an increase in urinary 1-OHP during the early period of pregnancy (odds ratio [OR]: 1.84; 95% confidence interval [CI]: 1.05, 3.23; by one log-transformed unit of 1-OHP µg/g creatinine). The increased risk of infantile allergic diseases associated with urinary 1-OHP during the early period of pregnancy was limited to the maternal GSTT1 null type (OR: 2.69; 95% CI: 1.17, 6.21, by one log-transformed unit of 1-OHP µg/g creatinine); however, the Relative Excess Risk due to Interaction was not statistically significant. CONCLUSIONS: The present study found that infantile allergic diseases could be affected by intrauterine PAH exposure, particularly in the early prenatal period and the risk was limited to the maternal GSTT1 null type.

Factors related to depressive symptoms in Korean self-employed workers.

BACKGROUND: We examined factors related to depressive symptoms in Korean self-employed workers. METHODS: This secondary analysis examined data of 14,454 self-employed individuals from the fifth Korean Working Conditions Survey (2017). Multiple logistic regression analysis was used to assess the relationship of depressive symptoms with different variables. RESULTS: Self-employed workers who had a good work-life balance, a good subjective health, and worked 40 to 48 hours or 48 to 60 hours/week were less likely to report depressive symptoms (all p < 0.05). However, those who always interacted with angry clients, had severe exposure to ergonomic risk factors, and were exposed to moderate or severe abusive behaviors were more likely to report depressive symptoms (all p < 0.05). Age, gender, weekly work days, and working at very fast speed were unrelated to depressive symptoms. CONCLUSIONS: Several factors known to be related to depressive symptoms do not lead to depression in self-employed individuals. Different interventions may therefore be needed to prevent depression in self-employed workers.

Association of weekly working hours with poor psychological well-being and moderation by employment status in Korean workers.

We examined the association of weekly working hours with poor psychological wellbeing in Korean workers and the moderating effect of employment status. This secondary analysis examined data from the fifth Korean Working Conditions Survey (2017). There were 30,108 waged employees and 14,459 self-employed individuals. The two groups were compared using a moderated regression model with Hayes' PROCESS macro for SPSS. The self-employed had a greater mean age than the waged employees. Higher percentages of the self-employed had short weekly working hours (<40), excessively long weekly working hours (≥60), and poor psychological well-being. After controlling for age, gender, education, monthly income, and occupational class, the interaction between weekly working hours and employment status on psychological well-being was significant (p<0.001). Among the self-employed, the well-being score was lowest in the short working hour group (<40 h/week), highest in the long working hour (48-59 h/week) groups, and intermediate in the excessively long working hours (≥60 h/week) group. For waged employees, psychological wellbeing was the greatest in the short working hour group and decreased continuously as the number of weekly working hours increased. In conclusion, employment status (employee vs. self-employed) moderated the relationship between weekly working hours and psychological well-being.

Association of blepharoptosis with refractive error in the Korean general population.

BACKGROUND/OBJECTIVES: We investigated the effect of blepharoptosis on refractive errors across different age groups in Korean population. SUBJECTS/METHODS: This cross-sectional study was performed with data obtained in the Korea National Health and Nutrition Examination Survey (KNHANES) from 2008 to 2012. A total of 33,103 participants were enroled in our study. Blepharoptosis was defined as a marginal reflex distance 1 (MRD1) less than 2 mm, and was diagnosed in 3,305 (9.98%) participants. Ophthalmic examinations were performed, including measurements of MRD1, spherical equivalent, and degree of astigmatism. The age range was divided into three groups: less than 20 years old; more than 20 years and less than 60 years old; and more than 60 years old. RESULTS: The mean spherical equivalent were -0.28 ± 2.23 D in the ptotic eyelids and -1.13 ± 2.30 D in the non-ptotic eyelids (p < 0.001, 95% CI: -0.93, -0.77). The mean cylinder dioptre were -1.03 ± 0.87 D and -0.80 ± 0.77 D respectively (p < 0.001, 95% CI: 0.20, 0.26). The association with the eyelid position and refractive error significantly differed according to the age group and body mass index. Increased positive spherical change and increased astigmatism were prominent among ptotic participants aged less than 60 years. CONCLUSIONS: A decrease in MRD1 was associated with a hyperopic shift and higher astigmatism. Mechanical compression of the ptotic eyelid may affect ocular biometry, with the effect being particularly prominent in younger participants who had greater eyelid tension.

Joint association of prenatal bisphenol-A and phthalates exposure with risk of atopic dermatitis in 6-month-old infants.

BACKGROUND: Prenatal exposure to bisphenol A (BPA) and phthalates could trigger immune response. Few studies have investigated the association between prenatal BPA and phthalate exposure and atopic dermatitis (AD) in infants. OBJECTIVE: We aimed to clarify the joint association of prenatal exposure to BPA and phthalate metabolites with AD incidence in 6-month-old infants. METHODS: We included 413 mother-child pairs from the Mothers and Children's Environmental Health (MOCEH) in a prospective birth cohort study. Maternal urinary BPA, mono-2-ethyl-5-hydroxyhexyl phthalate (MEHHP), mono-2-ethyl-5-oxohexyl phthalate (MEOHP), and mono-n-butyl phthalate (MnBP) concentrations were measured during early and late pregnancy. We applied the Bayesian kernel machine regression (BKMR) with probit regression to estimate the association of BPA and phthalate metabolites with AD incidence after adjusting for potential confounders. Individual association was estimated by differences in predicted probabilities comparing each individual chemical concentration at 75th versus 25th percentiles, while other chemicals were set at their median. Overall joint effect was estimated by differences in predicted probabilities comparing all chemical concentrations at 75th versus 25th percentiles. RESULTS: Individual effect of MEHHP in late pregnancy was strongly associated with incident AD [Difference: 0.244 (95% credible interval: -0.066, 0.554)] in the model including both early and late exposures. Furthermore, we confirmed overall joint association of urinary BPA and phthalate metabolites during pregnancy with a higher risk of AD [0.347 (0.168, 0.526) for late pregnancy exposure, and 0.307 (0.094, 0.521) for both early and late pregnancy]. Additionally, the joint association was more prominent among girls than that in boys. CONCLUSIONS: The joint association of prenatal exposure to BPA and phthalates could be associated with the incident AD in 6-month-old infants. Further studies are needed to confirm the synergistic effect of BPA and phthalate exposures on AD in children.

Factors that Affect Depression and Anxiety in Service and Sales Workers Who Interact With Angry Clients.

INTRODUCTION: We evaluated depression and anxiety in service and sales workers from Korea who interacted with angry clients to identify factors that mediated and moderated depression and anxiety in these workers. METHODS: This was a secondary analysis of data from the fifth Korean Working Conditions Survey conducted in 2017. A structural equation model was used for mediation and moderation analysis. RESULTS: Service and sales workers who had more interactions with angry clients had increased risk for depression and anxiety. Experiencing clients' adverse behaviors (acute episodes) mediated the relationship between interacting with angry clients (a chronic situation) on depression and anxiety. Job satisfaction and managers' support moderated the relationship between interacting with angry clients and mental health problems. CONCLUSION: We suggest that employers of service and sales workers should recruit staff based on their aptitude for such work, thus ensuring job satisfaction, and train them to deal with angry clients in such a way that they experience less emotional burden. Employers should also make bylaws requiring managers to directly take care of adverse social behavior by clients. Furthermore, a sociocultural campaign to prevent adverse social behavior by clients is also needed.

Factors related to psychological well-being in unskilled manual workers.

OBJECTIVES: The authors characterized the demographic, socioeconomic, and psychosocial work factors associated with performance of unskilled manual work, and then identified the modifiable psychosocial work factors that affected the psychological well-being of these workers. MATERIAL AND METHODS: This study analyzed data from the fifth Korean Working Condition Survey conducted in 2017. The study subjects were 37 081 Korean employees. The occupational classes investigated were: managers, professionals, and clerks; service and sales workers; and skilled or unskilled manual workers. RESULTS: Unskilled manual workers were more likely to be elderly and less educated, to have low income, to work fewer hours weekly, to have a shorter work duration, to perform temporary or daily jobs, and to report poor subjective health and well-being. Unskilled manual workers were also more likely to experience psychosocial hazards, such adverse social behaviors, a lack of job satisfaction, a lack of support from managers, and a poor social climate. However, with statistical adjustment for demographic, socioeconomic, and psychosocial work factors, unskilled manual work was no longer associated with poor psychological well-being, but psychosocial work factors were associated with poor psychological well-being. CONCLUSIONS: The poor psychological well-being of unskilled manual workers cannot be explained by the intrinsic nature of this type of work. Instead, the poor psychological well-being of these workers is associated with unfavorable psychosocial work factors, such as a poor employment status, a lack of job satisfaction, a lack of support from managers, and a bad social climate. These results thus suggest that the modification of psychosocial work factors may improve the psychological well-being of unskilled manual workers. Int J Occup Med Environ Health. 2021;34(6):789-804.