Publications (6) View all
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Article: Association of ozone exposure with asthma, allergic rhinitis, and allergic sensitization.
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ABSTRACT: Children are vulnerable to air pollution, which is known to be related to the recent increasing trend of allergic disease. To investigate the effects of air pollution on respiratory allergic diseases in school children. A prospective survey of parental responses to International Study of Asthma and Allergies in Childhood questionnaires, together with allergy evaluation, was conducted in 1743 school children selected from metropolitan cities and industrial areas during a 2-year period. Individual exposure to air pollution was estimated by using a geometric information system with the 5-year mean concentration of air pollutants. A total of 1,340 children (male:female ratio, 51.4:48.6) with a mean (SD) age of 6.84 (0.51) years were included in the analysis. Each child underwent allergy evaluation at the time of enrollment and at a 2-year follow-up. After 2 years, the 12-month prevalence of wheezing was significantly decreased, whereas the lifetime prevalence of allergic rhinitis showed a significant increase. Ozone exposure was significantly associated with the 12-month prevalence of wheeze (odds ratio per 5 ppb, 1.372; 95% confidence interval, 1.016-1.852). Ozone was also associated with allergic rhinitis in children who reside in industrial areas. In addition, significant positive associations between ozone and the rate of newly developed sensitization to outdoor allergen were found (P for trend = .007). Exposure to ozone was associated with current wheeze and allergic rhinitis. An increased rate of newly developed sensitization to outdoor allergen by ozone may explain the association.Annals of allergy, asthma & immunology: official publication of the American College of Allergy, Asthma, & Immunology 09/2011; 107(3):214-9.e1. · 2.83 Impact Factor -
Article: Occupational stress and depression in Korean employees.
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ABSTRACT: The purpose of this study is to analyze what aspects of occupational stress predict depression among Korean workers, and determine which components of occupational stress or job characteristics is more strongly associated with depression. In this cross-sectional study, a total of 8,522 workers (21-65 years of age) from a nationwide sample were recruited. A self-administered questionnaire was used to assess socio-demographics, job characteristics, depressive symptoms measured by the Center for Epidemiologic Studies Depression Scale, and occupational stress assessed by the Korean occupational stress scale (KOSS). Multivariate analyses show that inadequate social support (OR = 1.58, 95% CI = 1.52, 1.66) and discomfort in occupational climate (OR = 1.25, 95% CI = 1.18, 1.32) were more important risk factors for depression than organizational injustice, job demand and job control. Compared to the 'business activities' industries, 'recreational, cultural and sporting activities' (OR = 3.45, 95% CI = 1.80, 6.58), 'hotel and restaurants' (OR = 3.34, 95% CI = 1.92, 5.80), 'real estate and renting and leasing' (OR = 2.24, 95% CI = 1.13, 4.44), 'wholesale and retail' (OR = 1.85, 95% CI = 1.28, 2.67), 'transportation' (OR = 1.85, 95% CI = 1.11, 3.07), and 'financial institute and insurance' (OR = 1.60, 95% CI = 1.04, 2.48) industries had significantly greater risk of depression after controlling for gender, age, marital status, duration of employment and all subscale of KOSS. The finding that inadequate social support and discomfort in occupational climate is a better predictor of depressive symptoms than organizational injustice in Korea, indicates that the newly developed KOSS has cultural relevance for assessing occupational stress in Korea. Future studies need to understand factors such as "emotional labor" within certain industries where increased risk for depression is observed.Archiv für Gewerbepathologie und Gewerbehygiene 11/2008; 82(1):47-57. · 1.89 Impact Factor -
Article: Effect of occupational manganese exposure on the central nervous system of welders: 1H magnetic resonance spectroscopy and MRI findings.
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ABSTRACT: This study investigated the relationship between long-term occupational manganese (Mn) exposure on the regional Mn concentration in the brain, neuronal loss, and neurobehavioral effects on welders. 1H MRS of the basal ganglia (BG) was performed on 20 male welders and 10 age- and gender-matched, non-office, control workers in a shipyard to assess the metabolic change, and the N-acetylaspartate (NAA)/creatine (Cr), choline (Cho)/Cr and NAA/Cho ratios, by the level of Mn exposure. We also assessed the signal intensity of T1-weighted image of magnetic resonance imaging (MRI) on globus pallidus (GP) compared to that of the frontal white matter (pallidal index, PI). The welders had significantly higher signal intensity than the controls. PI showed a significant dose-response relationship with cumulative exposure index (CEI) (r=0.54, p=0.002). CEI and PI showed different relationships with NAA/Cr according to smoking status, and the correlation was evident only in non-smokers (r=-0.73 and -0.57, respectively). There were no significant differences between the welders and the controls in NAA/Cr, Cho/Cr, and NAA/Cho ratios obtained from BG. CEI was positively correlated with simple reaction time. PI was positively correlated with mean sway (MSWAY), sway area (SWAYA), and sway intensity (SWAYI), and negatively correlated with maximum frequency (MAXF). After categorizing the subjects into two groups according to NAA/Cr ratio level, the low NAA/Cr ratio group showed significantly lower score on digit span backward and significantly higher score on MSWAY, SWAYA and SWAYI in regression analysis than the high NAA/Cr ratio group. We speculated that the NAA/Cr ratio of MRS in BG seems to reflect the cumulative effect of Mn exposure on the human brain. Due to uneven distribution of smoking among the welders and the controls, in addition to the small number of subjects in our study, our findings are needed further studies with a larger number of subjects.NeuroToxicology 04/2007; 28(2):276-83. · 3.10 Impact Factor -
Article: Effect of manganese exposure on the neuroendocrine system in welders.
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ABSTRACT: To evaluate the effect of occupational exposure to manganese (Mn) on serum prolactin (PRL) and the interrelationship among other hypophyseal-pituitary hormones, a cross-sectional study was conducted on 251 welders and 100 age-matched, office workers. We analyzed serum PRL, dopamine (DA), thyroid stimulating hormone releasing hormone (TRH), follicle stimulating hormone (FSH), luteinizing hormone (LH) and testosterone (TST) and measured current airborne Mn concentration in the welders. Cumulative exposure index (CEI) of airborne Mn was calculated. CEI and the present Mn level of the welders were 1.4+/-1.1mg/m3 year (range: 0.0-4.9) and 0.4+/-3.84 mg/m3 (range: 0.0-3.8), respectively. TRH, FSH and LH were higher in welders (5.08 pg/ml, 7.40 and 4.91 mIU/ml, respectively) than in office workers (3.91 pg/ml, 6.15 and 4.00 mIU/ml, respectively) (p<0.05). DA was decreased and TRH was increased significantly with increasing CEI. DA increased up to CEI 2.0mg/m3 year or mean Mn level up to 0.2mg/m3, then decreased. PRL showed increasing tendency above the CEI and mean Mn level at which DA started to decrease. PRL was positively associated with DA in the office workers. However, such a normal feedback control of DA on PRL was not observed in the welders. Structural equation model (SEM) analysis showed that CEI was positively related to TRH and negatively related to DA. TRH increased PRL. PRL increased LH and perhaps FSH, and on the other hand, decreased TST. These results showed that Mn suppresses the inhibitory feedback control of DA on the hypophyseal-pituitary axis. In conclusion, we postulate that suppressed dopaminergic inhibitory function on the hypophyseal-pituitary axis might be the mechanism for the increased PRL exhibited in the welders.NeuroToxicology 03/2007; 28(2):263-9. · 3.10 Impact Factor -
Article: [Epidemiology of psychosocial distress in Korean employees].
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ABSTRACT: To estimate the magnitude of psychosocial distress and examine eligible factors associated with the development of psychosocial distress in Korean employees, using a nationwide sample. A total of 6977 workers were recruited from 245 companies. A structured questionnaire was used to assess sociodemographics, health-related behaviors, job characteristics, social support at work, personality traits (locus of control, type A behavior pattern), self-esteem, and psychosocial distress. The results showed that 23% of workers were categorized as high stress, 73% as moderate, and 5% as normal. Hierarchical multiple regression analysis showed that psychosocial distress was more common in younger workers, both male and female. Regular exercise was negatively associated with increase of psychosocial distress. In job characteristics, as expected, low decision latitude, high job insecurity, and low social support at work were related to high psychosocial distress. Personality traits such as locus of control and type A behavior pattern, and self-esteem were more powerful predictors of psychosocial distress than general characteristics, health-related behavior, and job characteristics. There were some gender differences. While men who are less educated and single (unmarried, divorced, and separated) experienced higher levels of psychosocial distress than those who are educated and married, women who feel high job demand experienced higher levels of psychosocial distress than those who feel low job demand. The proportion of the high stress group was higher than expected, and psychosocial factors like social support and personality characteristics (e.g. locus of control, type A behavior pattern and self-esteem) were more significant factors for psychosocial distress than other variables. This finding suggests that some psychosocial factors, especially inadequate social support, low self-esteem and lack of internal locus of control for the development of psychosocial distress, will also operate as an intervention strategy in the worksite stress reduction program. It is strongly required that worksite stress reduction programs should be established in at both occupational and level as well as in individual levels.Journal of Preventive Medicine and Public Health 03/2005; 38(1):25-37.
