Dong-Hee Koh

Association between Use of Synthetic Metalworking Fluid and Risk of Developing Rhinitis-related Symptoms in an Automotive Ring Manufacturing Plant

Association between Use of Synthetic Metalworking Fluid and Risk of Developing Rhinitis‐related Symptoms in an Automotive Ring Manufacturing Plant: Dong‐Uk Park, et al. Department of Environmental Health, Korea National Open University, Korea—The main objective of this study was to determine the association between synthetic metalworking fluid (MWF) and rhinitis‐related symptoms. At a plant manufacturing piston rings for automobiles, we interviewed grinders (19) and manufacturing workers (142) in operations where synthetic or semisynthetic MWF is handled, and administrative office workers (44) regarding the principal symptoms of rhinitis (nasal stuffiness, runny nose, anosmia, nasal itchiness, rhinorrhea, headache, epistaxis, and post‐nasal drip). In addition, we assessed the current exposure of workers handling MWF to MWF aerosols, fungi, and endotoxins. Logistic regression analysis was used to examine the association between MWF surrogates indicative of MWF exposure and each rhinitis‐related nasal symptom. Odds ratios (ORs) and 95% confidence intervals were adjusted for sex, age, smoking habit, and duration of employment. Among grinders handling synthetic MWF, the frequency of complaints of the dominant symptoms was 66.7% for nasal stuffiness, 77.8% for anosmia, 77.8% for runny nose, and 50.0% for headache. These rates are quite high even allowing for the common occurrence of rhinitis in the general population. Twenty eight of 34 grinding and manufacturing workers (82.4%) sampled were exposed to MWF mist above the threshold limit of 0.2 mg/m3listed as a notice of intended change by the American Conference for Governmental Industrial Hygienists (ACGIH). The percentage of workers exposed to MWF mist >0.5 mg/m3was 17.6%. Most workers were exposed to fungi levels >103CFU/m3. All exposures to endotoxins were <50 EU/m3. Logistic regression analysis found that use of synthetic MWF was significantly associated with excess risk of nasal stuffiness (OR 3.5), nasal itchiness (OR 2.0), and runny nose (OR 2.1). The use of semi‐synthetic MWF had little or no impact on the risk of developing rhiniti‐srelated nasal symptoms. Grinding workers handling synthetic MWF had an increased risk of nasal stuffiness (OR 7.9), anosmia (OR 23.2), nasal itchiness (OR 8.3), runny nose (OR 20.4), post nasal drip (OR 18.4), and headache (OR 7.4) compared to administrative workers. Synthetic MWF may play an important role in the development of the dominant symptoms of rhinitis. Further study is needed to establish the risk of rhinitis or rhinitis‐related symptoms according to MWF type.

Alanine aminotransferase and gamma-glutamyl transferase have different dose-response relationships with risk of mortality by age.

It remains unclear whether the respective dose‐response relationships between serum alanine aminotransferase (ALT) and gamma‐glutamyl transferase (GGT) levels and risk of mortality are consistent by age.

Lung cancer risk in professional drivers in Korea: A population-based proportionate cancer incidence ratio study

Lung cancer risk in professional drivers in Korea: A population‐based proportionate cancer incidence ratio study: Dong‐Hee Koh, et al. Department of Occupational and Environmental Medicine, International St. Marys Hospital, Catholic Kwandong University, Republic of Korea

Cancer incidence and mortality among temporary maintenance workers in a refinery/petrochemical complex in Korea

Abstract Background: Petrochemical plant maintenance workers are exposed to various carcinogens such as benzene and metal fumes. In Korea, maintenance operations in petrochemical plants are typically performed by temporary employees hired as contract workers. Objectives: The purpose of this retrospective study was to evaluate cancer risk in temporary maintenance workers in a refinery/petrochemical complex in Korea. Methods: Subjects consisted of 14 698 male workers registered in a regional petrochemical plant maintenance workers union during 2002–2007. Cancer mortality and incidence were identified by linking with the nationwide death and cancer registries during 2002–2007 and 2002–2005, respectively. Standardized mortality ratios (SMRs) and standardized incidence ratios (SIRs) were calculated for each cancer. Results: Increased SMR 3·61 (six cases, 95% CI: 1·32–7·87) and SIR 3·18 (five cases, 95% CI: 1·03–7·42) were observed in oral and pharyngeal cancers. Conclusion: Our findings may suggest a potential association between oral and pharyngeal cancers and temporary maintenance jobs in the petrochemical industry. Future studies should include a longer follow-up period and a quantitative exposure assessment.

1132 Estimation of lead exposure prevalence in korean population through combining multiple experts’ judgment based on objective data sources

Objectives Estimation of exposure prevalences of carcinogens is important for preventing occupational cancers. For developing Korean CAREX (CARcinogen EXposure) which is a carcinogen surveillance system employed in many countries, as an exemplary carcinogen, we estimated lead exposure prevalences in Korean working population. Methods We used three nationwide data sources to retrieve objective default estimates of lead exposure prevalence across industries: the work-environment monitoring database (WEMD), the special health examination database (SHED), and the Work Environment Condition Survey (WECS). Furthermore, we surveyed experts for their judgment about lead exposure prevalence across industries after reviewing the default estimates computed from aforementioned three exposure databases. We developed various estimation methods combining experts’ judgment, and then compared with each other. The 2010 Census was used as the reference population to estimate the number of lead-exposed workers for the 228 industries through multiplying the exposure prevalence with the number of workers in each industry. Results Default estimates of exposure prevalence for 228 industries were calculated using the WEMD and SHED collected between 2009–2011, and the 2009 WECS. A total of 52 experts who have 20 or more experience in industrial hygiene practice participated in the study and provided their judgment on the lead exposure prevalences as a number for the 228 industries. Among various estimation methods, the median values of experts’ responses were selected for our estimates of lead exposure prevalence in each industry. As a result, a total of 129,247 Korean workers was estimated to be exposed to lead in the year of 2010. Conclusions We developed a method estimating exposure prevalences combining experts’ judgment based on objective databases. Our effort for estimating the exposure prevalences of CAREX may introduce an unbiased approach to the development process accounting for uncertainty of exposure.

1131 Combining lead exposure measurements and experts’ opinion through a bayesian framework

Objectives CAREX (CARcinogen EXposure) is a carcinogen surveillance system employed in many countries. To initiate Korean CAREX, we focused on estimating the exposure intensity of lead across industries, which is a suspected carcinogen. Methods We extracted airborne lead measurements from the work environment measurement database (WEMD) which is the Korean nationwide measurement database. In addition, we elicited the experts’ opinion about lead exposure intensity across industries by conducting a questionnaire. Experts provided estimates of lead exposure levels as the boundary of the 5th and 95th percentiles. We assumed that experts provided their estimates based on the assumption of log-normal distributions of exposure. First, for each industry, estimates of log-transformed geometric means (logGM) and log-transformed geometric standard deviations (logGSD) were extracted from the experts’ responses, followed by combining them to quantify the experts’ prior Normal-Inverse-Gamma prior distribution. Then, the corresponding logGM and logGSD from lead measurement data for each industry were updated with the experts’ prior distribution through a Bayesian framework, yielding posterior distributions of logGM and logGSD. Results WEMD contains 83 035 airborne lead measurements collected between 2002–2007. Total 17 occupational hygiene professionals with more than 20 year experience provided lead exposure estimates. In industries where measurement data is abundant, the measurement data dominate the posterior exposure estimates, while in industries with a limited number of measurements, experts’ opinion played an important role in determining posterior exposure estimates. For example, rubber manufacturing industry with 246 measurements (GM 1.72; GSD 1.94) and 6 experts’ responses (GM 0.79; GSD 6.73) showed posterior exposure estimates of GM 1.60 and GSD 2.34. Conclusions Our method of estimating the exposure intensity of CAREX may introduce an unbiased approach to the development process by utilising both prior knowledge of experts and measurement data simultaneously. In addition, it will supply a framework for future updates.

Comparison of personal air benzene and urine t,t -muconic acid as a benzene exposure surrogate during turnaround maintenance in petrochemical plants

Previous studies have shown that biomarkers of chemicals with long half-lives may be better surrogates of exposure for epidemiological analyses, leading to less attenuation of the exposure-disease association, than personal air samples. However, chemicals with short half-lives have shown inconsistent results. In the present study, we compared pairs of personal air benzene and its short-half-life urinary metabolite trans,trans-muconic acid (t,t-MA), and predicted attenuation bias of theoretical exposure-disease association. Total 669 pairs of personal air benzene and urine t,t-MA samples were taken from 474 male workers during turnaround maintenance operations held in seven petrochemical plants. Maintenance jobs were classified into 13 groups. Variance components were calculated for personal air benzene and urine t,t-MA separately to estimate the attenuation of the theoretical exposure-disease association. Personal air benzene and urine t,t-MA showed similar attenuation of the theoretical exposure-disease association. Analyses for repeated measurements showed similar results, while in analyses for values above the limits of detection (LODs), urine t,t-MA showed less attenuation of the theoretical exposure-disease association than personal air benzene. Our findings suggest that there may be no significant difference in attenuation bias when personal air benzene or urine t,t-MA is used as a surrogate for benzene exposure.