The Association between Trans, Trans-Muconic Acid as a Biomarker for Benzene Exposure and the Platelet Count / 대한산업의학회지

OBJECTIVE: Recent researches suggest that trans,trans-muconic acid (t,t-MA) would be an adequate metabolic biomarker for low-level benzene exposure. Few study have investigated the association between the t,t-MA and platelet count, and this is the primary aim of this study. METHODS: From May 2004 to June 2004, 326 chemical factory workers took part in a questionnaire survey and they underwent urinary t,t-MA and CBC assessment. The questionnaire covered general aspects of health and the occupational and smoking histories. Statistical analyses of outcomes were performed using SPSS 14.0 for Windows. RESULTS: The subjects' urinary t,t-MA concentration (geometric mean and geometric standard deviation) was 0.28 mg/g creatinine (2.62). No significant differences between different occupations among the chemical workers were found. The urinary t,t-MA concentrations in the smokers and non-smokers were 0.32 mg/g creatinine (2.44) and 0.25 mg/g creatinine (2.77) respectively, and the difference was statistically significant (p<0.05). There was no significant difference in the platelet count based on occupation and the smoking history. There was significant correlation between log(platelet) and log(t,t-MA)(r=-0.116 p=0.039). The regression equation log(platelet) = -0.002xAge + [-0.029xlog(t,t-MA)] + 2.436, R2=0.032, was calculated from linear regression analysis with log(platelet) as the dependent variable. Cross-tabulation between 2 subgroups that were divided by the 90-percentile level of the t,t-MA (0.819 mg/g creatinine), and 2 subgroups that were divided by the 10-percentile level of the platelet count (175,000) was conducted. Higher distribution in subgroup with platelet count below 175,000 was demonstrated in the subgroup with a urinary t,t-MA above the 90-percentile, with an odds ratio of 3.01. CONCLUSIONS: The study may be limited by not taking into account factors such as smoking quantity and sorbic acid, which may confound urinary the t,t-MA concentration as well as medication and infection that may affect the platelet count. Yet it is meaningful that the correlation between the urinary t,t-MA concentration and the platelet count was found through linear regression analysis and the chi-square test, and further, this outcome may be used as a basis for a study to establish the acceptable limit of urinary t,t-MA in Korea.

Incidence of Dimethylacetamide Induced Toxic Liver Injury among Workers in a Synthetic Fiber Manufacturing Company / 대한산업의학회지

OBJECTIVES: The main goal of this study was to find the incidence of the dimethylacetamide (DMAc) induced toxic liver injury among workers who were exposed to DMAc for about 5 years in a synthetic fiber factory. METHODS: In our investigation, total 1,021 workers had been exposed to DMAc from 1st February, 2000 to 30th June, 2004. Among them, 24 workers who had initial abnormal hepatic enzyme level or was viral hepatitis B carrier were excluded. Finally, 997 DMAc exposed workers were followed up for their incidence of toxic liver injury. To find out DMAc induced toxic liver injury case, we carried out regular examinations including liver enzyme tests such as AST and ALT. RESULTS: We followed up 997 workers and among them 72 cases coincided with our case definition. Incidence density method was 6.05 per 100 person-year. and, a cumulative incidence by life table method was 0.0965 within a year. The incidence of the DMAc-induced toxic liver injury peaked at 4 to 5 in weeks after employment. There was no toxic liver injury case within second week after exposure to DMAc. Five new cases developed in 2th to 3th week, 25 cases in 4th to 5th week, 14 cases in 6th to 7th week, 12 cases in 8th to 9th week, 5 cases in 10th to 11th week, 4 cases in 12th to 13th week, 4 cases in 14th to 15th week, 1 case in 16th to 17th week, 1 case in 30th to 31th week, and there was one case in 48th to 49th week. CONCLUSIONS: The incidence rate of toxic liver injury was considerably high during the 1st year after a worker is placed. So it is needed to take careful monitoring of hepatic enzyme level for newly exposed worker.

Surveillance of Work-related Diseases in Kumi / 대한산업의학회지

OBJECTIVES: Area-based occupational disease surveillance in Kumi (KODS) was used to collect data on occupational diseases. The data was used to estimate the magnitude of the diseases, to analyze for their characteristics, and to find links for their intervention and prevention. METHODS: Since January 2001, occupational physicians and nurses in Occupational Health Service (OHS)have reported six major occupational diseases; occupational musculoskeletal disorders of the upper extremities(MSDUE), occupational dermatoses, toxic hepatitis, occupational asthma (OA), hand-arm vibration syndrome(HAVS), and occupational cancer. For the respective diseases, a reporting sheet and operational diagnostic criteria were developed by the KODS. An analysis of the KODS data, collected over a certain period, was compared with data from the Korea Labor Workers Corporation (KLWC) and the Specific Health Examination (SHE), and the incidence rates of the diseases estimated. RESULTS: Between Jan 2001 and Apr 2002, 287 cases of the six major occupational disease were reported. Of these, there were 132 (46.0%), 100 (34.8%), 34 (11.8%), 16 (5.6%), and 5 (1.7%), cases of MSDUE, occupational dermatoses, toxic hepatitis, OA, and HAVS, respectively. But, there were no cases of occupational cancer. 33 (11.5%) of the incidence were reported via the OHS, 206 (71.7%) from health checkups, and the other 48(16.8%) from other routes. The synthetic fibers and electronic components manufacturing industries accounted for the greatest number of reported cases. With respect to occupation, the greatest numbers of incidence were reported from the elementary occupations, textile workers, assemblers, and cooks and food services worker, in that order. Of the MSDUE cases, carpal tunnel syndrome and epicondylitis were the two most common diseases. Most of the occupational dermatoses were due to contact dermatitis, with organic solvents (59%), nickel (6%), and epoxy resin (5%) accounting for the majority of these cases. All cases of toxic hepatitis were induced by dimethylformamide or dimethylacetamide, which were reported by a unique monitoring system. During same period, there were no cases claimed by workers to the KLWC, and only three cases from SHE, were identified. Using data from workers' number and surveillance, the annual incidences of MSDUE, dermatoses, hepatitis, OA, and HAVS, per 100,000 workers were 63.6, 48.2, 17.9, 7.7, and 2.4, respectively. CONCLUSIONS: These results show that an area-based surveillance system can be very effective for the collection of data on work-related diseases, at least in Kumi.