Annals of Occupational and Environmental Medicine

Original Article

The Etiologic Fraction of Isocyanate-related Asthma in Isocyanate-exposed Workers: Yeon Soon Ahn, Dong Hee Koh, Ki Tae Moon; Korean Journal of Occupational and Environmental Medicine 2007;19(4):276-284. Published online December 31, 2007; DOI: https://doi.org/10.35371/kjoem.2007.19.4.276

OBJECTIVES
Isocyanate-induced asthma is the most prevalent occupational asthma in Korea. The main purpose of this study was to estimate the etiologic fraction of isocyanate-related asthma in isocyanateexposed (EFe) workers and to measure the magnitude of preventable occupational asthma.
METHODS
Asthma admissions from 2000 to 2005 were analyzed in a cohort containing 10,861 isocyanate-exposed workers and 324,618 isocyanate non-exposed workers who underwent the specialized health examination from January, 2000 to December, 2004. The cohorts of Isocyanate and noise-exposed workers were established using the same data base of Korea Occupational Safety and Health Agency (KOSHA). Asthma admissions were investigated by matching the National Health Insurance Claim Data (NHICD). The standardized rate ratio (SRR) of admission was estimated by Poisson regression method to allow unbiased comparisons across exposure and other variables such as age and sex. The etiologic fraction for the isocyanate-exposed (EFe) workers was calculated using this formula (Efe=SRR-1/SRR).
RESULTS
Twenty-eight asthma admissions among the isocyanate-exposed workers and 321 non-exposed workers were observed during 2000~2005. The crude admission rate was 57.2 per 100,000 person-years for the isocyanate-exposed workers and 25.0 for the noise-exposed workers. Compared to the noiseexposed workers, the isocyante-exposed workers had significantly higher asthma admission (SRR=2.80 95%CI=1.89~4.14). The etiologic fraction for the isocyanate-exposed (EFe) workers was 64%.
CONCLUSIONS
This study was limited by the restriction to admission cases and the short follow-up periods. Any difference of admission accessibility between the isocyanate-exposed and non-exposed workers will lead to either over- or under-estimation of the biased etiologic fraction for the isocyanateexposed workers. The etiologic fraction for the isocyanate-exposed workers was 64% indicated that 64% of the asthma cases occurred in the isocyanate-exposed workers are preventable through occupational health management.

Citations

Citations to this article as recorded by

Association Study of NDFIP2 Genetic Polymorphism with Asthma in the Korean Population
Eun Hye Choi, Dahyun Hwang
The Korean Journal of Clinical Laboratory Science.2021; 53(3): 249. CrossRef

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Original Article

A Study on Comparison of the Metabolites Related with Working Methods and Immunity of the Toluene diisocyanate-Exposed Workers: Su Ill Lee, Byung Man Cho, In Kyung Hwang, Cheol Ho Lee, Jung Rae Park; Korean Journal of Occupational and Environmental Medicine 1998;10(3):320-332. Published online August 31, 1998; DOI: https://doi.org/10.35371/kjoem.1998.10.3.320

Abstract PDF

Following recent advanced industrialization. the amount of polyurethane to use as thermal insulating materials, upholstery mattresses and packing materials in automotive and furniture industry is increasing world-widely, and the number of polyurethane-producing worker will be increased. Because the numerous organic solvents are used in polyurethane-producing factory, the workers in this work site is exposed to many organic solvents. Of the organic solvents. Toluene Diisocyanate(TDI) has many hazardous effects to human. The effects of TDI on human are the irritation to respiratory mucosa and gastrointestinal symptoms. Conjunctival irritation, dermal inflammation (redness, pain, vesicular formation) and gastrointestinal symptom(nausea, vomiting, abdominal pain) are reported just after short-term exposure of TDI. TDI is known to give rise to bronchial asthma, as the immune disorder. And because of strongly volatile characteristics of TDI, it is suggested as a more injurious material to human health, especially human immune system, than other organic solvents. Bronchial asthma inducing mechanism of TDI is not clearly known, but on the analogy of TDI-induced symptoms and recent studies, early-onset asthma is type I hypersensitivity reaction mediated by immunoglobulin E(IgE), and late-onset asthma is maybe type III hypersensitivity reaction by circulating IgG. And we know that the complicated human immune function is likely to move in such that mechanisms, there are not studies on immune indices evaluating the bronchial asthma-related immune function. The evaluation of change patterns of humoral immunity including IgE and IgG and cellular immunity including T-helper cell, T-suppressor cell and T-cytotoxic cell will be helpful to evaluate exposure degrees and prognosis in TDI-exposed workers. Because TDA(toluene diamine) as a biological exposure index of TDI becomes the focus of interest, we know that a study on the correlation between urinary TDA and air TDI and immunological indices will make a contribution to biological effect monitoring indicies. We examined human immunity indicators such as WBC. %Lymph (percentile of Lymphocyte in WBC). %T-cell(percentile of T-lymphocyte in total lymphocyte). CD4, CD8, C3, C4, IgA, IgG, IgM, IgE in peripheral blood to evaluate the health hazard of the TDI-exposed workers. And we examined TDA to evaluate correlation between exposure and effect. Total 90 subjects was selected, 45 workers who worked in the polyurethane-producing factories as an exposed group, and 45 cases who were office workers(10 cases), other blue collors(27 cases), and medical college students(8 cases) as a control group. And the results were as follows ; 1. The logarithm of IgE -Log10(IgE)+/-SD- in peripheral blood of a exposed group was significantly higher than a control group, 2 22+/-.62 in case group compared with 1.98+/-.53 in control group.(p<0.05) 2. IgA and IgM in the polyurethane-producing workers were 261.02+/-3.12 mg/dl, 151.97+/-9.64 mg/dl, respectively, and 292.77+/-00.45, 179.17+/-00.78 in control group. IgA and IgM was slightly lower in polyurethane-producing group than control (p>0.05). 3. WBC, %Lymph, %T-cell, C3, C4, CD4, CD8, CD4/CDB ratio and IgG in case group were 6,391.1 ea/ml, 37.53%, 59.54%, 76.68 mg/dl, 30.54 mg/dl, 0.76x10(9) ea/L, 0.63x10(9) ea/L, 1.39, and 1606.29 mg/dl, respectively, and 6,974.7 ea/ml, 35.12%, 59.64%, 71.95 mg/dl, 33.94 mg/dl, 0.80x109 ea/L, 0.61x10(9) ea/L, 1.39, and 1581.51 mg/dl in control group. There was no statistical sinificance between two groups. (p>0.05) 4. In the comparison of each other companies, average of individual urinary TDA in polyurethane paint manufacturing companies is higher than that of polyurethane sponge foaming companies. And, the concentration of 2,6-TDA which is a metabolite of well-vaporized 2,6-TDI is higher than that of 2,4-TDA in the polyurethane sponge foaming companies. But, the concentration of 2,4-TDA which is a metabolite of illvaporized but well skin-absorbed 2,4-TDI is higher in polyurethane paint manufactures. 5. There were no statistical significance in the correlations between individual urinary TDA and immunologic indices.

Citations

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Biological Monitoring of Workers Exposed to Diisocyanates using Urinary Diamines
Jong Seong Lee, Boowook Kim, Jungah Shin, JinEe Baek, Jae Hoon Shin, Ji-hye Kim
Journal of Korean Society of Occupational and Environmental Hygiene.2016; 26(2): 178. CrossRef

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Original Article

Biological Monitorings of Workers Exposed to Toluene diisocyanate: Yeon Soon Ahn, Jae Hoon Roh, Chi Nyon Kim, Yun Jung Park, Sang Hyuk Jung; Korean Journal of Occupational and Environmental Medicine 1995;7(2):354-361. Published online October 31, 1995; DOI: https://doi.org/10.35371/kjoem.1995.7.2.354

Abstract PDF

Toluene diisocyanate (TDI) is widely used in the production of flexible polyurethane foams, as well as in the formulation of polyurethane paints and coatings. The commercial material is generally a mixture of 2,4- and 2,6-TDI, the predominant mix being 80% 2,4 and 20% 2,6-TDI. The 2,4-isomer is considerably more reactive than the 2,6-TDI at ambient temperatures due to steric factors involving the positions of the isocyanate groups relative to the ring methyl group. Because of this difference in the reactivities of the isomers, it seemed probable that there might be an increase in the amount of 2,6-TDI offgased relative to the 2,4-isomer. Therfore a relative enrichment of the 2,6-TDI has been found in industrial atmospheres. Toluene diamines, which are metabolites of TDI, in urine have a linear relation with exposure to TDI, so that urianry TDA could be used as a biological index of the exposure to TDI. This study was conducted to investigate the distribution of TDI isomer in industrial atmospheres and to propose proper biological monitoring methods by identifying the relationships between the environmental TDI exposure and concentration of TDA in urine. Concentrations of 2,4-TDI and 2,6-TDI in air were 4.38microgram/m3 and 25.43microgram/m3, respectively. The Threshold Limited Value of 40microgram/m3 was exceeded for the 2,6-TDI in about 46.8% (22samples) of the samples, while the 2,4-TDI was not at all exceeded. The ratio between 2,4-TDI and 2,6-TDI varied in air samples in the range, of 2.4%:97.6%-51.0%:49.0%. There was an enrichment of 2,6-TDI in air relative to the 2,4-TDL Concentrations of 2,4-TDA and 2,6-TDA in urine were 1.31microgram/g creatinine and 4.16microgram/g creatinine, respectively. The ratio between 2, 4-TDA and 2,6-TDA varied in urine samples in the range of 1.4%:98.6%-99.9%:0.1%. There was an enrichment of 2,6-TDA in urine relative to the 2,4-TDA. No relation between the concerations of TDA isomer in urine and concerations of TDI isomer in air was found. Above results of this study, workers were more exposed to the 2,6-TDI relative to the 2,4-TDI in industrial atmospheres. Therefore, the establishment of TLV for 2,6-TDI should be considered. Also, the further studies on biological monitorigs of workers exposed to TDI should be continued.

Citations

Citations to this article as recorded by

Biological Monitoring of Workers Exposed to Diisocyanates using Urinary Diamines
Jong Seong Lee, Boowook Kim, Jungah Shin, JinEe Baek, Jae Hoon Shin, Ji-hye Kim
Journal of Korean Society of Occupational and Environmental Hygiene.2016; 26(2): 178. CrossRef

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