鑄造業勞工暴露游離二氧化矽之肺功能及氧化傷害研究

The lung effect and oxidative damage of free silica exposure among foundry workers

林洺秀(Ming-Hsiu Lin)

指導教授 ： 劉紹興

共同指導教授 ： 張靜文(Ching-Wen Chang)

國立臺灣大學/公共衛生學院/環境衛生研究所/博士(2010年)

https://doi.org/10.6342/NTU.2010.03538

摘要

由於勞工長期暴露於含游離二氧化矽之粉塵作業環境中，易導致矽肺症，日後亦成為肺癌之高危險群。而以往文獻幾乎多著墨於動物實驗研究或人類流行病學調查，而有關實際進行職場暴露改善與人體健康效應間之量測，則少有研究探討。本研究將以鑄造業勞工為對象，以尿中之8-羥基去氧鳥糞核苷(8-OHdG)濃度作為氧化傷害指標；針對以實際工程改善介入工作現場，探討肺功能及8-OHdG等生物指標之變化，以期達到早期預防矽肺症及肺癌之產生。
本研究收集A、B、C鑄造廠廠研究對象共74人，進行胸部X光、肺功能、血液常規、生化、氧化傷害等檢查，了解肺功能與飲食攝取、氧化傷害、抗氧化能力指標、職場暴露、身體質量指數(BMI)等相關性。結果發現，肺功能中第一秒用力呼氣容量（FEV1）、FEV1%pred、一秒量率(FEV1/FVC%)與職場粉塵累積暴露濃度、BMI等趨勢分佈皆達顯著負相關。另外，針對A廠進行工廠作業環境改善及追蹤該廠作業員工之肺功能及8-OHdG濃度，在作業環境改善後三個月再次進行一次肺功能及尿中8-OHdG等檢查。結果發現， A鑄造廠在環境改善後可呼吸粉塵濃度及游離二氧化矽有減少之現象，針對同樣的研究對象進行肺功能指標重複施測，發現其肺功能指標FEV1、用力肺容量(FVC)、FEV1%pred、FVC%pred在作業環境改善後有明顯的增加，並達統計顯著差異。在針對B鑄造廠勞工DNA損傷、免疫毒性及職場暴露之分析方面，在校正一些干擾因子(如年齡、籍貫、教育程度、吸菸情形及維他命E使用情形等)後，發現累積暴露量與DNA傷害四參數，頭尾比例、尾部長度、尾部動量、Oliver尾矩皆具有統計上顯著意義。至於勞工細胞激素分佈方面，將年齡、籍貫、吸菸情形、BMI及是否罹患矽肺症等因子納入複迴歸分析模式中，可以了解白介素－2(IL-2)及白介素－10(IL-10)與是否罹患矽肺症具有統計上之顯著意義；即罹患矽肺症(含1/0以上)之勞工較未罹患矽肺症之勞工有較高IL-2、IL-10。
由本研究中勞工職場游離二氧化矽之累積暴露與健康效應方面，顯示職場暴露導致該族群之肺功能下降、DNA損傷；而藉由水霧工程之現場輔導，肺功能在作業環境改善後有明顯的增加。因此建議即時工程介入改善作業環境現場對於防治鑄造業勞工矽肺症是必要的。

關鍵字

游離二氧化矽 ； 鑄造業勞工 ； 8-羥基去氧鳥糞核苷DNA傷害 ； 細胞激素

並列摘要

Laborer workers are exposed to free silica long-term and lead to an increased risk of silicosis and lung cancer. Epidemiological and animal studies support that, then less research resulting from an engineering intervention to assess the health effect. The primary aim of this study was to evaluate changes in lung function and oxidative damage markers following the introduction of an engineering control intervention , whilst urinary 8-hydroxy-deoxyguanosine (8-OHdG) was used as a measure of oxidative DNA damage.
My study population was 74 male from 3 foundries in Taiwan. All subjects were carried on such inspections as chest X-rays, lung function, blood routine, oxidative damage,etc, in order to discuss the effects of dust exposure and BMI on foundry workers’ lung function and to determine whether the intake of dietary vitamins has any significant impact in improving lung function and anti-oxidant plasma activity. Our findings revealed that the lung function, FEV1, FEV1%pred and FEV1/FVC% of foundry workers is negatively affected by having a higher BMI and by exposure to dust. In addition, I studied one of 3 foundries before, and three months after, improvements to air exhaust control. Initial baseline biomarker measurements were taken of lung function and urinary 8-OHdG in all of the workers, with follow up measurements taken three months after the engineering control was put in place. Compared to initial baseline, significant improvements were found in lung function (FVC, FEV1, FVC%pred and FEV1%pred) amongst the workers after the engineering intervention to reduce the silica level. I estimated DNA damage by comet assay for another planet, after confounders were adjusted, A significant increase in L/H, TL, ETM, OTM of DNA damage with cumulative silica exposure. From the result of cytokines showed that the significant higher concentration of IL-2 and IL-10 in silicosis subjects (equal and more than ILO 1/0) than health workers.
These findings indicate that significant improvements in lung function among a small group of foundry workers following the implementation of an engineering intervention that effectively reduced the levels of respirable silica dust. These results suggest that engineering controls aimed at reducing occupational exposure to silica represent an effective approach that may have immediate benefits to workers.

並列關鍵字

free silica ； foundry worker ； 8-hydroxy-deoxyguanosine ； DNA damage ； cytokines

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