過去的研究已顯示廢紙回收造紙廠的噪音作業環境會引起不同程度的聽力損失，但並沒有相關的研究顯示是否會引起DNA損傷。本研究目的在探討某廢紙回收造紙廠勞工暴露於噪音作業環境對聽力與DNA損傷之影響。本研究經初步調查中部某縣市17家造紙業相關產業後，從中選取一家回收廢紙製造紙板的大型紙廠做為研究對象並做噪音暴露量之環境測定共三次，參加受測員工總共有310位，每位員工皆接受純音聽力測試及勞工問卷調查表和職業壓力指標量表之填寫；另外從聽力檢查結果中選取88人，分成對照組17人及聽力損失組71人，利用彗星分析法來探討DNA損傷程度。 經扣除年齡老化因素所得到的聽力損失修正值，結果顯示在談話性低頻率0.5KHz、1 KHz中，女性比男性聽力損失嚴重，並以女性、≧50歲、右耳、1 KHz 之平均值39.0±17.2dB為最高值，而於高頻率2KHz至8 KHz中，不同年齡層之比較，以男性、≧50歲、右耳、8KHz之平均值49.0±27.1dB為中度至重度聽力損失情形。在聽力損失方面，經多變項迴歸分析結果顯示，在右耳4KHz聽力損失之比較，以現場作業及10年以上之工作年資有統計上之相關性，aOR各為2.87（1.03～7.99）、2.75（1.65～4.58），並且噪音作業比非噪音作業之聽力損失多約40dB，並達統計上顯著差異（P=0.001）；而在左耳6 KHz聽力損失之比較，經多變項統計分析，結果顯示在10年以上之工作年資有統計上之相關性，aOR為1.74（1.01～3.01），並且噪音作業比非噪音作業之聽力損失多約44dB，並達統計上顯著差異（P=0.0008）。在DNA損傷方面，結果顯示噪音作業及未使用防護具的勞工，DNA損傷程度隨著噪音的暴露量增加及未使用防護具而更嚴重，但在年齡及抽菸習慣相關因素之影響，在統計上並無增加DNA損傷之相關性。 本研究建議紙業類作業勞工除了暴露在噪音作業環境中導致聽力損失及DNA損傷程度外，基於保護勞工免於噪音作業引起之健康問題，建議該作業區應加強實施聽力保護計畫等要項。; Long-term exposure to noise can induced permanent hearing loss and DNA damage in workers, but this link has not been clearly established with workers at the paper recycling mill. The objective of this study was to evaluate hearing threshold shifts and DNA damage using Pure-tone audiometry and comet assay in paper recycling workers who had been chronically exposed to noise in the workplace. The effect of occupational noise exposure on hearing threshold shifts is studied in workers of paper recycling mill. Study subjects included 291 males and 19 females accepted Pure-tone audiometry is performed personal history and Occupational Stress Indicator（OSI）questionnaires are adopted for the cross-sectional study. Blood samples were taken from 88 subjects and lymphocytes were isolated for analysis of DNA damage by single-cell gel electrophoresis (comet) technique. The noise-exposure group was regularly exposed to noise levels over 85dB, and work duration was over ten years. The average of hearing threshold shifts at high frequencies(4k, 6k, 8kHz) is considerably larger than that at low frequencies(0.5k, 1k, 2k Hz). The moderate to severe degree of hearing loss of the paper mill workplace of subjects showed maximum notches at the frequency of 4 kHz. The noise-exposure group grades of DNA damage were significantly higher then the controls. .Based on smoking status, grades of DNA damage were significantly higher in the noise-exposed group compared to the controls. Multiple regression model analysis revealed that noise-exposure and wearing personal protective equipment had a significant effect on grades of DNA damage, adjusting for other factors, but smoking habit had no significant effect. In conclusion, workers chronically exposed to noise had significantly greater DNA damage and Permanent Threshold Shift （PTS）, but the mechanisms involved are unclear. Also, some individual workers appeared to be much more susceptible to DNA damage than others. Comet assay was useful in evaluating the genotoxic effect of noise exposure.
