噪音作業勞工聽力損失相關危險因子之探討

A Study for Risk Factors on Hearing Loss among Noise-Exposed Workers

闕淳真(Chun-Chen Chueh)

指導教授 ： 何啟功

高雄醫學大學/健康科學院/職業安全衛生研究所/碩士(2006年)

https://doi.org/10.6832/KMU.2006.00017

摘要

研究目的：瞭解台灣南部地區噪音相關作業勞工聽力損失之情形及特性，探討聽力損失之相關危險因子；並以連續年度資料進行分析，以瞭解勞工聽力損失之演變情形、評估聽力保護措施實施之成效。
研究材料與方法：研究對象取自於民國92到93年間到台灣南部地區某醫學中心進行聽力健康檢查之1117位勞工，收集其純音聽力檢查結果，並以聽力保護問卷收集勞工之基本資料及職業暴露等相關資訊；連結某一事業單位（屬電力供應業）之160位健檢勞工民國91至94年之聽力檢查資料進行統計分析。
研究結果：1. 本研究之有效個案總數為604位從事噪音作業之男性勞工。年齡介於24~64歲，平均年齡則為46.5歲。年資方面，以入廠大於10年以上之個案數最多，有452人（75.6%）。依照American Academy of Otolaryngology-Head and Neck Surgery（AAO-HNS）之規範標準來評估勞工之聽力損失，發現有152位（25.2%）之勞工有聽力損失之情況。2. 無論左、右耳，勞工之最低平均聽力閾值皆出現在1000 Hz處（左耳：18.68 dB；右耳：18.20 dB）；最高之平均聽力閾值皆出現在6000 Hz處（左耳：30.27 dB；右耳：30.59 dB），且若以500、1000及2000 Hz三個頻率之平均聽力閾值來看，左耳（19.35 dB）較右耳（19.05 dB）有稍高之平均聽力閾值。在聽力圖的表現上，高頻部分以6000 Hz為谷底，出現約略對稱之凹谷（notch）圖形，和典型之噪音引起的聽力損失（noise-induced hearing loss, NIHL）最大聽力閾值轉換是發生在4000 Hz有所不同。3. 聽力損失相關危險因子：調整干擾因子之後發現，「每天嚼檳榔（參考族群：從未嚼檳榔）」、「直系血親於年幼罹患聽力障礙」、「有機溶劑暴露頻率≧1次/天（參考族群：暴露頻率0~1次/週）」及「喝酒頻率>3次/週（參考族群：沒有喝酒習慣）」者，其罹患聽力損失之相對危險性增加，OR值分別為：5.78、5.42、2.93及2.25。4. 聽力保護措施實施之成效：此160位噪音作業之男性勞工於頻率500、1k、2k、3k、4k及6k Hz之平均聽力損失進展速度分別為：1.61、1.43、1.54、1.71、2.25及2.43分貝/年。將此160位噪音作業之男性勞工其民國94年2k、3k及4k Hz三頻率之平均聽力閾值與民國91年之基準聽力圖相比，其任一耳之平均聽力閾值變差10 dB以上之發生率為21.3%；依照OSHA標準聽力閾值改變之定義，聽力損失發生率在9~18%之內，聽力損失措施績效被認為是可以接受的，但本研究160位勞工之聽力損失發生率超出可接受範圍。
結論：1. 建議勞工聽力檢查之測定頻率應包含8k Hz之純音。2.「年齡老化」、「嚼檳榔習慣」、「家族史」、「有機溶劑暴露」及「喝酒習慣」會增加聽力損失之發生風險，為聽力損失之危險因子。3. 現行之聽力保護措施尚有加強推展之空間。

關鍵字

聽力損失 ； 危險因子

並列摘要

Objective: To investigate the characteristics and risk factors of hearing loss among noise-exposed workers in southern Taiwan, and evaluate the progression of hearing loss and the effect of hearing protection measures.
Method: Questionnaire of personal data (personal habit, occupational and non-occupational exposure) and data of pure tone auditory threshold test of 1117 workers were collected while annual health examination performed in medical center in southern Taiwan during 2003~2004, and pure tone auditory threshold test of 160 workers were analyzed for searching serial change (2002~2005).
Result:
1. Our study population included 604 noise-exposed male workers. The workers’ average age was 46.5 years old. 152(25.2%) workers suffered from hearing loss according to the criteria established by AAO-HNS(a 25dB or greater loss in either ear at an average of: 500, 1000 & 2000 Hz).
2. The lowest level of mean auditory threshold is at 1000 Hz (left ear: 18.68 dB, right ear: 18.20 dB). The highest level of mean auditory threshold is at 6000 Hz (left ear: 30.27 dB, right ear: 30.59 dB). The results of pure tone auditory threshold test at 500, 1000 and 2000Hz reveal that the threshold level of left ear is higher than that of right ear (left ear: 19.35 dB, right ear: 19.05 dB). The greatest hearing threshold shift in our study occurred at 6000 Hz. This finding differs from those of a typical case of noise-induced hearing loss(NIHL). The greatest hearing threshold shift in typical NIHL usually occurs at 4000 Hz.
3. After adjusting the confounding factors, the relative risk of hearing loss are as followings: a. chewing betel nut everyday to no betel nut chewing habit (OR=5.78)；b. relatives had hearing loss in childhood (OR=5.42)；c. organic solvent exposure frequency ≧1 time/day to 0~1 time/week (OR=2.93)；d. alcohol consuming > 3 times/week to no alcohol consuming habit (OR=2.25).
4. The mean hearing loss rate of 160 workers at different frequency are as followings: 500 Hz (1.61 dB/year), 1k Hz (1.43 dB/year), 2k Hz (1.54 dB/year) , 3k Hz (1.71 dB/year), 4k Hz (2.25 dB/year) and 6k Hz (2.43 dB/year). Comparison of the 160 workers’ mean auditory threshold (2k, 3k, 4k Hz) in 2005 to baseline in 2002, the prevalence of mean auditory threshold of either ear increases above 10 dB is 21.3%. According to OSHA, 3~6% of the prevalence is acceptable. Compare to our data, hearing loss prevalence is beyond the limit by 9~18%.
Conclusion: 1. Pure tone auditory threshold test should include 8000 Hz. 2.
The risk factors associated with hearing loss are as followings: (1) Aging (2)
Betel nut chewing (3) Familial history (4) Organic solvent exposure (5)
Alcohol drinking habit. 3. Current hearing conservation program need to be
enforced.

並列關鍵字

hearing loss ； noise ； risk factors

參考文獻

第七章 參考文獻

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