用个体暴露评价脉冲噪声与稳态噪声所致高频听力损失的关系

目的用个体噪声暴露测量数据比较工业脉冲噪声与稳态噪声所致高频听力损失剂量反应关系的异同。方法1998至1999年,以32名接触脉冲噪声的机械制造工人和163名接触稳态噪声的纺织工人为观察对象,用噪声剂量计采集8h工作期间的噪声暴露数据,计算8h等效声级(LAeq.8h),并按等能量原理将LAeq.8h和噪声作业工龄合并为累积噪声暴露量(CNE)。用常规方法测量工人左右耳气导听阈,按GBZ492002对听阈做年龄性别校正,并诊断是否为高频听力损失。结果脉冲噪声组的CNE(103.2±4.2)dB(A)·年]明显低于稳态噪声组(110.6±6.0)dB(A)·年],脉冲噪声组高频听力损失患病率(68.8%)与稳态噪声组(65.0%)相似,分层分析和趋势卡方检验证实,两组CNE与高频听力损失患病率间均存在典型的剂量反应关系,差异有统计学意义;脉冲噪声100～104和105～109dB(A)·年两组的高频听力损失患病率(76.9%和90.9%)高出稳态噪声组(30.4%和50.0%)约1倍。logistic回归模型显示,脉冲噪声组CNE与高频听力损失患病率的剂量反应关系曲线与稳态噪声组相比出现曲线左移,斜率增大。结论采用个体噪声暴露数据计算时,在能量相同的情况下,脉冲噪声所致高频听力损失的危害大于稳态噪声。

Relationship between impulse noise and continuous noise inducing hearing loss by dosimeter measurement in working populations

OBJECTIVE: To compare the dose-response relationship differences between impulse noise exposure workers and continuous noise exposure workers in prevalence of noise inducing hearing loss using dosimeter measurement. METHODS: Thirty-two mechanical workers in a workshop were selected as impulse noise group and 163 textile workers in a textile factory as continuous noise group. SH-126 dosimeter was used to measure A weighted equal sound level of eight hours (L(Aeq.8 h)) during full working duration with equal energy rule for the selected workers. The cumulative noise exposure (CNE) was calculated by L(Aeq.8 h) and noise working years with equal energy rule for each worker. Hearing thresholds were measured by audiometer by routine method and adjusted by age and gender with GBZ49 - 2002. Hearing loss was diagnosed by GBZ49 - 2002 for each worker. RESULTS: CNE of impulse noise group (103.2 +/- 4.2) dB (A) .year] was found lower than the continuous noise group (110.6 +/- 6.0) dB (A) .year] by significance, P < 0.05. The hearing loss prevalence of impulse noise group (68.8%) was similar as continuous noise group (65%) without significance, P > 0.05. Strata analysis showed the hearing loss prevalence in 100 - 104 dB (A) .year and 105 - 109 dB (A) .year of impulse noise group was double than that of continuous noise group (76.9%, 90.9% vs 30.4%, 50.0%), P < 0.05. The chi-square test showed a relationship between CNE and hearing loss prevalence that was in high significance (P < 0.01) in both impulse noise group and continuous noise group. Logistic regression model showed the dose-response relationship curve of impulse noise group was left shift and sharp slope. CONCLUSION: The damage of impulse noise on hearing loss was much more than that of continuous noise according to equal energy rule of dosimeter data.