Chadambuka A, Mususa F, Muteti S
Department of Community Medicine, University of Zimbabwe.
Afr Health Sci. 2013 Dec;13(4):899-906. doi: 10.4314/ahs.v13i4.6.
Noise induced hearing loss (NIHL) is within the top five occupational illnesses in Zimbabwe. Workers at a mining company complained about loss of hearing at the mine clinic.
To determine the prevalence of NIHL among employees at the Mine.
We conducted a descriptive cross sectional study at the mine. Workers were proportionally selected to represent all the mine departments or working areas. We measured noise levels at various mine sites, conducted a walk-through survey to observe noise related worker practices and conducted audiometric testing.
Mean age for workers was 34.8±7.6 years and the mean duration of exposure to noise was 7.5±1.2 years. All workers could define noise. Ninety (53%) workers attributed NIHL to noisy work environment. Excessive noise levels were in Plant Processing (94 dBA), Underground Mining (102 dBA) and (Underground Workshop (103 dBA). Sixty two (36.7%) workers had NIHL. NIHL increased as a function of age (chi square=30.99 df=3 p<0.01) and was associated with work area (chi square=24.96 df=5 p<0.01). Observed workers took heed of noise warnings. There was no documented hearing conservation program at the mine.
The prevalence of NIHL of 37% is high. Age and work area were associated with NIHL. Studies reported that age tends to distort the relationship between noise exposure and NIHL. Mine management should institute a hearing conservation program to protect employees against hazardous noise. Management may meanwhile use administrative controls and adhere to permissible exposure limits according to the noise regulations.
噪声性听力损失（NIHL）是津巴布韦排名前五的职业病之一。一家矿业公司的工人在矿山诊所抱怨听力下降。
确定该矿山员工中噪声性听力损失的患病率。
我们在该矿山进行了一项描述性横断面研究。按比例挑选工人以代表矿山所有部门或工作区域。我们测量了矿山各个地点的噪声水平，进行了一次巡查以观察与噪声相关的工人操作，并进行了听力测试。
工人的平均年龄为34.8±7.6岁，平均噪声暴露时长为7.5±1.2年。所有工人都能对噪声进行定义。90名（53%）工人将噪声性听力损失归因于嘈杂的工作环境。过高的噪声水平出现在选矿厂（94分贝）、地下采矿区（102分贝）和地下车间（103分贝）。62名（36.7%）工人患有噪声性听力损失。噪声性听力损失随年龄增长而增加（卡方=30.99，自由度=3，p<0.01），并与工作区域有关（卡方=24.96，自由度=5，p<0.01）。观察到工人留意了噪声警告。该矿山没有记录在案的听力保护计划。
37%的噪声性听力损失患病率很高。年龄和工作区域与噪声性听力损失有关。研究报告称，年龄往往会扭曲噪声暴露与噪声性听力损失之间的关系。矿山管理层应制定听力保护计划，以保护员工免受有害噪声的影响。与此同时，管理层可采用行政控制措施，并根据噪声法规遵守允许的暴露限值。
