Study on hearing loss and its relationship with work in pesticide-exposed tobacco growers

ABSTRACT The Purpose of this case report is to present four cases of tobacco growers with hearing loss due to occupational exposure to pesticides. A qualitative case study comprising three cases of sensorineural hearing loss with causal nexus (Cases 1, 2 and 4), and one (Case 3) of sensorineural hearing loss compatible with ototoxicity by pesticides, with causal nexus mainly based on minor neuropsychiatric disorders. The sample was composed of rural workers with health problems, in working age, having started working early in life, exposed to various pesticides, including organophosphates. The auditory and neurovegetative symptoms reported were noise discomfort (n = 2), speech perception difficulty (n = 3), dizziness (n = 2), and imbalance (n = 2). The pure-tone audiometry revealed a sensorineural hearing loss in one or more high frequencies, and one of the cases presented alteration in the brainstem auditory evoked potentials. There is evidence, in this study, of an association between hearing loss and work in tobacco growers exposed to pesticides, with peripheral auditory damage in four cases, and central damage in one of them. Thus, the need for a complete audiological evaluation of pesticide-exposed populations is highlighted.摘要 本病例报告旨在报告4例因职业暴露于农药而罹患听力损失的烟草种植者病例。本研究为定性病例研究，其中3例（病例1、2及4）为存在因果关联的感音神经性听力损失（sensorineural hearing loss），1例（病例3）为符合农药耳毒性（ototoxicity）表现的感音神经性听力损失，其因果关联主要基于轻微神经精神障碍。研究样本为处于务工年龄、存在健康问题的农村劳动者，均早年即开始从事相关工作，且暴露于包括有机磷酸酯类（organophosphates）在内的多种农药。报告的听觉及自主神经症状包括：耳部不适（2例）、言语感知困难（3例）、眩晕（2例）及平衡失调（2例）。纯音测听（pure-tone audiometry）结果显示，4例病例均存在单频或多频高频区域的感音神经性听力损失，其中1例的脑干听觉诱发电位（brainstem auditory evoked potentials）存在异常。本研究证实，暴露于农药的烟草种植者的听力损失与职业暴露存在关联：4例均存在外周听觉损伤，其中1例还合并中枢听觉损伤。综上，本研究强调了对农药暴露人群开展全面听力学评估的必要性。