Cochlear function in students exposed to pesticides

Purpose  To estimate the degree of association between exposure to pesticides and the risk of alteration in cochlear function in students exposed to pesticides.

Methods  This study evaluated individuals aged 8 to 30, of both genders, residing in an area of heavy pesticide use in the town of Nova Friburgo, Rio de Janeiro State. Each study participant answered a questionnaire to assess their degree of pesticide exposure. To evaluate cochlear function, audiometry exams were performed, including transient evoked otoacoustic emissions (TEOAEs) and distortion product otoacoustic emissions (DPOAEs).

Results  The TEOAE responses were on average lower at higher frequencies, especially at 2.0 and 4.0 kHz, and lower at these frequencies among the most exposed individuals. A similar pattern was observed for DPOAE responses. The lowest response level in the DPOAE tests was observed at the frequency of 6 kHz in the group with the highest exposure score. The proportion of failures observed at more than one frequency in the TEOAE tests on the right ear was significantly higher in the highest exposure group when compared to the lowest exposure group. In the DPOAE test, the rate of failure was also greater in the group with highest exposure when compared to that of lowest exposure.

Conclusion  The results suggest that exposure to pesticides can significantly contribute to alterations in cochlear function in individuals with preserved audiometric thresholds.

Keywords
Pesticides; Evoked Otoacoustic Emissions; Outer Hair Cells; Cochlear Function; Student