Hearing loss in children with e-waste lead and cadmium exposure

Hearing loss is caused by exposure to a wide range of biological and environmental factors. Exposure to heavy metals has been proposed as an important risk factor for hearing loss. We evaluated the cross-sectional associations... [ view full abstract ]

Hearing loss is caused by exposure to a wide range of biological and environmental factors. Exposure to heavy metals has been proposed as an important risk factor for hearing loss. We evaluated the cross-sectional associations between blood lead (Pb) levels, urinary cadmium (Cd) levels and audio-metrically determined hearing thresholds in preschool children from Guiyu, an e-waste recycling area. A total of 234 children, 3-7 years of age, were recruited to participate in audiometric testing in 2014. Air conduction hearing thresholds were examined from 0.5 to 8 kHz, and hearing loss was defined as a pure-tone average (PTA) > 25 decibel (dB) in one or both ears. Higher Pb levels and urinary Cd levels were measured in the exposed group than the reference group (p < 0.01). Hearing thresholds in both ears increased with advancing age and declined with increasing frequency in both groups. After adjusting for age, the PTA in one or both ears was significantly higher in the exposed group (p < 0.01). Compared with the reference group, the exposed group had a significantly higher prevalence of hearing loss (21.2% vs 4.5%; p < 0.01). After adjustment, the multivariable adjusted odds ratios (ORs) for hearing loss were 4.855 (95% CI: 1.248, 18.882) and 0.667 (95% CI: 0.134, 3.319) in the highest versus the lowest blood Pb and urinary Cd quintiles, respectively. Results suggest that exposure to Pb in preschool children from an e-waste recycling area may be an important risk factor for hearing loss.