Exposure to polychlorinated biphenyls and hearing impairment in children.

The objective of this cross-sectional epidemiological study was to assess if long-term exposure to polychlorinated biphenyls (PCBs) is associated with hearing impairment. Four hundred and thirty-three children aged 8-9 years residing in an area polluted by PCBs in Eastern Slovakia were examined otoscopically, tympanometrically and by pure tone audiometry. PCB levels in their serum were determined by gas chromatography. Transient otoacoustic emissions (TEOAE) were measured in a subgroup of 161 children. The mean of the sum of PCB concentrations in serum was 528.2ng/g serum lipids (median 321ng/g serum lipids). Serum PCB concentrations were associated with an increase of hearing threshold at low frequencies and a negative correlation between serum PCBs and the amplitude of TEOAE response was observed in the uppermost tertile of children grouped with regard to serum PCBs, not related to thyroid hormone levels. It was concluded that long-term environmental exposure to PCBs is associated with subclinical but diagnosable hearing deficits.