Serum PCB Concentrations and Cochlear Function in 12-Year-Old Children

Abstract

Experimental evidence from animals indicates that exposure to polychlorinated biphenyls (PCBs) causes deterioration of the outer hair cells (OHCs) of the cochlea. To test this hypothesis in humans, we measured serum PCB concentrations in 574 12-year-old children residing in three districts in the Slovak Republic using high-resolution gas chromatography with micro-electron capture detection. As a marker of cochlear status, we measured transient evoked (TE) and distortion product (DP) otoacoustic emissions (OAEs), and assessed the cross-sectional association between serum PCBs and OAEs. Median total PCB concentrations were 352.8, 150.5, and 134.9 ng/g lipid in Michalovce, Svidnik, and Bratislava, respectively. In multivariate regression models where otoacoustic measures were modeled as a function of log (base 10) PCB concentrations with adjustment for gender, age, and site of examination, dioxin-like PCBs, non-dioxin-like PCBs and a PCB grouping targeting upregulation of hepatic uridine 5′-diphospho-glucuronosyltransferase were significantly associated with lower TEOAE powers at 1000 and 1500 Hz. At 1500 Hz, we observed a strong association with sum of PCBs and DL-PCBs, in the left ear only. The DPOAEs at 1000 Hz were associated with all 4 PCB groupings. The results of this study show that PCBs may affect the OHCs of the cochlea, a result consistent with findings from animal studies published to date.

Assessment of the Levels of Persistent Organic Pollutants and 1-Hydroxypyrene in Blood and Urine Samples from Mexican Children Living in an Endemic Malaria Area in Mexico

“…In other hand, in San Felipe Nuevo Mercurio, Zacatecas, Mexico, the mean levels found in children living in that community was 1,600 ng/g lipid (Costilla-Salazar et al 2011). When compared PCBs levels in blood found in this study with levels reported in others studies around the world, we can note that children living in El Ramonal had higher levels (5,892.1 ng/g lipid) than children living in China (40.6 ng/g lipid; Shen et al 2010) and children living in the Slovak Republic (352.8 ng/g lipid; Trnovec et al 2010).…”

Developmental exposure to PCBs alters the activation of the auditory cortex in response to GABA A antagonism

“…Impairments in auditory function are a consistent finding in human and rodent models examining effects of developmental PCBs (Jusko et al, 2014; Trnovec et al, 2010; Powers et al, 2006, 2009; Poon et al, 2011). Previously, our lab has reported that auditory brainstem response (ABR) thresholds were elevated across all frequencies tested in PCB-exposed rats, indicative of dysfunction in the cochlea or auditory nerve (Powers et al, 2006).…”

Biomarkers Linking PCB Exposure and Obesity.

“…boys were more susceptible than girls to growth restrictions [26]; (b) poor neurodevelopment, in which the results indicated an association of PCBs with decreased Mental Development Index (MDI), and reduced levels of thyroid hormone [27, 28]; hearing impairments, wherein the results showed that PCB exposures were associated with harmful effects on the outer hair cells of the cochlea [29]; endocrine disruption, characterized by an increase in the prevalence of several subclinical and overt thyroid and metabolic disorders [30, 112]; and diabetes, showing that increasing serum concentrations of individual POPs considerably increased the prevalence of pre-diabetics indicators [10]. …”