Prenatal and postnatal serum PCB concentrations and cochlear function in children at 45 months of age
Todd A Jusko1, Renata Sisto, Ana-Maria Iosif
1Division of Epidemiology, Department of Public Health Sciences, University of Rochester School of Medicine and Dentistry, Rochester, New York, USA.
Insights
Postnatal exposure to polychlorinated biphenyls (PCBs) is linked to poorer hearing function in children. This study found no association with prenatal PCB levels, highlighting critical developmental periods for PCB susceptibility.
Area of Science:
- Environmental Health
- Audiology
- Toxicology
Background:
- Emerging evidence suggests polychlorinated biphenyls (PCBs) may cause ototoxicity.
- Previous human studies on PCB exposure and hearing have yielded mixed results, often examining only prenatal or postnatal exposure.
- A comprehensive understanding of PCB exposure timing and its impact on auditory development is lacking.
Purpose of the Study:
- To investigate the association between prenatal and postnatal polychlorinated biphenyl (PCB) concentrations and cochlear status.
- To assess cochlear status using distortion product otoacoustic emissions (DPOAEs).
- To identify critical developmental windows of susceptibility to PCB-induced ototoxicity.
Main Methods:
- A cohort of 351 children in eastern Slovakia was studied.
- Maternal, cord, and child blood samples (at 6, 16, and 45 months) were analyzed for PCB concentrations.
- Distortion product otoacoustic emissions (DPOAEs) were measured at 11 frequencies in both ears at 45 months of age, with analyses adjusted for confounders.
Main Results:
- No association was found between maternal or cord PCB-153 concentrations and DPOAEs at 45 months.
- Elevated postnatal PCB levels at 6, 16, and 45 months correlated with reduced DPOAE amplitudes, indicating poorer cochlear function.
- Increased postnatal PCB-153 exposure (25th to 75th percentile) was associated with a significant decrease in DPOAE amplitude (-1.6 dB SPL).
Conclusions:
- Postnatal exposure to polychlorinated biphenyls (PCBs), not maternal or cord levels, was significantly associated with impaired otoacoustic emission results at 45 months.
- These findings suggest that the postnatal period is a critical window for PCB-induced ototoxicity.
- Further research is warranted to elucidate the mechanisms and long-term implications of postnatal PCB exposure on auditory health.
Background:
Some experimental and human data suggest that exposure to polychlorinated biphenyls (PCBs) may induce ototoxicity, though results of previous epidemiologic studies are mixed and generally focus on either prenatal or postnatal PCB concentrations exclusively.
Objectives:
Our aim was to evaluate the association between pre- and postnatal PCB concentrations in relation to cochlear status, assessed by distortion product otoacoustic emissions (DPOAEs), and to further clarify the critical periods in development where cochlear status may be most susceptible to PCBs.
Methods:
A total of 351 children from a birth cohort in eastern Slovakia underwent otoacoustic testing at 45 months of age. Maternal pregnancy, cord, and child 6-, 16-, and 45-month blood samples were collected and analyzed for PCB concentrations. At 45 months of age, DPOAEs were assessed at 11 frequencies in both ears. Multivariate, generalized linear models were used to estimate the associations between PCB concentrations at different ages and DPOAEs, adjusting for potential confounders.
Results:
Maternal and cord PCB-153 concentrations were not associated with DPOAEs at 45 months. Higher postnatal PCB concentrations at 6-, 16-, and 45-months of age were associated with lower (poorer) DPOAE amplitudes. When all postnatal PCB exposures were considered as an area-under-the-curve metric, an increase in PCB-153 concentration from the 25th to the 75th percentile was associated with a 1.6-dB SPL (sound pressure level) decrease in DPOAE amplitude (95% CI: -2.6, -0.5; p = 0.003).
Conclusions:
In this study, postnatal rather than maternal or cord PCB concentrations were associated with poorer performance on otoacoustic tests at age 45 months.
