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PCBs and impaired cochlear function in children: comparing pre- and postnatal exposures.

Barrett JR - Environ. Health Perspect. (2014)

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A new study reported in EHP specifically links postnatal—but not prenatal—PCB exposure with impaired cochlear function... The cochlea, an extremely sensitive organ in the inner ear, converts soundwave vibrations to nerve impulses transmitted to the brain... Cochlear damage can impair hearing and is a well-known side effect of certain antibiotics and chemotherapeutic drugs... At 45 months, the children also underwent otological and auditory testing, including an assessment of distortion product otoacoustic emissions (DPOAEs), a measure of cochlear function... Blood tests measured 15 PCB congeners, but analyses focused on PCB-153, which was detected in nearly all samples and closely correlated with total PCB concentrations... An inverse relationship existed between decreased DPOAE amplitude (a marker of diminished cochlear function) and postnatal serum PCB concentrations, with the strongest association observed for cumulative levels of PCBs... No association was observed between prenatal PCB exposure and decreased DPOAE amplitude... The PCB-associated decrease in DPOAE amplitude was not large. “Certainly, the hearing impairment would be subclinical,” says study coauthor Tomáš Trnovec, a professor of environmental medicine at Slovak Medical University in Bratislava... However, the cochlea is vulnerable to any number of environmental insults, including noise, organochlorine pesticides, and drugs, among others, Trnovec says. “The combined effect of these factors is completely unknown,” he says, adding that “under different settings and other data treatment … a prenatal exposure effect cannot be excluded. ” It’s also unknown whether effects persist and whether continued exposure (combined with other stressors) builds on early damage. “In my opinion, PCB ototoxicity may be involved in the pathogenesis of hearing impairment in the adult population,” says Kyoung-Bok Min, an assistant professor in occupational and environmental medicine at South Korea’s Ajou University School of Medicine, who was not involved in the study... Min and colleagues recently reported an association between PCB serum levels and increased prevalence of hearing impairment in adults who participated in the National Health and Nutrition Examination Survey. “Further epidemiologic studies are needed in terms of whether the impact of exposure to PCBs on cochlear function changes throughout the life span of the human,” he says... In addition, Susan Schantz, a professor of veterinary biosciences and psychology at the University of Illinois at Urbana–Champaign, raises the possibility of potential impacts beyond hearing. “One of the things that really interests me—and that I don’t know the answer to—is what does that kind of a decrease [in DPOAE amplitude] mean? Previous PCB cohort studies have shown an adverse impact on cognitive function, including verbal abilities. “I’ve always wondered whether subtle changes in hearing could be affecting language development, and then that could be affecting verbal abilities,” Schantz says... The new study features a particularly strong design based on multiple PCB measurements in a well-characterized population.

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Clusters of hair cells populate the cochlea and detect sounds transmitted to the inner ear.© David Spears FRPS FRMS/Corbis
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d35e108: Clusters of hair cells populate the cochlea and detect sounds transmitted to the inner ear.© David Spears FRPS FRMS/Corbis


PCBs and impaired cochlear function in children: comparing pre- and postnatal exposures.

Barrett JR - Environ. Health Perspect. (2014)

Clusters of hair cells populate the cochlea and detect sounds transmitted to the inner ear.© David Spears FRPS FRMS/Corbis
© Copyright Policy - public-domain
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4216154&req=5

d35e108: Clusters of hair cells populate the cochlea and detect sounds transmitted to the inner ear.© David Spears FRPS FRMS/Corbis

View Article: PubMed Central - PubMed

AUTOMATICALLY GENERATED EXCERPT
Please rate it.

A new study reported in EHP specifically links postnatal—but not prenatal—PCB exposure with impaired cochlear function... The cochlea, an extremely sensitive organ in the inner ear, converts soundwave vibrations to nerve impulses transmitted to the brain... Cochlear damage can impair hearing and is a well-known side effect of certain antibiotics and chemotherapeutic drugs... At 45 months, the children also underwent otological and auditory testing, including an assessment of distortion product otoacoustic emissions (DPOAEs), a measure of cochlear function... Blood tests measured 15 PCB congeners, but analyses focused on PCB-153, which was detected in nearly all samples and closely correlated with total PCB concentrations... An inverse relationship existed between decreased DPOAE amplitude (a marker of diminished cochlear function) and postnatal serum PCB concentrations, with the strongest association observed for cumulative levels of PCBs... No association was observed between prenatal PCB exposure and decreased DPOAE amplitude... The PCB-associated decrease in DPOAE amplitude was not large. “Certainly, the hearing impairment would be subclinical,” says study coauthor Tomáš Trnovec, a professor of environmental medicine at Slovak Medical University in Bratislava... However, the cochlea is vulnerable to any number of environmental insults, including noise, organochlorine pesticides, and drugs, among others, Trnovec says. “The combined effect of these factors is completely unknown,” he says, adding that “under different settings and other data treatment … a prenatal exposure effect cannot be excluded. ” It’s also unknown whether effects persist and whether continued exposure (combined with other stressors) builds on early damage. “In my opinion, PCB ototoxicity may be involved in the pathogenesis of hearing impairment in the adult population,” says Kyoung-Bok Min, an assistant professor in occupational and environmental medicine at South Korea’s Ajou University School of Medicine, who was not involved in the study... Min and colleagues recently reported an association between PCB serum levels and increased prevalence of hearing impairment in adults who participated in the National Health and Nutrition Examination Survey. “Further epidemiologic studies are needed in terms of whether the impact of exposure to PCBs on cochlear function changes throughout the life span of the human,” he says... In addition, Susan Schantz, a professor of veterinary biosciences and psychology at the University of Illinois at Urbana–Champaign, raises the possibility of potential impacts beyond hearing. “One of the things that really interests me—and that I don’t know the answer to—is what does that kind of a decrease [in DPOAE amplitude] mean? Previous PCB cohort studies have shown an adverse impact on cognitive function, including verbal abilities. “I’ve always wondered whether subtle changes in hearing could be affecting language development, and then that could be affecting verbal abilities,” Schantz says... The new study features a particularly strong design based on multiple PCB measurements in a well-characterized population.

Show MeSH
Related in: MedlinePlus