Related Experiment Video
Updated: Feb 3, 2026
Tuning the Acidity of Pt/ CNTs Catalysts for Hydrodeoxygenation of Diphenyl Ether
Published on: August 17, 2019
Polybrominated diphenyl ether (PBDE) neurotoxicity: a systematic review and meta-analysis of animal evidence
David C Dorman1, Weihsueh Chiu2, Barbara F Hales3
1a Department of Molecular and Biomedical Sciences , College of Veterinary Medicine, North Carolina State University , Raleigh , NC , USA.
Insights
Prenatal exposure to polybrominated diphenyl ethers (PBDEs) may impact children's IQ. This review of animal studies suggests PBDEs affect learning, with moderate evidence for specific compounds like BDE 47, 99, and 209.
Area of Science:
- Environmental Toxicology
- Neuroscience
- Developmental Toxicology
Background:
- Human studies link prenatal polybrominated diphenyl ethers (PBDE) exposure to decreased child IQ.
- PBDEs are flame retardants found in consumer products, raising public health concerns.
- Understanding PBDE neurotoxicity in animal models is crucial for risk assessment.
Purpose of the Study:
- To systematically review experimental animal studies on PBDE-mediated neurotoxicity.
- To assess impacts on learning, memory, and attention, paralleling human intelligence outcomes.
- To evaluate the overall body of evidence and risk of bias in animal studies.
Main Methods:
- Systematic review of non-human mammalian studies from PubMed, Embase, and Toxline.
- Evaluation of risk of bias and evidence levels following National Toxicology Program guidance.
- Meta-analysis of Morris water maze studies for learning impairment.
Main Results:
- Moderate evidence suggests BDEs 47, 99, and 209 exposure impacts learning in animals.
- Meta-analysis of 6 studies showed increased latency in PBDE-exposed animals (effect size 25.8).
- Inconsistent findings and poor study reporting limited dose-response conclusions for most PBDEs.
Conclusions:
- The meta-analysis provided stronger evidence than qualitative review, highlighting learning deficits.
- Incomplete study reporting raises concerns about risk of bias.
- Further research with improved reporting is needed to clarify PBDE neurotoxicity.
Abstract:
A recent systematic review (SR) and meta-analysis of human studies found an association between prenatal serum polybrominated diphenyl ethers (PBDE) concentrations and a decrease in the IQ of children. A SR of experimental developmental animal PBDE-mediated neurotoxicity studies was performed in the present study. Outcomes assessed included measures related to learning, memory, and attention, which parallel the intelligence-related outcomes evaluated in the human studies SR. PubMed, Embase, and Toxline were searched for relevant experimental non-human mammalian studies. Evaluation of risk of bias (RoB) and overall body of evidence followed guidance developed by the National Toxicology Program. Animal studies using varying designs and outcomes were available for BDEs 47, 99, 153, 203, 206, and 209 and the technical mixture DE-71. Study reporting of methods and results was often incomplete leading to concerns regarding RoB. A meta-analysis of 6 Morris water maze studies showed evidence of a significant increase in last trial latency (effect size of 25.8 [CI, 20.3 to 31.2]) in PBDE-exposed animals with low heterogeneity. For most endpoints, there were unexplained inconsistencies across studies and no consistent evidence of a dose-response relationship. There is a "moderate" level of evidence that exposure to BDEs 47, 99, and 209 affects learning. For other PBDEs and other endpoints, the level of evidence was "low" or "very low". The meta-analysis led to stronger conclusions than that based upon a qualitative review of the evidence. The SR also identified RoB concerns that might be remedied by better study reporting.
Related Concept Videos
02:55The Evidence for Evolution
02:29Ethers from Alcohols: Alcohol Dehydration and Williamson Ether Synthesis
Ethers can be prepared from organic compounds by various methods. Some of them are discussed below,
Preparation of Ethers by Alcohol Dehydration
In this method, in the presence of protic acids, alcohol dehydrates to produce alkenes and ethers under different conditions. For example, in the presence of sulphuric acid, dehydration of ethanol at 413 K yields ethoxyethane, whereas it yields ethene at 443 K.
01:10Review and Preview
Percentiles are a type of fractile that partition data into...
01:13Review and Preview
02:36Crown Ethers
02:28Structure and Nomenclature of Ethers
Ethers are organic compounds with an ether functional group which is characterized by an oxygen atom connected to two — identical or different — alkyl, aryl, or vinyl groups. The C–O–C linkage in dimethyl ether — the simplest ether — has an approximately tetrahedral bond angle of 110.3 degrees. The oxygen atom is sp3- hybridized, with the C–O distance being about 140 pm.
Classification of Ethers
Based on their attached substituent...