title: Do flame retardant chemicals increase the risk for thyroid dysregulation and cancer?
abstract: Flame retardant chemicals are added to consumer products to reduce fire incidence and severity; approximately 1.5 million tons of these chemicals are used annually. However, their widespread use has led to their ubiquitous presence in the environment and chronic accumulation in human tissues. We summarize current trends in human flame retardant chemical exposure, and review recent data highlighting concerns for thyroid dysregulation and cancer risk in human populations.
  
  
  
  Polybrominated diphenyl ethers were once commonly used as flame retardant chemicals, but recently were phased out. Exposure is associated with thyroid dysregulation (mainly T4 reductions) in animals, with new work focusing on specific mechanisms of action. Polybrominated diphenyl ethers also impact human thyroid regulation and are related to clinical thyroid disease, but associations appear both dose and life-stage dependent. Emerging data suggest that common alternate flame retardant chemicals may be more potent thyroid disruptors than their predecessors, which is particularly concerning given increasing levels of exposure.
  
  
  
  Potential health impacts of flame retardant chemicals are only beginning to be understood for 'legacy flame retardant chemicals' (i.e., polybrominated diphenyl ethers), and are largely unevaluated for newer-use chemicals. Cumulatively, current data suggest impact on thyroid regulation is likely, potentially implicating flame retardant chemicals in thyroid disease and cancers for which thyroid dysregulation impacts risk or prognosis.
authors.affiliation: aNicholas School of the Environment, Duke University bDepartments of Surgery and Medicine cDuke Cancer Institute and Duke Clinical Research Institute, Duke University Medical Center, Durham, North Carolina, USA.
authors.forename: Kate
authors.initials: K
authors.lastname: Hoffman
authors.forename: Julie A
authors.initials: JA
authors.lastname: Sosa
authors.forename: Heather M
authors.initials: HM
authors.lastname: Stapleton
mesh_terms: D004781:Environmental Exposure; D005411:Flame Retardants / Q000032:analysis / Q000506:poisoning*; D055768:Halogenated Diphenyl Ethers / Q000032:analysis / Q000506:poisoning; D006801:Humans; D007037:Hypothyroidism / Q000139:chemically induced / Q000378:metabolism; D013961:Thyroid Gland / Q000187:drug effects / Q000378:metabolism; D013964:Thyroid Neoplasms / Q000139:chemically induced* / Q000378:metabolism; D013974:Thyroxine / Q000378:metabolism
chemical_list: D005411:Flame Retardants; D055768:Halogenated Diphenyl Ethers; D013974:Thyroxine