Are Higher Exposures to Flame Retardant Chemicals Associated with Papillary Thyroid Cancer?

Papillary thyroid cancer (PTC) occurrence has been significantly increasing throughout the world, and particularly in the US, for several decades. At the same time the use of flame retardants (FR) chemicals has increased, as reflected by increasing concentrations in human tissues. In this study we sought to determine whether flame retardants exposures are higher in individuals recently diagnosed with papillary thyroid cancer relative to a healthy population. The study group included people diagnosed with PTC at the Duke Cancer Center, and controls were matched by age and sex who are recruited from the Duke Health System. Flame retardants (FRs) exposure were estimated from silicone wristband worn for 7 days by participants, which have been validated against traditional biomarkers of exposure. Results indicated that both obesity, and higher levels of the FR Tris (1,3-dichloro-isopropyl) phosphate (TDCPP), were related to increased odds of being a papillary thyroid cancer patient relative to a control. In adjusted statistical models, each log unit increase in TDCPPs on the wristband was found to be associated with a 57% increase in being a case vs a control, while each log unit increase in BMI will result in a 7.1% increase. Therefore, these results indicated that some FRs exposure may be associated with increased PTC incidence.