Chronic inflammation in a radium dial painter cohort: elevated neutrophil to lymphocyte ratio and radiation-induced hearing loss.

Abstract

The radium dial painters (RDP) are a well-described group of predominantly young women who incidentally ingested 226Ra and 228Ra as they painted luminescent watch dials in the first part of the twentieth century. In 1974 pathologist Dr. William D. Sharpe published complete clinical and autopsy results for 42 former radium dial painters evaluated in the New Jersey Radium Research Project (NJRRP). This was an important paper due to the completeness of the observations. Surprisingly, in this study, clinicians noted a 35.5% incidence of hearing loss, both conductive and mixed etiologies. Since the 1974 publication, there has developed a considerable literature on radiation-induced hearing loss in patients undergoing radiotherapy for head and neck cancers. It is expected that hearing loss would also be associated with systemic inflammation. Recently, the neutrophil to lymphocyte ratio (NLR) has been shown in many cancer and non-cancer studies to be a nonspecific marker of inflammation. In prior collaborative efforts with the United States Transuranium and Uranium Registries (USTUR) and with the NCRP Million Person Study, it has been possible to evaluate NLR from medical records of a cohort of 166 former radium dial painters previously evaluated at Argonne National Laboratory. In addition, NLR was available in historic medical records of the sarcoma and nasopharyngeal cancer patients described in Rowland's summary of the Argonne studies. . Using elevation of the neutrophil to lymphocyte ratio (NLR) as a non-specific marker of inflammation, chronic inflammation has been observed in all cohorts with significant dose. The RDP cohort has had a unique exposure to radium, but the incidence of radiation-induced hearing loss here is uncertain. Due to cosmic radiation dose to astronauts in space flight, there is a significant interest in high LET radiation dose to the brain, including the auditory system. .