A major update was made to the International Nuclear Workers Study (INWORKS), an international epidemiological study of workers in the nuclear sector to assess their risks of cancer and non-cancerous diseases.

David Richardson, PhD, professor of environmental and occupational health at UC Irvine Joe C. Wen School of Population & Public Health, was the principal investigator for this study and senior author of a publication in The Lancet Haematology that outlines the new findings.

With the study update, Richardson and colleagues sought to understand the associations between low-dose exposure to penetrating forms of ionizing radiation and its effect on risk of leukaemia, lymphoma and multiple myeloma.

The researchers assembled a cohort of more than 300,000 radiation-monitored workers from France, the United Kingdom and the United States, employed at nuclear facilities between 1944 and 2016. Using Poisson regression methods, researchers measured the amount of radiation that got absorbed into bone marrow.

Since radiation exposure is a known risk factor for leukaemia, excluding chronic lymphocytic leukaemia, the study primarily focused on measuring the incidence of leukaemia and other cancer subtypes such as myelodysplastic syndromes, Hodgkin and non-Hodgkin lymphomas, and multiple myeloma.

The study revealed a positive association between prolonged low-dose exposure to ionizing radiation and mortality from these haematological cancers. The study concluded that health risk remains low at low exposure levels. Nevertheless, the evidence of associations between total radiation exposure and multiple myeloma and myelodysplastic syndromes signals the necessity for future radiation studies to expand the discussion on radiation protection and occupational safety measures on a global scale.

"Our studies of people exposed to low doses of radiation add to our understanding of radiation risks at the exposure levels encountered in many contemporary settings," said Richardson who is the associate dean for research at Wen Public Health. "Our results can inform radiation protection standards and will provide input for discussions on protections from radiation."