Cognitive effects of low dose of ionizing radiation – Lessons learned and research gaps from epidemiological and biological studies

• Published in: Environment international Vol. 147; p. 106295
• Main Authors: Pasqual, Elisa, Boussin, François, Bazyka, Dimitry, Nordenskjold, Arvid, Yamada, Michiko, Ozasa, Kotaro, Pazzaglia, Simonetta, Roy, Laurence, Thierry-Chef, Isabelle, de Vathaire, Florent, Benotmane, Mohammed Abderrafi, Cardis, Elisabeth
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Ltd 01-02-2021; Elsevier
• Subjects: Animals; Atomic bombing; Biomarkers; Chernobyl accident; Cognition; Humans; Ionizing radiation; Life Sciences; Low doses; Medical radiation; Medicin och hälsovetenskap; MELODI; Neurodegeneration; Neurodevelopment; Radiation Exposure - adverse effects; Radiation Injuries - epidemiology; Radiation, Ionizing; ADHD; Low doses; SRA; MRI; SGZ; Cognition; AHS; SD; Ionizing radiation; CBVD; Neurodegeneration; MMSE; SVZ; SR; Atomic bombing; GHQ-28; IR; CASI; FACT-Cog; BPRS-18; RAVLT; CT; MELODI; Neurodevelopment; Medical radiation; ICRP; NCQ; Chernobyl accident; RP
• ISSN: 0160-4120; 1873-6750; 1873-6750
• DOI: 10.1016/j.envint.2020.106295

•Reviewed evidence indicates potential effects of low doses of IR on cognition.•Gaps in our understanding of radiation induced cognitive deficit were identified.•Childhood cancer, A-bomb survivors and occupational cohorts may be informative to study radiation cognitive changes.•Animal models may elucidate the mechanism of radiation induced cognitive effects.
The last decades have seen increased concern about the possible effects of low to moderate doses of ionizing radiation (IR) exposure on cognitive function.
An interdisciplinary group of experts (biologists, epidemiologists, dosimetrists and clinicians) in this field gathered together in the framework of the European MELODI workshop on non-cancer effects of IR to summarise the state of knowledge on the topic and elaborate research recommendations for future studies in this area.
Overall, there is evidence of cognitive effects from low IR doses both from biology and epidemiology, though a better characterization of effects and understanding of mechanisms is needed.
There is a need to better describe the specific cognitive function or diseases that may be affected by radiation exposure. Such cognitive deficit characterization should consider the human life span, as effects might differ with age at exposure and at outcome assessment.
Measurements of biomarkers, including imaging, will likely help our understanding on the mechanism of cognitive-related radiation induced deficit. The identification of loci of individual genetic susceptibility and the study of gene expression may help identify individuals at higher risk.
The mechanisms behind the radiation induced cognitive effects are not clear and are likely to involve several biological pathways and different cell types.
Well conducted research in large epidemiological cohorts and experimental studies in appropriate animal models are needed to improve the understanding of radiation-induced cognitive effects. Results may then be translated into recommendations for clinical radiation oncology and imaging decision making processes.