Ionizing radiation is a known human carcinogen that can induce a variety of biological effects depending on the physical nature, duration, doses and dose-rates of exposure. However, the magnitude of health risks at low doses and dose-rates (below 100mSv and/or 0.1mSvmin-1) remains controversial due to a lack of direct human evidence. It is anticipated that significant insights will emerge from the integration of epidemiological and biological research, made possible by molecular epidemiology studies incorporating biomarkers and bioassays. A number of these have been used to investigate exposure, effects and susceptibility to ionizing radiation, albeit often at higher doses and dose rates, with each reflecting time-limited cellular or physiological alterations. This review summarises the multidisciplinary work undertaken in the framework of the European project DoReMi (Low Dose Research towards Multidisciplinary Integration) to identify the most appropriate biomarkers for use in population studies. In addition to logistical and ethical considerations for conducting large-scale epidemiological studies, we discuss the relevance of their use for assessing the effects of low dose ionizing radiation exposure at the cellular and physiological level. We also propose a temporal classification of biomarkers that may be relevant for molecular epidemiology studies which need to take into account the time elapsed since exposure. Finally, the integration of biology with epidemiology requires careful planning and enhanced discussions between the epidemiology, biology and dosimetry communities in order to determine the most important questions to be addressed in light of pragmatic considerations including the appropriate population to be investigated (occupationally, environmentally or medically exposed), and study design. The consideration of the logistics of biological sample collection, processing and storing and the choice of biomarker or bioassay, as well as awareness of potential confounding factors, are also essential.
Bibliographical noteFunding Information:
This work was financially supported by the EU FP7 (Grant Number 249689 for the network of excellence DoReMi), the FANC CT-SCAN contract (CO-90-09-2329-00) and by the institutes in which the authors are currently employed. The views expressed in this publication are those of the authors and not necessarily those of the funding bodies.
There is therefore a need to improve the evidence available on which to base low dose/low dose-rate radiation risk assessment. This is widely recognised throughout the world and several research programmes address this issue. In Europe, the DoReMi (Low Dose Research towards Multidisciplinary Integration) Network of Excellence ( http://www.doremi-noe.net ) aims to encourage and develop multidisciplinary approaches to low dose risk research. DoReMi is funded by the European Commission's EURATOM programme for a 6 year period. In the longer term it is envisaged that coordination and integration of European research will be facilitated by MELODI (Multidisciplinary European Low Dose Radiation Risk Research Initiative; http://www.melodi-online.eu /).
- Low dose ionizing radiation
- Molecular epidemiology