Dose-responses for mortality from cerebrovascular and heart diseases in atomic bomb survivors: 1950\u20132003

Helmut Schöllnberger,Cristoforo Simonetto,Jan Christian Kaiser,Markus Eidemüller,Harry M Cullings,Frauke Neff

doi:10.1007/s00411-017-0722-5

Abstract

The scientific community faces important discussions on the validity of the linear no-threshold (LNT) model for radiation-associated cardiovascular diseases at low and moderate doses. In the present study, mortalities from cerebrovascular diseases (CeVD) and heart diseases from the latest data on atomic bomb survivors were analyzed. The analysis was performed with several radio-biologically motivated linear and nonlinear dose–response models. For each detrimental health outcome one set of models was identified that all fitted the data about equally well. This set was used for multi-model inference (MMI), a statistical method of superposing different models to allow risk estimates to be based on several plausible dose–response models rather than just relying on a single model of choice. MMI provides a more accurate determination of the dose response and a more comprehensive characterization of uncertainties. It was found that for CeVD, the dose–response curve from MMI is located below the linear no-threshold model at low and medium doses (0–1.4 Gy). At higher doses MMI predicts a higher risk compared to the LNT model. A sublinear dose–response was also found for heart diseases (0–3 Gy). The analyses provide no conclusive answer to the question whether there is a radiation risk below 0.75 Gy for CeVD and 2.6 Gy for heart diseases. MMI suggests that the dose–response curves for CeVD and heart diseases in the Lifespan Study are sublinear at low and moderate doses. This has relevance for radiotherapy treatment planning and for international radiation protection practices in general.

Highlights

High doses of ionizing radiation (IR) can cause non-cancer diseases including cardiovascular-related detrimental health outcomes
With respect to cancer the linear no-threshold (LNT) model is applied in international radiation protection practices
As for cancer, these debates relate to the questions which dose–response models should be applied to radio-epidemiological cohorts, whether they should include threshold and other nonlinear models and whether risk increases linearly from lowest doses up to the high doses applied in radiotherapy (Little et al 2012, 2013; Schöllnberger and Kaiser 2012; Schöllnberger et al 2013)

Summary

Introduction

High doses of ionizing radiation (IR) can cause non-cancer diseases including cardiovascular-related detrimental health outcomes Such evidence stems from analyzing cohorts of radiotherapy patients (Darby et al 2013) and animal experiments (Stewart et al 2006). With respect to cancer the linear no-threshold (LNT) model is applied in international radiation protection practices This has been challenged and the discussions continue for CVD. As for cancer, these debates relate to the questions which dose–response models should be applied to radio-epidemiological cohorts, whether they should include threshold and other nonlinear models and whether risk increases linearly from lowest doses (such as those occurring due to environmental exposures) up to the high doses applied in radiotherapy (Little et al 2012, 2013; Schöllnberger and Kaiser 2012; Schöllnberger et al 2013). The question of IR-induced risks for CVD is of great importance to the societies given the widespread and increasing use of medical applications such as CT scans and radiotherapy as well as in the context of nuclear energy production and accident related long-term risks

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