A semiparametric approach to evaluate the harm of low-dose exposures

While moderate to high levels of radiation exposure is known to cause adverse health effects, there
is still controversy about the lowest dose that could be harmful. Given that epidemiological studies
of practical sizes are unlikely to provide sufficient statistical power to detect a small risk in
the low-dose range of concern, greater emphasis should be given to evaluating low-dose risk
uncertainty. Using simulations under various dose –response relationships with a threshold, we show
that a conventional approach based on simple parametric models (e.g. the linear model with or
without a threshold) can be inefficient, biased and/or inaccurate in uncertainty evaluations at low
doses. Alternatively, we consider a Bayesian semiparametric model of a connected piecewise-linear
function allowing for autocorrelations between adjacent line sections. With no specific assumption,
this can describe various plausible dose –response curves while appropriately handling the risk
uncertainty. In ...

Source: Journal of Radiological Protection - January 29, 2018 Category: Physics Authors: Kyoji Furukawa and Munechika Misumi Source Type: research