Problems of Radiation Medicine and Radiobiology

Berkson errors in radiation dose assessments and their impact on radiation risk estimates

S. V. Masiuk1, S. V. Shklyar2, A. G. Kukush2
1State Institution “National Research Center for Radiation Medicine of the National Academy of MedicalSciences of Ukraine”, Melnykov str., 53, Kyiv, 04050, Ukraine
2Taras Shevchenko National University of Kyiv, Pr. Glushkov, 4-е

Objective. To estimate the influence of Berkson errors in exposure doses on the results of risk analysis within example of radiation epidemiological studies of the thyroid cancer prevalence.
Materials and methods. The impact of Berkson errors of the thyroid doses in a dose-response analysis is studied by the method of stochastic simulation.
Results. Presence of errors in doses results in bias of the naive estimations of baseline morbidity and absolute risk excess in the linear logistic regression model. With the increase of dose errors the bias of the naive estimate increases almost linearly. The use of the full maximum likelihood method developed by authors improves essentially the estimates of parameters in the excess absolute risk model.
Conclusion. Ignoring of the significant Berkson errors in dose assessment leads to the bias in estimates of background morbidity (overestimated) and of the excess absolute risk (underestimated). At that the bias is essentially less than the one for the case of classical error.

Key words: doses of exposure, radiation risk, Berkson error, full maximum likelihood method, naive estimator.

Problems of radiation medicine and radiobiology. 2013;18:119–126.