Hill’s Temporality Criterion: Reverse Causation and Its Radiation Aspect

Abstract

This review considers various aspects of the temporality causation criterion and the corresponding confounders within the framework of temporal bias, including facts for radiation epidemiology. It is noted that this guideline is the only criterion in all sets of rules for assessing causation for nonexperimental (observational) disciplines, since falsification of it immediately eliminates the likelihood of causation. The exact terminology of the criterion, its philosophical essence, going back to the works of D. Hume and J. Mill (the cause must be before the effect), the epidemiological meaning (the need to observe a plausible latency period for the pathology under study), and the difficulties of establishing the temporal relationship in retrospective studies and its nonabsoluteness for individual disciplines and situations in the biomedical field are analyzed. The definitions of the concept “reverse causation” (protopathic bias) from fundamental sources, as well as confounders close to it within the framework of temporal biases (indications, contraindications, and severity of pathology/prognosis) are presented. Approaches to eliminate these temporal biases are listed. There are numerous examples of reverse causation from both everyday life (sociology, political science, and psychology) and the field of epidemiology and medicine. The facts of reverse causation for carcinogenesis in radiation epidemiology are considered in detail, all of which are within the framework of diagnostic or therapeutic irradiation, often prescribed to patients with pre-existing conditions for malignant neoplasms. The most important example is irradiation of children and young people during computed tomography; this paper briefly reviews all large-scale epidemiological studies on this theme (2012–2019) in relation to the problem of reverse causation. It is concluded that a review can serve for better orientation in the facts of reverse causation not only in epidemiology and medicine, but also in everyday life.