What is epidemiology? Changing definitions of epidemiology 1978-2017.

CONTEXT: Epidemiology is a discipline which has evolved with the changes taking place in society and the emergence of new diseases and new discipline related to epidemiology. With these evolutions, it is important to understand epidemiology and to analyse the evolution of content of definitions of epidemiology. OBJECTIVES: The main objective of this paper was to identify new definitions of epidemiology available since 1978. Secondary objectives were to analyse the content of these definitions, to compare them with those used by Lilienfeld and to determine whether changes have taken place over the last forty years. METHODS: A review of grey literature and published literature was conducted to find the definitions of epidemiology written between 1978 and 2017. RESULTS: 102 definitions of epidemiology were retained. They helped to highlight 20 terms and concepts related to epidemiology. Most of them were already used in the definitions used by Lilienfeld. Five terms were present in more than 50% of definitions from the period 1978 to 2017: "population", "study", "disease", "health" and "distribution". Several developments have occurred: strengthening of the terms "control" and "health" already used, the concept of "disease" was less frequently encountered whereas the concepts "infectious diseases", "mass phenomenon" are no longer used in definitions from 1978 to 2017. CONCLUSION: This evolution of content of definition of epidemiology is absent from books on epidemiology. A thematic analysis of definitions of epidemiology could be conducted in order to improve our understanding of changes observed.

Factors influencing inclusion in digestive cancer clinical trials: A population-based study.

BACKGROUND: Inclusion in a randomized therapeutic trial represents an optimal therapeutic strategy. AIMS: To determine the influence of demographic characteristics and deprivation on the enrolment of patients in digestive cancer clinical trials. METHODS: Between 2004 and 2010, 4632 patients were recorded by the Burgundy Digestive Cancer Registry. According to a balancing score, the 136 patients included in a clinical trial were matched with 272 patients who met the eligibility criteria for trials. Deprivation was measured by the ecological European deprivation index. A conditional multivariate logistic regression was performed. RESULTS: Patients aged over 75 years were significantly less likely to be included in clinical trials than younger patients (odds ratio 0.33; [0.13-0.87]). Patients treated in private institutions were also less likely to be enrolled than those treated in public institutions (odds ratio 0.04; [0.01-0.16]; p<0.001). A relationship between type of institution and the European deprivation index was observed (p=0.017). Deprived patients were less likely to be included in clinical trials when they were managed in private institutions (odds ratio 0.706; [0.524-0.952]; p=0.022). The European deprivation index had no impact when patients were managed in other institutions. CONCLUSION: The relationship between type of institution and deprivation underlines the necessity for improving patients' chance of being recruited in digestive cancer clinical trials.