La scienza di sommare mele e pere: simposio scientifico EFSA-EBTC sull'integrazione delle evidenze nella valutazione dei rischi
XXIII Colloquio scientifico EFSA: simposio congiunto EFSA-EBTC (Evidence Based Toxicology Collaboration)
Lisbona (Portogallo), 25 e 26 ottobre 2017
Eminenti scienziati hanno preso parte a un colloquio scientifico organizzato congiuntamente da EFSA ed EBTC per esplorare i futuri orientamenti in materia di integrazione delle evidenze nella valutazione dei rischi per l’uomo legati agli agenti chimici. Gli 82 partecipanti, provenienti da 19 diversi Paesi, hanno intavolato vivaci dibattiti portando con sé una molteplicità di esperienze, approcci metodologici e competenze pratiche.
Didier Verloo, che ha co-presieduto la riunione in rappresentanza dell’EFSA, ha dichiarato: "Siamo fortunati ad avere con noi oggi alcuni dei personaggi chiave e migliori menti del mondo relativamente piccolo ma molto influente delle metodologie di valutazione dei rischi.
Ci siamo concentrati sui temi essenziali nella nostra prassi di integrazione delle evidenze: dall’uso di varie applicazioni sino all’adattamento di diversi metodi e quadri. L'ampliamento del numero di approcci sta consentendo ai valutatori di utilizzare meglio quantitativamente e qualitativamente tutte le evidenze disponibili in una valutazione, tenendo conto, ad esempio, dei pregiudizi nonché dell’incertezza e sensibilità complessive".
La co-presidente Katya Tsaioun, dell'EBCT presso la Johns Hopkins Bloomberg School of Public Health, ha aggiunto: "Riconoscere a che punto siamo ora ha contribuito a inquadrare la scena e a mappare i temi della nostra direzione futura. Abbiamo sottolineato l'importanza di disporre di una terminologia e di concetti standardizzati, di apprendere e sperimentare, di formare e fare pratica. Ma la comunità dei valutatori deve anche comunicare e condividere i propri approcci, perfezionandoli man mano che si va avanti ".
Le sessioni plenarie di apertura e di chiusura sono state trasmesse in diretta via webstreaming. La registrazione è disponibile qui appresso:
I relatori principali sono stati Donald Rubin e Stijn Vansteelandt (inferenza causale), Julian Higgins e Sofia Dias (sintesi delle evidenze, meta-analisi), Kris Thayer e Holger Schunemann (sintesi delle evidenze, GRADE e metodi su base GRADE) e Marc Aerts, Wout Slob e Matthew Wheeler (modellazione dose-risposta).
Gli 82 partecipanti provenivano da 15 Paesi europei, e da Canada, Qatar, Tunisia e Stati Uniti. Tra essi personale dell'EFSA ed esperti esterni dei gruppi scientifici e dei gruppi di lavoro dell'EFSA, 6 membri EBTC e rappresentanti di 16 autorità nazionali e 23 università/istituti di ricerca. Hanno partecipato anche rappresentanti di organizzazioni internazionali, ONG e organismi del settore privato.
Il dott. Verloo ha così concluso: "C'è un vero e proprio desiderio non solo di orientamenti per rendere l'integrazione delle evidenze trasparente ed efficace, ma anche di esempi di vita reale che ci aiutino a metterli in pratica".
Ha aggiunto la dott.ssa Tsaioun: "Dobbiamo essere aperti, flessibili e iterativi in modo da poter imparare, provare, fare e migliorare lungo il percorso".
Si tratta del XXIII colloquio scientifico EFSA e il primo a essere organizzato congiuntamente con l’EBTC della Johns Hopkins Bloomberg School of Public Health.
Evidence-based scientific assessments involve applying structured and standardised approaches to minimise bias and maximise impartiality and transparency in the process for collecting, evaluating and combining evidence relevant to well-formulated research questions, according to pre-defined protocols. These approaches are well-established for healthcare intervention questions and their value has been extensively acknowledged also in the field of chemical risk assessment, where their application continues to be explored.
In evidence-based scientific assessments, evidence synthesis is the step that occurs after appraising the validity of the individual studies selected for the assessment. In evaluations of the efficacy of therapeutic interventions, this is usually done through meta-analysis, which encompasses statistical methods for combining data from similar, readily-comparable studies.
In hazard identification and characterisation for chemical risk assessment, the underlying evidence bases are diverse and not readily comparable. Unlike in medicine, in this research field heterogeneity of evidence stems from not only varying degrees of validity and precision of studies and diverse data types (e.g. individual Vs aggregated), but also from dissimilar designs/settings/models, endpoints, routes of exposure, or evidence streams (human observational studies, experimental animal studies, in vitro and computational models data). As such, a process for combining evidence not only within- but also across evidence streams is needed. This process is defined as ‘evidence integration’ and is particularly relevant for assessing effects caused by exposure to a chemical substance (hazard identification), and for deriving health-based guidance values through dose-response modelling (hazard characterisation).
Evidence integration is a recognised challenge in evidence-based risk assessment and to be conducted soundly, it has to draw on valid approaches to collecting and evaluating evidence in prior steps in the risk assessment, and the integration methodology itself needs to be valid. Different methods for integrating evidence exist, ranging from approaches based on expert judgement, through structured qualitative methods, to complex quantitative methods.
Objectives of the Colloquium
EFSA and EBTC have organised a colloquium, guided by experts in the field, with the goal of developing a multi-stakeholder understanding of the best practices for evidence integration in human risk assessment of chemicals, with a specific focus on hazard identification and on combining multiple studies and endpoints for dose-response modelling in hazard characterisation.
We will discuss current practice, challenges, recent developments and innovative approaches to integrating evidence within and across evidence streams and to combining multiple studies and endpoints. Even if the case-studies and examples discussed throughout the colloquium will be specific for the field of chemicals, we aim at addressing these methodological aspects from a broad, cross-cutting perspective, relevant to other research contexts (e.g. dietary reference values).
Relevant EFSA projects
EFSA PROMETHEUS (PROmoting METHods for Evidence Use in Scientific Assessments) project: https://www.efsa.europa.eu/en/methodology/evidence
EFSA (European Food Safety Authority) Scientific Committee, 2016. Guidance on Uncertainty in EFSA Scientific Assessment - Draft version for internal testing. Available at https://www.efsa.europa.eu/en/topics/topic/uncertainty-scientific-assessments
EFSA (European Food Safety Authority) Scientific Committee, 2017. Guidance on The Use of the Weight of Evidence Approach in Scientific Assessments - Draft version for public consultation. Available at https://www.efsa.europa.eu/sites/default/files/consultation/170306-0.pdf
EFSA (European Food Safety Authority) Scientific Committee, 2017. Guidance on Biological Relevance- Draft version for public consultation. Available at http://www.efsa.europa.eu/sites/default/files/consultation/170306.pdf
Structure of the meeting
Colloquia are not consensus meetings: their objective is to convene leading scientists from Europe and beyond. Rather than offering a series of lectures, this Colloquium will provide ample opportunity for an exchange of expert opinions and scientific debate. Following the opening plenary session with introductory key note speeches, the meeting will be structured to enable participants to reach conclusions and make recommendations in small groups, focusing the discussions on four specific topics.
The four discussion groups (DGs) will focus on the following themes:
- DG 1 – Qualitative methods for integrating evidence within- and across evidence streams for hazard identification
- DG 2 – Bias-adjusted meta-analysis
- DG 3 – Quantitative approaches to combining evidence across evidence streams for hazard identification
- DG 4 – Using multiple endpoints and multiple studies for dose-response modelling: quantitative approaches
The outcome of the discussion groups will be presented and discussed in a final plenary session to formulate conclusions of the Colloquium and, as appropriate, recommendations. The outcomes of the Colloquium will be summarised in an overall report after the meeting.