EFSA approach for human health risk-benefit assessment of foods

Transcription

1 EFSA approach for human health risk-benefit assessment of foods Bernard Bottex Scientific Committee & Advisory Forum Unit EFET conference on scientific challenges and directions for policy making in nutrition 22 October Athens

2 Terms of Reference Scope and objective, harmonised language Situations for which RBA may be appropriate Guidance on problem formulation Consideration of methods and approaches needed to assess risks and benefits and how to compare them (common scale of measurement) Usefulness of toxicological, nutritional and epidemiological data to assess risks and benefits Extrapolation of animal and other data to the human situation Identification of potential limitations of any RBA Review of ongoing activities Recommendations on future initiatives to overcome current limitations 2

3 Definitions Risk: The probability of an adverse effect in an organism, system, or (sub)population in reaction to exposure to an agent (IPCS, 2004). Benefit: The probability of a positive health effect and/or the probability of a reduction of an adverse health effect in an organism, system, or (sub)population, in reaction to exposure to an agent. Risk Hazard Benefit Positive health effect 3

4 Risk-benefit assessment paradigm 4

5 When to perform a RBA? Where a single compound or food constituent has both positive and negative health effects Where similar levels of dietary exposures can be associated with both risk and benefit Where positive and negative health effects, either in the same or different populations result from different components in the same food Before the start of an intervention Where significant change of dietary consumption patterns has or may occur Where new knowledge emerges with major implications for either the risk(s) or the benefit(s) in a previous risk benefit assessment 5

6 Stepwise approach for RBA Problem Formulation Terms of Reference (I) for the Risk Benefit Assessment STEP 1 Initial Assessment Risks >> Benefits Risks and Benefits do not clearly outweigh each other Risks << Benefits and proposal to stop and proposal for refinement of the assessment Identification of data needs and proposal to stop Involvement of the Risk Benefit Assessor and the Risk Benefit Manager (RBM) Task of the Risk Benefit Assessor 6

7 Stepwise approach for RBA STEP 2 Terms of Reference (II) for the Risk Benefit Assessment Risks >> Benefits Refinement of the Assessment Refinement of the exposure (e.g. comparison of different scenarios) Refinement of the hazard/positive health effect (e.g. dose response modelling) Consideration of different populations Risks << Benefits proposal to stop Risks and Benefits do not clearly outweigh each other proposal to stop No conversion into composite metric possible Conversion into composite metric possible but no data available Conversion into composite metric possible and data available End of the assessment identification of data needs identification of data needs Proposal for refined assessment using a composite metric Involvement of the Risk Benefit Assessor and the Risk Benefit Manager (RBM) Task of the Risk Benefit Assessor 7

8 Stepwise approach for RBA STEP 3 Terms of Reference (III) for the Risk Benefit Assessment Comparing risk(s) and benefit(s) using a composite metric End of the assessment identification of data needs Involvement of the Risk Benefit Assessor and the Risk Benefit Manager (RBM) Task of the Risk Benefit Assessor Outcome = single net health impact value 8

9 Composite metric comparison 9

10 Composite metric comparison 10

11 Example: selenium (Se) Indispensable nutrient Chronic toxicity observed in humans with blood selenium concentrations > 100 µg/dl Type of effect Endpoint Target Population Human health relationship Risk Selenosis Whole population Increased risk of selenosis at intakes above the Upper Level (UL) Benefit Cancer Adult population Reduced risk of cancer Benefit Normal levels of selenoenzymes and other selenoproteins Whole population No signs of deficiency, e.g. normal thyroid function at intakes above the Lower Threshold Intake (LTI) Problem formulation: What is the balance between risks and benefits at the current levels of selenium intake in the population? 11

12 Stepwise approach for RBA Problem Formulation Terms of Reference (I) for the Risk Benefit Assessment STEP 1 Initial Assessment Risks >> Benefits Risks and Benefits do not clearly outweigh each other Risks << Benefits and proposal to stop and proposal for refinement of the assessment Identification of data needs and proposal to stop Involvement of the Risk Benefit Assessor and the Risk Benefit Manager (RBM) Task of the Risk Benefit Assessor 12

13 RBA of selenium Step 1 Scenario 1: Maximising the risks (identify a high level of current dietary exposure to Se) a. High level of dietary exposure to Se above the UL (and above the LTI) risk of Se toxicity + benefit Step 2: identify appropriate dietary intake reducing the risk without affecting the benefit b. High level of dietary exposure to Se below the LTI (and below the UL) risk of Se deficiency stop RBA (= RA) c. High level of dietary exposure to Se below the UL and above the LTI no risk of Se toxicity + benefit stop RBA (= BA) 13

14 RBA of selenium Step 1 Scenario 2: Minimising the risks (identify a low level of current Se intake in the population) d. Low level of dietary exposure to Se above the UL (and above the LTI) clear risk of Se toxicity + benefit Step 2: identify appropriate dietary intake e. Low level of dietary exposure to Se below the LTI (and below the UL) appreciable risk of Se deficiency Step 2: identify appropriate dietary intake f. Low level of dietary exposure to Se below the UL and above the LTI no risk of Se toxicity + benefit. Risks at higher level of exposure will be determined by the outcome of scenario 1 (outcome a and c ). 14

15 Stepwise approach for RBA STEP 2 Terms of Reference (II) for the Risk Benefit Assessment Risks >> Benefits Refinement of the Assessment Refinement of the exposure (e.g. comparison of different scenarios) Refinement of the hazard/positive health effect (e.g. dose response modelling) Consideration of different populations Risks << Benefits proposal to stop Risks and Benefits do not clearly outweigh each other proposal to stop No conversion into composite metric possible Conversion into composite metric possible but no data available Conversion into composite metric possible and data available End of the assessment identification of data needs identification of data needs Proposal for refined assessment using a composite metric Involvement of the Risk Benefit Assessor and the Risk Benefit Manager (RBM) Task of the Risk Benefit Assessor 15

16 Conclusions Stepwise approach conclusion may already be reached after step 1 or 2, without going to a full quantitative assessment (e.g. CONTAM opinion on nitrate in vegetables: Importance of the problem formulation and iterative dialogue after each step between the risk-benefit assessor and the risk-benefit manager Complexity of a risk-benefit assessment, already when entering the first steps of the assessment 16

17 Recommendations Further work needed to define metrics for measuring positive health effects and well being. metrics used in risk-benefit assessment and weight factors associated to most common diseases should be internationally agreed upon in order to ensure harmonisation and recognition of the assessments. 17

18 Acknowledgements Members of the EFSA Scientific Committee Working Group on Risk Benefit Assessment: Ada Knaap (Chair), Diane Benford, Alan Boobis, Helmut Heseker, Rolaf van Leeuwen, Hildegard Przyrembel, Ivonne Rietjens, Josef Schlatter and Ivar Vågsholm. Thank You for your attention! 18