2 This includes both a factor for converting the LOAEL to a NOAEL and an additional factor for the uncertainty associated with that conversion. In this example for peanuts, there are data on both subjective and objective NOAELs and LOAELs. If the NOAEL values are used, the uncertainty factor is 1-fold (i.e., not applicable). If the LOAELs had been used, this value would have been higher. If subjective symptoms observed at lower levels are used, a different uncertainty factor may be considered.
3 This includes uncertainty associated with an additional margin of protection to account for the potential severity of reaction (e.g., lethality) for the highly sensitive subpopulation.
Finding 3. The safety assessment-based approach, based on currently available clinical data, is a viable way to establish thresholds for food allergens. If this approach is employed, the LOAEL or NOAEL determinations used should be based on evidence of the “initial objective sign.” Individual thresholds should be established for each of the major food allergens. If it is not feasible to establish individual thresholds, a single threshold based on the most potent food allergens should be established. In those instances where a LOAEL is used rather than a NOAEL to establish a threshold, an appropriate uncertainty factor should be used. Thresholds established using this approach should be reevaluated periodically as new data and tools become available.
c. Risk Assessment-Based Approach. The use of the risk assessment-based approach requires analysis of the population distributions of allergic sensitivities for each of the major food allergens. These distributions would then be used in conjunction with data on exposures to assess the probability of an adverse effect. These distributions could also be used to evaluate the likely efficacy of different risk reduction strategies.
Advantages. The quantitative risk assessment-based approach is the most scientifically rigorous approach and provides the most insight into both the level of protection and the degree of uncertainty associated with an exposure level. Several recent publications that present preliminary quantitative risk assessments based on data from clinical trials suggest that this approach shows promise (Bindslev-Jensen et al., 2002; Moneret-Vautrin and Kanny, 2004; Cordle, 2004; Wensing et al., 2002a).
Limitations. Quantitative risk assessments require the most data of any approach to establish thresholds for food allergens, because they are based on determining the entire dose-response curve, not simply a NOAEL or LOAEL. The data currently available in the literature for food allergens are generally not detailed enough to be useful for quantitative risk assessment. Further, the underlying mathematical procedures and assumptions have not been fully described for the models that have been published. No consensus has been reached regarding the most appropriate mathematical model to use for analyzing allergen reaction data.
Finding 4. Of the four approaches described, the quantitative risk assessment- based approach provides the strongest, most transparent scientific analyses to establish thresholds for the major food allergens. However, this approach has only recently been applied to food allergens, and the currently available data are not sufficient to meet the requirements of this approach. A research program should be initiated to develop applicable risk assessment tools and to acquire and evaluate the clinical and epidemiological data needed to support the quantitative
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