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4. Main elements of the Qalibra framework

The Qalibra framework is constructed as a logical sequence of steps through the calculation of DALYs or QALYs. The steps in the framework comprise:

1.       Problem formulation including specification of the dietary scenarios and the population to be considered.

2.       Identification of the adverse and beneficial health effects to be assessed.

3.       Estimation of the intakes or exposures that cause those health effects.

4.       Modelling of the dose-response relationship for each effect, including the probability of onset at the current age and, if the effect is continuous, the magnitude of the effect.

5.       Estimation of the probabilities of recovery and mortality for affected individuals.

6.       Selection of a common currency (DALY or QALY)

7.       Specification of the severity and duration of the effect.

8.       Calculation of the net health impact.

These steps are illustrated graphically in Figure 2. Note that steps 3-5 and 7 must be repeated for each adverse and beneficial effect considered. In principle, any number of effects can be included.

The Qalibra software includes a “wizard” function which guides the user through steps 1-8 in sequence. However, steps 3-5 and 7 can actually be done in any order and the software allows this as an alternative, which may be more convenient for experienced users.

Figure 2. Diagrammatic representation of the Qalibra framework for risk-benefit assessment using DALYs or QALYs. See text for explanation.

The following sections describe in more detail the DALY/QALY calculations, and then discuss the data required for steps 1-8.