In this section we establish notation and provide the formulae that are operationalized in the macro. The description of the SAS macro follows in Section 5.

4.1. Data structure

Alzheimer's disease develops insidiously over time as compared to other events, such as stroke, that occur suddenly. For this reason, its development is reported using a year (rather than a specific dale) of diagnosis. To be consistent, we use years as the measure of lime for all analyses. Consider the following three subjects:


Date of birth

Year of AD diagnosis

Dare of death

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