Basing drug target identification on observational epidemiologic cohort studies has many unique advantages that compliment other strategies for drug discovery. The case of hypertension as a risk factor for AD provides an example of how observational epidemiologic data can be used to compliment other research strategies to identify drugs to reduce the risk for AD. There are several observational studies of the association of AD risk to levels of blood pressure and to anti-hypertensive drug class (AHDC) and AD risk. However, it is not clear whether treating level of blood pressure is important for reducing risk, or taking a specific, currently available anti-hypertensive medication. This presentation will address this dilemma. A brief overview will be given on blood pressure-brain epidemiologic and trial findings, as well as methodologic issues in studying these relationships. Preliminary data will be presented from a new meta-analysis of population-based follow-up studies examining the risk for dementia associated various anti-hypertensive medications.