This article is about the recent and profound changes in the conceptualization of dementia, especially the turn towards prevention. The main argument is that more attention needs to be paid to "situated prevention" - the framing of internationally circulating data on the "new dementia" in different contexts. After introducing some of the more problematic issues related to the "new dementia," a first comparison of major preventive clinical trials in Europe and in North America will be provided. The major insight stemming from situating the global message of preventing dementia is recognition of the responsibility researchers and policy makers bear with respect to the implicit and potential moral narratives in emerging scientific landscapes.