To the Editor A recent study reported that higher caffeinated coffee and tea intake was associated with lower dementia risk and modestly better cognitive performance in participants from the Nurses’ Health Study (NHS) and the Health Professionals Follow-Up Study (HPFS). In adjusted models, participants in the highest vs lowest quartile of caffeinated coffee consumption had a hazard ratio (HR) of 0.82 (95% CI, 0.76-0.89) for dementia, with the most pronounced difference at a moderate intake of approximately 2 to 3 cups per day. We propose that, in addition to neurobiological effects of caffeine, part of this association may reflect more socially active lifestyles among regular coffee drinkers, which themselves protect against dementia.