Gregson J, et al. - Because blood pressure (BP) is thought to fall during the prodromal phase of dementia development, researchers studied correlations by categories of time since BP measurement (< 5 years, 5-10 years, > 10 years), and by dementia subtypes. To explore the connection between BP and physician-diagnosed dementia, Poisson regression models were used. The study sample consisted of 2,593,629 individuals from the United Kingdom Clinical Practice Research Database (aged ≥ 40 years) with a BP measurement between 1992 and 2011, and no prior record of dementia. Investigators found 65,618 cases of dementia during a median follow up of 8.2 years: 49,161 Alzheimer's, 13,816 vascular dementia, and 2,541 other subtypes. In the short-term, elevated BP is linked to a reduced risk of dementia, possibly due to reverse causation. BP's long-term dementia associations are less marked and vary by subtype of dementia.