Midlife hypertension is associated with an approximately 60% increased risk of dementia.
1 However, in late life, this association disappears, with few studies finding associations with increased risk and most studies reporting neutral or even decreased risks associated with hypertension.
2-4 Potentially explaining this heterogeneity, some studies have reported that U-shaped associations in late life exist, with both high and low blood pressure (BP) signaling increased dementia risk.
4,5 However, studies of these U-shaped associations are scarce and lack the necessary details.
2,5,6 It is unknown whether these U-shaped associations are generalizable in older populations, how they develop with aging, and with which comorbidities. Identifying relevant subgroups may be important given that opposite associations (association of higher BP with higher dementia risk in one group vs association of higher BP with lower dementia risk in another group) in those with vs those without a particular comorbidity may yield U-shaped associations when analyzed together. Addressing the competing risk of death is essential because increased mortality in individuals who are hypertensive may be a factor in the decline of dementia incidence.
7,8 Such mechanisms could change the shape of the association between BP and incident dementia.