Introduction: In addition to average blood pressure (BP) values, BP variability has been suggested to be associated with lower cognitive function. It is unclear how long-term BP variability throughout young adulthood is associated with cerebrovascular structure (e.g., hippocampus) and function in midlife.
Methods: Using data from the Coronary Artery Risk Development in Young Adults (CARDIA) study, which recruited healthy young adults ages 18 to 30 years (mean age 25 years) in 1985-1986, we assessed average BP over visits and visit-to visit BP variability (average real variability [ARV], defined as the absolute differences of BP between successive BP measurements) during 25-year follow-up (8 visits). Normal brain volume, abnormal brain volume, brain integrity assessed by fractional anisotropy, and cerebral blood flow were calculated by 3-Tesla MRI at the Year 25 follow-up (n=557, 52.2 % women, and 34.5 % African Americans).
Results: For the 557 participants, mean ARV of SBP was 7.8±3.1 mm Hg. Higher ARV of SBP was associated with lower normal total brain volume, gray matter, and hippocampus after adjustment for covariates including intracranial volume and average BP during follow-up (Table). Higher average SBP during follow-up was associated with higher abnormal brain volume and lower integrity in the whole brain and the white matter, and lower blood flow in the hippocampus.
Conclusions: Long-term visit-to-visit BP variability for 25 years beginning in young adulthood was associated with midlife cerebrovascular structural and functional alterations, independent of average BP during follow-up. Focusing not only on BP values alone but also on visit-to-visit BPV may be important to identify younger adults who may be at risk for developing lower cognitive function later.