Background:
Blood pressure variability (BPV) consists of short-term BPV (e.g., diurnal BPV) and long-term BPV (e.g., visit-to-visit BPV). The prospective association of long-term BPV though young adulthood with cognition in midlife is unknown.
Methods:
CARDIA is a multicenter community-based study that included participants (ppts) aged 18 to 30 years at baseline (Year 0: Y
0
) in 1985-86 with follow-up examinations at Y
2
, Y
5
, Y
7
, Y
10
, Y
15
, Y
20
, and Y
25
. BP was measured at each exam, and visit-to-visit BPV was assessed by standard deviation (SD), coefficient of variation (CV), maximum minus minimum BP difference (MMD), and average real variability (ARV) across 7 visits (Y
0-20
). Cognitive function was assessed at Y
25
by the Digit Symbol Substitution Test (DSST, a measure of psychomotor speed; n=2,318), the Rey Auditory Verbal Learning Test (RAVLT, a measure of short-term verbal memory; n=2,321), and the modified Stroop test (executive function; n=2,307). We performed separate multivariable-adjusted linear regression models, and also adjusted for baseline BP (Y
0
), change of BP (Y
20
-Y
0
), or cumulative BP from Y
0
to Y
20
(mmHg х year) to determine whether BPV is associated with cognition independent of long-term BP level.
Results:
At the Y
25
examination, included ppts had a mean age of 50 years, 57% were women and 43% were black. BPV measured by higher SD and ARV in both systolic and diastolic BP was significantly associated with lower DSST and lower RAVLT. SD and ARV remained significant even after further adjustment for baseline BP, change of BP, or cumulative BP (Table). Measures of BPV were not associated with the Stroop test. Associations between the CV and MMD measures of BPV with cognitive function were similar to those of SD (not shown).
Conclusions:
Long-term BPV over 20-years through young adulthood is associated with worse psychomotor speed and verbal memory in midlife, independent of BP levels. These results may have implications for understanding the pathogenesis of cognitive dysfunction in older adults.
Long-Term Blood Pressure Variability Throughout Young Adulthood and Cognitive Function in Midlife