Associations of blood pressure fluctuation patterns with cognitive function: the mediating role of cumulative blood pressure.

Background: The impact of different fluctuation patterns of blood pressure (BP) on episodic memory remains underexplored, and the role of cumulative BP in this association remains unclear.

Methods: Using data from the China Health and Retirement Longitudinal Study, 6563 participants aged 45 years or more were analyzed. BP was measured in wave 1 (2011), wave 2 (2013), and wave 3 (2015). Cumulative systolic BP (SBP) during wave 1-3 (area under the curve) and the SBP difference between wave 1-2 and wave 2-3 were calculated. Then, SBP differences in the two intervals were used to identify patterns by K-means cluster analysis. Episodic memory, including immediate and delayed memory, was assessed in wave 4 (2018). Linear regression and mediation analysis were conducted, with multivariable adjustment.

Results: Three fluctuation patterns of SBP were identified, characterized as an increase-decrease (19.9%), decrease-increase (25.7%), and stable (54.4%) pattern. Before cumulative SBP adjustment, compared to the stable SBP pattern, the β (95% CIs) for episodic memory at wave 4 was -0.14 (-0.27, -0.01) for immediate memory, -0.12 (-0.31, 0.06) for delayed memory, and -0.27 (-0.57, 0.03) for total memory in the increase-decrease SBP pattern, and -0.06 (-0.18, 0.07), 0.01 (-0.15, 0.18), and -0.03 (-0.30, 0.25) in the decrease-increase SBP pattern. The overall association between the increase-decrease SBP pattern and immediate memory was partly mediated by cumulative SBP (29%).

Conclusion: The increase-decrease pattern of SBP was associated with lower immediate memory three years later, and cumulative SBP partly mediated the association.