Effects and Thresholds of Young to Midlife Vascular Risks on Brain Health.
Level 3 - non-randomized controlled study
Prospective cohort study analyzing longitudinal exposure to vascular risk factors and midlife brain outcomes.
PubMed 39041216 · doi:10.1161/HYPERTENSIONAHA.123.22824
What was done
In the prospective CARDIA study, researchers tracked vascular risk factors—systolic blood pressure (SBP), diastolic blood pressure, total cholesterol, fasting blood glucose, and body mass index—measured every 2 to 5 years over 30 years. At year 30, participants completed the Montreal Cognitive Assessment (MoCA), domain-specific cognitive tests, and brain magnetic resonance imaging to measure white matter hyperintensity (WMH) volume. Individual longitudinal exposure trajectories were modeled using mixed-effects spline functions and analyzed against year-30 brain health outcomes, adjusting for sex, race, age, and education.
What was found
Rate of change in SBP up to age 33 was negatively associated with year-30 MoCA scores (-0.29 Z score per mm Hg/year change [95% CI, -0.49 to -0.09]; P = 0.005). SBP change between ages 33 and 49 showed a non-significant negative association (-0.08 [95% CI, -0.16 to 0.01]; P = 0.08). SBP exposures across these periods were significantly associated with poorer domain-specific cognitive scores and increased WMH volume (all P < 0.05). An SBP of ≤111 mm Hg was identified as the empirical threshold below which harmful associations with midlife cognitive performance were not observed.
Why it matters
The findings indicate that blood pressure elevation beginning in early adulthood (prior to age 33) adversely affects midlife cognitive performance and brain structure. The suggested threshold of 111 mm Hg indicates that vascular-related subclinical brain injury may begin at blood pressure levels well below standard diagnostic cutoffs for hypertension.
Limits
The abstract does not report the exact sample size or participant retention rate over the 30-year follow-up. Cognitive and MRI brain outcomes were measured cross-sectionally at year 30 rather than tracked longitudinally from baseline, precluding direct assessment of within-person cognitive decline. Observational associations cannot definitively establish causality.
Cited by
- supports Cumulative exposure to elevated blood pressure from a young age significantly increases the risk of dementia later in life by causing damage to the small vessels of the brain.