Abstract P191: Association Between Blood Pressure And Brain Volumes Vary By Sex And Age

Objective: To quantify the association between blood pressure (BP) across its full range and brain volumes and white matter lesions (WMLs) while investigating the effects of age, sex, body mass index (BMI), antihypertensive medication, and other risk factors. Methods: UK Biobank participants ( N =36,260) aged 40 to 70 years were included and stratified by sex and age into four groups (age ≤ 45, 46-55, 56-65 and > 65 years old). Multi-level regression analyses were used to assess the association between mean arterial (MAP), systolic (SBP), and diastolic (DBP) blood pressure, and brain volumes segmented using the FreeSufer software (gray matter [GMV], white matter [WMV], left [L] and right hippocampal volume [RHCV]) and WMLs. We also investigated the interaction effects between body mass index (BMI) and antihypertensive medication and BP in predicting brain volumes and WMLs. Results: Every 10-mmHg higher DBP was associated with lower brain volumes (GMV: -1300– -2800) [SE=34–90]; WMV: -903.44– -1171.7[SE=34.66–53.03]; LHCV: -7.7– -14.26 [SE=0.44–0.57]; RHCV: -6.25– -22.64[SE=0.32–0.95]) across all age groups. A similar pattern was detected in both sexes, although it was weaker, in men. Also, every 10-mmHg higher MAP was associated with larger WMLs across all age groups but peaked > 65 years (0.1 [SE=0.002]). Both lower BMI and anti-hypertensive medication appeared to afford a protective effect. Conclusion: Higher BP is associated with worse cerebral health across the full BP range from middle adulthood and across the life course. Therefore, it is important that prevention efforts be directed at younger adults with focus on achieving optimal BP to decrease future risk of developing dementia.