The contribution of cumulative blood pressure load to dementia, cognitive function and mortality in older adults

Abstract

Background: Few studies evaluated the contribution of long-term elevated blood pressure (BP) towards dementia and deaths. We examined the association between cumulative BP (cBP) load and dementia, cognitive decline, all-cause and cardiovascular deaths in older Australians. We also explored whether seated versus standing BP were associated with these outcomes. Methods: The Sydney Memory and Aging Study included 1037 community-dwelling individuals aged 70–90 years, recruited from Sydney, Australia. Baseline data was collected in 2005–2007 and the cohort was followed for seven waves until 2021. cSBP load was calculated as the area under the curve (AUC) for SBP ≥140 mmHg divided by the AUC for all SBP values. Cumulative diastolic BP (cDBP) and pulse pressure (cPP) load were calculated using thresholds of 90 mmHg and 60 mmHg. Cox and mixed linear models were used to assess associations. Results: Of 527 participants with both seated and standing BP data (47.7% men, median age 77), 152 (28.8%) developed dementia over a mean follow-up of 10.5 years. Higher cPP load was associated with a higher risk of all-cause deaths, and cSBP load was associated with a higher risk of cardiovascular deaths in multivariate models (P for trend < 0.05). Associations between cPP load, dementia and cognitive decline lost statistical significance after adjustment for age. Differences between sitting and standing BP load were not associated with the outcomes. Conclusion: Long-term cPP load was associated with a higher risk of all-cause deaths and cSBP load associated with a higher risk of cardiovascular deaths in older Australians.