Introduction: Growing evidence suggests a link between orthostatic blood pressure changes and cognitive function - this association has been reported even with subsyndromal orthostatic hypotension (OH). Orthostatic intolerance (OI) may reflect transient cerebral hypoperfusion resulting from orthostatic challenge. Subjective Memory Complaints (SMC) in the absence of objective deficits in older adults have been suggested as a possible early indicator of future cognitive decline yet present a diagnostic dilemma given significant overlaps with mood disorders and personality traits. Both SMC and OH have been associated with cerebral white matter hyperintensities on MRI. Building on earlier work from our group, we hypothesised that OI may be more common in those with SMC.
Methods: Cross-sectional in design, participants were those aged 50 and older who completed the TILDA health centre assessment which included comprehensive cognitive testing, screening for SMC and measurement of orthostatic phasic blood pressure changes using beat-to-beat digital photoplethysomography (Finometer®). OI was defined as reporting feelings of dizziness, light-headedness or unsteadiness during active stand.
Results: 4,672 participants were free from dementia (MMSE > 23; DWR > 2). 4018 (84%) rated their memory as excellent, very good or good and 654 (14%) rated their memory as fair or poor. 1,730 (37%) expressed symptoms of OI upon standing. A logistic regression model found that in addition to male gender, treatment with antidepressant medications, high levels of neuroticism and higher educational background, orthostatic intolerance was independently associated with SMC (OR 1.37; CI 1.05-1.8; p < 0.05).
Conclusions: These preliminary findings suggest a link between OI and SMC in community-dwelling older adults at population level while controlling for a broad range of bio-psycho-social variables (notably depression, anxiety and personality variables).