Background It is postulated that orthostatic hypotension ( OH ), a reduction in blood pressure (≥20/10 mm Hg) within 3 minutes of standing, may increase cognitive decline because of cerebral hypoperfusion. This study assesses the impact of OH on global cognition at 4-year follow-up, and the impact of age and hypertension on this association. Methods and Results Data from waves 1 and 3 of TILDA (The Irish Longitudinal Study on Ageing) were used. Baseline blood pressure response to active stand was assessed using beat-to-beat blood pressure monitoring. Two measures of OH were used-at 40 seconds ( OH 40) and 110 seconds ( OH 110). Global cognition was measured using the Montreal Cognitive Assessment. Mixed-effects Poisson regression assessed whether baseline OH was associated with a decline in global cognition at 4-year follow-up. The analysis was repeated, stratifying by age (age 50-64 years and age ≥65 years), and including an interaction between OH and hypertension. Baseline OH 110 was associated with an increased error rate in Montreal Cognitive Assessment at follow-up (incident rate ratio 1.17, P=0.028). On stratification by age, the association persists in ages 50 to 64 years (incident rate ratio 1.25, P=0.048), but not ages ≥65 years. Including an interaction with hypertension found those with co-existent OH 110 and hypertension (incident rate ratio 1.27, P=0.011), or OH 40 and hypertension (incident rate ratio 1.18, P=0.017), showed an increased error rate; however, those with isolated OH 110, OH 40, or isolated hypertension did not. Conclusions OH is associated with a decline in global cognition at 4-year follow-up, and this association is dependent on age and co-existent hypertension.
Keywords: age; aging; cognition; cognitive impairment; hypertension; orthostatic hypotension.