Greater Beat-To-Beat Blood Pressure Variability is Associated With Lower Cognitive Performance Independent of Mean Blood Pressure Among Cigarette Smokers

Introduction: Cigarette smoking is associated with increased cerebrovascular disease risk and reduced cognitive performance, particularly in domains sensitive to vascular insults, such as executive function and processing speed. Short-term blood pressure variability (BPV) is associated with cognitive decline among older adults with and without hypertension (HTN) and BPV is significantly greater among smokers than non-smokers. However, it is unknown if greater short-term BPV contributes to lower cognitive performance in smokers. We hypothesized that greater beat-to-beat BPV would be associated with lower cognitive performance in smokers and that this relation would be independent of mean blood pressure (BP). Methods: Twenty-three smokers (3 current/20 former; age 69 ± 9; pack-years 33 ± 17; systolic BP (SBP) 133 ± 18; diastolic BP (DBP) 71 ± 8; anti-HTN medication use 16Y/7N)), without chronic obstructive pulmonary disease, completed measurements of beat-to beat BPV by 10 minutes of finger plethysmography and electrocardiography, and neuropsychological testing. Age-adjusted neuropsychological test t-scores were grouped into four cognitive domains (executive function, processing speed, language and memory recall). Results: Greater systolic BPV was associated with lower cognitive performance in the executive function (r=-0.59, p<0.01), processing speed (r=-0.60, p<0.01) and language (r=-0.49, p<0.01) domains. The associations between systolic BPV with executive function and processing speed remained significant after adjusting for age, sex, pack-years, years of education, mean SBP and anti-HTN medication use (all p<0.05). Similarly, greater mean BPV was associated with lower executive function (r=-0.50 p=0.01), processing speed (r=-0.60, p<0.01) and language (r=-0.59, p<0.01). However, only the association between mean BPV and executive function remained significant after adjusting for age, sex, pack-years, years of education, mean SBP and anti-HTN medication use (p<0.05). There was no association between systolic or mean BPV and memory recall. Conclusion: These data suggest that greater beat-to-beat BP variability may contribute to lower cognitive performance in smokers and that this relation is independent of mean SBP.