Pilot Study on the Influence of Race and Sex on beat‐to‐beat Blood Pressure Variability in Healthy Young Adults

Abstract

BACKGROUNDAugmented beat‐to‐beat blood pressure (BP) variability is prognostic of target organ damage and cardiovascular events. A recent study demonstrated greater BP variability in healthy young Black males compared to White males, but whether these differences appear in females remains unclear. Therefore, we sought to examine race and sex differences in beat‐to‐beat BP variability in healthy young Black and White adults.METHODS52 adults including 13 Black females (age 21.5 ± 0.8 yrs, BMI 27.0 ± 4.2 kg/m2, resting BP 126 ± 10/78 ± 12 mmHg; Mean ± SD), 13 White females (21.2 ± 0.7 yrs, 24.0 ± 3.8 kg/m2, 116 ± 8/66 ± 11 mmHg), 9 Black males (21.6 ± 0.7 yrs, 25.5 ± 4.3 kg/m2, 131 ± 11/75 ± 11 mmHg), and 17 White males (21.5 ± 0.7 yrs, 25.0 ± 3.7 kg/m2, 123 ± 11/67 ± 9 mmHg) participated in this study. Non‐invasive beat‐to‐beat BP was continuously measured at the participant’s middle finger via photoplethysmography (Finapres NOVA) for 10 minutes while sitting semi‐recumbent in a dimly lit room. The finger pressure was calibrated using resting oscillometric brachial BP. Heart rate was measured via 3‐lead electrocardiogram (ECG) and BP was gated to R‐waves from the ECG signal. BP variability was assessed with the average real variability (ARV) index and standard deviation (SD) of all BP readings. Statistical procedures included two‐way analysis of variance (sex x race) with Bonferroni post‐hoc test when appropriate (a priori α < 0.05).RESULTSNo significant differences existed for systolic BP ARV (sex p= 0.85, race p= 0.41, interaction p= 0.63; Black females 2.02 ± 0.64, White females 1.84 ± 0.44, Black males 1.98 ± 0.24, White males 1.93 ± 0.44) or diastolic BP ARV (sex p= 0.31, race p= 0.76, interaction p= 0.51). For systolic BP SD, there was a significant main effect of sex (p= 0.008) suggesting greater systolic BP variability in males than females, and a trend for race by sex interaction (p= 0.08) but no difference for race (p= 0.79); (Black females 4.80 ± 1.07, White females 5.80 ± 2.10, Black males 7.77 ± 3.89, White males 6.42 ± 1.74). However, there were no significant differences for diastolic BP SD (sex p= 0.19, race p= 0.55, interaction p= 0.46).CONCLUSIONThese preliminary findings suggest males have significantly greater systolic BP variability than females from systolic BP ARV. No significant differences were identified for diastolic BP SD and BP ARV (systolic and diastolic) by race and sex, but additional data are needed.