Background: Females of Black African and Black Caribbean heritage have higher rates of hypertension and experience greater end-organ damage compared with other ethnic groups. Blood pressure (BP) reactivity, 24-hour ambulatory BP variability and nighttime BP dipping are prognostic for future cardiovascular disease and stroke and are altered in Black females. Greater lifetime stress exposure may contribute to these health disparities; however, its effects on BP reactivity, ambulatory BP variability and nighttime BP dipping remain unclear.
Methods: We examined associations between lifetime stress and BP parameters in Black and White female volunteers. Seventeen healthy Black females (37±12yrs, BMI: 24.8 ± 4.0kg/m2) and 17 age and BMI-matched White females (37±13yrs, BMI: 24.6 ± 4.3kg/m2) completed a mental arithmetic task, 24-h ambulatory BP monitoring and venous blood sampling. Resting BP, Peak BP response to a mental arithmetic task, average real variability (ARV) in 24-hour BP (calculated as mean of absolute differences between successive readings) and BP dipping (absolute dip and nighttime:daytime BP ratio) were measured. The Stress and Adversity Inventory (STRAIN) was used to assess total lifetime stress count (StressC) and total lifetime stress severity (StressS), as well as early-life adversity stress count (Early StressC) and early-life adversity stress severity (Early StressS), alongside resting cortisol levels. Data were compared using T-tests or Mann Whitney U, and associations between BP parameters and STRAIN scores were assessed using Pearson correlation. Data are presented as mean ± SD
Results: There was no difference in resting systolic (115±9 vs 116±6 mmHg, P=0.880) and diastolic BP (76±7 vs 76±6 mmHg, P=0.757), peak BP reactivity (SBP ∆19±13 mmHg vs ∆23±16 mmHg, P =0.335; DBP ∆12±9 vs ∆13±4 mmHg, P=0.712) and 24-hour ARV in SBP (9.9±2.2 vs 10.8±2.5 mmHg, P=0.323) and DBP (7.4±1.9 vs 8.3±1.8 mmHg, P=0.236) between Black females and White females. However, Black females exhibited an attenuated nighttime systolic (∆-9±7 vs. ∆-12±7mmHg, P=0.034) and diastolic (∆-11±4 vs. ∆-14±4mmHg, P=0.024) BP dipping and a greater systolic (0.93±0.06 vs 0.88±0.06 P=0.024) and diastolic (0.86±0.04 vs 0.81±0.05 P=0.022) dip ratio. Resting cortisol levels (175.3±133.7 vs 195.8±97.3nmol/L, P=0.152) lifetime stress exposure (StressC: 23±16 vs 18±10, P=0.166; StressS: 58±32 vs 40±19, P=0.099) and early-life adversity stress scores (Early StressC: 5±6 vs 4±3 , P=0.415; Early StressS: 14±12 vs 9±6, P=0.159) were not different between groups. STRAIN scores were not correlated with nighttime BP dipping or BP reactivity in either group (P>0.05). However, lifetime stressor count (Black females r=-0.57, P=0.026; White females r= -0.69, P=0.003) and lifetime stressor severity (Black females r=-0.56, P=0.023; White females r =-0.64, p=0.007) were negatively correlated to 24-hour DBP ARV in both groups, with early adversity stress count (Black females r=-0.64, P=0.009) and severity (Black females r=-0.74, P=0.002) also correlated with 24-hour DBP ARV in Black females, but not White females.
Conclusion: Our findings suggest that lifetime stress exposure may contribute to BP variability in females, with early-life adversity also associated with BP variability in Black females. Further research is required to determine how stress exposure BP variability influence cardiovascular and stroke risk, particularly in Black females.