Morning blood pressure surge in young black and white adults: The African-PREDICT Study

Allostatic load and cardiometabolic health in a young adult South African population: the African-PREDICT study

Sustained stress, assessed as a high allostatic load score (ALS), is an independent cardiovascular disease (CVD) risk factor in older adults but its associations in young people are undefined. Since neurological maturation impacts stress adaptation and CVD risk, we assessed the relationship of ALS with CVD profile by using a tiered approach stratified by age [emerging adults (EA) aged 20-24 yr vs. young adults (YA) aged 25-30 yr] and ALS (high vs. low). In 1,054 healthy participants of the African Prospective Study on Early Detection and Identification of Cardiovascular Disease and Hypertension (African-PREDICT), we determined: 1) ALS in EA versus YA; 2) the relationship between ALS and cardiovascular (CV) health, and 3) the odds of high ALS > 4 to identify masked hypertension (HT) and prediabetes as cardiometabolic outcomes. A nine-component, four-domain ALS was compiled: neuroendocrine [dehydroepiandrosterone (DHEA), cortisol], inflammatory [interleukin-6 (IL-6), C-reactive protein (CRP)], cardiovascular [systolic blood pressure (SBP) and diastolic blood pressure (DBP)], and metabolic [total cholesterol, high density lipoprotein cholesterol (HDL-cholesterol), body mass index (BMI)]. Retinal vessel caliber, pulse wave velocity (PWV), and cardiac structure and function were assessed. Median ALS was 3 (range: 1-9). A high-ALS > 4 was more common in YA versus EA (47 vs. 35%, P = 0.032). Higher ALS associated with narrower retinal arteries (P < 0.01), greater PWV (P ≤ 0.01), lower diastolic function (P < 0.01), and left ventricular (LV) function (P < 0.01). High-ALS increased the odds of having masked hypertension, prediabetes, narrower retinal arteries, higher LV mass, poorer diastolic and ventricular functions (all P ≤ 0.01), in EA and YA independent of traditional CVD risk factors. The composite ALS identified early-stress dysregulation in cardiometabolic health and higher odds for masked hypertension and prediabetes in young adults. Cumulative stress may be a modifiable, independent cardiometabolic risk factor in younger populations that needs further investigation.NEW & NOTEWORTHY This is the first study to assess the effect of stress, as a composite allostatic load score, on micro-, macrovascular, and central cardiac features in healthy emerging and young adults, independent of traditional cardiovascular risk markers. It exemplifies independent stress-induced changes throughout the cardiovascular tree, which may increase the risk of cardiometabolic complications, masked hypertension, and prediabetes. Sustained stress may be a key etiological factor in cardiometabolic disease development in a young population.

Patient-specific multifactorial mortality risk assessment using classification and regression tree analysis in the context of ambulatory blood pressure monitoring

BACKGROUND

Ambulatory blood pressure monitoring is essential for understanding blood pressure patterns beyond clinical visits, aiding in risk assessment, treatment evaluation, and managing hypertension. This retrospective cohort study aimed to identify risk factors for all-cause mortality and major cardiovascular events in patients who underwent ambulatory blood pressure monitoring.

METHODOLOGY

Eligible participants aged 18 or older, with an estimated glomerular filtration rate (eGFR) > 60 ml/min/1.73 m2, who underwent ambulatory blood pressure monitoring for various reasons, were included in the study. Data were gathered through telephone interviews, electronic health records, and the national health record system. Descriptive analysis and classification and regression tree modeling were used to uncover significant risk factors related to all-cause mortality and cardiovascular events, and to assess the model's performance compared to traditional Cox survival analysis.

RESULTS

The study included 1291 patients, primarily male (51.8%) with a mean age of 61.1 ± 15.2 years. During a mean follow-up of 46.9 months, 76 (5.9%) patients died of any cause, and 195 (15.1%) had a cardiovascular event. The highest survival rates were observed in patients with a diastolic blood pressure (BP) dipping percentage between - 2% and 29%, nighttime systolic BP variability below 32 mmHg, and age below 72. Conversely, smokers with a diastolic BP dipping percentage below - 10% showed the lowest survival rates. The best cardiovascular outcomes were observed in patients with diastolic BP dipping above - 11%, nighttime mean systolic BP < 144 mmHg, no statin use, normotensive status, and daytime mean heart rate ≥ 60 bpm. Conversely, the worst outcomes were seen in patients with diastolic BP dipping below - 11% and a morning surge ≥ 14 mmHg. In all-cause mortality and cardiovascular event analysis, the combined model demonstrated excellent calibration and predictive power, like the classification and regression tree model and traditional analysis.

CONCLUSION

These findings highlight the potential of a combined model for assessing mortality and cardiovascular event risk in patients who have undergone ambulatory blood pressure monitoring.

Morning Blood Pressure Surge and Glaucomatous Visual Field Progression in Normal-Tension Glaucoma Patients With Systemic Hypertension

PURPOSE

To investigate the impact of a morning blood pressure surge (MBPS) at baseline on subsequent visual field (VF) progression in hypertensive, normal-tension glaucoma (NTG) patients receiving oral anti-hypertensive treatment.

DESIGN

Retrospective cohort study.

METHODS

A total of 127 eyes from 127 newly diagnosed NTG patients treated for systemic hypertension and followed up for at least 2 years were analyzed. All patients underwent baseline 24-hour ambulatory blood pressure monitoring (ABPM) and at least 5 serial VF examinations during the follow-up period. VF progression was defined according to the Early Manifest Glaucoma Trial criteria. The associations of VF progression with 24-hour ABPM-based blood pressure (BP) parameters (including MBPS) and other clinical variables were analyzed using Cox regression analyses. Kaplan-Meier survival analysis was used to compare VF survival estimates in patients with and without MBPS.

RESULTS

VF progression was detected in 38 eyes (29.9%) over a 5.2-year mean follow-up. In the multivariate Cox regression model, a greater MBPS (hazard ratio [HR] = 1.033; P = .024) and lower nighttime mean arterial pressure (MAP) trough (HR = 0.965; P = .031) at baseline were significant independent predictors of subsequent VF progression. The likelihood of VF progression was significantly greater in patients with higher MBPS (P = .021) at baseline according to Kaplan-Meier survival analysis.

CONCLUSIONS

An increased MBPS at baseline is a significant independent predictor of subsequent VF progression in NTG patients with systemic hypertension. This may be another relevant BP parameter associated with VF progression in hypertensive NTG patients receiving oral anti-hypertensive treatment.

Clinical usability of morning surge blood pressure for predicting future hypertension in a young population

Objective    Early diagnosis of hypertension (HT) is a critical issue for physicians. This study was conducted to determine if morning surge blood pressure (MSBP) could be used to predict future HT. The study also examined which demographic data in a regression model might help to detect future HT without any invasive procedure.Material and methods    A young population between 18 and 40 yrs of age was included in the study. MSBP and demographic data were used to determine an optimal model for predicting future HT by using Bayesian information criteria and binary logistic regression.Results    1321 patients with 24 hr ambulatory blood pressure monitoring were included in this study. The odds ratio of 10 units of increase in diastolic MSBP was 1.173511 in the model, which indicates that a 10 mmHg increase in diastolic MSBP increases the odds of future HT in the patient by 17.4 %. The odds ratio of age was 1.096365, meaning that at each age above 18 yrs, the patients' odds of future HT rise by 9.6 %. The odds ratios for gender (male) and previous HT were 1.656986 and 3.336759, respectively. The odds of future HT in males were 65 % higher than for females, and a history of HT implies that the odds of future HT were higher by 230 %.Conclusion    Diastolic MSBP can be used to predict HT in young individuals. In addition, age, male gender, and previous HT add more predictive power to diastolic MSBP. This statistically significant, predictive model could be useful in lessening or preventing future HT.

Potassium excretion and blood pressure are associated with heart rate variability in healthy black adults: The African-PREDICT study

BACKGROUND AND AIMS

Heart rate variability (HRV) is a main determinant of autonomic function and related to the development of hypertension and cardiovascular (CV) disease. Hypertension develops in black populations at an earlier age, which could be due to differences in the autonomic nervous system activity and sodium/potassium handling in black and white populations. We investigated whether HRV is associated with 24 h urinary sodium and potassium excretion and blood pressure (BP) in a young bi-ethnic cohort.

METHODS AND RESULTS

We examined 423 black and 483 white healthy adults (aged 24.5 ± 3.1 years) for 24 h HRV, including standard deviation of normal RR intervals (SDNN) reflecting autonomic variations over time, and root mean square of successive differences (RMSSD) reflecting parasympathetic activity. We measured 24 h urinary sodium and potassium concentration and BP. The black group had lower SDNN and potassium excretion as well as higher RMSSD, sodium and Na/k ratio compared to the white group (all p < 0.05). Only in black individuals, urinary potassium excretion was independently and negatively associated with SDNN (β[95% CI];-0.26[-0.50;-0.02]ms) and RMSSD (-0.14[-0.27;-0.01]ms, p < 0.05). One unit increase in sodium/potassium (Na/K) ratio was associated with higher SDNN (β[95% CI]; 3.04[0.89; 5.19]ms) and RMSSD (1.60[0.41; 2.78]ms) in the black cohort only (both p < 0.001). In both groups elevated 24 h diastolic BP was associated with lower RMSSD (p < 0.05).

CONCLUSION

Lower potassium excretion and higher Na/K ratio related independently to higher HRV in young and healthy black adults. A better ethnic-specific understanding of sodium and potassium handling is required as part of preventive cardiology, especially in black individuals.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03292094; URL: https://clinicaltrials.gov/ct2/show/NCT03292094.

Adiposity and physical activity are related to heart rate variability: the African-PREDICT study

BACKGROUND

Physical inactivity contributes significantly to the development of obesity-related cardiovascular disease. Adiposity may lead to reduced heart rate variability (HRV), whereas increased physical activity (PA) has the potential to improve autonomic activity. These associations remain largely unexplored in healthy individuals. We therefore investigated whether adiposity and physical activity (PA) are associated with reduced heart rate variability (HRV) in young adults.

MATERIALS AND METHODS

We examined 403 black and 461 white healthy adults (aged 20-30 years) for HRV, including standard deviation of normal RR intervals (SDNN) and root mean square of successive differences (RMSSD). We measured adiposity, PA levels and blood pressure (BP). Body mass index (BMI) of ≥ 30 kg/m² indicated obesity.

RESULTS

Participants with obesity had lower mean HRV than normal weight (SDNN [95% CI]; 138 [131-145]s vs 161 [158-165]ms), where those with the highest PA had higher SDNN (164 [160-169]ms) and RMSSD (51 [49-53]ms) than the least active individuals (150 [146-155]s) and 46 [44-48]ms)(all P < .01). BMI, waist circumference and body fat associated with lower SDNN (P < .001). With each unit increase of vigorous PA, a favourable higher RMSSD was found (P < .05). One unit increase in diastolic BP was associated with decreased SDNN and RMSSD (P < .001). These findings remained significant in multivariable-adjusted analyses.

CONCLUSIONS

Adiposity and low PA associated independently with depressed autonomic activity in young healthy adults. Sympathovagal imbalance seems to already contribute to elevated diastolic BP at young ages. Our study supports population-based prevention programmes in young adults, improving PA and healthy diet, to curb the development of cardiovascular disease.

Retinal microvasculature and masked hypertension in young adults: the African-PREDICT study

Masked hypertension is known to induce microvascular complications. However, it is unclear whether early microvascular changes are already occurring in young, otherwise healthy adults. We therefore investigated whether retinal microvascular calibers and acute responses to a flicker stimulus are related to masked hypertension. We used the baseline data of 889 participants aged 20-30 years who were taking part in the African Prospective study on the Early Detection and Identification of Cardiovascular Disease and Hypertension. Clinic and 24-h ambulatory blood pressure were measured. The central retinal artery equivalent (CRAE) and central retinal vein equivalent were calculated from fundus images, and retinal vessel dilation was determined in response to flicker light-induced provocation. A smaller CRAE was observed in those with masked hypertension vs. those with normotension (157.1 vs. 161.2 measuring units, P < 0.001). In forward multivariable-adjusted regression analysis, only CRAE was negatively related to masked hypertension [adjusted R² = 0.267, β = -0.097 (95% CI = -0.165; -0.029), P = 0.005], but other retinal microvascular parameters were not associated with masked hypertension. In multivariable logistic regression analyses, masked hypertension [OR = 2.333, (95% CI = 1.316; 4.241), P = 0.004] was associated with a narrower CRAE. In young healthy adults, masked hypertension was associated with retinal arteriolar narrowing, thereby reflecting early microvascular alterations known to predict cardiovascular outcomes in later life.

Clinical applications for out-of-office blood pressure monitoring

Hypertension is one of the most common chronic diseases as well as the leading risk factor for cardiovascular disease (CVD). Efficient screening and accurate blood pressure (BP) monitoring are the basic methods of detection and management. However, with developments in electronic technology, BP measurement and monitoring are no longer limited to the physician's office. Epidemiological and clinical studies have documented strong evidence for the efficacy of out-of-office BP monitoring in multiple fields for managing hypertension and CVD. This review discusses applications for out-of-office BP monitoring, including home blood pressure monitoring (HBPM) and ambulatory blood pressure monitoring (ABPM), based on recent epidemiological data and clinical studies regarding the following factors: the detection of abnormal BP phenotypes, namely, white coat hypertension and masked hypertension; stronger ability to determine the prognosis for target organ damage and mortality; better BP control; screening for hypotension; and unique approaches to identifying circadian BP patterns and BP variability.

Ambulatory blood pressure monitoring and morning surge in blood pressure in adult black and white South Africans

We examined whether there were differences in the circadian variation in blood pressure and the morning surge in blood pressure between black and white Africans. Clinic and ambulatory blood pressure data obtained from the Sympathetic Activity and Ambulatory Blood Pressure in Africans (SABPA) study was examined (n = 406; 49% black African). Ambulatory blood pressure readings were fitted to a six-parameter double logistic equation to determine the power and rate of the morning surge in blood pressure. Multiple linear regression analysis was used to examine differences in blood pressure between black and white participants. Clinic and ambulatory blood pressure were higher in black participants throughout the day and night. In those taking medications, blood pressure was less well controlled in black subjects. Despite the higher systolic blood pressure, the day-night difference estimated by the logistic function was similar in black and white participants. However, the rate of rise and power in the morning surge in blood pressure was lower in black participants. We conclude that black participants of the SABPA study present with higher blood pressure throughout the day and night but have a lower power of the morning surge in blood pressure due to a slower morning rate of increase. Moreover, they had an increased prevalence of undiagnosed hypertension and, in those taking medication, were less likely to have their blood pressure controlled than their white counterparts.

Visceral fat, cardiometabolic risk factors, and nocturnal blood pressure fall in young adults with primary hypertension

The aims of this study were to assess associations of body fat levels and distribution with metabolic profiles and 24-hour blood pressure in young adults with primary hypertension. Visceral fat (VF) was estimated using dual-energy X-ray absorptiometry. VF was highly significantly associated with a high frequency of overweight/obesity, impaired fasting glucose, increased levels of triglycerides and LDL-cholesterol, and lowered level of HDL-cholesterol. The value of systolic blood pressure (SBP) nocturnal fall was similar between patients receiving RAAS inhibitors, beta-blockers, and calcium channel blockers. In multiple regression, the VF/weight ratio after adjusting for age, gender, total fat, and chronotherapeutic drug delivery was associated with the percentage SBP nocturnal fall (β = -.3108; 95% CI: -0.5923; -0.0980; P = .013). In males, excess VF increased the odds by 2.3 times for non-dipping blood pressure. Our results suggest that in young adult hypertensives, the VF/weight ratio might be associated with non-dipping blood pressure.

The African Prospective study on the Early Detection and Identification of Cardiovascular disease and Hypertension (African-PREDICT): Design, recruitment and initial examination

Background

Globally hypertension is stabilising, but in sub-Saharan Africa the incidence of hypertension remains on an increase. Although this might be attributed to poor healthcare and ineffective antihypertensive treatment, there is a limited understanding of population and individual-specific cardiovascular pathophysiology – necessary for effective prevention and treatment strategies in Africa. As there is a lack of longitudinal studies tracking the early pathophysiological development of hypertension in black populations, the African-PREDICT study was initiated. The purpose of this paper is to describe the detailed methodology and baseline cohort profile of the study.

Methods and results

From 2013 to 2017, the study included 1202 black (N = 606) and white (N = 596) men and women (aged 20–30 years) from South Africa – screened to be healthy and clinic normotensive. At baseline, and each 5-year follow-up examination, detailed measures of health behaviours, cardiovascular profile and organ damage are taken. Also, comprehensive biological sampling for the ‘omics’ and biomarkers is performed. Overall, the baseline black and white cohort presented with similar ages, clinic and 24-hour blood pressures, but black adults had lower socioeconomic status and higher central systolic blood pressure than white individuals.

Conclusions

The prospective African-PREDICT study in young black and white adults will contribute to a clear understanding of early cardiovascular disease development.