24-h ambulatory blood pressure monitoring in healthy young adult Anglo, Hispanic, and African-American subjects

Interplay of Race and Neighborhood Deprivation on Ambulatory Blood Pressure in Young Adults

Background

Ambulatory blood pressure (BP) monitoring measures nighttime BP and BP dipping, which are superior to in-clinic BP for predicting cardiovascular disease (CVD), the leading cause of death in America. Compared with other racial/ethnic groups, Black Americans exhibit elevated nighttime BP and attenuated BP dipping, including in young adulthood. Social determinants of health contribute to disparities in CVD risk, but the contribution of neighborhood deprivation on nighttime BP is unclear. Therefore, we examined associations between neighborhood deprivation with nighttime BP and BP dipping in young Black and White adults.

Methods

We recruited 21 Black and 26 White participants (20 M/27 F, mean age: 21 years, body mass index: 25±4 kg/m2) for 24-hour ambulatory BP monitoring. We assessed nighttime BP and BP dipping (nighttime:daytime BP ratio). The area deprivation index (ADI) was used to measure neighborhood deprivation. Associations between ADI and ambulatory BP were examined.

Results

Black participants exhibited higher nighttime diastolic BP compared with White participants (63±8 mmHg vs 58±7 mmHg, p=0.003), and attenuated BP dipping ratios for both systolic (0.92±0.06 vs 0.86±0.05, p=0.001) and diastolic BP (0.86±0.09 vs 0.78±0.08, p=0.007). Black participants experienced greater neighborhood deprivation compared with White participants (ADI scores: 110±8 vs 97±21, p<0.001), and ADI was associated with attenuated systolic BP dipping (ρ=0.342, p=0.019).

Conclusions

Our findings suggest neighborhood deprivation may contribute to higher nighttime BP and attenuated BP dipping, which are prognostic of CVD, and more prevalent in Black adults. Targeted interventions to mitigate the effects of neighborhood deprivation may help to improve nighttime BP.

Clinical Trial Registry

URL: https://www.clinicaltrials.gov; Unique identifier: NCT04576338.

Sampling rate influences measures of blood pressure variability in ambulatory blood pressure monitoring

BACKGROUND

Ambulatory blood pressure monitoring (ABPM) is a valuable tool in the diagnosis and management of hypertension and it is a good predictor of future cardiovascular events. Lack of normal threshold values of ABPM parameters and inconsistency in the sampling rate of recording are hurdles in its wider usage. The aim of the present investigation was to study the influence of sampling rate on ABPM.

METHODS

ABPM was performed in 47 healthy subjects and the effect of different sampling rates was studied on ABPM parameters.

RESULTS

When data were down-sampled, there was a trend towards decreased concordance and increased dispersion with less frequent recordings. Percent dispersion of MESOR, 24-h average, 24 h standard deviation (SD), awake hours average and sleep hours average of systolic BP (SBP) were around 10% for a sampling interval of 1 h. While average real variability (ARV), morning surge and percent dip in SBP exhibited more than 30% dispersion at a sampling interval of 30 min.

CONCLUSION

24-h average blood pressure (BP) is less sensitive to sampling rate whereas BP variability parameters such as ARV, morning surge and percent dip in SBP are highly sensitive. We suggest that for improving the accuracy of BP variability parameters, a higher sampling rate is desirable around the time of awakening (~2 h before and after the expected time of awakening). At other times, a lower sampling rate may be used for maximizing patient comfort without compromising measurement accuracy.

Models of Variability and Circadian Rhythm in Heart Rate, Blood Pressure, and QT Interval for Healthy Subjects Who Received Placebo in Phase I Trials

This work characterized the time‐course, circadian rhythm, and inherent variability in key cardiovascular variables (heart rate, corrected QT interval, and systolic and diastolic blood pressure) that are routinely collected as part of safety monitoring in phase I trials. Longitudinal data from 1,035 healthy volunteers who received placebo in 65 single‐dose and multiple‐dose phase I trials conducted by AbbVie were compiled and analyzed using nonlinear mixed‐effects modeling. An independent nonlinear mixed‐effects model was developed for each variable, and combinations of cosine functions were used to capture circadian oscillations. Gender, race, age, and body weight were significant covariates for variability in baseline measures, and the contributions of these covariates were quantitatively characterized. Based on the extensive data set analyzed, the developed models represent valuable tools to help contextualize and differentiate inherent variability that can be expected in a typical phase I setting from true drug‐related cardiovascular safety signals. In addition, these placebo models can be used to support exposure–response analyses that estimate treatment‐related effects on the evaluated cardiovascular measures.

Sources of inaccuracy in the measurement of adult patients' resting blood pressure in clinical settings: a systematic review

BACKGROUND

To interpret blood pressure (BP) data appropriately, healthcare providers need to be knowledgeable of the factors that can potentially impact the accuracy of BP measurement and contribute to variability between measurements.

METHODS

A systematic review of studies quantifying BP measurement inaccuracy. Medline and CINAHL databases were searched for empirical articles and systematic reviews published up to June 2015. Empirical articles were included if they reported a study that was relevant to the measurement of adult patients' resting BP at the upper arm in a clinical setting (e.g. ward or office); identified a specific source of inaccuracy; and quantified its effect. Reference lists and reviews were searched for additional articles.

RESULTS

A total of 328 empirical studies were included. They investigated 29 potential sources of inaccuracy, categorized as relating to the patient, device, procedure or observer. Significant directional effects were found for 27; however, for some, the effects were inconsistent in direction. Compared with true resting BP, significant effects of individual sources ranged from -23.6 to +33 mmHg SBP and -14 to +23 mmHg DBP.

CONCLUSION

A single BP value outside the expected range should be interpreted with caution and not taken as a definitive indicator of clinical deterioration. Where a measurement is abnormally high or low, further measurements should be taken and averaged. Wherever possible, BP values should be recorded graphically within ranges. This may reduce the impact of sources of inaccuracy and reduce the scope for misinterpretations based on small, likely erroneous or misleading, changes.

Utility of ambulatory blood pressure monitoring in children and adolescents

Diagnosis of hypertension is critically dependent on accurate blood pressure measurement. "Accurate" refers to carefully following the guidelines for blood pressure measurement laid out for children and adults to minimize observer and subject errors that commonly occur in clinical blood pressure measurement. Accurate blood pressure measurement is more important in children and adolescents as the misdiagnosis of hypertension may have a life-long adverse impact on insurability and employment. Automated blood pressure measurement offers multiple advantages in achieving high-quality blood pressure determinations by reducing observer errors. The most commonly used form of automated blood pressure measurement is 24-h ambulatory blood pressure measurement (ABPM). Information on ABPM in children has grown exponentially over the last decade. Normative data exists for diagnosis of hypertension in children using ABPM including a novel method for determining normal values with the LMS method. There is further information about the utility of different determinants of 24-h blood pressure such as dipping status, morning surge and blood pressure load. ABPM has been able to detect significant differences in blood pressure in many disease states in children including chronic renal failure, polycystic kidney disease, solitary functioning kidney, and after renal transplantation. Increasingly nonambulatory automated blood pressure determinations have been used in management of hypertension in children. Although nonambulatory automated readings lack information about nocturnal blood pressure or blood pressure during daily activity, studies have suggested that home automated blood pressure measurements are a helpful adjunct to the usual office blood pressure reading.

Acculturation to Western society as a risk factor for high blood pressure: a meta-analytic review

OBJECTIVE

A number of studies have documented that acculturation to western society is related to an increase in blood pressure (BP). Although there is evidence that higher socioeconomic status appears related to better cardiovascular health, increasing acculturation to western society appears related to worse cardiovascular health. The purpose of this meta-analysis was to investigate the association between acculturation and BP.

METHODS

Literature searches yielded 125 relevant research manuscripts, which were coded by teams of two independent raters. This study was conducted in 2003 and 2004, and research databases such as MEDLINE and PsychINFO were searched through 2004. Measures of association (effect sizes) were extracted for both systolic blood pressure (SBP) and diastolic blood pressure (DBP) readings. Random effects models were used to analyze the resulting data.

RESULTS

The overall effect sizes associated with acculturation were 0.28 for SBP and 0.30 for DBP, with increasing acculturation to western society related to higher BP. More acculturated individuals had an average of 4 mm Hg higher BP than less acculturated individuals, which is similar to the effect sizes of known risk factors for high BP such as diet and physical activity. The effects of acculturation on BP appear to be universal, with similar effect sizes found across all regions of the world. Change in BP due to acculturation was not related to body mass index (BMI) or cholesterol but was related to length of residence in the new culture, with the largest effect sizes seen on initial entry and then decreasing rapidly within the first few years. Sudden cultural changes, such as migration from rural to urban settings, resulted in the largest effect sizes, which finding supports the hypothesis that the stress of cultural change is important role in the acculturation effect.

CONCLUSIONS

Acculturation to western society is associated with higher BP, and the distress associated with cultural change appears to be more influential than changes in diet or physical activity. Future studies would benefit from investigating how cultural change affects health and examining whether some non-Western cultural values and practices are health protective.

Does the white-coat effect in people of African and South Asian descent differ from that in White people of European origin? A systematic review and meta-analysis

OBJECTIVE

To assess whether the white-coat effect in people of African (Blacks) and South Asian descent differs from that of people of European origin (Whites), and if so, whether this explains demonstrated ethnic variations in blood pressure.

METHODS

A systematic literature review was carried out using Medline 1966-2003, Embase 1980-2003, and citations from references. The meta-analysis was performed using the Cochrane review manager software (RevMan version 4.2; Oxford, UK).

RESULTS

Eight studies were examined, four studies from the UK and four from the USA. The mean systolic and diastolic white-coat effect was similar in Blacks and Whites. The weighted mean difference in systolic white-coat effect was 0.31 [confidence interval 95% (CI)=-1.96, 2.57; P=0.79] and in diastolic white-coat effect was 0.18 (95% CI=-1.70, 1.35; P=0.82). Two studies reported on South Asians. Both systolic and diastolic white-coat effect was significantly lower in South Asians than in Whites; the weighted mean difference in systolic white-coat effect was -8.90 (95% CI=-13.04, -4.76; P<0.0001) and in diastolic white-coat effect was -4.66 (95% CI=-7.29, -2.03; P<0.0001).

CONCLUSION

The blood pressure differences between Blacks and Whites are unlikely to be a result of variations in white-coat effect. In contrast, the slightly lower clinic blood pressure in some South Asian populations such as Bangladeshis might be partly caused by a low white-coat effect but more studies are needed in this subject.

Does nocturnal blood pressure fall in people of African and South Asian descent differ from that in European white populations? A systematic review and meta-analysis

OBJECTIVE

To assess whether nocturnal blood pressure fall in people of African (Black) and South Asian descent differs from that of the European origin white populations (White).

METHODS

A systematic literature review was carried out using Medline 1966-2003 and Embase 1980-2003, and citations from references. The meta-analysis was performed using Cochrane review manager software (RevMan version 4.2; The Cochrane Collaboration, Oxford, UK).

RESULTS

Seventeen studies were identified; 11 studies from the USA, one from the USA and Canada, and six studies from the United Kingdom. The mean percentage systolic blood pressure (SBP) nocturnal fall was below 10% (non-dipping) in 10 of 17 studies (59%) and the diastolic blood pressure (DBP) nocturnal fall was below 10% in four of 16 studies (25%) in Blacks compared with four of 17 studies (24%) in SBP and none in DBP nocturnal falls in Whites. Compared with Whites, Blacks had a significantly lower mean percentage nocturnal fall; the overall weighted mean difference in SBP was -3.07 (95% confidence interval, -3.81, -2.33; P < 0.00001) and in DBP was -2.98 (95% confidence interval, -3.97, -2.00; P < 0.00001). Two studies on South Asians showed a higher SBP but a similar mean DBP nocturnal fall compared with Whites.

CONCLUSION

Smaller nocturnal blood pressure falls and a higher prevalence of non-dipping may contribute to the higher levels of hypertension complications seen in Black people. No such phenomenon was seen in South Asians but more research is needed to explore their higher stroke mortality.

Associations between arterial compliance and anthropometry of children from four ethnic groups in south africa: the THUSA BANA Study

AIM

To investigate whether associations and differences exist regarding the arterial compliance, dietary intake and anthropometric parameters of children of four different ethnic groups in South Africa.

STUDY DESIGN

In this study, 1244 children from four ethnic groups, aged 10-15 years, were randomly selected from five regions of the North West Province. Blood pressure was measured with a Finapres apparatus and analysed to obtain systemic arterial compliance. Measurements were done to obtain body mass index (BMI), waist-to-hip ratio and percentage body fat. Dietary intake was determined with a 24-h dietary recall questionnaire.

RESULTS

The black and mixed-origin subjects indicated the lowest values (p < or = 0.05) for BMI, percentage body fat, and dietary intake, whereas the white and Indian subjects showed significantly higher values than the other ethnic groups. The white and Indian children had significantly higher arterial compliance than the black and mixed-origin children at all ages from 10 to 15 years. Compliance showed significant correlations with all anthropometric parameters.

CONCLUSION

Since black and mixed-origin children have the highest prevalence of undernutrition and stunted growth, it is suggested that parental undernutrition and inadequate nutrition in early life, associated with lower arterial compliance, may lead to the onset of adult hypertension.

Race and diurnal blood pressure patterns. A review and meta-analysis

Investigators have reported variable findings regarding the role of race in diurnal blood pressure patterns. We performed a review and meta-analysis of this literature to identify the overall effect of race on circadian blood pressure patterns. Eighteen studies involving 2852 participants were reviewed. Meta-analyses were conducted using effect sizes calculated from the data provided directly in the study reports. Separate meta-analyses were conducted on effect sizes for differences between blacks and whites in daytime and nighttime systolic and diastolic blood pressure and nocturnal dip in systolic and diastolic blood pressure. To evaluate discrepancies in findings from studies involving American versus non-American blacks, overall meta-analyses as well as within-subset meta-analyses of black/white differences were conducted for comparisons involving American and non-American blacks. Results of overall meta-analyses indicate that blacks experience higher levels of systolic and diastolic blood pressure, both at night and during the day. These differences were significantly greater at night than during the day (P<0.05). Results of within-subset analyses involving American blacks mirrored those for all black/white comparisons, except that the effect of race on nocturnal dip, ie, that American blacks experienced less of a dip in both systolic and diastolic blood pressure at night, was significant (P<0.05). In contrast, the effect of race on nocturnal dip was not significant for comparisons involving non-American blacks. These results suggest a consistent difference in the chronobiology of blood pressure, particularly in American blacks.

Racial differences in ambulatory blood pressure and echocardiographic left ventricular geometry

We examined the racial differences in left ventricular (LV) geometric pattern in relation to 24-hour ambulatory blood pressure (BP) monitoring and the presence or absence of a nocturnal BP dip. Our study confirms the blunting of nocturnal BP dip among black hypertensives. Body mass index, rather than race, was a major determinant of left ventricular hypertrophy. We did not observe a difference in prevalence of left ventricular hypertrophy by race. However, left ventricular adaptation to hypertension differed in hypertensive black and white individuals; whereas most of the white patients with Stage 1-2 hypertension had a normal ventricular pattern, LV concentric remodeling and concentric hypertrophy were the most common adaptive ventricular patterns in blacks with Stage 1-2 hypertension. A six-fold higher prevalence of concentric remodeling was observed in blacks as compared with whites. The impaired nocturnal BP dip in blacks may contribute to the different hemodynamic pattern. Determinants of myocardial oxygen consumption were significantly higher in black hypertensives.