High blood pressure in the young: why should we care?

Longitudinal study of birthweight, blood pressure, and markers of arterial stiffness in children age six among the TIDES cohort

OBJECTIVE

Although some studies have observed an association between birthweight and cardiovascular disease in adulthood, fewer have investigated whether birthweight is linked to cardiovascular health in early childhood. This study assesses the association between birthweight and cardiovascular outcomes in children 6 years of age.

STUDY DESIGN

Birthweight, blood pressure (BP), and markers of arterial stiffness in children, including brachial artery distensibility and carotid-femoral pulse wave velocity (cfPWV), were obtained from 324 participants in The Infant Development and the Environment Study, a prospective multisite pregnancy cohort. Birthweight was converted into sex-specific birthweight-for-gestational-age (bw/ga) z -scores based on the INTERGROWTH-21st standard. Following 2017 American Academy of Pediatrics guidelines, SBP and DBP were transformed into sex, age, and height-specific z -scores. Associations between birthweight and cardiovascular outcomes were assessed using nested multivariable linear regression models among the overall and sex-stratified samples.

RESULTS

Among the overall sample, bw/ga z -score was positively associated with cfPWV [b = 0.11 m/s, 95% confidence interval (CI): 0.01 m/s, 0.21 m/s] in crude and adjusted models. No associations between birthweight and cardiovascular outcomes were detected among the sex-stratified analyses.

CONCLUSION

Overall, birthweight was not related to cardiovascular outcomes in children 6 years old. However, infants born with a higher birthweight may be at risk for higher cfPWV in childhood. Early intervention in pregnant people at risk of delivering high birthweight infants may be warranted if results are replicated.

A Unique High-Output Cardiac Hypertrophy Phenotype Arising From Low Systemic Vascular Resistance in Cantu Syndrome

Background Cardiomegaly caused by left ventricular hypertrophy is a risk factor for development of congestive heart failure, classically associated with decreased systolic and/or diastolic ventricular function. Less attention has been given to the phenotype of left ventricular hypertrophy with enhanced ventricular function and increased cardiac output, which is potentially associated with high-output heart failure. Lack of recognition may pose diagnostic ambiguity and management complexities. Methods and Results We sought to systematically characterize high-output cardiac hypertrophy in subjects with Cantu syndrome (CS), caused by gain-of-function variants in ABCC9, which encodes cardiovascular KATP (ATP-sensitive potassium) channel subunits. We studied the cardiovascular phenotype longitudinally in 31 subjects with CS with confirmed ABCC9 variants (median [interquartile range] age 8 years [3-32 years], body mass index 19.9 [16.5-22.9], 16 male subjects). Subjects with CS presented with significant left ventricular hypertrophy (left ventricular mass index 86.7 [57.7-103.0] g/m2 in CS, n=30; 26.6 [24.1-32.8] g/m2 in controls, n=17; P<0.0001) and low blood pressure (systolic 94.5 [90-103] mm Hg in CS, n=17; 109 [98-115] mm Hg in controls, n=17; P=0.0301; diastolic 60 [56-66] mm Hg in CS, n=17; 69 [65-72] mm Hg in control, n=17; P=0.0063). Most (21/31) subjects with CS exhibited eccentric hypertrophy with normal left ventricular wall thickness. Congestive heart failure symptoms were evident in 4 of the 5 subjects with CS aged >40 years on long-term follow-up. Conclusions The data define the natural history of high-output cardiac hypertrophy resulting from decreased systemic vascular resistance in subjects with CS, a defining population for long-term consequences of high-output hypertrophy caused by low systemic vascular resistance, and the potential for progression to high-output heart failure.

Identification of genetic loci shared between Alzheimer's disease and hypertension

Alzheimer's disease (AD) and high blood pressure (BP) are prevalent age-related diseases with significant unexplained heritability. A thorough analysis of genetic pleiotropy between AD and BP will lay a foundation for the study of the associated molecular mechanisms, leading to a better understanding of the development of each phenotype. We used the conditional false discovery rate (cFDR) method to identify novel genetic loci associated with both AD and BP. The cFDR approach improves the effective sample size for association testing by combining GWAS summary statistics for correlated phenotypes. We identified 50 pleiotropic SNPs for AD and BP, 7 of which are novel and have not previously been reported to be associated with either AD or BP. The novel SNPs located at STK3 are particularly noteworthy, as this gene may influence AD risk via the Hippo signaling network, which regulates cell death. Bayesian colocalization analysis demonstrated that although AD and BP are associated, they do not appear to share the same causal variants. We further performed two sample Mendelian randomization analysis, but could not detect a causal effect of BP on AD. Despite the inability to establish a causal link between AD and BP, our findings report some potential novel pleiotropic loci that may influence disease susceptibility. In summary, we identified 7 SNPs that annotate to 4 novel genes which have not previously been reported to be associated with AD nor with BP and discuss the possible role of one of these genes, STK3 in the Hippo signaling network.

Family history of arterial hypertension and central adiposity: impact on blood pressure in schoolchildren

BACKGROUND

A family history of arterial hypertension is an important risk factor for arterial hypertension. This study aimed to verify the mediating role of high central adiposity in the relationship between family history of arterial hypertension and blood pressure in schoolchildren.

METHODS

Cross-sectional study with 118 schoolchildren of both sexes aged between 11 and 17 years. Weight, height, waist circumference and body mass index z score were verified. Somatic maturation was predicted by age for peak growth velocity. The family history of arterial hypertension was verified and defined as hypertensive schoolchildren with systolic blood pressure or diastolic blood pressure. Mediation analysis was used with linear regression models applied by PROCESS macro for SPSS (version 22.0), with significance p < 0.05.

RESULTS

It was observed that 34.7% of the students have family history of arterial hypertension, 36% of the girls and 44.2% of the boys have arterial hypertension. In girls, the relationship between waist circumference and systolic blood pressure was direct (β = 0.535 p = 0.005), and those with a family history of arterial hypertension and who had a waist circumference greater than those without a family history of arterial hypertension was significant (β = -5,437 p = 0.009). Likewise, the relationship between family history of arterial hypertension and systolic blood pressure was attenuated when waist circumference was included in the model (β = -5.544; p = 0.103), indicating waist circumference as a mediator with an influence percentage of 19%. For boys, waist circumference is not a mediator of the relationship between family history of arterial hypertension and blood pressure.

CONCLUSIONS

Elevated central adiposity was a mediator of the relationship between family history of arterial hypertension and high blood pressure in girls, indicating the importance of family health strategies in the prevention and management of arterial hypertension in children and adolescents.

Handgrip Strength-Related Factors in a Colombian Hypertensive Population: A Cross-Sectional Study

(1) Background: This study determined the factors associated with manual grip strength in people with high blood pressure (HBP); (2) Methods: 219 subjects participated in this cross-sectional study, which evaluated muscle strength (manual dynamometer), sociodemographic factors, clinical characteristics, level of physical activity (International Physical Activity Questionnaire-IPAQ score), and depression (Zung's Depression Self-Rating Scale); (3) Results: The bivariate analysis found that handgrip strength in people with HPB was associated with sex (p = 0.000), age (p = 0.000), ethnicity (p = 0.019), smoking habits (p = 0.037), alcohol consumption (p = 0.004), diastolic blood pressure (p = 0.012), weight (p = 0.000), height (p = 0.000), measurement of waist circumference (p = 0.002), depression (p = 0.041), and IPAQ score (p = 0.000). Regardless of being male or female, handgrip strength was associated with age (p = 0.009), IPAQ (p = 0.000), weight (p = 0.038), height (p = 0.000), DPB units (p = 0.043), and depression (p = 0.020). The multivariate generalized linear gamma regression model showed that the coefficient with the greatest weight, regardless of sex, was age (p = 0.043), level of physical activity (24% more at high level than at low level, p = 0.031), and depression (moderate/severe depression level) associated with lower handgrip strength (p = 0.025); (4) Conclusions: Handgrip strength showed an association with level of physical activity, age, and level of depression in a middle-aged population with HBP.

Hypertension in adolescents: The role of obesity and family history

We evaluated the combined effect of obesity and family history (FH) on the risk of hypertension in adolescents. We studied 1288 school‐aged adolescents aged 16.0 ± 0.5 years (49.0% males) attending the medical examination for enrollment in the city of Nanning, China. Their blood pressure, weight, and height were measured. A questionnaire was administered to both adolescents and their parents to obtain information on the participants’ medical history. Multiple logistic regression analysis, according to bodyweight categories and adjusted for age, gender, and body mass index (BMI), was done to determine the association of FH with hypertension. Hypertension was found in 14.1% of adolescents. The prevalence of hypertension was significantly higher in adolescents with obesity and positive FH than their normal weight and negative FH counterparts. For adolescents with normal weight and waist circumstance (WC), those with a positive FH in parents compared to those without had an significantly increased risk for hypertension (odds ratio [OR], 2.15; 95% confidence interval [CI] 1.28–3.61, and 1.96; 95% CI 1.16–3.32, respectively). These findings were adjusted for age, gender, and BMI. Our study showed that routine screening for pediatric hypertension should be performed in adolescents who are overweight and obese. Furthermore, parental FH of hypertension played an important role in predicting the hypertension phenotype among adolescents with normal weight.

A demographic approach to assess elevated blood pressure and obesity in prepubescent children: the ExAMIN Youth South Africa study

BACKGROUND

Obesity and hypertension prevalence among children are a concern, with limited evidence available on sex and ethnic differences in childhood blood pressure. We aimed to determine the number of children with hypertension and obesity to identify unique adiposity and blood pressure characteristics by sex and ethnicity, and to estimate the odds of having elevated blood pressure with increasing adiposity.

METHODS

We included 1062 healthy children (5-9 years of age) in an observational school-based study in South Africa. Pediatric validated automated devices were used to measure brachial blood pressure and performed pulse wave analysis to assess central hemodynamics. Standard anthropometry was carried out to determine body composition and demographic questionnaires were completed.

RESULTS

Almost 20% of children were overweight/obese and 14.1% had elevated blood pressure or hypertension (22.8%). Ethnic differences included greater adiposity in white compared with black children (all P < 0.0001), but higher DBP and total vascular resistance in black compared with white children (both P < 0.05). DBP and total vascular resistance were also higher in girls than boys (both P < 0.01). A 51-60% increased risk of developing elevated blood pressure was observed for 1SD (standard deviation) increase of sex-specific BMI [1.60 (1.4-1.8); P < 0.0001] and waist/height ratio [1.51 (1.3-1.7); P < 0.0001].

CONCLUSION

Unique sex and ethnic differences in body composition and blood pressure exist in prepubescent children, with overweight/obesity increasing the risk of elevated blood pressure. Our findings support primary prevention strategies to combat the growing burden of hypertension and obesity-related diseases in youth.

TRIAL REGISTRATION

The study is registered on ClinicalTrials.gov (NCT04056377).

Influence of Blood Pressure Percentile Reporting on the Recognition of Elevated Blood Pressures

OBJECTIVES

To explore the impact of displaying blood pressure (BP) percentiles with BP readings in the electronic health record (EHR) on the recognition of children with elevated blood pressures (EBPs).

METHODS

This was a retrospective cohort study of children (ages 1-17), including inpatients and outpatients, with at least 1 EHR noninvasive BP recording. In phase 1, BP percentiles were calculated, stored, and not displayed to clinicians. In phase 2, percentiles were displayed adjacent to the EHR BP. Encounters with 1 BP ≥95th percentile were classified as elevated. EBP recognition required the presence of at least 1 EBP-related International Classification of Diseases, Ninth Revision or International Classification of Diseases, 10th Revision code. We compared recognition frequencies across phases with logistic regression.

RESULTS

In total, 45 504 patients in 115 060 encounters were included. Inpatient recognition was 4.1% (238 of 5572) in phase 1 and 5.5% (338 of 5839) in phase 2. The adjusted odds ratio (OR) associated with the intervention was 1.22 (95% confidence interval [CI]: 0.90-1.66). Outpatient recognition rates were 8.0% (1096 of 13 725 EBP encounters) in phase 1 and 9.7% (1442 of 14 811 encounters) in phase 2. The adjusted OR was 1.296 (95% CI: 0.999-1.681). Overall, recognition rates were higher in boys (outpatient OR: 1.51; 95% CI: 1.15-1.98) and older children (outpatient/inpatient OR: 1.08/1.08; 95% CI: 1.05-1.11/1.05-1.11) and lower for those on a surgical service (outpatient/inpatient: OR: 0.41/0.38; 95% CI: 0.30-0.58/0.27-0.52).

CONCLUSIONS

Addition of BP percentiles to the EHR did not significantly change EBP recognition as measured by the addition of an EBP diagnosis code. Girls, younger children, and patients followed on a surgical service were less likely to have their EBP recognized by providers.

Remodeling of Arterial Tone Regulation in Postnatal Development: Focus on Smooth Muscle Cell Potassium Channels

Maturation of the cardiovascular system is associated with crucial structural and functional remodeling. Thickening of the arterial wall, maturation of the sympathetic innervation, and switching of the mechanisms of arterial contraction from calcium-independent to calcium-dependent occur during postnatal development. All these processes promote an almost doubling of blood pressure from the moment of birth to reaching adulthood. This review focuses on the developmental alterations of potassium channels functioning as key smooth muscle membrane potential determinants and, consequently, vascular tone regulators. We present evidence that the pattern of potassium channel contribution to vascular control changes from K_ir2, K_v1, K_v7 and TASK-1 channels to BK_Ca channels with maturation. The differences in the contribution of potassium channels to vasomotor tone at different stages of postnatal life should be considered in treatment strategies of cardiovascular diseases associated with potassium channel malfunction.

Racial differences of early vascular aging in children and adolescents

The prevalence of non-communicable disease (NCDs) is rising globally, with a large burden recorded in sub-Saharan countries and populations of black race/ethnicity. Accelerated vascular deterioration, otherwise known as early vascular aging (EVA), is the underlying factor for highly prevalent NCDs such as hypertension. The etiology of EVA is multifactorial with a central component being arterial stiffness with subsequent development of hypertension and cardiovascular complications. Although arterial stiffness develops with increasing age, many children and adolescents are subjected to the premature development of arterial stiffness, due to genetic or epigenetic predispositions, lifestyle and behavioral risk factors, and early life programming. Race/ethnic differences in pediatric populations have also been reported with higher aortic stiffness in black (African American) compared with age-matched white (European American) counterparts independent of blood pressure, body mass index, or socioeconomic status. With known evidence of race/ethnic differences in EVA, the pathophysiological mechanisms underlying graded differences in the programming of EVA are still sparse and rarely explored. This educational review aims to address the early life determinants of EVA in children and adolescents with a particular focus on racial or ethnic differences.

Changes in physical activity behavior and development of cardiovascular risk in children

The study aimed to investigate the association of changes in physical activity, screen time, and cardiorespiratory fitness (CRF) with development of body mass index (BMI), blood pressure (BP), and retinal microvascular health in children over four years. In 2014, 391 children aged 6-8 years were screened, and thereof 262 children were reexamined after four years following standardized protocols. Retinal arteriolar (CRAE) and venular diameters were measured by a retinal vessel analyzer. CRF was objectively assessed by a 20 m shuttle run, physical activity, and screen time by use of a questionnaire. Children who achieved higher CRF levels reduced their BMI (β [95% CI] -0.35 [-0.46 to -0.25] kg/m² per stage, P ≤ .001) and thereby developed wider CRAE (β [95% CI] 0.25 [0.24 to 0.48] µm per stage, P = .03) at follow-up. Moreover, children with elevated or high systolic BP at baseline, but lower levels of screen time during the observation period, had wider CRAE at follow-up (β [95% CI] -0.37 [-0.66 to -0.08] µm per 10 min/d, P = .013). Change in CRF was not directly associated with better microvascular health at follow-up. However, an increase of CRF over four years was associated with a reduced BMI and consequently wider retinal arterioles at follow-up. In children with elevated or high systolic BP, a reduction of screen time significantly improved retinal microvascular health as a primary prevention strategy to promote childhood health and combat development of manifest CV disease later in life.

Cross-Talk Between Large Artery Stiffness and Retinal Microvasculature in Children: The ExAMIN Youth SA Study

Background: Cross-talk between the macro-and microvasculature is considered an important contributor to target organ damage. Previous findings were predominantly in adult populations and investigation into this mechanism in children may provide insight into the development of early adverse vascular changes. Whether any ethnic differences in cross-talk is evident, also remains to be determined. Objective: To determine whether retinal microvascular diameters are associated with large artery stiffness in young children and whether ethnic differences are evident. Materials and Methods: In this cross-sectional study, 730 black (n = 437) and white (n = 293) school children aged 5-9 years were included. Pulse wave velocity (PWV) was measured and the central retinal arteriolar equivalent (CRAE) and central retinal venular equivalent (CRVE) diameters were calculated from fundus images. The arterio-venous ratio (AVR) was subsequently calculated. Results: Pulse wave velocity was lower (p ≤ 0.001) in the black group when compared to the white group. The black group had a narrower CRAE, wider CRVE and lower AVR (all p < 0.001). Pulse wave velocity associated negatively with CRAE (r = -0.141, p = 0.003) and AVR (r = -0.185, p ≤ 0.001) in the black group only. A positive association between PWV and CRVE was seen in the black (r = 0.174, p ≤ 0.001) and white (r = 0.119, p = 0.043) group. Conclusion: Large artery stiffness is associated with retinal arterial narrowing and venular widening in children, suggesting cross-talk between the macro-and microvasculature. Ethnic differences in these associations are also evident. Our findings warrant further investigation into environmental and sociocultural risk factors contributing to premature cardiovascular disease development.

Acute severe hypertension associated with acute gastroenteritis in children

Acute severe hypertension in otherwise healthy children with acute illness requiring hospitalization for BP management is uncommon and warrants immediate evaluation. We describe 10 cases of children presenting with acute gastroenteritis and found to have acute severe hypertension. They required admission to the hospital for antihypertensive treatment, including 2 to the intensive care unit, but all had normalization of BP and were able to stop treatment with resolution of the acute illness. All patients had thorough testing for secondary causes of hypertension and for signs of end-target organ damage, which were unremarkable. To our knowledge, acute severe hypertension in the setting of acute gastroenteritis without underlying kidney pathology and with complete resolution after illness has not been previously described. The mechanism of this association is not clear, although activation of the sympathetic nervous system is suspected. These cases illustrate the importance of thoroughly assessing BP in the acute setting.

Prevalence of Hypertension and Its Associated Factors among Indonesian Adolescents

Background

Given that hypertension in adulthood has its onset in childhood, it is not surprising that the prevalence of hypertension among adolescents has also increased in recent years. However, there are limited data on the prevalence of hypertension and also the new AAP guideline has not yet been applied to the Indonesian adolescent population. Thus, this study aimed to evaluate the prevalence of hypertension using the new AAP guideline and to assess the occurrence of its associated factors among Indonesian adolescents.

Methods

This was a cross-sectional study conducted at twelve senior high schools in Palembang, South Sumatera, Indonesia, from June to December 2019. The study included adolescents aged 13 to 18 years old. Anthropometric measurements were obtained. Multiple logistic regression was used to assess the risk factors most associated with hypertension among adolescents, and then an equation model was created. The prevalence of hypertension was evaluated, together with several factors such as age group, sex, ethnicity, family history of hypertension, nutritional status, physical activity, perceived stress, sleep duration, nutritional intake, and smoking.

Results

In total, 1200 adolescents aged 15.9 ± 0.99 years were evaluated. The prevalence of hypertension and elevated blood pressure among adolescents was 8% and 12.2%, respectively. There were significant associations between sex, family history of hypertension, hypertensive father, nutritional status, physical activity, perceived stress, and hypertension among Indonesian adolescents (p < 0.05). Stress was the most powerful risk factor of hypertension with an odds ratio of 5.83 (95% confidence interval 2.91–11.6).

Conclusions

Nowadays, the prevalence of hypertension among Indonesian adolescents is quite high. This may be caused by lifestyle or behavior changes among adolescents. Sex, family history of hypertension, nutritional status, physical activity, and perceived stress influenced the 27% hypertension prevalence rate among Indonesian adolescents, particularly in Palembang, South Sumatera. In order to decrease the prevalence of hypertension in adults, concern about lifestyle or behavior changes and hypertension among adolescents should be given.

TASK-1 channel blockade by AVE1231 increases vasocontractile responses and BP in 1- to 2-week-old but not adult rats

Background and Purpose

The vasomotor role of K2P potassium channels during early postnatal development has never been investigated. We tested the hypothesis that TASK‐1 channel (K2P family member) contribution to arterial vascular tone and BP is higher in the early postnatal period than in adulthood.

Experimental Approach

We studied 10‐ to 15‐day‐old (“young”) and 2‐ to 3‐month‐old (“adult”) male rats performing digital PCR (dPCR) (using endothelium‐intact saphenous arteries), isometric myography, sharp microelectrode technique, quantitative PCR (qPCR) and Western blotting (using endothelium‐denuded saphenous arteries), and arterial pressure measurements under urethane anaesthesia.

Key Results

We found mRNA of Kcnk1–Kcnk7, Kcnk12, and Kcnk13 genes to be expressed in rat saphenous artery, and Kcnk3 (TASK‐1) and Kcnk6 (TWIK‐2) were most abundant in both age groups. The TASK‐1 channel blocker AVE1231 (1 μmol·L⁻¹) prominently depolarized arterial smooth muscle and increased basal tone level and contractile responses to methoxamine of arteries from young rats but had almost no effect in adult rats. The level of TASK‐1 mRNA and protein expression was higher in arteries from young compared with adult rats. Importantly, intravenous administration of AVE1231 (4 mg·kg⁻¹) had no effect on mean arterial pressure in adult rats but prominently raised it in young rats.

Conclusion and Implications

We showed that TASK‐1 channels are important for negative feedback regulation of vasocontraction in young but not adult rats. The influence of TASK‐1 channels most likely contributes to low BP level at perinatal age.

Clinical Decision Support for Recognizing and Managing Hypertensive Blood Pressure in Youth: No Significant Impact on Medical Costs

OBJECTIVE

To evaluate economic costs from the health system perspective of an electronic health record-based clinical decision support (CDS) tool, TeenBP, designed to assist in the recognition and management of hypertension in youth.

METHODS

Twenty primary care clinics within an integrated health system were randomized to the TeenBP CDS or usual care (UC), with patient enrollment from 4/15/14 to 4/14/16. The 12-month change in standardized medical care costs for insured patients aged 10 to 17 years without prior hypertension were calculated for each study arm. The primary analysis compared patients with ≥1 visit with blood pressure (BP) ≥95th percentile (isolated hypertensive BP), and secondary analyses compared patients with ≥3 visits within one year with BP ≥95th percentile (incident hypertension). Generalized estimating equation models estimated the difference-in-differences in costs between groups over time.

RESULTS

Among 925 insured patients with an isolated hypertensive BP, the pre-to-post change in overall costs averaged $22 more for TeenBP CDS versus UC patients over 12 months, but this difference was not statistically significant (P = .723). Among 159 insured patients with incident hypertension, the pre-to-post change in overall costs over 12 months was higher by $227 per person on average for TeenBP CDS versus UC patients, but this difference also was not statistically significant (P = .313).

CONCLUSIONS

The TeenBP CDS intervention was previously found to significantly improve identification and management of hypertensive BP in youth, and in this study, we find that this tool did not significantly increase care costs in its first 12 months of clinical use.

Retinal Vessel Diameters and Blood Pressure Progression in Children

The prevalence of high childhood blood pressure (BP) is rising globally and has been associated with subclinical vascular impairments in children. Longitudinal data on the association of microvascular alterations with the development of high BP in children are lacking. We aimed to analyze the association of central retinal arteriolar (CRAE) and venular (CRVE) diameters with development of higher BP over 4 years in young school children. In 2014, 391 children aged 6 to 8 years were screened for BP and retinal vessel diameters using standardized protocols. Retinal vessel analysis was performed using a retinal vessel analyzer to determine CRAE and central retinal venular equivalent. In the follow-up of 2018, all parameters were assessed in 262 children using the same standardized protocols. During follow-up, systolic and diastolic BP increased significantly (Δ 3.965±8.25 and 1.733±7.63 mm Hg, respectively), while CRAE decreased by Δ -6.325±8.55 µm without significant changes in central retinal venular equivalent (Δ -0.163±7.94 µm). Children with narrower CRAE at baseline developed higher systolic BP after four years (β [95% CI] 0.78 [0.170-1.398] mm Hg per 10 µm decrease, P=0.012). Children with increased systolic or diastolic BP at baseline developed narrower CRAE (β [95% CI] -0.154 [-0.294 to -0.014] µm per 1mmHg, P=0.031 and β [95% CI] -0.02 [-0.344 to -0.057] µm per 1 mmHg, P=0.006, respectively) at follow-up. Narrowing of retinal arterioles predicted evolution of systolic BP. In turn, higher initial systolic and diastolic BP was associated with subsequent development of microvascular impairments. Our results give good evidence for a bivariate temporal relationship between BP and microvascular health in children.

The Exercise, Arterial Modulation and Nutrition in Youth South Africa Study (ExAMIN Youth SA)

Background: The impact of a sedentary and unhealthy lifestyle on cardiovascular health is well-documented, however the current obesity and hypertension trends among children is concerning. The ExAMIN Youth SA study aims to investigate the impact of lifestyle behaviors (physical fitness/activity, dietary intake and psychosocial factors) involved in early vascular aging among South African children. Methods: This study is an analytical, multidisciplinary, observational cohort study in a school-based setting. We aim to phenotype a cohort of ~1,000 primary school children (black and white boys and girls between ages 5-9 years) based on current clinical childhood conditions including hypertension and obesity. The primary phenotype is large artery stiffness and retinal microvascular diameters, both biomarkers of early vascular aging. The risk factors and mediators of early vascular aging and also responsible for the clinical conditions include physical inactivity, unhealthy diet, and life stress. Additionally, urinalysis and salivary analyses will be performed to identify biomarkers related to the pathophysiology of early vascular aging. Discussion: In line with the growing prevalence of obesity and hypertension responsible for the development of early vascular aging from childhood to adulthood, this study will address the critical areas in which we observe unfavorable arterial modulation related to dietary behaviors, physical inactivity, and early life stress. Implementation of novel biological markers may further contribute to our understanding of early cardiovascular adaptations in childhood, and aid in the development of primary prevention programs. Trial registration: The study was retrospectively registered on ClinicalTrials.gov on 15 August 2019 (NCT04056377).

Ambient Airborne Particulates of Diameter ≤1 μm, a Leading Contributor to the Association Between Ambient Airborne Particulates of Diameter ≤2.5 μm and Children's Blood Pressure

Evidence on the associations between airborne particulates of diameter ≤1 μm (PM₁) and airborne particulates of diameter ≤2.5 μm (PM_2.5) and childhood blood pressure (BP) is scarce. To help to address this literature gap, we conducted a study to explore the associations in Chinese children. Between 2012 and 2013, we recruited 9354 children, aged 5 to 17 years, from 62 schools in 7 northeastern Chinese cities. We measured their BP with a mercury sphygmomanometer. We used a spatiotemporal model to estimate daily ambient PM₁ and PM_2.5 exposures, which we assigned to participants' home addresses. Associations between particulate matter exposure and BP were evaluated with generalized linear mixed regression models. The findings indicated that exposure to each 10 mg/m³ greater PM₁ was significantly associated with 2.56 mm Hg (95% CI, 1.47-3.65) higher systolic BP and 61% greater odds for hypertension (odds ratio=1.61 [95% CI, 1.18-2.18]). PM₁ appears to play an important role in associations reported between PM_2.5 exposure and BP, and we found that the ambient PM₁/PM_2.5 ratio (range, 0.80-0.96) was associated with BP and with hypertension. Age and body weight modified associations between air pollutants and BP (P<0.01), with stronger associations among younger (aged ≤11 years) and overweight/obese children. This study provides the first evidence that long-term exposure to PM₁ is associated with hypertension in children, and that PM₁ might be a leading contributor to the hypertensive effect of PM_2.5. Researchers and policy makers should pay closer attention to the potential health impacts of PM₁.

Research Gaps in Primary Pediatric Hypertension

Hypertension affects >40% of the US population and is a major contributor to cardiovascular-related morbidity and mortality. Although less common among children and adolescents, hypertension affects 1% to 5% of all youth. The 2017 Clinical Practice Guideline for the Diagnosis and Management of High Blood Pressure in Children and Adolescents provided updates and strategies regarding the diagnosis and management of hypertension in youth. Despite this important information, many gaps in knowledge remain, such as the etiology, prevalence, and trends of hypertension; the utility and practicality of ambulatory blood pressure monitoring; practical goals for lifestyle modification that are generalizable; the long-term end-organ impacts of hypertension in youth; and the long-term safety and efficacy of antihypertensive therapy in youth. The Eunice Kennedy Shriver National Institute of Child Health and Human Development, in collaboration with the National Heart, Lung, and Blood Institute and the US Food and Drug Administration, sponsored a workshop of experts to discuss the current state of childhood primary hypertension. We highlight the results of that workshop and aim to (1) provide an overview of current practices related to the diagnosis, management, and treatment of primary pediatric hypertension; (2) identify related research gaps; and (3) propose ways to address existing research gaps.

SHIP-AHOY (Study of High Blood Pressure in Pediatrics: Adult Hypertension Onset in Youth)

Although hypertension is identifiable in children and adolescents, there are many knowledge gaps on how to best define and manage high blood pressure in the young. SHIP-AHOY (Study of High Blood Pressure in Pediatrics: Adult Hypertension Onset in Youth) is being conducted to address these knowledge gaps. Five hundred adolescents will be recruited and will undergo ambulatory blood pressure monitoring, echocardiographic, vascular, and cognitive assessments, as well as epigenetic studies to identify mechanisms that underlie the development of hypertensive target organ damage. Details of the design and methods that will be utilized in SHIP-AHOY are presented here, as well as baseline characteristics of the first 264 study participants. The primary aim of the study is to develop a risk-based definition of hypertension in the young that will result in better understanding of the transition from blood pressure in youth to adult cardiovascular disease.

Disaster-related trauma and blood pressure among young children: a follow-up study after Great East Japan earthquake

The 11 March 2011 earthquake and tsunami in Japan resulted in ~19,000 lost lives and the displacement of nearly a quarter million people owing to extensive property damage and evacuation from the nuclear meltdown in Fukushima. We sought to prospectively examine whether exposure to disaster-related trauma affected blood pressure levels among young children. We sampled children in three affected prefectures (Miyagi, Fukushima, Iwate) and one unaffected prefecture (Mie). The participants (mean age 6.6 years) and their caregivers answered a baseline survey (N = 320) and a follow-up survey 4 years after the earthquake (N = 227, follow-up rate 71%). Disaster-related trauma was assessed at the baseline, and blood pressure measurements were taken at the follow-up. We converted blood pressure data into age/sex/height-specific z-scores. In linear regression models, we controlled for body mass index, income, age, sex, and housing situation (living in the same house as before the disaster, in a shelter, or in a new house). The number of traumatic experiences was related to diastolic blood pressure in a dose-dependent manner but was not related to systolic blood pressure. Children reporting four or more traumatic experiences had marginally significant elevated diastolic blood pressure (β = 0.43, p = 0.059). Among specific types of disaster trauma, witnessing a fire was significantly related to higher diastolic blood pressure (β = 0.60, p = 0.009). In conclusion, disaster-related trauma was associated with higher diastolic blood pressure among young children 4 years after the traumatic events.

White-coat hypertension from a paediatric perspective

AIM

This mini review explored the prevalence of white-coat hypertension (WCH), which is very common in children. It results in elevated office blood pressure (BP) but normal ambulatory BP monitoring (ABPM) readings.

METHODS

WCH can only be identified by analysing and comparing office BP readings and ABPM, which periodically records BP every 20-30 minutes over 24-hour period. This study provides initially the background for WCH in adults, together with a comprehensive overview of the most relevant paediatric data on WCH.

RESULTS

Accurate measurements of BP are very important for the diagnosis and management of hypertension. It is important to acknowledge the clinical relevance of WCH and follow up children who display this BP phenotype by carrying out ABPM, so that clinicians can build up an accurate picture of their BP. It is also important to identify children who have BP issues and are overweight or obese, so that treatment of this modifiable cardiovascular risk factor can be initiated.

CONCLUSION

Using ABPM provides paediatricians with a more precise evaluation of a child's BP readings than office BP readings. It is the gold standard for diagnosing WCH.