Blood pressure in children and adolescents: current insights

Association between fluoride exposure and blood pressure in children and adolescents aged 6 to19 years in the United States: NHANES, 2013-2016

To examine the association between fluoride exposure and childhood blood pressure (BP), we used data involving 3260 subjects participating in the National Health and Nutrition Examination Survey (NHANES) from 2013 to 2016. Both plasma and water fluoride concentrations were measured using the ion-specific electrode. Outcome variables were systolic blood pressure (SBP) and diastolic blood pressure (DBP). For a 1-mg/L increase in water fluoride concentration, the participants' SBP decreased by 0.473 mm Hg (95% CI: -0.860, -0.087). Specifically, inverse associations were found between water fluoride and SBP in girls (β= -0.423, 95% CI: -0.886, -0.021), adolescents (β= -0.623, 95% CI: -0.975, -0.272), and non-Hispanic whites (β= -0.694, 95% CI: -1.237, -0.151). Also, every 1-μmol/L increase in plasma fluoride concentration was associated with a 1.183 mm Hg decrease in SBP among other races (95% CI: -2.258, -0.108). This study suggested that fluoride exposure may affect childhood blood pressure.

Hypertension and Associated Lipid, Glucose, and Adiposity Parameters in School-Aged Adolescents in the Federal District, Brazil

BACKGROUND

The prevalence of hypertension and other metabolic disorders has increased in young individuals. However, no representative studies have been conducted in the population of the Federal District, Brazil.

OBJECTIVE

To estimate the prevalence of hypertension and its association with lipid, glucose, and adiposity markers in school-aged adolescents living in the Federal District.

METHODS

This cross-sectional study included participants of the Study of Cardiovascular Risks in Adolescents (Portuguese acronym, ERICA). Blood pressure, blood glucose, glycated hemoglobin, insulin, homeostatic model assessment for insulin resistance (HOMA-IR), triglycerides, total cholesterol, high-density lipoprotein, low-density lipoprotein, body mass index (BMI), waist circumference, and economic, demographic, and sexual maturity variables were assessed. The data were analyzed in Stata, and the analysis was divided into different stages: descriptive, crude, and adjusted. Significant results were set at p < 0.05.

RESULTS

In total, 1,200 adolescents were included, and their mean age was 14.8 years. The prevalence of hypertension was 8% (95% confidence interval: 6.3; 9.9). Most parameters were associated with blood pressure in crude analysis. In adjusted analysis, glucose, lipid, and adiposity markers maintained the associations, and the highest magnitudes were those of BMI and HOMA-IR.

CONCLUSION

The study revealed a high prevalence of hypertension in adolescents living in the Federal District, and blood pressure levels were associated with other markers of lipid, glucose, and adiposity profile. The findings indicate the relevance of health surveillance for planning effective actions aimed at reversing this situation and preventing new cases.

Early ventricular contraction in children with primary hypertension relates to left ventricular mass

AIMS

In hypertensive adults, first-phase ejection fraction (EF1), a measure of early ventricular contraction is reduced and associated with prolonged systolic contraction and diastolic dysfunction. Whether this is true in children with primary hypertension is unknown.

METHODS

Echocardiography was performed in 47 normotensive and 81 hypertensive children. Hypertensive children were stratified according to tertiles of LVMi (g/m2.7). EF1 was calculated from the fraction of LV volume ejected up to the time of peak aortic flow. E/e' was used as a measure of diastolic function. Myocardial wall stress (MWS) was calculated in a subsample of children from LV volumes and central aortic pressure. Time to onset of relaxation (TOR) was defined as time to peak MWS over ejection time.

RESULTS

Normotensive and hypertensive children were of similar age. Hypertensive children in tertiles 2 and 3 of LVMi had higher BMI z-score than normotensives. EF1 was significantly increased in hypertensive children in tertile 1 compared with normotensive children (P < 0.001), whereas in those in tertile 3, it was significantly lower than in normotensive children (P < 0.001). EF1 was negatively associated with LVMi (β = -0.505, P < 0.001), LVM (β = -0.531, P = 0.001) and E/e' ratio (β = -0.409, P < 0.001); in children who had MWS measured, TOR was negatively associated with EF1 (β = -0.303, P = 0.007) and positively associated with E/e' (β = 0.459, P < 0.001).

CONCLUSION

EF1 is preserved or enhanced in hypertensive children with similar LVMi to normotensive children but is increasingly reduced in those with greater LVMi. This reduction of EF1 is associated with prolonged myocardial wall stress and reduced diastolic function.

Pulmonary Manifestations of Renal Disorders in Children

The causes of kidney disease in pediatric patients are evenly divided between congenital abnormalities of the kidney and urinary tract and acquired disorders. Nearly 10% to 15% of adults in the United States have chronic kidney disease (CKD); there are no comparable data in children. Regardless of patient age, CKD is a systemic problem that affects every organ system, including the lung. We review the tests used to diagnose and evaluate kidney disease and the main clinical syndromes that are likely to be encountered to aid the pulmonology consultant who is asked to evaluate patients with kidney disease.

Maternal prenatal urinary bisphenol A level and child cardio-metabolic risk factors: A prospective cohort study

Exposure to endocrine disrupting chemicals during the first 1000 days of life may have long-lasting adverse effects on cardio-metabolic risk in later life. This study aimed to examine the associations between maternal prenatal Bisphenol A (BPA) exposure and child cardio-metabolic risk factors at age 2 years in a prospective cohort. During 2012-2013, 218 pregnant women were enrolled at late pregnancy from Shanghai, China. Urinary BPA concentration was measured in prenatal and child 2-year spot urine samples, and classified into high, medium and low tertiles. Child adiposity anthropometric measurements, random morning plasma glucose, serum insulin, and lipids (high-density lipoprotein, low-density lipoprotein, cholesterol, triglyceride), systolic (SBP) and diastolic blood pressure (DBP) were measured. Linear regression was used to evaluate the associations between prenatal BPA and each of the cardio-metabolic risk factors in boys and girls, respectively, adjusting for pertinent prenatal, perinatal and postnatal factors. BPA was detectable (>0.1 μg/L) in 98.2% of mothers prenatally and 99.4% of children at age 2 years. Compared to those with low prenatal BPA, mean SBP was 7.0 (95%CI: 2.9-11.2) mmHg higher, and DBP was 4.4 (95%CI: 1.2-7.5) mmHg higher in girls with high prenatal BPA levels, but these associations were not found in boys. In boys, medium maternal prenatal BPA level was associated with 0.36 (95% CI: 0.04-0.68) mmol/L higher plasma glucose. No associations were found between prenatal BPA and child BMI, skinfold thicknesses, serum lipids, or insulin in either girls or boys. There were no associations between concurrent child urinary BPA and cardio-metabolic risk factors. These results support that BPA exposure during prenatal period, susceptible time for fetal development, may be associated with increase in child BP and plasma glucose in a sex-specific manner. Further independent cohort studies are needed to confirm the findings.

Association of physical fitness with skin autofluorescence-derived advanced glycation end products in children

BACKGROUND

Advanced glycation end products (AGEs) accumulate with age and development of cardiovascular disease. Higher AGEs have been shown in children with diabetes but little is known about their association with lifestyle conditions in childhood. We hypothesized that BMI, blood pressure and cardiorespiratory fitness (CRF) are associated with subcutaneous AGEs formation in children.

METHODS

In this cross-sectional study, 1075 children (aged 7.2 ± 0.4 years) were screened for subcutaneous AGEs (skin autofluorescence; SAF), body mass index (BMI), blood pressure (BP), and CRF using standardized procedures. Group comparisons were performed in clinical BP and BMI categories and tertiles of CRF.

RESULTS

Children with higher physical fitness showed lower SAF (0.99(1.03;1.10)au) compared to children with low CRF (1.09(1.03;1.05)au, p < 0.001). An increase of one shuttle run stage was associated with a mean reduction in SAF of -0.033(CI: -0.042;-0.024)au, independent of BMI and BP (p < 0.001). BMI and BP were not independently associated with SAF-derived AGEs in this large cohort of primary school children.

CONCLUSIONS

Low physical fitness but not BMI and BP were associated with higher levels of AGEs. Primary prevention programs in young children may need to focus on improving physical fitness in game settings in order to reduce the growing prevalence of metabolic disorders during childhood.

Associations of body mass index, physical activity and sedentary time with blood pressure in primary school children from south-west England: A prospective study

Elevated blood pressure in children is a significant risk factor for the development of cardiovascular disease in adulthood. We examined how children’s body mass index (BMI), physical activity and sedentary time at ages 9 and 11 are associated with blood pressure at age 11. Data were from 1283 children from Bristol, UK, who participated in the study aged 11 years, 797 of whom also participated in the study aged 9 years. Child height, weight and blood pressure were measured, and children wore accelerometers for five days, from which moderate-to-vigorous-intensity physical activity and sedentary minutes per day were derived. Multiple imputation of missing data and adjusted linear and logistic regression models were used to examine associations. Child BMI at 11 years was cross-sectionally associated with higher systolic and diastolic blood pressure (mean difference [95% confidence interval]: 0.91 [0.32 to 1.50] mm Hg and 1.08 [0.54 to 1.62] mm Hg, respectively, per standard deviation (SD) of BMI). BMI at age 9 was also positively associated with diastolic blood pressure at age 11 (1.16 mmHg per two years [0.49 to 1.84], per SD of BMI). For girls, sedentary time at age 9 years was associated with increased odds of having high systolic blood pressure at age 11 (odds ratio: 1.08 [1.01 to 1.16], per 10 minutes per day). There was no evidence of associations between sedentary time and blood pressure among boys. Similarly, there was little evidence that physical activity was associated with blood pressure in either cross-sectional or prospective analyses. Effective strategies are needed to prevent excess bodyweight among children in order to reduce cardiovascular disease risk.

Comparison of the SphygmoCor XCEL device with applanation tonometry for pulse wave velocity and central blood pressure assessment in youth

BACKGROUND

Vascular phenotype by assessing carotid-femoral pulse wave velocity (cf-PWV) and central SBP (cSP) in the young could be used as an intermediate cardiovascular outcome measure. Tonometry is considered the gold-standard technique, but its use is challenging in clinical practice, especially when used in children. The purpose of this study was to validate cf-PWV and cSP assessment with novel oscillometric device (SphygmoCor XCEL) in children and adolescents.

METHODS

cf-PWV and cSP were measured in 72 children and adolescents aged 6-20 years. Measurements were performed by applanation tonometry and by the SphygmoCor XCEL device at the same visit under standardized conditions. Regression analysis and Bland-Altman plots were used for comparison of the tonometer-based with oscillometric-based method.

RESULTS

Mean cf-PWV measured by applanation tonometry was 4.85 ± 0.81 m/s and measured by SpygmoCor XCEL was 4.75 ± 0.81 m/s. The mean difference between the two devices was 0.09 ± 0.47 m/s (P = NS). cSP measured by SpygmoCor XCEL was strongly correlated with cSP measured by applanation tonometry (R = 0.87, P < 0.001). Mean cSP measured by applanation tonometry was 103.23 ± 9.43 mmHg and measured by SpygmoCor XCEL was 103.54 ± 8.87 mmHg. The mean cSP difference between the two devices was -0.30 ± 3.34 mmHg (P = NS), and fulfilled the AAMI criterion 1. The estimated intersubject variability was 2.17 mmHg.

CONCLUSION

The new oscillometric SphygmoCor XCEL device provides equivalent results for cf-PWV and cSP values to those obtained by tonometry in children and adolescents. Thus, the SphygmoCor XCEL device could be appropriate for assessing cf-PWV and cSP in the pediatric population.

Obesity, High Blood Pressure, and Physical Activity Determine Vascular Phenotype in Young Children

Cardiovascular disease often develops during childhood, but the determinants of vascular health and disease in young children remain unclear. The study aimed to investigate the association of obesity and hypertension, as well as physical fitness with retinal microvascular health and large artery stiffness, in children. In this cross-sectional study, 1171 primary school children (aged 7.2±0.4 years) were screened for central retinal arteriolar equivalent (CRAE) and central retinal venular equivalent (CRVE) diameters, pulse wave velocity (PWV), body mass index, blood pressure (BP), and cardiorespiratory fitness by standardized procedures for children. BP was categorized according to the reference values of the population-based German KiGGS study (Kinder- und Jugendgesundheitssurvey [Children- and Adolescents Health Survey]) and the American Academy of Pediatrics guidelines. Overweight (mean [95% CI]: CRAE, 200.5 [197.9-203.2] µm; CRVE, 231.4 [228.6-234.2] µm; PWV, 4.46 [4.41-4.52] m/s) and obese children (CRAE, 200.5 [196.4-204.7] µm; CRVE, 233.3 [229.0-237.7] µm; PWV, 4.51 [4.43-4.60] m/s) had narrower CRAE, wider CRVE, and higher PWV compared with normal-weight children (CRAE: 203.3 [202.5-204.1] µm, P<0.001; CRVE: 230.1 [229.1-230.9] µm, P=0.07; PWV: 4.33 [4.31-4.35] m/s, P<0.001). Children with high-normal BP (CRAE, 202.5 [200.0-205.0] µm; PWV, 4.44 [4.39-4.49] m/s) and BP in the hypertensive range (CRAE, 198.8 [196.7-201.0] µm; PWV, 4.56 [4.51-4.60] m/s) showed narrower CRAE, as well as higher PWV, compared with normotensive peers (CRAE: 203.7 [202.9-204.6] µm, P<0.001; PWV: 4.30 [4.28-4.32] m/s, P<0.001). With each unit increase of body mass index and systolic BP, CRAE decreased and PWV increased significantly. Children with the highest cardiorespiratory fitness had wider CRAE, narrower CRVE, and lower PWV compared with least fit children. Childhood obesity and hypertension, even at preclinical stages, are associated with microvascular and macrovascular impairments in young children. Primary prevention programs targeting physical activity behavior may have the potential to counteract development of small and large vessel disease early in life. Clinical Trial Registration- URL: http://www.clinicaltrials.gov . Unique identifier: NCT02853747.

Childhood obesity in New Zealand

BACKGROUND

Paediatric obesity has reached epidemic proportions globally, resulting in significant adverse effects on health and wellbeing. Early life events, including those that happen before, during, and after pregnancy can predispose children to later obesity. The purpose of this review is to examine the magnitude of obesity among New Zealand children and adolescents, and to determine their underlying risk factors and associated comorbidities.

DATA SOURCES

PubMed, Web of Science, and Google Scholar searches were performed using the key terms "obesity", "overweight", "children", "adolescents", and "New Zealand".

RESULTS

Obesity is a major public health concern in New Zealand, with more than 33% of children and adolescents aged 2-14 years being overweight or obese. Obesity disproportionately affects Māori (New Zealand's indigenous population) and Pacific children and adolescents, as well as those of lower socioeconomic status. New Zealand's obesity epidemic is associated with numerous health issues, including cardiometabolic, gastrointestinal, and psychological problems, which also disproportionately affect Māori and Pacific children and adolescents. Notably, a number of factors may be useful to identify those at increased risk (such as demographic and anthropometric characteristics) and inform possible interventions.

CONCLUSIONS

The prevalence of overweight and obese children and adolescents in New Zealand is markedly high, with a greater impact on particular ethnicities and those of lower socioeconomic status. Alleviating the current burden of pediatric obesity should be a key priority for New Zealand, for the benefit of both current and subsequent generations. Future strategies should focus on obesity prevention, particularly starting at a young age and targeting those at greatest risk.

Salt sensitivity of blood pressure at age 8 years in children born preterm

Preterm birth and low birth weight have been associated with an increased risk of hypertension; postnatal growth and dietary salt intake may contribute to these associations. In adults, the change of blood pressure (BP) in response to modifications in salt intake, i.e., salt sensitivity of BP, has been independently associated with cardiovascular disease. Little is known about salt sensitivity in children. We hypothesize that it may partly explain the association between preterm birth and higher BP in later life. We assessed salt sensitivity of BP at age 8 years in 63 preterm-born children, and explored its association with postnatal growth, sodium intake, and body composition from infancy onwards. BP was measured at baseline and after a 7-day high-salt diet. The difference in mean arterial pressure (MAP) was calculated; salt sensitivity was defined as an increase in MAP of ≥5%. Ten children (16%) showed salt sensitivity of BP, which was associated with neonatal growth restriction as well as with lower fat mass and BMI from infancy onwards. At age 8 years, children classified as salt sensitive had a lower weight-for-age SD-score (-1.5 ± 1.3 vs. -0.6 ± 1.1) and BMI (13.8 ± 1.7 vs. 15.5 ± 1.8 kg/m²) compared to their salt resistant counterparts. Sodium intake was not associated with (salt sensitivity of) BP. Salt sensitivity of BP was demonstrated in preterm-born children at age 8 years and may contribute to the development of cardiovascular disease at later age. Long-term follow-up studies are necessary to assess reproducibility of our findings and to explore clustering with other cardiovascular risk factors.

Oscillometric blood pressure by age and height for non overweight children and adolescents in Lubumbashi, Democratic Republic of Congo

Background

The diagnosis of hypertension in children is complex because based on normative values by sex, age and height, and these values vary depending on the environment. Available BP references used, because of the absence of local data, do not correspond to our pediatric population. Accordingly, our study aimed to provide the BP threshold for children and adolescents in Lubumbashi (DRC) and to compare them with German (KIGGS study), Polish (OLAF study) and Chinese (CHNS study) references.

Methods

We conducted a cross-sectional study among 7523 school-children aged 3 to 17 years. The standardized BP measurements were obtained using a validated oscillometric device (Datascope Accutor Plus). After excluding overweight and obese subjects according to the IOTF definition (n = 640), gender-specific SBP and DBP percentiles, which simultaneously accounted for age and height by using an extension of the LMS method, namely GAMLSS, were tabulated.

Results

The 50th, 90th and 95th percentiles of SBP and DBP for 3373 boys and 3510 girls were tabulated simultaneously by age and height (5th, 25th, 50th, 75th and 95th height percentile).

Before 13 years the 50th and 90th percentiles of SBP for boys were higher compared with those of KIGGS and OLAF, and after they became lower: the difference for adolescents aged 17 years was respectively 8 mmHg (KIGGS) and 4 mmHg (OLAF). Concerning girls, the SBP 50th percentile was close to that of OLAF and KIGGS studies with differences that did not exceed 3 mmHg; whereas the 90th percentile of girls at different ages was high. Our oscillometric 50th and 90th percentiles of SBP and DBP were very high compared to referential ausculatory percentiles of the CHNS study respectively for boys from 8 to 14 mmHg and 7 to 13 mmHg; and for girls from 10 to 16 mmHg and 11 to 16 mmHg.

Conclusions

The proposed BP thresholds percentiles enable early detection and treatment of children and adolescents with high BP and develop a local program of health promotion in schools and family.

Electronic supplementary material

The online version of this article (10.1186/s12872-018-0741-4) contains supplementary material, which is available to authorized users.

What's new in paediatric hypertension?

Paediatric hypertension predisposes to hypertension and cardiovascular disease in adult life. Despite clear guidelines, there remains a lack of screening. Diagnosis remains challenging given the high rate of false-positive high blood pressure (BP) readings at a single visit; thus, multiple visits are required to confirm the diagnosis. Depending on the normative data sets used, hypertension in overweight and obese children can be underestimated by up to 20%. Specific BP targets are required for subgroups such as adolescents, children with chronic kidney disease (CKD) and type 1 diabetes. High dietary salt intake is a risk factor for cardiovascular disease. Given the rise in processed food consumption, children in developed nations are likely to benefit from salt restriction at a population-based level.

Prehypertension among 2.19 million adolescents and future risk for end-stage renal disease

OBJECTIVE

Persistent hypertension in adulthood is a leading cause of end-stage renal disease (ESRD). Whether lower blood pressure (BP) values, in the range of prehypertension, are also associated with future occurrence of ESRD is unclear. Even less clear is the potential risk of early prehypertension appearing in adolescence. To address this question, we examined whether BP measurements in the prehypertensive range at age 16-19 years predict adult ESRD.

METHODS

Medical data on 2194 635 16-19-year-old adolescents examined for medical fitness prior to military service from 1977 to 2013 were linked to the Israeli ESRD registry in this nationwide population-based cohort study. Incident cases of ESRD were recorded. Survival models were applied.

RESULTS

During 35 007 506 person-years of follow-up (median follow-up 16.8 years), there were 690 ESRD cases, with an overall incidence rate of 1.97 cases per 100 000 person-years. Examinees with elevated BP readings in the prehypertensive range (BP between the 90th and 95th percentiles or between 120 and 139/80-89 mmHg) had increased incidence of ESRD with a hazard ratio of 1.32 (95% confidence interval, 1.11-1.58) adjusted for year of birth, age at examination, sex, BMI, education, socioeconomic status, and country of origin. Hypertension (BP above the 95th percentile or above 140/90 mmHg) was associated with a hazard ratio of 1.44 (95% confidence interval, 1.17-1.79). A spline model demonstrated a nadir of risk at SBP values as low as 94 mmHg.

CONCLUSION

Asymptomatic, healthy adolescents with prehypertension have a 32% increased risk for subsequent ESRD, compared with adolescents with optimal BP.

2016 European Society of Hypertension guidelines for the management of high blood pressure in children and adolescents

Increasing prevalence of hypertension (HTN) in children and adolescents has become a significant public health issue driving a considerable amount of research. Aspects discussed in this document include advances in the definition of HTN in 16 year or older, clinical significance of isolated systolic HTN in youth, the importance of out of office and central blood pressure measurement, new risk factors for HTN, methods to assess vascular phenotypes, clustering of cardiovascular risk factors and treatment strategies among others. The recommendations of the present document synthesize a considerable amount of scientific data and clinical experience and represent the best clinical wisdom upon which physicians, nurses and families should base their decisions. In addition, as they call attention to the burden of HTN in children and adolescents, and its contribution to the current epidemic of cardiovascular disease, these guidelines should encourage public policy makers to develop a global effort to improve identification and treatment of high blood pressure among children and adolescents.

Sympathetic neural activity, metabolic parameters and cardiorespiratory fitness in obese youths

OBJECTIVE

The main objective of this cross-sectional study is to assess the cardiac autonomic neural activity in the presence of abnormally increased body weight in youths and its relationship to metabolic risk factors and cardiorespiratory fitness (CRF).

METHODS

Sixty-four overweight and obese patients, aged 9-17 years, of both sexes, stratified according to the international BMI cut-off, were enrolled. Continuous ECG was recorded during 15 min in resting conditions, and the heart rate variability (HRV) was measured in the time domain, frequency domain and for nonlinear dynamics. In addition, cardiometabolic risk factors and CRF in effort conditions were assessed.

RESULTS

Among the overweight and obese youths, no significant differences were observed regarding metabolic parameters and heart rate, although CRF was the lowest in the severely obese youths. Likewise, no significant differences were observed in HRV, independent of how it was assessed. A positive and significant relationship, independent of the degree of obesity, pubertal stage and breathing rate under resting conditions, has been observed among sympathovagal balance, insulin and the homeostatic model assessment index. Furthermore, CRF assessed by volume oxygen peak was associated with insulin levels (r = -0.273; P < 0.05), the SD of the NN interval series (r = 0.268, P < 0.05) and the long-term variation using the Poincaré plot (PS1: r = 0.275, P < 0.05; PS2: r = 0.273, P < 0.05).

CONCLUSION

The key findings of the present study were the presence of a link among fasting insulin, HRV and CRF independent of the degree of obesity, indicating the heterogeneity of obese children and adolescents.

Central blood pressure and pulse wave amplification across the spectrum of peripheral blood pressure in overweight and obese youth

OBJECTIVE

To identify vascular phenotypes across blood pressure (BP) conditions in overweight and obese youths, by assessing office BP (oBP), and central BP (cBP), and pulse pressure (PP) amplification. Whether or not 24-h ambulatory BP monitoring (ABPM) and pulse wave velocity (PWV) add insight to the issue has also been examined.

METHODS

White youths of both sexes with overweight or obesity and of European origin, ranging from 8 to 18 years of age, were included. oBP, cBP, PWV, and 24-h ABPM were measured. oBP conditions and 'white-coat' hypertension were defined as recommend by European Society Hypertension Guidelines in Children and Adolescents. Patients were divided into subgroups of 'normal' or 'high' according to cBP and PP ratio.

RESULTS

A total of 593 patients (mean age, 12.2 ± 2.3 years; 275 women) were included in the study. The largest differences between office SBP and central SBP correspond to the isolated systolic hypertension (ISH) group, in which only 25% of patients have high cBP, in contrast to 50% of the systo-diastolic hypertension (SDH) group. Two patterns emerged based on cBP and PP ratio - while the highest cBP was among the SDH, the highest PP amplitude was in the ISH group. Ninety percent of the SDH were confirmed with 24-h ABPM, in contrast to 75% of the ISH, who were white-coat hypertensive. PWV showed a progressive increment across the groups from normotension to SDH. Significant differences were observed only when compared with the normotensive, but not among all other groups.

CONCLUSION

In overweight and obese hypertensive patients, ISH is prevalent, posing a challenge for the clinician of whether these may therefore be diagnosed and managed as hypertensive patients. Until prospective studies can give more knowledge, 24-h ABPM can offer information for making clinical decisions.

Blood pressure-to-height ratio as a screening indicator of elevated blood pressure among children and adolescents in Chongqing, China

We aimed to evaluate the performance of blood pressure-to-height ratio (BPHR) and establish their optimal thresholds for elevated blood pressure (BP) among children aged 6 to 17 years in Chongqing, China. Data were collected from 11 029 children and adolescents aged 6-17 years in 12 schools in Chongqing according to multistage stratified cluster sampling method. The gold standard for elevated BP was defined as systolic blood pressure (SBP) and/or diastolic blood pressure (DBP) ⩾95th percentile for gender, age and height. The diagnostic performance of systolic BPHR (SBPHR) and diastolic BPHR (DBPHR) to screen for elevated BP was evaluated through receiver-operating characteristic curves (including the area under the curve (AUC) and its 95% confidence interval, sensitivity and specificity). The prevalence of elevated BP in children and adolescents in Chongqing was 10.36% by SBP and/or DBP ⩾95th percentile for gender, age and height. The optimal thresholds of SBPHR/DBPHR for identifying elevated BP were 0.86/0.58 for boys and 0.85/0.57 for girls among children aged 6 to 8 years, 0.81/0.53 for boys and 0.80/0.52 for girls among children aged 9 to 11 years and 0.71/0.45 for boys and 0.72/0.47 for girls among adolescents aged 12-17 years, respectively. Across gender and the specified age groups, AUC ranged from 0.82 to 0.88, sensitivity were above 0.94 and the specificities were over 0.7. The positive predictive values ranged from 0.30 to 0.38 and the negative predictive values were ⩾0.99. BPHR, with uniform values across broad age groups (6-8, 9-11 and 12-17 years) for boys and for girls is a simple indicator to screen elevated BP in children and adolescents in Chongqing.