Obese children and adolescents have elevated nighttime blood pressure independent of insulin resistance and arterial stiffness

Wall Properties of Elastic and Muscular Arteries in Children and Adolescents at Increased Cardiovascular Risk

BACKGROUND

Pulse wave velocity (PWV) assessment represents a simple method to estimate arterial distensibility. At present, carotid-femoral PWV (cf-PWV) is considered the gold standard method in the non-invasive evaluation of the elastic properties of the aorta. On the other hand, the mechanical properties of muscular arteries can be evaluated on the axillo-brachial-radia axis by estimating the carotid-radial PWV (cr-PWV). While a number of studies have addressed these issues in adults, limited information is available on the respective features of cf-PWV and cr-PWV and on their modulating factors in children and adolescents at increased cardiovascular risk.

METHODS

The mechanical properties of the predominantly elastic (aorta) and muscular (axillo-brachial-radial axis) arteries were evaluated in a pediatric population characterized by either elevated blood pressure (BP) or excess body weight, and the main factors affecting cf-PWV and cr-PWV values in these individuals were investigated.

RESULTS

443 children and adolescents (median age 11.5 years, 43.3% females) were enrolled; 25% had BP values >90th percentile and 81% were excess weight. The cf-PWV values were significantly lower than the cr-PWV values: median (Q1-Q3) = 4.8 m/s (4.3-5.5) and 5.8 m/s (5.0-6.5), respectively (p < 0.001). The pubertal development (p < 0.03), systolic BP and diastolic BP z-scores (p = 0.002), heart rate (p < 0.001), and waist-to-height ratio (p < 0.005) were significantly associated with cf-PWV values. No significant association was found between BMI z-score and cf-PWV. Predictors of high cf-PWV (>95th percentile) were the heart rate (OR 1.07, 95%CI 1.04-1.10, p < 0.001) and waist-to-height ratio (OR 1.06, 95%CI 1.0-1.13, p = 0.04). The variables significantly related with cr-PWV values were diastolic BP z-score (p = 0.001), heart rate (p < 0.01), and HOMA index (p < 0.02). No significant association was found between the cr-PWV and BMI z-score or waist-to-height ratio.

CONCLUSIONS

Systolic and diastolic BP values and central obesity are associated with aortic stiffness in a population of children and adolescents at increased cardiovascular risk. In contrast, diastolic BP, heart rate, and levels of insulin resistance appear to be related to distensibility of the upper limb vascular district.

Cardiovascular rhythmicity in overweight and obese children

INTRODUCTION

Obesity is thought to play a role in the disruption of cardiac rhythmicity in obese children, but this is mostly an unexplored field of investigation. We aimed to evaluate the impact of overweight and obesity on circadian and ultradian cardiovascular rhythmicity of prepubertal children, in comparison with normal weight counterparts.

METHODS

We performed a cross sectional study of 316 children, followed in the birth cohort Generation XXI (Portugal). Anthropometrics and 24-hour ambulatory blood pressure were measured and profiles were examined with Fourier analysis for circadian and ultradian blood pressure (BP) and heart rate (HR) rhythms.

RESULTS

Overweight/obese children presented more frequently a non-dipping BP pattern than normal weight counterparts (31.5% vs. 21.6%, p = 0.047). The prevalence of 24-hour mean arterial pressure (MAP) and 8-hour HR rhythmicity was significantly lower in obese children (79.3% vs. 88.0%, p = 0.038 and 33.3% vs. 45.2%, p = 0.031, respectively). The prevalence of the remaining MAP and HR rhythmicity was similar in both groups. No differences were found in the median values of amplitudes and acrophases of MAP and HR rhythms.

DISCUSSION

The alterations found in rhythmicity suggest that circadian and ultradian rhythmicity analysis might be sensitive in detecting early cardiovascular dysregulations, but future studies are needed to reinforce our findings and to better understand their long-term implications.

Waist-to-height-ratio is associated with sustained hypertension in children and adolescents with high office blood pressure

Background

Waist-to-height-ratio (WHtR) has been proposed as another indicator for cardiometabolic risk factors including hypertension. Normally, hypertension can be diagnosed in the office setting by detecting high blood pressure for three occasions. However, patients with high office blood pressure may not exhibit high blood pressure outside the office. Ambulatory blood pressure monitoring (ABPM) is a procedure to measure blood pressure over 24-h. Sustained hypertension is characterized as hypertension detected by both office measurement and ABPM. This study aimed to evaluate the performance of WHtR in the diagnosis of sustained hypertension in patients with high office blood pressure.

Materials and methods

Demographic data, height, body weight, body mass index (BMI), and waist circumference were retrospectively reviewed in children and adolescents who underwent ABPM due to persistently high office blood pressure. Patients were separated into two groups: a sustained hypertension group and a normal ABPM group. BMI was adjusted to z-score using the WHO Anthroplus software. WHtR was calculated by the formula: waist circumference (cm)/height (m). The performances of different parameters were analyzed using the receiver operating characteristic (ROC) curve and multivariate logistic regression.

Results

Sixty patients (63% male) with a mean age of 12.9 ± 3.7 years had persistently high office blood pressure. Twenty-nine (48.3%) had high ambulatory blood pressure parameters so-called "sustained hypertension." The sustained hypertension group had a higher mean BMI z-score (2.32 vs. 1.31, p = 0.01) and a higher mean WHtR (57.7 vs. 49.2 cm/m, p < 0.001) than those of the normal ABPM group. For the diagnosis of sustained hypertension, the ROC analysis revealed that WHtR had a greater area under the ROC curve (AUC) than that of BMI z-score (0.772 vs. 0.723). WHtR remained associated with sustained hypertension (OR 1.2, 95% CI 1.022-1.408, p = 0.026) after adjusting for age, gender, and BMI z-score.

Conclusions

Apart from being a more user-friendly metric, WHtR tended to outperform BMI z-score in predicting sustained hypertension in children and adolescents with persistently high office blood pressure.

Markers of obesity in Danish pediatric liver transplantation recipients

BACKGROUND

Long-time survivors of pediatric liver transplantation have an increased incidence of the metabolic syndrome. Adult recipients have an increased risk of post-transplantation obesity; however, pediatric data are limited.

METHODS

The study included 42 recipients of pediatric liver transplantation in Denmark, transplanted between 1990 and 2014. The study participants were examined with anthropometric measures, dual-energy X-ray scans and blood samples. From the anthropometric measures, body mass index (BMI) and BMI standard deviation score (SDS) were calculated. From the dual-energy X-ray scans, fat percent was assessed, and body fat mass index (BFMI) was calculated.

RESULTS

The median age was 17.4 years (range 4.1-38.9) at the time of the study, and the median time since transplantation was 8.5 years (range 0.4-23.9). The prevalence of overweight and obesity was 31.0% based on BMI SDS (age below 18) and BMI (age 18 and above). When compared to the participants with normal weight, the participants with overweight and obesity had a higher BFMI (9.29 vs 5.57 kg/m² , p < .001) and fat percent (38.35% vs 29.50%, p = .006). They had higher levels of total cholesterol (4.3 vs 3.6 mmol/L, p = .023) and low-density lipoprotein (2.5 vs 1.7, p = .015), and had had longer time since transplantation (15.6 vs 8.5 years respectively, p = .045).

CONCLUSIONS

Long-time survivors of pediatric liver transplantation have a higher BMI or BMI SDS than the general pediatric population. The obesity is characterized by a higher BFMI, fat percent, and cholesterols levels, when compared to recipients without overweight or obesity.

Association of blood pressure, obesity and physical activity with arterial stiffness in children: a systematic review and meta-analysis

Central pulse wave velocity (cPWV) is a biomarker for cardiovascular (CV) risk and a predictor for CV events in adulthood. Alterations of arterial stiffness have also been associated with CV risk in childhood. The study aimed to systematically review and meta-analyze the association of blood pressure (BP), body mass index (BMI), and cardiorespiratory fitness (CRF) with cPWV in children. Literature search was through the databases PubMed, Web of Science, Embase and the Cochrane Register of Controlled Trials. Twenty-two articles were included in the systematic review and eight articles in the meta-analysis. Higher systolic and diastolic BP were associated with higher cPWV (pooled estimated effect size (ES) 0.02 (95% CI: 0.012-0.027; P < 0.001), and ES 0.02 (95% CI: 0.011-0.029; P < 0.001); respectively). Higher BMI correlated with higher cPWV (ES 0.025 (95% CI: 0.013-0.038; P < 0.001)). CRF was inversely associated with cPWV (ES -0.033 (95% CI: -0.055 to -0.011; P = 0.002)). In children, higher BP and BMI are already related to increased cPWV, and enhanced CRF may be a preventive strategy to counteract development of CV disease later in life. IMPACT: This meta-analysis suggests that elevated blood pressure and body mass index in childhood correlate with increased central pulse wave velocity. Children with higher cardiorespiratory fitness appear to have favorably lower arterial stiffening. Elevated blood pressure and altered arterial stiffness originate early in life and childhood risk stratification as well as timely initiation of exercise treatment may help counteract development of manifest cardiovascular disease later in life.

Is Office Blood Pressure Measurement Reliable in Obese Adolescents?

BACKGROUND

Although it is not reflected in the OBP measurement in obese children, ambulatory BP changes are known to occur. MH, non-dipper pattern and nocturnal hypertension have been reported to increase in obese children. On the other hand, the factors that indicate a high risk of hypertension are still unclear. The aim of our study is to especially detect masked hypertension by 24-hour BP measurement in obese adolescents and to evaluate the relationship of masked hypertension with metabolic syndrome parameters, anthropometric measurements and hepatosteatosis in these patients.

METHODS

A total of 63 adolescents diagnosed with obesity were evaluated between January 2019 and December 2019. Office blood pressure was measured for all children, and all of them underwent ABPM. Patients with and without hypertension in ABPM were compared in terms of clinical and laboratory findings.

RESULTS

The mean age was 14.0 ± 1.7 years, females composed 49.2% of the study population. Office blood pressure measurement revealed hypertension in 4 (6.3%) patients and prehypertension in 15 (23.8%) patients. Thirteen patients (20.9%) were diagnosed with masked hypertension, white coat hypertension was diagnosed in 3 (4.7%) patients. Abnormal ABPM patterns were found to be significantly more frequent in patients with severely obesity (with obesity: 26.4% vs severe obesity: 55.6%, p = 0.03) and patients with a higher waist circumference and waist circumference/height ratio.

CONCLUSION

The prevalence of masked hypertension in obese adolescents has been found to be quite high. Therefore, we recommend ABPM in adolescents with high waist circumference/height ratio and severe obesity, even if their office blood pressure measurements are normal.

What Change in Body Mass Index Is Required to Improve Cardiovascular Outcomes in Childhood and Adolescent Obesity through Lifestyle Interventions: A Meta-Regression

Background: Using meta-regression, this article aims at establishing the minimum change in BMI-standard deviation score (SDS) needed to improve lipid profiles and blood pressure in children and adolescents with obesity, to aid future trials and guidelines. Methods: Studies with participants involved in lifestyle interventions, aged 4-19 years, with a diagnosis of obesity according to defined BMI thresholds, were considered for inclusion in a large systematic review. Interventions had to report pre- and post-intervention (or mean change in) BMI-SDS, plus either systolic blood pressure (SBP), high-density lipoprotein (HDL) cholesterol, low-density lipoprotein (LDL) cholesterol, and/or triglycerides (TGs). Random-effects meta-regression quantified the relationship between mean change in BMI-SDS and mean change in cardiovascular outcomes. Results: Seventy-one papers reported various cardiovascular measurements and mean change in BMI-SDS. Fifty-four, 59, 46, and 54 studies were analyzed, reporting a change in SBP, HDL, LDL, and TG, respectively. Reduction in mean BMI-SDS was significantly related to improvements in SBP, LDL, TG, and HDL (p < 0.05); BMI-SDS reductions of 1, 1.2, and 0.7 ensured a mean reduction of SBP, LDL, and TG, respectively, although an equivalent value for HDL improvement was indeterminate. Conclusion: Reductions in mean BMI-SDS of >1, >1.2, or >0.7 are likely to reduce SBP, LDL, and TG, respectively. Further studies are needed to clarify the optimal duration, intensity, and setting for interventions. Consistency is required regarding derived BMI values to facilitate future systematic reviews and meta-analyses.

Blood Pressure and Body Weight Have Different Effects on Pulse Wave Velocity and Cardiac Mass in Children

Background: High blood pressure (BP) and excess weight can lead to early cardiovascular organ damage already in children. Carotid-femoral pulse wave velocity (cf-PWV) is the non-invasive gold standard method for assessing aortic stiffness, while carotid-radial PWV (cr-PWV) provides information on the distensibility of the upper limb arteries. The aim of this study was to evaluate the relationship of BP and BMI z-scores with arterial stiffness and left ventricular mass index (LVMI) in a pediatric population. Methods: In 343 children (57.7% males; age ± SD 11.7 ± 2.9 years), systolic (SBP) and diastolic (DBP) BP, BMI, cf-PWV, cr-PWV and LVMI were measured. A multiple linear regression model was used to assess the impact of BMI and SBP (or DBP) z-scores on cf-PWV, cr-PWV and LVMI. Results: About 21% of children were normal weight, 34% were overweight and 45% obese. Adjusted for possible confounders, SBP and DBP z-scores were significantly associated with cf-PWV (p < 0.001), while only DBP z-scores were related to cr-PWV (p < 0.01). BMI was neither associated with cf-PWV nor with cr-PWV values but was a strong predictor of LVMI (<0.001), whereas cardiac mass and BP z-scores were not related. Conclusions: Our study suggests that, in children, elevated BP values and excess weight may have different effects on the heart and the vessels in causing early cardiovascular alterations.

Associations between thyroid-stimulating hormone, blood pressure and adiponectin are attenuated in children and adolescents with overweight or obesity

Background The association between thyroid-stimulating hormone (TSH) concentrations and blood pressure is well described in adults, but only studied to a limited extent in children and adolescents and almost entirely in population-based cohorts. The present study investigates the association between TSH and blood pressure, and the influence of leptin and adiponectin, in a cohort of children and adolescents enrolled in obesity treatment compared with a population-based cohort. Methods We studied 4154 children and adolescents aged 6-18 years from an obesity clinic cohort and a population-based cohort from The Danish Childhood Obesity Data- and Biobank. Anthropometrics, blood pressure and biochemical markers, including TSH, leptin and adiponectin concentrations, were collected. Adjusted correlation and interaction analyses were performed. Results Patients from the obesity clinic cohort exhibited higher concentrations of TSH and higher blood pressure than participants from the population-based cohort. TSH standard deviation scores (SDS) were significantly associated with all blood pressure-related variables in the population-based cohort, but only with systolic blood pressure SDS and hypertension in the obesity clinic cohort. The interaction between TSH SDS and adiponectin was found to be independently associated with systolic blood pressure and hypertension in the population-based cohort only. Conclusions The significant associations between TSH, adiponectin and blood pressure, observed in children and adolescents from a population-based cohort, are attenuated or absent in children and adolescents with overweight or obesity, suggesting that childhood obesity distorts the healthy interplay between the thyroid axis, thyroid-adipokine interaction and blood pressure.

Peripheral and Central Aortic Pressure, Wave-Derived Reflection Parameters, Local and Regional Arterial Stiffness and Structural Parameters in Children and Adolescents: Impact of Body Mass Index Variations

AIM

The aim was to analyze and compare the associations between body mass index (BMI) and structural and functional cardiovascular variables measured in children and adolescents.

METHODS

609 healthy subjects (mean age/range 12/4-18 years, 45% females) were studied. Subjects' BMI and the corresponding z-scores (z-BMI) were determined. Cardiovascular measurements: peripheral and aortic blood pressure (BP), aortic wave-derived parameters, common carotid, femoral and brachial artery diameters and stiffness, carotid intima-media thickness, carotid-radial and carotid-femoral pulse wave velocity (crPWV, cfPWV) and cfPWV/crPWV ratio. Cardiovascular data were standardized (z-scores) using equations (fractional polynomials) obtained from a sub-group (reference population, n = 241) non-exposed to cardiovascular risk factors (CVRFs). Simple and multiple regression models were obtained for the associations between cardiovascular z-scores and z-BMI and/or z-BMI, age, sex and CVRFs.

RESULTS

z-BMI was associated with standardized cardiovascular variables, regardless of age, sex and CVRFs. BP (peripheral rather than aortic) was the variable with the greatest variations associated with z-BMI. Systolic (SBP) and pulse pressure (PP; in that order) were the variables with the highest variations associated with z-BMI. Carotid, but not femoral or brachial stiffness showed BP-dependent variations associated with z-BMI. Arterial diameters were associated with z-BMI, without differences among arteries.

CONCLUSION

In children and adolescents, z-BMI was gradually and positively associated with haemodynamic (peripheral and central BP) and vascular parameters (structural and functional) with independence of age, sex and other CVRFs (Dyslipidemia, Hypertension, Smoke, Diabetes). There were differences in the associations depending on the arteries studied and on whether central or peripheral haemodynamic parameters were analyzed.

Comparison of ambulatory blood pressure monitoring and office blood pressure measurements in obese children and adolescents

BACKGROUND

Obesity in adults has been related to hypertension and abnormal nocturnal dipping of blood pressure, which are associated with poor cardiovascular and renal outcomes. Here, we aimed to resolve the relationship between the degree of obesity, the severity of hypertension and dipping status on ambulatory blood pressure in obese children.

METHODS

A total 72 patients with primary obesity aged 7 to 18 years (mean: 13.48 ± 3.25) were selected. Patients were divided into three groups based on body mass index (BMİ) Z-score. Diagnosis and staging of ambulatory hypertension based on 24-h blood pressure measurements, obtained from ambulatory blood pressure monitoring.

RESULTS

Based on our ambulatory blood pressure data, 35 patients (48.6%) had hypertension, 7 (20%) had ambulatory prehypertension, 21 (60%) had hypertension, and 7 patients (20%) had severe ambulatory hypertension. There was a significant relationship between severity of hypertension and the degree of obesity (p < 0.05). Thirty-one patients (88.6%) had isolated nighttime hypertension, and 53 patients (73.6%) were non-dippers. All systolic blood pressure results and loads were similar between groups. Diastolic and mean arterial blood pressure levels during the night, diastolic blood pressure loads, and heart rate during the day were significantly higher in Group 3 (p < 0.05). Nocturnal non-dipping was not associated with severity of obesity.

CONCLUSION

Obesity was associated with severity of hypertension, higher diastolic blood pressure at night, mean arterial pressure at night, diastolic blood pressure loads and heart rate at day. Increase in BMI Z-score does not a significant impact on daytime blood pressure and nocturnal dipping status.

Interactions Between Air Pollution and Obesity on Blood Pressure and Hypertension in Chinese Children

BACKGROUND

Little information exists regarding the effect of interaction of obesity and long-term air pollution exposure on children's blood pressure and hypertension in areas with high levels of air pollution. The aim of this study is to assess effect modification by obesity on the association between exposure and blood pressure in Chinese children.

METHODS

We studied 9,354 Chinese children, ages 5-17 years old, from 24 elementary schools and 24 middle schools in the Seven Northeastern Cities during 2012-2013. Four-year average concentrations of particles with an aerodynamic diameter ≤10 µm (PM10), sulfur dioxide, nitrogen dioxides, and ozone (O3) were measured at the monitoring stations in the 24 districts. We used generalized additive models and two-level logistic regression models to examine the health effects.

RESULTS

Consistent interactions were found between exposure and obesity on blood pressure and hypertension. The association between exposure and hypertension was consistently larger for overweight/obese children than for children with normal-weight, with odds ratios for hypertension ranging from 1.16 per 46.3μg/m for O3 (95% confidence interval [CI] = 1.12, 1.20) to 2.91 per 30.6μg/m for PM10 (95% CI = 2.32, 3.64), and estimated increases in mean systolic and diastolic blood pressure ranging from 0.57 mmHg (95% CI = 0.36, 0.78) and 0.63 mmHg (95% CI = 0.46, 0.81) per 46.3 μg/m for O3 to 4.04 mmHg (95% CI = 3.00, 5.09) and 2.02 mmHg (95% CI = 1.14, 2.89) per 23.4 μg/m for sulfur dioxide.

CONCLUSIONS

Obesity amplifies the association of long-term air pollution exposure with blood pressure and hypertension in Chinese children.

Prognostic Value of Ambulatory Blood Pressure in the Obese: The Ambulatory Blood Pressure-International Study

The purpose of this study was to compare the predictive value of ambulatory blood pressure (BP) vs office BP for cardiovascular events during a 5.8-year follow-up period in the obese and nonobese participants of the Ambulatory Blood Pressure-International Study (n=10,817). Both ambulatory BP and office BP considered separately were predictive of cardiovascular events. However, in Cox models including both pressures, only ambulatory BP was associated with outcome. Among obese patients, the hazard ratios for a 10-mm Hg increase in 24-hour and office systolic BPs were 1.37 (95% confidence interval, 1.20-1.53) and 0.91 (95% confidence interval, 0.76-1.07), respectively. Among nonobese patients, the corresponding hazard ratios were 1.39 (95% confidence interval, 1.31-1.47) and 0.94 (95% confidence interval, 0.88-1.00) (P=not significant vs obese). Similar results were obtained for diastolic BP and for daytime and nighttime BPs. Ambulatory BP has similar predictive capacity in obese and nonobese patients, suggesting that ambulatory BP monitoring is a useful diagnostic tool for the assessment of obese individuals.

Kidney injury molecule-1 and neutrophil gelatinase associated lipocalin in normoalbuminuric diabetic children

BACKGROUND

We aimed at evaluating the urinary levels of kidney injury molecule-1 ( KIM-1) and neutrophil gelatinase associated lipocalin (NGAL), and the relationship between these markers and clinical and laboratory variables in normoalbuminuric children with type 1 diabetes (T1D).

METHODS

The study group consisted of 60 (F/M: 28/32) children with T1D with a median age of 13 (min: 7.1-max: 17.9) years and a mean HbA1c of 8.6%. The average period of treatment was 6.8±2.2 years. The control group consisted of 60 healthy children [(F/M: 32/28); median age: 13.6 (min: 6.9-max: 17.9) years].

RESULTS

Urinary KIM-1 and NGAL levels were significantly elevated in the diabetic group (KIM-1: 0.50±0.34 ng/mg-cr; NGAL: 33±31 ng/mg-cr) compared with the nondiabetic control subjects (KIM-1: 0.26±0.25 ng/mg-cr, NGAL 13.3±14.5 ng/mg-cr) (p<0.001). No significant associations were observed between NGAL or KIM-1 and the duration of diabetes and HbA1c levels. NGAL was found to be weakly correlated with KIM-1 (p<0.005, r=0.289).

CONCLUSIONS

NGAL and KIM are high in normoalbuminuric diabetic children before reduction in glomerular filtration rate. High NGAL and KIM-1 levels may indicate early diabetic kidney injury; however, we did not observe any relationship between these markers and diabetic indices. For clinical usefulness of these markers, long-term studies are required.

Obesity and Arterial Stiffness in Children

Objective—

Childhood obesity is associated with risk factors for cardiovascular disease. Arterial stiffness is considered one of the earliest detectable measures of vascular damage. There is controversy in the literature regarding the effects of childhood obesity on arterial stiffness. The objective of this study is to systematically review the literature and to conduct a meta-analysis comparing measures of central arterial stiffness in children and adolescents with obesity to healthy body mass index controls.

Approach and Results—

Literature searches were conducted using databases (eg, MEDLINE, EMBASE) and citations cross-referenced. Studies assessing central pulse wave velocity or β-stiffness index were included. A random effects meta-analysis of the standardized mean difference and 95% confidence intervals in arterial stiffness between children with obesity and control children was performed for each arterial stiffness measure. A total of 523 studies were identified. Fifteen case–control studies were included, with 2237 children/adolescents (1281 with obesity, 956 healthy body mass index controls) between 5 and 24 years of age. All studies measuring carotid and aortic β-stiffness index and 10/12 studies measuring central pulse wave velocity reported greater arterial stiffness in children/adolescents with obesity compared with controls. A random effects meta-analysis was performed revealing a significant effect of obesity on pulse wave velocity (standardized mean difference=0.718; 95% confidence interval=0.291–1.415), carotid β-stiffness index (0.862; 0.323–1.402), and aortic β stiffness index (1.017; 0.419–1.615).

Conclusion—

These findings indicate that child/adolescent obesity is associated with greater arterial stiffness. However, further research is needed to address confounders, such as pubertal status, that may affect this relationship in children. In the future, these techniques may be useful in risk stratification and guiding clinical management of obese children to optimize cardiovascular outcomes.