Impacts of Measurement Protocols on Blood Pressure Tracking From Childhood Into Adulthood

Association of blood pressure and heart rate with carotid markers of vascular remodeling in the young: a case for early prevention

OBJECTIVE

The association of childhood blood pressure (BP) and heart rate (HR) with intermediate markers of cardiovascular disease several decades later has been shown, but studies on more short-term outcomes are scarce. Using population-based data, this study investigates the association of four BP parameters and HR in childhood with three carotid markers for vascular remodeling one decade later.

METHODS

At the 11-year follow-up, 4607 participants of the nationwide KiGGS cohort aged 14 to 28 years had semi-automated sonographic carotid intima media thickness (CIMT) measurements. We investigated associations of baseline (age 3-17 years) and follow-up SBP, DBP, mean arterial pressure (MAP), pulse pressure (PP) and resting heart rate (RHR), with CIMT and lumen diameter at or above the 90th percentile and distensibility coefficient at or below the tenth percentile in logistic regressions. Analyses were further adjusted using a composite cardiovascular risk (CVR) score of BMI, triglycerides, total/HDL-cholesterol-ratio and HbA1c.

RESULTS

SBP, DBP, MAP and RHR were significantly and similarly associated with all carotid measures 11 years later, for example an odds ratio (OR) of 1.17 [confidence interval (CI) 1.06-1.29] for one standard deviation SBP increase with elevated CIMT when adjusting for sex, age and CVR score. Cross-sectionally, the strongest association was found for MAP with reduced distensibility coefficient (OR 1.76; CI 1.59-1.94).

CONCLUSION

This population-based cohort study shows robust and consistent associations between childhood BP and RHR and three carotid measures of vascular remodeling only one decade later, clearly underscoring the potential importance of preventing high BP already early in the life course.

Hypertension and Associated Risk Factors among Children with Intellectual Disability: A Cross-Sectional Study

To investigate the prevalence of hypertension and associated risk factors in Chinese children with intellectual disability, a cross-sectional study was conducted in a sample of 558 children with intellectual disability aged 6–18 years in Hong Kong, and 452 (81.0%) with valid data were included in the data analysis. Blood pressure was measured according to a standard protocol. Hypertension was defined using the age-, gender-, and height-specific classification criteria recommended by the 2018 Chinese Guidelines for Children. Multivariate and hierarchical logistic regression was fitted to examine the associations of hypertension with potential risk factors. Overall, 31.4% of the participants were classified as having hypertension. Obese children were more likely to develop hypertension than non-obese children (adjusted OR = 2.77, 95% CI: 1.28, 5.99, p = 0.010). A paternal education of college or above and a paternal occupation of clerks, sales representatives, and workers were also associated with an increased risk of hypertension. The prevalence of hypertension is high among Chinese children with intellectual disability. Obesity was the strongest risk factor. Further longitudinal studies are warranted to confirm our findings. Nevertheless, preventions against obesity are promising to receive doubled benefits in reducing both obesity and hypertension, given its strong relationship with hypertension in this special population.

Long-term effects of PM2.5 components on blood pressure and hypertension in Chinese children and adolescents

Growing evidence has linked fine particulate matter (PM_2.5) exposure to elevated blood pressure, but the effects of PM_2.5 components are unclear, particularly in children and adolescents. Based on a cross-sectional investigation in China, we analyzed the associations between long-term exposure to PM_2.5 and its major components with elevated blood pressure in children and adolescents. A representative sample (N = 37,610) of children and adolescents with age 7-18 years was collected in seven Chinese provinces. Exposures to PM_2.5 and five of its major components, including black carbon (BC), organic matter (OM), inorganic nitrate (NO₃^-), sulfate (SO₄^2-), and soil particles (SOIL), were estimated using satellite-based spatiotemporal models. The associations between long-term exposures to PM_2.5 and its components and diastolic blood pressure (DBP), systolic blood pressure (SBP), and hypertension were investigated using mixed-effects logistic and linear regression models. Within the populations, 11.5 % were classified as hypertension. After adjusting for a variety of covariates, per interquartile range (IQR) increment in PM_2.5 mass and BC levels were significantly associated with a higher hypertension prevalence with odds ratios (ORs) of 1.56 (95% confidence interval (CI): 1.08, 2.25) for PM_2.5 and 1.19 (95% CI: 1.04, 1.35) for BC. Long-term exposures to PM_2.5 and BC have also been associated with elevated SBP and DBP. Additionally, OM and NO₃^- were significantly associated with increased SBP, while SOIL was significantly associated with increased DBP. In the subgroup analysis, the associations between long-term exposures to BC and blood pressure vary significantly by urbanicity of residential area and diet habits. Our study suggests that long-term exposure to PM_2.5 mass and specific PM_2.5 components, especially for BC, are significantly associated with elevated blood pressure and a higher hypertension prevalence in Chinese children and adolescents.

Nocturnal non-dipping on 24-h Ambulatory Blood Pressure Monitoring in children and adolescents with obesity is associated with higher total cholesterol levels

BACKGROUND

Few studies indicate the occurrence of abnormal nocturnal dipping of blood pressure (BP) in 35-50% of children and adolescents with obesity. The relation between that phenomenon and metabolic complications of obesity remains unclear. To evaluate the association between disorders of glucose and lipid metabolism, and nocturnal non-dipping in pediatric patients with obesity.

METHODS

In 207 children (53.14% girls, mean age 14 (range 2-17), mean BMI Z-SCORE 4.38, range 2.07-10.74) standard 24-h Ambulatory Blood Pressure Monitoring was performed. Normal dipping was defined as a ≥ 10% decline in BP during the night.

RESULTS

There were 106 (51.21%) cases of non-dippers. The mean 24-h nocturnal systolic BP (SBP) reduction (%) was 9.9 ± 5.5. The mean 24-h nocturnal diastolic BP (DBP) reduction (%) was 15.8 ± 8.5. There was a significant correlation between BMI Z-SCORE and mean day-time SBP (r = 0.14 P = .042). There are positive correlations between 24-h heart rate (beats/min) and BMI Z-SCORE (r = 0.15, P = .027), between fasting glucose and systolic BP Z-SCORE (r = 0.17, P = .03) and between mean diastolic BP and LDL cholesterol (r = 0.23, P = .004). Total cholesterol level was significantly higher in non-dippers (4.34 vs. 3.99 mmol/L, P = .034). There were no significant differences between non-dippers and dippers regarding fasting glucose (4.6 vs. 4.8 mmol/L), 120'post load glucose (5.7 vs. 5.9 mmol/L), insulin (19 vs. 20.2 µIU/mL), HOMA-IR (2.36 vs. 2.44), LDL cholesterol (2.64 vs. 2.51 mmol/L), HDL cholesterol (1.06 vs. 1.03 mmol/L) or triglycerides (1.36 vs. 1.34 mmol/L) levels.

CONCLUSION

Nocturnal non-dipping is frequent in pediatric patients with obesity. It is associated with higher total cholesterol levels.

Elevated Blood Pressure in Childhood or Adolescence and Cardiovascular Outcomes in Adulthood: A Systematic Review

There remains some uncertainty about the magnitude of the associations between elevated blood pressure (BP) in childhood or adolescence and cardiovascular morbidity and mortality in adulthood. We summarized evidence on the long-term impact of elevated BP in childhood or adolescence on cardiovascular morbidity and mortality in adulthood. PubMed and Embase databases were searched up to August 1, 2019, and retrieved studies were reviewed manually. Our systematic review included all eligible prospective cohort studies on the associations between BP status in childhood or adolescence and intermediate markers or hard outcomes of cardiovascular disease in adults, including high pulse wave velocity, high carotid intima-media thickness, left ventricular hypertrophy, and cardiovascular disease (fatal and nonfatal) and total mortality. A total of 19 articles were finally included, and 12 could be synthesized by meta-analysis. Elevated BP in childhood or adolescence was significantly associated, in adulthood, with high pulse wave velocity (3 articles, N=3725; pooled odds ratio [OR], 1.83 [95% CI, 1.39-2.40]); high carotid intima-media thickness (2 articles, N=4152; OR, 1.60 [95% CI, 1.29-2.00]); and left ventricular hypertrophy (2 articles, N=3019; OR, 1.40 [95% CI, 1.20-1.64]). Additionally, our systematic review also shows evidence of associations of elevated BP in youth with cardiovascular disease and mortality in adulthood. In conclusion, our systematic review and meta-analysis confirms that elevated BP in childhood or adolescence is associated with several intermediate markers and hard outcomes of cardiovascular disease in adulthood. These findings emphasize the importance for children and adolescents to have their BP within normal values.

Development of a prediction model to target screening for high blood pressure in children

Targeted screening for childhood high blood pressure may be more feasible than routine blood pressure measurement in all children to avoid unnecessary harms, overdiagnosis or costs. Targeting maybe based e.g. on being overweight, but information on other predictors may also be useful. Therefore, we aimed to develop a multivariable diagnostic prediction model to select children aged 9-10 years for blood pressure measurement. Data from 5359 children in a population-based prospective cohort study were used. High blood pressure was defined as systolic or diastolic blood pressure ≥ 95th percentile for gender, age, and height. Logistic regression with backward selection was used to identify the strongest predictors related to pregnancy, child, and parent characteristics. Internal validation was performed using bootstrapping. 227 children (4.2%) had high blood pressure. The diagnostic model included maternal hypertensive disease during pregnancy, maternal BMI, maternal educational level, parental hypertension, parental smoking, child birth weight standard deviation score (SDS), child BMI SDS, and child ethnicity. The area under the ROC curve was 0.73, compared to 0.65 when using only child overweight. Using the model and a cut-off of 5% for predicted risk, sensitivity and specificity were 59% and 76%; using child overweight only, sensitivity and specificity were 47% and 84%. In conclusion, our diagnostic prediction model uses easily obtainable information to identify children at increased risk of high blood pressure, offering an opportunity for targeted screening. This model enables to detect a higher proportion of children with high blood pressure than a strategy based on child overweight only.

Identifying critical windows of prenatal particulate matter (PM2.5) exposure and early childhood blood pressure

BACKGROUND

Exposure to air pollution is associated with increased blood pressure (BP) in adults and children. Some evidence suggests that air pollution exposure during the prenatal period may contribute to adverse cardiorenal health later in life. Here we apply a distributed lag model (DLM) approach to identify critical windows that may underlie the association between prenatal particulate matter ≤ 2.5 μm in diameter (PM_2.5) exposure and children's BP at ages 4-6 years.

METHODS

Participants included 537 mother-child dyads enrolled in the Programming Research in Obesity, GRowth Environment, and Social Stress (PROGRESS) longitudinal birth cohort study based in Mexico City. Prenatal daily PM_2.5 exposure was estimated using a validated satellite-based spatio-temporal model and BP was measured using the automated Spacelabs system with a sized cuff. We used distributed lag models (DLMs) to examine associations between daily PM_2.5 exposure and systolic and diastolic BP (SBP and DBP), adjusting for child's age, sex and BMI, as well as maternal education, preeclampsia and indoor smoking report during the second and third trimester, seasonality and average postnatal year 1 PM_2.5 exposure.

RESULTS

We found that PM_2.5 exposure between weeks 11-32 of gestation (days 80-226) was significantly associated with children's increased SBP. Similarly, PM_2.5 exposure between weeks 9-25 of gestation (days 63-176) was significantly associated with increased DBP. To place this into context, a constant 10 μg/m³ increase in PM_2.5 sustained throughout this critical window would predict a cumulative increase of 2.6 mmHg (CI: 0.5, 4.6) in SBP and 0.88 mmHg (CI: 0.1, 1.6) in DBP at ages 4-6 years. In a stratified analysis by sex, this association persisted in boys but not in girls.

CONCLUSIONS

Second and third trimester PM_2.5 exposure may increase children's BP in early life. Further work investigating PM_2.5 exposure with BP trajectories later in childhood will be important to understanding cardiorenal trajectories that may predict adult disease. Our results underscore the importance of reducing air pollution exposure among susceptible populations, including pregnant women.

Utility of Different Blood Pressure Measurement Components in Childhood to Predict Adult Carotid Intima-Media Thickness

Childhood blood pressure (BP) levels predict adult subclinical atherosclerosis. However, the best childhood BP component for prediction has not been determined. This study comprised 5925 participants aged 3 to 18 years from 6 cohorts who were followed into adulthood (mean follow-up 25.8±6.2 years). Childhood BP was measured by using a standard mercury sphygmomanometer in all cohorts. Study-specific carotid intima-media thickness ≥90th percentile was used to define subclinical atherosclerosis. Per SD change in the predictor, childhood systolic BP (SBP; age- and sex-adjusted odds ratio [95% CI], 1.24 [1.13-1.37]), mean arterial pressure (1.10 [1.07-1.13]), and pulse pressure (1.15 [1.05-1.27]) were associated with increased adulthood intima-media thickness. In age- and sex-adjusted analyses, area under the receiver operating characteristic curves for SBP ( C value [95% CI], 0.677 [0.657-0.704]) showed significantly improved prediction compared with diastolic BP (0.669 [0.646-0.693], P=0.006) or mean arterial pressure (0.674 [0.653-0.699], P=0.01). Pulse pressure provided a C value that was not different from SBP (0.676 [0.653-0.699], P=0.16). Combining different BP components did not improve prediction over SBP measurement alone. Based on the associations with adult carotid intima-media thickness, cut points for elevated SBP were 105 mm Hg for 3- to 6-year-old boys, 108 mm Hg for 3- to 6-year-old girls, 108 mm Hg for 7- to 12-year-old boys, 106 mm Hg for 7- to 12-year-old girls, 123 mm Hg for 13- to 18-year-old boys, and 115 mm Hg for 13- to 18-year-old girls. Our analyses suggest that several childhood BP measurement components are related to adulthood carotid intima-media thickness. Of these, SBP provided the best predictive ability.

Effect of Prenatal Docosahexaenoic Acid Supplementation on Blood Pressure in Children With Overweight Condition or Obesity: A Secondary Analysis of a Randomized Clinical Trial

IMPORTANCE

The blood pressure-lowering property of docosahexaenoic acid (DHA) in children and adults is known, and an observational study from the Netherlands has linked higher intrauterine DHA exposure to lower childhood blood pressure. However, the association of prenatal intake of DHA supplement with childhood blood pressure has not been evaluated in randomized clinical trials.

OBJECTIVE

To determine the effect of DHA supplementation during pregnancy on childhood blood pressure.

DESIGN, SETTING, AND PARTICIPANTS

This prespecified secondary analysis of the Kansas University DHA Outcome Study (KUDOS), a phase 3, double-blind, randomized, placebo-controlled clinical trial was conducted at several local hospitals in the Kansas City, Kansas, metropolitan area. Pregnant women (n = 350) were enrolled in the KUDOS trial between January 10, 2006, and November 17, 2009, and were followed up until their children were 18 months of age. During pregnancy, the women received either 3 capsules per day of placebo or 600 mg per day of DHA from a mean (SD) of 14.5 (3.7) weeks' (all before 20 weeks) gestation until birth. The parents of 190 children consented to additional follow-up of their children until 6 years, which ended April 29, 2016. Study personnel involved in testing were blind to the randomization until all children had completed the trial. Data analysis was performed from May 23, 2017, to July 10, 2018.

INTERVENTIONS

Pregnant women were assigned to either 600 mg per day of DHA or a placebo that was half soy and half corn oil. Both placebo and DHA were provided in 3 capsules per day.

MAIN OUTCOMES AND MEASURES

Childhood blood pressure was a planned secondary outcome of a study powered to measure cognitive development. The hypothesis was that DHA would lower blood pressure prior to data analysis. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured at 4, 4.5, 5, 5.5, and 6 years and were analyzed for possible covariates using mixed models to generate a final model.

RESULTS

In total, 171 children (88 [51.5%] female) were included in this analysis. Of these children, 89 (52.0%) were randomized to the DHA group and 82 (47.9%) to the placebo group. A statistically significant interaction was found between treatment (placebo or DHA) and child weight status (5-year body mass index ≤85th or >85th percentile) for both SBP and DBP. Children who were overweight or obese whose mothers received placebo during pregnancy had higher SBP and DBP compared with children who were overweight or obese whose mothers received DHA (mean [SE] SBP, 104.28 [1.37] mm Hg vs 100.34 [1.02] mm Hg; DBP, 64.7 [1.23] mm Hg vs 59.76 [0.91] mm Hg). No differences in the SBP and DBP were found between children who were overweight or obese whose mothers received DHA and children who were not overweight or obese. In the mixed model analysis, the child's age at blood pressure measurement and the maternal prepregnancy body mass index were the only other statistically significant variables (child age, SBP: F = 7.385; P = .001; DBP: F = 7.39; P = .001; prepregnancy BMI, SBP: r = 0.284; P = .001; DBP: r = 0.216; P = .01).

CONCLUSIONS AND RELEVANCE

Maternal docosahexaenoic acid intake during pregnancy appeared to mitigate the association between childhood overweight condition or obesity and blood pressure.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02487771.

Differences between the fourth and fifth Korotkoff phases among children and adolescents

BACKGROUND

The relative importance of the fourth (K4) and fifth (K5) Korotkoff phases as the indicator of diastolic blood pressure (DBP) levels among children remains uncertain.

METHODS

In a sample of 11,525 youth aged 5-17, we examined interexaminer differences in these 2 phases and the relation of theses 2 phases to adult blood pressure levels and hypertension. The longitudinal analyses were conducted among 2,156 children who were re-examined after age 25 years.

RESULTS

Mean (±SD) levels of DBP were 62 (±9) mm Hg (K4) and 49 (±13) mm Hg (K5). K4 showed less interobserver variability than did K5, and 7% of the children had at least 1 (of 6) K5 value of 0mm Hg. Longitudinal analyses indicated that K4 was more strongly associated with adult blood pressure levels and hypertension. In correlational analyses of subjects who were not using antihypertensive medications in adulthood (n = 1,848), K4 was more strongly associated with the adult DBP level than was K5 (r = 0.22 vs. 0.17; P < 0.01). Analyses of adult hypertension (based on high blood pressure levels or use of antihypertensive medications) indicated that the screening performance of childhood levels of K4 was similar to that of systolic blood pressure and was higher than that of K5, with areas under the receiver operator characteristic curves of 0.63 (systolic blood pressure), 0.63 (K4), and 0.57 (K5).

CONCLUSIONS

As compared with K5 levels among children, K4 shows less interobserver variability and is more strongly associated with adult hypertension.

Comparison of calf and brachial blood pressures in infants: is there a difference between calf and brachial blood pressures?

The standard of care is to obtain a noninvasive blood pressure (NIBP) measurement from the right upper arm. However, in the pediatric population it is common practice to take blood pressure (BP) measurements from the calf/upper ankle. Nurses commonly take calf NIBPs for many reasons, but there is little evidence to support calf BPs as a reliable site for BP measurement. Furthermore, there is conflicting evidence. Some studies suggest no difference between the calf and the upper arm BPs, whereas others conclude great variability between the two. The purpose of this study was to demonstrate the reliability of calf BPs, by showing no difference between brachial and calf BP measurements in neonates and infants ≤ 1 year old. From July 2008 to December 2008, a convenience sample of 52 subjects admitted to the Neonatal and Infant Critical Care Unit were enrolled into the study. Limb selection was not randomized. Three BPs were taken from the arm and 3 BPs were taken from the calf. Data were analyzed using a mixed analysis of variance (P = 0.05). The difference was not significant for systolic (P = 0.6159) or mean BP (P = 0.1298), but it was significant for diastolic (P = 0.0263). The authors concluded that these results support the current practice of bedside nurses and contribute to the limited knowledge on this topic. Because there was a difference in the diastolic BPs, further investigation is needed.

Effects of long-term averaging of quantitative blood pressure traits on the detection of genetic associations

Blood pressure (BP) is a heritable, quantitative trait with intraindividual variability and susceptibility to measurement error. Genetic studies of BP generally use single-visit measurements and thus cannot remove variability occurring over months or years. We leveraged the idea that averaging BP measured across time would improve phenotypic accuracy and thereby increase statistical power to detect genetic associations. We studied systolic BP (SBP), diastolic BP (DBP), mean arterial pressure (MAP), and pulse pressure (PP) averaged over multiple years in 46,629 individuals of European ancestry. We identified 39 trait-variant associations across 19 independent loci (p < 5 × 10(-8)); five associations (in four loci) uniquely identified by our LTA analyses included those of SBP and MAP at 2p23 (rs1275988, near KCNK3), DBP at 2q11.2 (rs7599598, in FER1L5), and PP at 6p21 (rs10948071, near CRIP3) and 7p13 (rs2949837, near IGFBP3). Replication analyses conducted in cohorts with single-visit BP data showed positive replication of associations and a nominal association (p < 0.05). We estimated a 20% gain in statistical power with long-term average (LTA) as compared to single-visit BP association studies. Using LTA analysis, we identified genetic loci influencing BP. LTA might be one way of increasing the power of genetic associations for continuous traits in extant samples for other phenotypes that are measured serially over time.

Associations of obesity susceptibility loci with hypertension in Chinese children

CONTEXT

Recent genome-wide association studies have identified several single-nucleotide polymorphisms (SNPs) that are associated with body mass index (BMI)/obesity.

OBJECTIVE

As obesity is an independent risk factor for hypertension, the objective of the study was to investigate the associations of obesity susceptibility loci with blood pressure (BP)/hypertension in a population of Chinese children.

DESIGN, SETTING AND PARTICIPANTS

This was a genotype-phenotype association study. Participants included 3077 Chinese children, aged 6-18 years. Based on the Chinese age- and sex-specific BP standards, 619 hypertensive cases and 2458 controls with normal BP were identified.

MAIN OUTCOME MEASURES

BP was measured by auscultation using a standard clinical sphygmomanometer.

RESULTS

Of the 11 SNPs, only FTO rs9939609 was significantly associated with systolic BP (SBP; P=0.034) and three SNPs were significantly associated with diastolic BP (DBP; GNPDA2 rs10938397: P=0.026; FAIM2 rs7138803: P=0.015; NPC1 rs1805081: P=0.031) after adjustment for age, sex and hypertension status. In addition, three SNPs were significantly associated with hypertension risk after adjustment for age and sex (FTO rs9939609: odds ratio (OR)=1.35, 95% confidence interval (CI) 1.12-1.62, P=0.001; MC4R rs17782313: OR=1.22, 95% CI 1.06-1.42, P=0.007; GNPDA2 rs10938397: OR=1.17, 95% CI 1.02-1.34, P=0.021). After additional adjustment for BMI, none remained significant. The genetic risk score (GRS), based on three significant SNPs (FTO rs9939609, MC4R rs17782313, GNPDA2 rs10938397), showed a positive association with SBP (P=5.17 × 10(-4)) and risk of hypertension (OR=1.22, 95% CI 1.12-1.33, P=6.07 × 10(-6)). Further adjustment for BMI abolished the positive associations (SBP: P=0.220; DBP: P=0.305; hypertension: P=0.052). Only FTO rs9939609 and GRS were statistically associated with hypertension risk in the age- and sex-adjusted model after correction for multiple testing.

CONCLUSIONS

The present study demonstrated that FTO rs9939609 and combined SNPs were significantly associated with risk of hypertension, which seems to be dependent on BMI.

Screening for hypertension in children and adolescents to prevent cardiovascular disease

BACKGROUND AND OBJECTIVE

The prevalence of hypertension is increasing in children, and may persist into adulthood. This systematic review was conducted for the US Preventive Services Task Force recommendation on the effectiveness of screening asymptomatic children and adolescents for hypertension in order to prevent cardiovascular disease.

METHODS

Eligible studies were identified from Medline and the Cochrane Library (through July 2012). We included trials and controlled observational studies in asymptomatic children and adolescents on the effectiveness and harms of screening and treatment, as well as accuracy of blood pressure measurement. One author extracted study characteristics and results, which were checked for accuracy by a second author.

RESULTS

No studies evaluated the effects of screening for hypertension on health outcomes. Two studies of screening tests for elevated blood pressure reported moderate sensitivities (0.65, 0.72) and specificities (0.75, 0.92). Sensitivities and specificities of child hypertension for the later presence of adult hypertension (7 studies) were wide ranging (0-0.63 and 0.77-1.0, respectively), and associations between child hypertension and carotid intima media thickening and proteinuria in young adults (3 studies) were inconsistent. Seven studies reported that drug interventions effectively lowered blood pressure in adolescents over short follow-up periods. No serious treatment-related adverse effects were reported.

CONCLUSIONS

There is no direct evidence that screening for hypertension in children and adolescents reduces adverse cardiovascular outcomes in adults. Additional studies are needed to improve diagnosis and risk stratification of children with elevated blood pressure and to quantify risks and benefits of interventions.

Cardiovascular disease risk in healthy children and its association with body mass index: systematic review and meta-analysis

OBJECTIVES

To describe the association and its magnitude between body mass index category, sex, and cardiovascular disease risk parameters in school aged children in highly developed countries.

DESIGN

Systematic review and meta-analysis. Quality of included studies assessed by an adapted version of the Cochrane Collaboration's risk of bias assessment tool. Results of included studies in meta-analysis were pooled and analysed by Review Manager version 5.1.

DATA SOURCES

Embase, PubMed, EBSCOHost's cumulative index to nursing and allied health literature, and the Web of Science databases for papers published between January 2000 and December 2011.

REVIEW METHODS

Healthy children aged 5 to 15 in highly developed countries enrolled in studies done after 1990 and using prospective or retrospective cohort, cross sectional, case-control, or randomised clinical trial designs in school, outpatient, or community settings. Included studies had to report an objective measure of weight and at least one prespecified risk parameter for cardiovascular disease.

RESULTS

We included 63 studies of 49 220 children. Studies reported a worsening of risk parameters for cardiovascular disease in overweight and obese participants. Compared with normal weight children, systolic blood pressure was higher by 4.54 mm Hg (99% confidence interval 2.44 to 6.64; n=12 169, eight studies) in overweight children, and by 7.49 mm Hg (3.36 to 11.62; n=8074, 15 studies) in obese children. We found similar associations between groups in diastolic and 24 h ambulatory systolic blood pressure. Obesity adversely affected concentrations of all blood lipids; total cholesterol and triglycerides were 0.15 mmol/L (0.04 to 0.25, n=5072) and 0.26 mmol/L (0.13 to 0.39, n=5138) higher in obese children, respectively. Fasting insulin and insulin resistance were significantly higher in obese participants but not in overweight participants. Obese children had a significant increase in left ventricular mass of 19.12 g (12.66 to 25.59, n=223), compared with normal weight children.

CONCLUSION

Having a body mass index outside the normal range significantly worsens risk parameters for cardiovascular disease in school aged children. This effect, already substantial in overweight children, increases in obesity and could be larger than previously thought. There is a need to establish whether acceptable parameter cut-off levels not considering weight are a valid measure of risk in modern children and whether methods used in their study and reporting should be standardised.

Blood pressure and associated factors in a North African adolescent population. a national cross-sectional study in Tunisia

Background

In southern and eastern Mediterranean countries, changes in lifestyle and the increasing prevalence of excess weight in childhood are risk factors for high blood pressure (BP) during adolescence and adulthood. The aim of this study was to evaluate the BP status of Tunisian adolescents and to identify associated factors.

Methods

A cross-sectional study in 2005, based on a national, stratified, random cluster sample of 1294 boys and 1576 girls aged 15-19 surveyed in home visits. The socio-economic and behavioral characteristics of the adolescents were recorded. Overweight/obesity were assessed by Body Mass Index (BMI) from measured height and weight (WHO, 2007), abdominal obesity by waist circumference (WC). BP was measured twice during the same visit. Elevated BP was systolic (SBP) or diastolic blood pressure (DBP) ≥ 90th of the international reference or ≥ 120/80 mm Hg for 15-17 y., and SBP/DBP ≥ 120/80 mm Hg for 18-19 y.; hypertension was SBP/DBP ≥ 95th for 15-17 y. and ≥ 140/90 mm Hg for 18-19 y. Adjusted associations were assessed by logistic regression.

Results

The prevalence of elevated BP was 35.1%[32.9-37.4]: higher among boys (46.1% vs. 33.3%; P < 0.0001); 4.7%[3.8-5.9] of adolescents had hypertension. Associations adjusted for all covariates showed independent relationships with BMI and WC: - obesity vs. no excess weight increased elevated BP (boys OR = 2.1[1.0-4.2], girls OR = 2.3[1.3-3.9]) and hypertension (boys OR = 3.5[1.4-8.9], girls OR = 5.4[2.2-13.4]), - abdominal obesity (WC) was also associated with elevated BP in both genders (for boys: 2nd vs. 1st tertile OR = 1.7[1.3-2.3], 3rd vs.1st tertile OR = 2.8[1.9-4.2]; for girls: 2nd vs. 1st tertile OR = 1.6[1.2-2.1], 3rd vs.1st tertile OR = 2.1[1.5-3.0]) but only among boys for hypertension. Associations with other covariates were weaker: for boys, hypertension increased somewhat with sedentary lifestyle, while elevated BP was slightly more prevalent among urban girls and those not attending school.

Conclusion

Within the limits of BP measurement on one visit only, these results suggest that Tunisian adolescents of both genders are likely not spared from early elevated BP. Though further assessment is likely needed, the strong association with overweight/obesity observed suggests that interventions aimed at changing lifestyles to reduce this main risk factor may also be appropriate for the prevention of elevated BP.

Tracking of obesity-related behaviours from childhood to adulthood: A systematic review

Obesity in childhood carries a wide range of physical, psychological and social disbenefits and also increases the risk of adult obesity with its well-recognised, enhanced risk of several common complex diseases as well as adverse socioeconomic and psychosocial sequelae. Understanding the tracking of the two key modifiable behaviours, food consumption and physical activity, between childhood and adulthood may illuminate the childhood determinants of adult obesity and contribute to the development of effective interventions. We performed a systematic review of the available literature on tracking of both physical activity and of dietary intake between childhood and adulthood by searching MEDLINE, EMBASE, CINAHL, PSYCInfo, Google and Google Scholar. For inclusion, studies had to report baseline measurements when the children were less than, or equal to, 18 years and to report follow-up for at least 5 years to any age over 18 years. After removal of duplicates, 9625 search hits were screened by title and/or abstract and 79 potentially relevant papers were identified and full papers obtained. In total 39 papers were included in this analysis. Of these, 11 papers (from 5 studies) reported data on tracking of diet from childhood to adulthood and 28 papers (from 16 studies) reported data on tracking of physical activity or inactivity. Despite the diversity of study design and measurement methodology, we found evidence of tracking of both physical activity and of diet between childhood and adulthood with estimates of strength of tracking of a similar order for both behaviours. Because of the inherent methodological difficulties in quantifying habitual behaviour, it is likely that the reported estimates of strength of tracking under-estimate the true degree of tracking. The evidence of tracking reported here may give greater impetus to the development of interventions aimed to prevent the persistence of obesity from childhood into adulthood and its attendant adverse socioeconomic, psychosocial and health sequelae.

Tracking of blood pressure from childhood to adolescence in a Greek cohort

BACKGROUND

Studies have reported tracking of blood pressure (BP) from childhood to adulthood but with inconsistent results mainly due to methodological and ethnic differences. We aimed to examine BP tracking during a 7-year period in a Greek cohort.

METHODS

This is a longitudinal school-based study conducted during 1990-96 in Athens, Greece. Children underwent BP and anthropometric measurements on two to three visits annually (averaged to annual values) for 7 years.

RESULTS

A total of 166 children with complete yearly follow-up data for the examined period were included (mean baseline age 9 ± 1.7 years, range: 5-12 years, 89 boys). At baseline, the prevalence of pre- and hypertension was 22.9 and 24.1% respectively and at the end of the follow-up 24.1% (P = NS vs. baseline) and 13.3% (P = 0.02 vs. baseline) respectively. Systolic/diastolic BP tracking correlation coefficients between 1990 and 1996 were 0.38 (P < 0.001)/0.20 (P = 0.06) for boys and 0.30 (P = 0.007)/0.22 (P = 0.06) for girls. Among children with baseline BP ≥90th centile (systolic and/or diastolic), 44% remained in the same BP range after 7 years. In stepwise multiple regression analysis, baseline systolic BP, male gender, baseline body mass index (BMI) and change in BMI from baseline to the end of the follow-up (ΔBMI) were significant predictors of systolic BP levels at the end of the follow-up. Baseline diastolic BP, baseline BMI and ΔBMI were significant predictors of diastolic BP at the end of the follow-up.

CONCLUSIONS

These data suggest that the risk of developing high BP during adolescence can be predicted by BP and BMI at childhood.

Hypertension in children: new trends and challenges

Childhood HTN (hypertension) has become a widely investigated topic within the last decade due to its increasing prevalence. In the present review, we examine new developments and trends that have significantly contributed to aetiology, diagnosis, evaluation and management of childhood HTN. Many recent reports document an increasing prevalence of HTN, mainly essential HTN, in children worldwide. This is probably related to the increase of childhood obesity, although obesity is not the only factor. Evidence has been accumulating to suggest a rather complex interplay between obesity, uric acid level, dietary sodium intake, inflammation, inheritance and other factors, which lead to increased risk of developing HTN in childhood and adulthood. The detection and monitoring of HTN has significantly improved with the use of ABPM (ambulatory blood pressure monitoring), which allows not only for a more accurate classification and staging of HTN, but also for the calculation of more sophisticated parameters such as the AASI (ambulatory arterial stiffness index). Measurement of arterial stiffness enables assessment of arterial dysfunction, which may precede structural vascular changes evaluated by carotid intima media thickness. Sustained HTN eventually leads to end-organ damage [LVH (left ventricular hypertrophy), central nervous system], which in turn increases the risk of cardiovascular morbidity and mortality. New developments in childhood HTN, as outlined in the present review, will hopefully contribute to better screening and management of HTN in children.

Assessment and management of hypertension in children and adolescents

The epidemic of overweight and obesity in youth is increasing the prevalence of prehypertension and hypertension among children and adolescents. The younger the child is at presentation and the more severe the blood pressure abnormality, the more likely a secondary cause of hypertension is to be present. Measurement of blood pressure in children requires adaptation to the age and size of the child. Interpretation must be related to normative values specific for age, sex, and height. Evaluation is primarily aimed at identifying secondary causes of hypertension, associated comorbidities, additional risk factors, and evidence of target-organ damage. Ambulatory blood pressure monitoring is emerging as a useful tool for evaluation of some patients, particularly for those with suspected 'white coat' hypertension. Management of prehypertension and hypertension is directed at the underlying cause, exacerbating factors, and the magnitude of the blood pressure abnormality. Healthy behavioral changes are a primary management tool for treating hypertension and, more particularly, prehypertension and for addressing other cardiovascular risk factors, such as obesity. Pharmacological management is reserved for patients with hypertension who do not respond to behavioral changes, have additional cardiovascular risk factors or diabetes, are symptomatic, or have developed target-organ damage.

Meta-analysis of blood pressure tracking from childhood to adulthood and implications for the design of intervention trials

AIM

Blood pressure (BP) is related with cardiovascular disease. BP tracking in childhood and its implication for intervention trials are unknown.

METHODS

A systematic review and meta-analysis were conducted to estimate BP tracking.

RESULTS

In 29 independent studies on 27,820 subjects, follow-up length and baseline age were associated with systolic BP tracking (both p < 0.05), while gender, BP measurement method and study place were not (p = 0.215, p = 0.185 and p = 0.391). The overall adjusted systolic BP correlation coefficient was 0.44 between 10 and 11 years and decreased to 0.37 between 10 and 20 years. Comparison of BP changes before and after intervention need a 26% increased sample size for a 10-year follow-up of 10 year olds, while trials comparing BP values at study end only require smaller sample sizes.

CONCLUSION

Blood pressure tracking from childhood to adulthood affects trials assessing long-term effects on BP and was low-to-moderate. Therefore, regular BP controls are also needed in children with normal BP measurements possibly identifying hypertensive children earlier. A slight short-term intervention effect on BP may not have any long-term effects because of low BP tracking and its decrease by age.

A 15-year longitudinal study on ambulatory blood pressure tracking from childhood to early adulthood

This study evaluates the tracking stability of office blood pressure (BP), ambulatory BP (ABP), BP variability (BPV) and nocturnal BP drops (dipping) from childhood to early adulthood, and their dependence on ethnicity, gender and family history (FH) of essential hypertension (EH). Generalized estimating equations (GEEs) were used to estimate tracking coefficients for 295 European Americans and 252 African Americans, with a maximum of 12 measurements over a 15-year period. Office BP and ABP had moderate-to-relatively high tracking coefficients (r= 0.30-0.59; P<or=0.001). Twenty-four hour readings tracked better than office readings for diastolic BP (DBP; 0.57 vs. 0.46, P=1.72 x 10(-6)) and pulse pressure (PP) (0.59 vs. 0.51, P=2.70 x 10(-4)), and equally well for systolic BP (SBP; 0.55 vs. 0.54, P=0.805). Daytime readings tracked better than their night-time counterparts for SBP (0.50 vs. 0.37, P=7.62 x 10(-13)), DBP (0.49 vs. 0.30, P=7.98 x 10(-32)) and PP (0.55 vs. 0.50, P=0.0061). All BPV (r=0.08-0.28; P<or=0.001) and dipping measures (r=0.07-0.12; odds ratio, 1.60-1.73; P<or=0.001) had low tracking coefficients. Males had significantly higher tracking stability for office SBP, DBP and ambulatory PP than females (P<0.01). Subjects with a positive FH of EH had significantly higher tracking stability for daytime and night-time DBP and dipping indexed by continuous variables than those with a negative FH (P<0.001). No significant ethnic differences were observed. The high tracking stability of 24-h ABP highlights the importance of using ambulatory BP monitoring in both research and clinical settings.

Discordant secular trends in elevated blood pressure and obesity in children and adolescents in a rapidly developing country

BACKGROUND

The effect of the increasing prevalence of obesity on blood pressure (BP) secular trends is unclear. We analyzed BP and body mass index secular trends between 1998 and 2006 in children and adolescents of the Seychelles, a rapidly developing island state in the African region.

METHODS AND RESULTS

School-based surveys were conducted annually between 1998 and 2006 among all students in 4 school grades (kindergarten and 4th, 7th, and 10th years of compulsory school). We used the Centers for Disease Control and Prevention criteria to define obesity and elevated BP. The same methods and instruments were used in all surveys. Some 25 586 children and adolescents 4 to 18 years of age contributed 43 867 observations. Although the prevalence of obesity in boys and girls increased from 5.1% and 6.0%, respectively, in 1998 to 2000 to 8.0% and 8.7% in 2004 to 2006, the prevalence of elevated BP decreased from 8.4% and 9.8% to 6.9% and 7.8%. During the interval, mean age-adjusted body mass index increased by 0.57 kg/m(2) in boys and 0.58 kg/m(2) in girls. Mean age- and height-adjusted systolic BP decreased by -3.0 mm Hg in boys and -2.8 mm Hg in girls, whereas mean diastolic BP did not change substantially in boys (-0.2 mm Hg) and increased slightly in girls (0.4 mm Hg).

CONCLUSIONS

At a population level, the marked increase in the prevalence of obesity in children and adolescents in the Seychelles was not associated with a commensurate secular rise in mean BP.