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Hypertension Editors' Picks: Air Pollution.

Exposure to ambient air pollution has been associated with greater risk of elevated blood pressure (BP) in adults and children. Recent evidence suggests that air pollution exposure in pregnancy may also portend increased risk for the next generation; however, few studies have examined this relationship. We conducted a prospective study of 1293 mothers in the Boston Birth Cohort (enrolled 1998-2012) and their children who had follow-up visits between 3 and 9 years of age and complete exposure and outcome data. Our primary exposure, ambient particulate matter ≤2.5 µm (PM2.5) concentration during pregnancy, was estimated by matching mother's residential address to the US Environmental Protection Agency's air quality monitors. We defined our primary outcome child systolic BP (SBP) percentile according to US reference (Fourth Report) and classified elevated BP as SBP ≥90th percentile. Our multivariable-adjusted cubic spline showed a sharp increase in offspring SBP percentile and risk for elevated BP when third-trimester PM2.5 concentration was ≥13 μg/m3 The highest versus lowest tertile of third-trimester PM2.5 exposure was associated with a 4.85 (95% confidence interval: 1.38-8.37) percentile increase in child SBP or a 1.61 (95% confidence interval: 1.13-2.30) times higher risk of child elevated BP. A 5-μg/m3 increment in PM2.5 during the third trimester was associated with a 3.49 (95% confidence interval: 0.71-6.26) percentile increase in child SBP or a 1.47 (95% confidence interval: 1.17-1.85) times higher risk of elevated BP. Our findings suggest that exposure to ambient PM2.5 during the third trimester of pregnancy is associated with elevated BP in children, ages 3 to 9 years.

Introduction: Technological advances have made high-altitude ski slopes easily accessible to skiers of all ages. However, research on the effects of hypoxia experienced during excursions to such altitudes on physiological systems, including the ocular system, in children is scarce. Retinal vessels are embryologically of the same origin as vessels in the brain, and have similar anatomical and physiological characteristics. Thus, any hypoxia-related changes in the morphology of the former may reflect the status of the latter. Objective: To compare the effect of one-day hypoxic exposure, equivalent to the elevation of high-altitude ski resorts in North America and Europe (∼3,000m), on retinal vessel diameter between adults and children. Methods: 11 adults (age: 40.1 ± 4.1years) and 8 children (age: 9.3 ± 1.3years) took part in the study. They spent 3days at the Olympic Sports Centre Planica (Slovenia; altitude: 940m). During days 1 and 2 they were exposed to normoxia (FiO2 = 0.209), and day 3 to normobaric hypoxia (FiO2 = 0.162 ± 0.03). Digital high-resolution retinal fundus photographs were obtained in normoxia (Day 2) and hypoxia (Day 3). Central retinal arteriolar equivalent (CRAE) and venular equivalents (CRVE) were determined using an Automated Retinal Image Analyser. Results: Central retinal arteriolar and venular equivalents increased with hypoxia in children (central retinal arteriolar equivalent: 105.32 ± 7.72µm, hypoxia: 110.13 ± 7.16µm, central retinal venular equivalent: normoxia: 123.39 ± 8.34µm, hypoxia: 130.11 ± 8.54µm) and adults (central retinal arteriolar equivalent: normoxia: 105.35 ± 10.67µm, hypoxia: 110.77 ± 8.36µm; central retinal venular equivalent: normoxia: 126.89 ± 7.24µm, hypoxia: 132.03 ± 9.72µm), with no main effect of group or group*condition interaction. A main effect of condition on central retinal arteriolar and venular equivalents was observed (central retinal arteriolar equivalent:normoxia: 105.34 ± 9.30µm, hypoxia: 110.50 ± 7.67µm, p < 0.001; central retinal venular equivalent: normoxia: 125.41 ± 7.70µm, hypoxia: 131.22 ± 9.05µm, p < 0.001). Conclusion: A 20-hour hypoxic exposure significantly increased central retinal arteriolar and venular equivalents in adults and children. These hypoxia-induced increases were not significantly different between the age groups, confirming that vasomotor sensitivity of the retinal vessels to acute hypoxia is comparable between adults and prepubertal 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.

Despite substantial attention paid to the threat of elevated blood pressure in children and adolescents in high-income countries and the epidemic of hypertension in African adult populations, data on the burden of elevated blood pressure in African children and adolescents have not yet been synthesised. We did a systematic review and meta-analysis to provide estimates of the prevalence of elevated blood pressure and assess associated factors among children and adolescents in Africa. We searched Embase, PubMed, African Journals Online, and African Index Medicus to identify articles published from Jan 1, 1996, to Feb 2, 2017, and searched the reference list of retrieved articles. Each study was independently reviewed for methodological quality. We used a random-effects model to estimate the prevalence of elevated blood pressure across studies and heterogeneity (I2) was assessed via the χ2 test on Cochran's Q statistic. This review is registered with PROSPERO, number CRD42015019029. We included 51 studies in qualitative synthesis and 25 in the meta-analysis reporting data of a pooled sample of 54 196 participants aged 2-19 years. Study quality was high with only four medium-quality studies and no low-quality studies. Prevalence of elevated blood pressure varied widely across studies (range 0·2-24·8%). The pooled prevalence of elevated blood pressure (systolic or diastolic blood pressure ≥95th percentile) was 5·5% (95% CI 4·2-6·9), whereas that of slightly elevated blood pressure (systolic or diastolic blood pressure ≥90th percentile and <95th percentile) was 12·7% (2·1-30·4). The prevalence of elevated blood pressure was largely associated with body-mass index (BMI), with a prevalence of elevated blood pressure six times higher in obese (30·8%, 95% CI 20·1-42·6) versus normal-weight children (5·5%, 3·1-8·4; p<0·0001). This study suggests a high prevalence of elevated blood pressure among children and adolescents in Africa, with overweight and obesity being an important risk factor. Efforts to address this burden of elevated blood pressure in children and adolescents should mainly focus on primary prevention at the community level, by promoting healthy lifestyles and avoiding other cardiovascular risk factors, especially overweight and obesity. This study also stresses the need for more elaborate studies using uniform and reliable diagnostic methods to reliably map the burden of elevated blood pressure in children and adolescents in Africa. None.

Multiple perinatal and early life risk factors have been implicated in the development of hypertension. The BT20 (Birth to Twenty Plus) cohort in urban Soweto, South Africa, previously showed a prevalence of elevated blood pressure (EBP) that ranged from 22.4% at 5 years of age to 34.9% at 18 years of age. We sought to determine the prevalence of EBP at 23 years of age within this cohort and whether this could be linked to any maternal and early life factors and childhood and adolescent blood pressure trajectories. Blood pressure and anthropometric measurements were completed on cohort participants aged 23 years (n=1540; 49% men). Early life and maternal factors were obtained from previous data. Thirty-six percent of participants had EBP of whom 63% were men ( P<0.001). The only association with maternal or early life factors was greater linear growth from birth to 2 years of age, which conferred a 19% increased risk (odds ratio, 1.19; 95% CI, 1.01-1.41). Women had a 77% lower risk of EBP (odds ratio, 0.23; 95% CI, 0.16-0.34) per SD. Participants within the highest systolic and diastolic blood pressure trajectories (where blood pressure was elevated early and remained elevated) were at significantly increased risk of EBP in early adulthood. For those in the highest systolic trajectory, this resulted in a 4-fold increased risk and for those in the highest diastolic trajectory, a 5-fold increased risk. These findings suggest that risk for EBP in adulthood may be set in childhood and adolescence.

Objective: To investigate the prevalence trend of high normal blood pressure and elevated blood pressure in children and adolescents aged 7 to 17 years in China from 2010 to 2019. Methods: Students aged 7-17 years were selected from the Chinese National Survey on Students' Constitution and Health from 2010 to 2019. High normal blood pressure and elevated blood pressure were determined according to the "Reference of screening for elevated blood pressure among children and adolescents aged 7-18 years" (WS/T 610-2018). The Chi-square test was performed to determine whether there was a difference in the prevalence of high normal blood pressure and elevated blood pressure by gender, residence and age group. Results: In 2019, the prevalence of high normal blood pressure in children and adolescents aged 7-17 years was 15.3% (29 855/195 625), which was higher in boys (20.2%, 19 779/97 847) and rural areas (15.4%, 15 066/97 567) than that in girls (10.3%, 10 076/97 778) and urban areas (15.1%, 14 789/98 058), respectively (all P<0.05). The prevalence of elevated blood pressure was 13.0% (25 377/195 625), which was higher in girls (13.2%, 12 925/97 778) and rural areas (14.1%, 13 753/97 567) than that in boys (12.7%, 12 452/97 847) and urban areas (11.9%, 11 624/98 058) (all P<0.05). From 2010 to 2019, the prevalence of high normal blood pressure showed an increasing trend, with an annual average growth rate from 1.14% to 3.18%. The overall prevalence of elevated blood pressure also showed an increasing trend from 2010 to 2019 but decreased in 2014. The annual average growth rate of elevated blood pressure was-1.07% from 2010 to 2014 and 9.33% from 2014 to 2019. About 17 provinces had an increasing trend in the prevalence of elevated blood pressure from 2010 to 2014, and 22 provinces with an increasing trend from 2014 to 2019. There were obvious regional differences in the annual average growth rate of the prevalence of high normal blood pressure and elevated blood pressure. The regions with the highest annual average growth rate of the prevalence of high normal blood pressure were the Northeast (5.47%) from 2010 to 2014 and the Western region (5.21%) from 2014 to 2019. For elevated blood pressure, the Northeast had the highest annual average growth rate from 2010 to 2014 (12.35%), while the Central (15.79%) and Western (12.87%) had the highest growth rate from 2014 to 2019. Conclusion: From 2010 to 2019, the prevalence of high normal blood pressure and elevated blood pressure in Chinese Han children and adolescents aged 7 to 17 shows an increasing trend, with regional disparities.

The identification of elevated blood pressure (BP) in children and adolescents relies on complex percentile tables. The present study compares the performance of 11 simplified methods for assessing elevated or high BP in children and adolescents using individual-level data from 7 countries. Data on BP were available for a total of 58 899 children and adolescents aged 6 to 17 years from 7 national surveys in China, India, Iran, Korea, Poland, Tunisia, and the United States. Performance of the simplified methods for screening elevated or high BP was assessed with receiver operating characteristic curve (area under the curve), sensitivity, specificity, positive predictive value, and negative predictive value. When pooling individual data from the 7 countries, all 11 simplified methods performed well in screening high BP, with high area under the curve values (0.84-0.98), high sensitivity (0.69-1.00), high specificity (0.87-1.00), and high negative predictive values (≥0.98). However, positive predictive value was low for most simplified methods, but reached ≈0.90 for each of the 3 methods, including sex- and age-specific BP references (at the 95th percentile of height), the formula for BP references (at the 95th percentile of height), and the simplified method relying on a child's absolute height. These findings were found independently of sex, age, and geographical location. Similar results were found for simplified methods for screening elevated BP. In conclusion, all 11 simplified methods performed well for identifying high or elevated BP in children and adolescents, but 3 methods performed best and may be most useful for screening purposes.

Hypertension in children in sub-Saharan Africa: primordial prevention is crucial

Background: Risk factors for high blood pressure (BP) in children start in utero . Cord blood metabolites reflect exposures of the developing fetus to the in utero environment. No studies have examined whether cord blood metabolites are associated with BP in children. Objectives: To examine prospective associations of cord blood metabolites with systolic BP (SBP), diastolic BP (DBP), and risk of elevated BP in childhood and adolescence. Methods: We used data from the Boston Birth Cohort. Metabolites were measured in cord blood plasma samples collected at birth. SBP and DBP were measured at clinic visits between 3 to 18 years. We calculated BP percentiles per the 2017 American Academy of Pediatrics Clinical Practice Guideline. We examined associations of cord metabolites with SBP and DBP percentiles using linear mixed models and with elevated BP using mixed-effects Poisson regression. We used the False Discovery Rate (FDR) method to adjust for multiple comparisons. Results: Our study included 902 mother-child dyads (60% Black, 23% Hispanic, 45% female). Children were followed for a median of 9.2 (IQR: 6.7-11.7) years, and the median number of BP observations per child was 7 (IQR: 4-11). After FDR adjustment, 3, 94, and 22 metabolites were respectively associated with SBP, DBP, and risk of elevated BP; 2 metabolites (1-methylnicotinamide, dimethylguanidino valeric acid) were associated with all three outcomes, and 22 metabolites were associated with both DBP and risk of elevated BP. After multivariable adjustment, 48 metabolites remained significantly associated with DBP. Metabolites that showed the strongest associations with SBP, DBP, and risk of elevated BP included nucleotides (e.g., xanthosine, hypoxanthine, xanthine) and acylcarnitines (e.g., C6 and C7 carnitines), which represent fatty acid oxidation and purine metabolism pathways. Conclusions: In this predominantly urban, low-income, minority cohort, cord blood metabolites were prospectively associated with BP and risk of elevated BP from childhood to adolescence. Acylcarnitines and purine metabolism may be involved in the early life origins of hypertension. Cord metabolites may explain the intergenerational effects of in utero environments on BP in childhood and adolescence.

Objectives: To examine the waist circumference (WC)'s predict role to elevate blood pressure (BP) among children and adolescents aged 7–17 years old who have normal body mass index (BMI), and provide scientific evidence for prevention and intervention of elevated BP in children and adolescents. Methods: Data were combined from the China Health and Nutrition Survey, which was conducted during the period of 1993–2011. A total of 9038 children and adolescents aged 7–17 years old who had normal BMI were included in the final data analysis. Data were on gender, age, WC, systolic blood pressure (SBP), diastolic blood pressure (DBP), and the prevalence of elevated BP. After adjusted for sex and age, the multiple liner regression model was used to analyze the trend in mean BP with increase of WC levels. Logistic regression model was conducted to examine the trend in elevated BP prevalence and the risk of elevated BP with increase of WC levels. Results: Both the mean value of BP and prevalence of elevated BP showed rising trends with the increase of WC levels among children and adolescents with normal BMI (SBP/DBP ranged from 96.0/63.1 mmHg to 102.4/68.0 mmHg; prevalence of elevated BP ranged from 6.9% to 21.8%, all P < 0.001), independently of age and sex. When WC < P25 as the referent group, the risk for elevated BP were 1.39, 1.70, 2.21 and 3.10, for groups of WC > = P25 and WC < P50, WC > = P50 and WC < P75, WC > = P75 and WC < P90, and WC > = P90, respectively, independently of age and sex(P < 0.01). Conclusion: WC can be used as an important predictor of elevated BP in children and adolescents. BMI should be in combined with WC in order to more effectively prevent risk of elevated BP in children and adolescents.

Objective With a computer-assisted program,retinal vascular calibers were measured quantitatively.In this study the relationship between retinal vascular calibers and components of the metabolic syndrome was examined.Methods A total of 450 hypertensive patients were collected.Medical history,physical examination,blood tests,and retinal photographs were taken.Retinal vascular calibers were measured quantitatively from digital retinal photographs.In the hypertensive population the associations of retinal vascular calibers with components of the metabolic syndrome were described,and the factors that influenced retinal vascular calibers were analyzed.Results In the enrolled population,mean age was (57.53 ± 10.01) years,mean systolic blood pressure (138 ± 17) mm Hg(1 mm Hg =0.133 kPa),diastolic blood pressure (84 ± 10) mm Hg.Mean central retinal arteriolar equivalent(CRAE) was(129.26 ± 12.68) μm,and mean central retinal venular equivalent (CRVE) (198.25 ± 18.37) μm.After adjusting for age,gender,etc,CRAE in group with poor blood pressure control was smaller than that in the group with good blood pressure control [(126.45 ± 15.74) μm vs (130.30 ± 11.30) μm,P =0.029].CRAE tended to be narrower with worsened blood pressure control (P =0.075).CRVE was smaller in patients with normal high density lipoprotein-cholesterol (HDL-C) than in those with abnormal level [(197.36 ±17.62) μm vs (203.07 ± 21.52) μm,P =0.040].The diastolic blood pressure was raised along with the decreasing CRAE(P=0.009).And the HDL-C level was reduced as CRVE was increasing(P=0.042).Old age (r =-0.090,P=0.013) and poor blood pressure control(r=-0.098,P=0.038) were independent risk factors for narrow CRAE,while lowered HDL-C (r =0.105,P =0.024) and smoking (r =0.141,P =0.010) were independent risk factors for wide CRVE.Conclusions Narrow CRAE was related to poor blood pressure control,while wide CRVE was related to lowed HDL-C.Aging and poor blood pressure control were independent risk factors for narrow CRAE,while lowed HDL-C and smoking were independent risk factors for wide CRVE in the hypertensive patients. Key words: Retinal vascular caliber; Hypertension ; Diabetes mellitus; Dyslipidaemia

The prevalence of high blood pressure in adolescence is increasing with the number of adolescence at risk of overweight or overweight. Due to the known relationship between high blood pressure and increased risk of coronary artery disease (CAD) and stroke, this is an obvious health concern for adolescent children. PURPOSE: To characterize the incidence of high normal blood pressure and hypertension in a large population of ninth grade, physical education students. METHODS: 884 ninth grade, physical education students (14 ± 1 yrs) participated. Blood pressure was initially recorded with an automated device (Omron, HEM-907XL). If the initial automated reading was above 120/80 mmHg, then a manual ausculatory re-measurement was taken. Blood pressure was classified as high normal blood pressure if the reading fell between the 90th and 95th percentile based on the CDC growth charts (National high blood pressure education program working group on high blood pressure in children and adolescents, 2001), while hypertension was defined as a reading above the 95th percentile. Frequency of high normal blood pressure and hypertension was calculated for two groups based on BMI: at risk for being overweight or overweight students and normal weight students. RESULTS: Overall, 8.5% of students were classified as having high normal blood pressure and 4.8% were considered hypertensive. The incidence was greater for high normal blood pressure for the at risk for being overweight or overweight group (11.9%) compared to the normal weight students (7.4%). Hypertension was present in 7.3% of the at risk for being overweight or overweight population and 3.9% of the normal weight population. The at risk for being overweight or overweight group and normal weight group had a mean systolic blood pressure of 117.5 ± 9 mmHg and 112.8 ±10 mmHg, respectively, and a mean diastolic blood pressure of 64.7 ± 7 mmHg and 61.2 ± 8 mmHg, respectively. CONCLUSION: Our data indicates that a large percentage of the at risk for being overweight or overweight population (19.2%) has elevated blood pressure. At risk for being overweight or overweight students have a greater incidence of high normal blood pressure, and are twice as likely as normal weight students to have hypertension. The at risk for being overweight or overweight group also has a higher mean systolic and diastolic blood pressure values. This is alarming because elevated blood pressure is associated with an increased risk of CAD and stroke, and is in itself a progressive chronic disease.

This study was intended to clarify the relation between fasting insulin, lipids, and blood pressure in adolescents before the onset of hypertension and to examine the association of these data with similar data obtained in their parents. The participants in this study were 183 adolescents 14 to 18 years old (96 girls) completing a 4-year intervention trial and their parents (164 mothers, 122 fathers). Blood pressure was measured twice on the right arm in a seated position using a random-zero sphygmomanometer. Fasting blood samples were obtained for lipid and insulin analyses. Fasting insulin was significantly correlated with systolic blood pressure in the adolescents and also in the parents before and after adjustment for body mass index. Fasting insulin was correlated significantly with levels of cholesterol, triglycerides, and HDL and LDL cholesterol in the adolescents. It was correlated only with triglycerides and HDL-cholesterol in mothers and fathers. After adjustment for body mass index, the correlations between fasting insulin and lipids in the children were not significant. A significant relation was shown between children's systolic blood pressure and mothers' fasting insulin and systolic blood pressure. Significant correlations were found between the children's and fathers' triglycerides and HDL-cholesterol, whereas significant correlations were found for fasting insulin and all lipids between mothers and children, and these remained significant after adjustment for body mass index. These results show (1) a significant relation between fasting insulin and both lipids and systolic blood pressure in adolescents and (2) a significant relation for these factors between adolescents and their parents. Although weight appears to play an important role in this relation during adolescence, genetic and environmental factors other than those mediated via weight may control insulin metabolism within families. The data support a role for studies during early biological development to address these issues.

The aim of this study was to assess the performance of the blood pressure-to-height ratio (BPHR) for screening elevated blood pressure (BP) in children and adolescents using a meta-analysis of eligible published studies. We retrieved studies that investigated the performance of the BPHR for identifying elevated BP from Pubmed and other databases. We performed meta-analyses by subgroups of sex, age and ethnicity using a fixed or random effect model based on whether there was between-study heterogeneity. A total of 13 publications including 262 830 children and adolescents aged 6-18 years on BPHR and a total of three publications including 95 343 children on the modified BPHR were included in this meta-analysis. The summary results suggested that BPHR performed well to identify pre-high BP and high BP for children aged 6-11 years and adolescents aged 12-18 years. The performance of BPHR was perfect for identifying severe high BP in adolescents aged 12-18 years. However, the modified BPHR did not improve accuracy for screening high BP in children aged 6-12 years. In summary, BPHR performed well for identifying elevated BP in children and adolescents, independently of sex, age and ethnicity group. In addition, the modified BPHR performed similarly with BPHR for screening high BP in childhood.