Development Of Hypertension In Children Research Articles

Dietary Strategies in the Prevention and Treatment of Hypertension in Children and Adolescents: A Narrative Review.

This study aims to gather information on effective dietary strategies for the prevention and treatment of hypertension (HTN) in children and adolescents. It discusses specific nutritional models such as the Diet Approaches to Stop Hypertension (DASH diet), traditional Asian diets, plant-based diets, the Southern European traditional Atlantic diet, and the Mediterranean diet, highlighting the benefits of these approaches. The manuscript also addresses dehydration resulting from insufficient fluid intake among children, as well as the consumption of inappropriate beverages, like soft drinks and energy drinks, which contributes to the development of HTN. Additionally, it examines the role of oxidative stress in the pathomechanism of HTN in children, particularly in relation to the antioxidant potential of food components such as selenium, magnesium, and selected vitamins. The relationship between sodium and potassium intake from food and the development of HTN in children is also explored. Finally, this study discusses public health strategies for the prevention of HTN in children. A comprehensive search was performed across multiple databases, such as PubMed/MEDLINE, the Cochrane Library, Science Direct, and EBSCO. This search focused on locating English-language meta-analyses, systematic reviews, randomized clinical trials, and observational studies from around the globe.

Risk factors for the development of arterial hypertension in children and young people in present-day developments

In modern society, there is an intensive increase in the incidence of hypertension among young people, which is mainly due to lifestyle features and associated risk factors. Purpose. To analyze the results of Russian and foreign scientific research concerning the study of risk factors in the development of hypertension in children and young people. Material and methods. A qualitative analysis of the current data available in the literature on the risk factors of hypertension and its prevention has been carried out. Results. It has been established that the occurrence of arterial hypertension in childhood is influenced not only by hereditary factors, but also by a number of environmental risk factors. Conclusion. Further research is needed to study new and established risk factors that need to be considered when conducting primary prevention of the disease in children and young people from the high-risk group.

Blood Pressure Trend in Children with Chronic Kidney Disease in Nigeria, Sub-Saharan African Region

Background: Various mechanisms are involved in the development of hypertension in children with chronic kidney disease (CKD), some of which are due to the disease process, while some are due to the treatments employed in CKD. Aim: The aim of the study was to determine the trend of blood pressure in Nigerian children with CKD comparable with controls. Materials and Methods: A cross-sectional study assessing the blood pressure of children from 6 to 17 years with CKD and selected age- and sex-matched controls who were recruited consecutively at the Paediatric Nephrology Clinic and Children Outpatient Clinic of University of Nigeria Teaching Hospital. Data obtained were analyzed using the Statistical Package for the Social Sciences (SPSS) version 17. Results: The mean systolic blood pressure (SBP) was 126.08 ± 37.43 mmHg for subjects compared to 105.04 ± 14.33 mmHg for controls, whereas the mean diastolic blood pressure (DBP) was 78.96 ± 22.74 mmHg for subjects compared to 66.25 ± 10.66 mmHg for controls. The distribution of SBP and DBP across the CKD stages showed more severe hypertension (Stages I and II) prevalence in the later stages of CKD (Stages 4 and 5) (χ y 2 = 7.21, P = 0.01, respectively). The mean value of the mean arterial blood pressure (MAP) was 94.67 ± 26.98 mmHg for subjects compared to 79.18 ± 10.61 mmHg for controls. The increase in MAP across the stages of CKD was significant. Conclusion: This study shows a high prevalence of the severe forms of high blood pressure in this group of children with CKD in the subregion.

Role of glucocorticoid metabolism in childhood obesity-associated hypertension.

ObjectiveChildhood obesity is associated with alterations in hypothalamus–pituitary–adrenal axis activity. We tested the hypothesis that multiple alterations in the metabolism of glucocorticoids are required for the development of hypertension in children who become overweight.MethodsSpot urine for targeted gas chromatography-mass spectrometry steroid metabolome analysis was collected from (1) overweight/hypertensive children (n = 38), (2) overweight/non-hypertensive children (n = 83), and (3) non-overweight/non-hypertensive children (n = 56).ResultsThe mean (± s.d.) age of participants was 10.4 ± 3.4 years, and 53% of them were male. Group 1 and group 2 had higher excretion rates of cortisol and corticosterone metabolites than group 3 (869 (interquartile range: 631–1352) vs 839 (609–1123) vs 608 (439–834) μg/mmol creatinine × m2 body surface area, P < 0.01, for the sum of cortisol metabolites), and group 1 had a higher excretion rate of naive cortisol than group 3. Furthermore, groups differed in cortisol metabolism, in particular in the activities of 11β-hydroxysteroid dehydrogenases, as assessed from the ratio of cortisol:cortisone metabolites (group 2 < group 3), 5α-reductase (group 1 > group 2 or 3), and CYP3A4 activity (group 1 < group 2 or 3).DiscussionThe sequence of events leading to obesity-associated hypertension in children may involve an increase in the production of glucocorticoids, downregulation of 11β-hydroxysteroid dehydrogenase type 1 activity, and upregulation of 5α-reductase activity, along with a decrease in CYP3A4 activity and an increase in bioavailable cortisol.

Порушення ниркової й периферичної гемодинаміки в розвитку серцево-судинних розладів у дітей із хронічним пієлонефритом

Актуальність. Своєчасне виявлення змін з боку серцево-судинної системи в дітей із хронічним пієлонефритом важливе для уповільнення розвитку артеріальної гіпертензії, прогресування хронічної хвороби нирок. На сьогодні сучасними неінвазивними методами ранньої діагностики серцево-судинних порушень є добове моніторування артеріального тиску та ультразвукова допплерографія судин нирок. Мета: визначити прогностичне значення ультрасонографічної симптоматики порушень ниркової гемодинаміки та показників добового артеріального тиску в дітей із хронічним пієлонефритом. Матеріали та методи. Проведено кореляційний аналіз показників добового моніторування артеріального тиску та ультразвукового допплерографічного обстеження в 107 дітей із хронічним пієлонефритом віком 3–17 років. Результати. Статистично вірогідні зв’язки були виявлені між такими показниками: пульсаційним індексом, індексом резистентності, систоло-діастолічним співвідношенням на рівні стовбурової й сегментарних ниркових артерій і добовими індексами (артеріального тиску, систолічного й діастолічного тиску), коефіцієнтом варіації нічним, середнім діастолічним тиском та діастолічним тиском вночі. Кореляційні зв’язки між ультрасонографічними показниками ниркової гемодинаміки та добового моніторування артеріального тиску на рівні інтерлобарних ниркових артерій були статистично невірогідними. У дітей із хронічним пієлонефритом на фоні аномалій сечовивідних шляхів був найбільш сильний зв’язок між індексами периферичного опору на рівні стовбурової ниркової артерій та показниками добового моніторування артеріального тиску. Висновки. Показники ниркової гемодинаміки — пульсаційний індекс, індекс резистентності, систоло-діастолічне співвідношення на рівні стовбурової й сегментарних артерій нирки можуть бути використані для характеристики ниркової гемодинаміки й прогнозування розвитку ренальної АГ у дітей із хронічним пієлонефритом. У 57 % випадків вираженість відхилень цих показників від норми ниркової гемодинаміки визначає тяжкість артеріальної гіпертензії.

Pet ownership in utero and in childhood decreases the effects of environmental tobacco smoke exposure on hypertension in children: A large population based cohort study.

Little is known about whether exposure to pets influences the association between hypertension and environmental tobacco smoke (ETS). The current study aims to examine the interaction of pet ownership on ETS exposure and the development of hypertension in children. From 2012 to 2013, a total of 9354 children, 5 to 17years of age, were recruited from 62 schools in seven northeastern cities. BP in children was measured and hypertension was defined as an average diastolic blood pressure (DBP) or systolic blood pressure (SBP) at or above the 95th percentile for that child's age, sex, and height. Pet ownership in three different time periods (in utero, past 2years, and currently) and ETS exposure data were collected from parents via a questionnaire. Two-level regressions were used for the data analyses. The data show consistent, significant interactions between exposure to pets and effects from ETS. Children who were not exposed to pets experienced stronger effects from ETS on hypertension when compared to those exposed to pets, and the protective effect of pet ownership became stronger with a greater number of pets in the home. Exposure to in utero ETS was associated with hypertension [adjusted odds ratio (aOR)=1.32, 95% confidence interval (CI): 1.13-1.54] only for those children without pet exposure in utero but not for those with pets (aOR=0.75; 95% CI: 0.49-1.15) (pinteraction<0.05). Moreover, household dog ownership was related to significantly lower effects of current ETS on hypertension (aOR=0.80, 95% CI: 0.61-1.05) compared with children without dogs (aOR=1.26, 95% CI: 1.11-1.44) (pinteraction=0.001). Interaction associations between ETS and pet ownership were more robust for girls than for boys and for younger than older children. This study indicates an inverse relationship between pet ownership and ETS, potentially pointing to pet ownership as protecting against the development of hypertension in children.

Transforming Growth Factor-Beta 1 and Endoglin Levels in Congenital Solitary Functioning Kidney.

Introduction:Glomerular hyperfiltration leads to hypertension, microalbuminuria, and impaired renal function in children with congenital solitary functioning kidney (cSFK). The purpose of this study was to investigate the associations between serum transforming growth factor β-1 (TGF) and endoglin levels and hypertension, renal function or microalbuminuria in children with cSFK.Materials and Methods:63 patients and 36 controls were included in the study. Serum endoglin and TGF-β1 level was measured using ELISA commercial kits.Results:Serum TGF-β1 and endoglin levels were higher in patients than those of controls (P = 0.04 and P < 0.001, respectively). The prevalence of hypertension was found to be 45.6%. There was a positive association between endoglin levels and the presence of masked hypertension (odds ratio: 1.121, P = 0.04). TGF-β1 and endoglin levels were positively associated with microalbuminuria (OR: 1.17, P = 0.04; OR: 1.836, P = 0.01). ROC curve analysis showed that serum endoglin and TGF-β1 levels had predictive value for microalbuminuria (cut-off value: 4.86 ng/mL, sensitivity: 94.7%, specificity: 54.5%, area under the curve ± standard error [AUC ± SE]: 0.888 ± 0.025, P = 0.01 for endoglin; cut-off value 561.24 pg/mL, sensitivity: 89.5%, specificity: 73%, AUC ± SE: 0.995 ± 0.334, P = 0.02 for TGF-β1). There were no significant relationships between glomerular filtration rate and serum TGF-β1 or endoglin levels.Conclusions:Endoglin and TGF-β1 may play an important role in the pathophysiology of microalbuminuria in cSFK. Endoglin may have a role in the development of hypertension in children with cSFK.

Fetal programming and the angiotensin-(1-7) axis: a review of the experimental and clinical data.

Hypertension is the primary risk factor for cardiovascular disease that constitutes a serious worldwide health concern and a significant healthcare burden. As the majority of hypertension has an unknown etiology, considerable research efforts in both experimental models and human cohorts has focused on the premise that alterations in the fetal and perinatal environment are key factors in the development of hypertension in children and adults. The exact mechanisms of how fetal programming events increase the risk of hypertension and cardiovascular disease are not fully elaborated; however, the focus on alterations in the biochemical components and functional aspects of the renin-angiotensin (Ang) system (RAS) has predominated, particularly activation of the Ang-converting enzyme (ACE)-Ang II-Ang type 1 receptor (AT1R) axis. The emerging view of alternative pathways within the RAS that may functionally antagonize the Ang II axis raise the possibility that programming events also target the non-classical components of the RAS as an additional mechanism contributing to the development and progression of hypertension. In the current review, we evaluate the potential role of the ACE2-Ang-(1-7)-Mas receptor (MasR) axis of the RAS in fetal programming events and cardiovascular and renal dysfunction. Specifically, the review examines the impact of fetal programming on the Ang-(1-7) axis within the circulation, kidney, and brain such that the loss of Ang-(1-7) expression or tone, contributes to the chronic dysregulation of blood pressure (BP) and cardiometabolic disease in the offspring, as well as the influence of sex on potential programming of this pathway.

Risk factors of the development of arterial hypertension in children in Uzbekistan regions

Risk factors of the development of arterial hypertension in children in Uzbekistan regions

Juvenile glaucoma: Long-term development of ocular hypertension in children

Juvenile glaucoma: Long-term development of ocular hypertension in children

What has changed in the prevalence of hypertension in dialyzed children during the last decade?

Background: Hypertension very often accompanies progression of chronic kidney disease (CKD) in children. A cross-sectional analysis of hypertension prevalence in dialyzed children in Poland was designed with a comparison with the data previously recorded 10 years earlier.Methods: Two cohorts of children were analyzed: 59 subjects dialyzed in 2013, and 134 children from the previous study performed in 2003 that were reevaluated according to the current methodology. The incidence of hypertension (defined by SDS of sBP or dBP >1.64), clinical data, medical history, dialysis modalities and selected biochemical parameters of dialysis adequacy were analyzed.Results: The prevalence of hypertension increased from 64% in 2003 to 78% in 2013. The efficacy of antihypertensive treatment remained unsatisfactory (61% proper BP control). Preservation of residual urine output and strict fluid balance may prevent development of hypertension in children on dialysis.Conclusions: Despite the higher awareness of hypertension and its complications in dialyzed children, the incidence of this entity has increased during the last decade, with the percentage of undertreated patients comparable to that observed 10 years ago. Thus, more attention should be paid to therapy efficacy in this population to prevent further damage to the cardiovascular system and to decrease morbidity.

Relation of Change in Weight Status to the Development of Hypertension in Children and Adolescents

Relation of Change in Weight Status to the Development of Hypertension in Children and Adolescents

Abstract P182: Role of Obesity for the Risk of Hypertension in Youth

Background: National data on the incidence of and risk factors for pediatric hypertension are scant and the role of obesity during childhood in the development of incident hypertension in children and adolescents is ill-defined. Study Design: For this population-based cohort of youth in southern California, members of a health plan between 3 and 17 years of age and without hypertension (n = 279,708) were passively followed. Blood pressure (BP) and baseline body mass index were extracted from electronic health records. We classified BP using the definitions of the Fourth Report (NHBPEP 2005). Results: The cohort was racially/ethnically diverse (52.5% Hispanic, 9.9% Black, 7.4% Asian) and 51.2% were under the age of 12 years. During 1,124,912 person-years of follow-up (over a median of 5.0 years), we identified 9,158 youth with incident hypertension. In analyses adjusted for age and sex, participants who were severely obese had a relative risk (RR) of hypertension of 5.34 (see table) compared to their normal weight counterparts. After additional adjustment for baseline BP (normotensive, single, or repeated medical visits with prehypertension), the association was substantially attenuated (RR of 4.44). When we further adjusted for race/ethnicity and socioeconomic status, the relation was essentially the same. Conclusions: Severe obesity was a strong predictor of hypertension in children and adolescents. Our study demonstrates a strong, graded and positive relationship between adiposity in youth and hypertension. Strategies aimed at prevention of adiposity in youth may play an important role in the prevention of hypertension.

RELATIONSHIP BETWEEN PATTERNS OF BREASTFEEDING AND BLOOD PRESSURE IN BRAZILIAN AND SPANISH SCHOOLCHILDREN

the relationship between early feeding and blood pressure in later life is still uncertain and sometimes contradictory. Some studies point to the protective effect of breastfeeding on cardiovascular disease, while others do not obtain conclusive results. the aim of this study was to analyze the relationship between breastfeeding patterns during the first months of life and blood pressure in childhood, in two samples of children from two populations with different socio-cultural characteristics, controlling for quality feeding in infancy. the study, with a transversal and retrospective design, was conducted with 492 schoolchildren aged between 8 and 10 years, it consists of two samples, both collected from public schools, one in Madrid (Spain) and one in Vitoria, Espirito Santo (Brazil). ninety percent of the sample was breastfed, 196 (44.2%) from Madrid and 247 (55.7%) from Vitória/ES. The average duration of exclusive breastfeeding (EBF) in Madrid was 12.89 weeks (std = 9.6) and in Vitória/ES, 22.00 weeks (std = 13.4), with statistically significant differences. The mean values of systolic and dyastolic blood pressure, were significantly higher in the Brazilian sample. The prevalences of borderline hypertension and hypertension were also higher in Brazil than in Spanish, 68% vs 32% and 60% vs 40%, respectively. Association between shorter duration of EBF and higher prevalence of hypertension in childhood, was observed in the two samples. Regarding the association between diet quality and blood pressure values, this was only significant in the Brazilian sample, but not in Spanish. in both samples a protective effect of breastfeeding on blood pressure was observed, however when comparing the two samples appear to be a contradiction since the Brazilian children were breastfed for longer than the Spaniards but their Pressure Arterial values and the Hypertension prevalence were higher in the Spanish sample. This contradiction is resolved by controlling the effect of feeding in infancy. The food quality of Brazilian children is worse than that of Spaniards, mainly due to a higher consumption of processed foods very high in sodium content. the possible protective effect of breastfeeding, is reduced at later stages of the life cycle if food habit are not appropriate or do not meet minimum quality requirements. Therefore, although breastfeeding plays an important role in preventing the development of hypertension in children is not enough to support the practice of breastfeeding but prevention work is ongoing and should insist on eating habits and promote healthy lifestyles throughout the entire life cycle of people.

Carotid intima-media thickness and elastic properties of aortas in normotensive children of hypertensive parents.

A significant correlation between hypertension history and high blood pressure has been observed with regard to age, race and gender. Investigating carotid intima-media thickness and aortic stiffness prior to the development of hypertension in children of hypertensive parents enabled us to evaluate these patients for subclinical atherosclerosis. We compared carotid intima-media thickness, aortic strain, distensibility, stiffness indices and elastic modulus in 67 normotensive children whose parents had a diagnosis of essential hypertension and 39 normotensive children with no parental history of hypertension. Although there were no significant differences between the two groups in terms of systolic blood pressure, diastolic blood pressure, average blood pressure and pulse pressure (P>0.05), systolic blood pressures were higher among patients 15 years and older in the study group. No significant differences were noted between the control and study groups regarding interventricular septal thickness, left-ventricular posterior wall thickness, left-ventricular systolic and diastolic diameter and aortic annulus diameter (P>0.05). The left atrium diameter was larger in the study group compared with that in the control group, mainly because of the values of the 15-year-old and older children (P=0.01). The mean, maximum and minimum values of carotid intima-media thickness were significantly different in the study group compared with the control group among all age groups (P<0.001, P<0.001, P=0.006, respectively). Aortic systolic and diastolic diameters were larger in normotensive children of hypertensive parents compared with the control group (P=0.014, P=0.001, respectively). Although there were no differences between the study and control groups regarding aortic strain, aortic distensibility, elastic modulus and stiffness indices (P>0.05), aortic distensibility was lower, and aortic stiffness indices were higher among children 15 years and older in the study group. An increase in the carotid intima-media thickness in all age groups and a decrease in aortic elastic properties in 15-year-old and older children of hypertensive parents may indicate subclinical atherosclerosis in these apparently healthy children.

Study of genetic susceptibility to the development of arterial hypertension in children in northwestern Russia

Using PCR-RFLP analysis of the frequencies of gene variants, CYP2J2,CYP4A11, and PTGIS, involved in the metabolism of arachidonic acid, were investigated in a group of children with fundamental arterial hypertension and a control group of children in Northwestern Russia. Also, alleles and genotype frequencies of gene variants CDH13, MTHFR, and CDKN2DAS, as well as the locus rs11191548, which were selected earlier due to their association with the development of arterial hypertension by GWAS in Europe and the United States in 2009, were analyzed. No association of any of the investigated markers with the development of arterial hypertension was confirmed.

Primary hypertension and special aspects of hypertension in older children and adolescents.

The prevalence of hypertension has increased at an accelerated rate in older children and adolescents. This has raised great concern about premature development of cardiovascular disease, which has major long-term health and financial implications. While obesity and sedentary habits largely explain this phenomenon, there are other social and cultural influences that may unmask genetic susceptibility to hypertension in the pediatric population. While it is essential to exclude numerous causes of secondary hypertension in every child, these disorders are not discussed in this review. Rather, the aim of this review is to familiarize pediatricians with casual and ambulatory blood pressure measurement, epidemiology, pathophysiology, and management of several common conditions that play a role in the development of hypertension in children and adolescents. Besides primary hypertension and obesity-related hypertension, emphasis is given to epidemiology, measurement of blood pressure, including ambulatory blood pressure monitoring, hypertension associated with drug use, teenage pregnancy, and video and computer games. Lastly, because pediatricians are increasingly confronted with special issues concerning the management of the hypertensive athlete, this topic is also addressed.

Can We Predict Hypertension Among Preterm Children?

Prematurity and low birth weight (LBW) cause hypertension (HTN), ischemic heart disease, and obesity in young adults. The objective of the study was to identify risk factors for the development of HTN in children born preterm or at a LBW and to assess pediatricians' awareness of the problem. A retrospective review of 160 cases was conducted. In total, 22% of babies born preterm/LBW developed HTN by age 15 years. The odds of developing HTN were 1.6 times greater for every one standard deviation increase in body mass index. Higher risk posses for those born small for gestational age and under 1000 g. Of the 35 cases of HTN identified, only 31% were recognized as abnormal by the primary care providers. The development of obesity and HTN appear related in preterm/LBW children. Awareness of prematurity or LBW as a risk factor for HTN should be raised among pediatric primary care providers.

The influence of different surgical procedures on hypertension after repair of coarctation

We measured resting and exercise haemodynamics, as well as 24-hour ambulatory blood pressure, so as to study the influence on development of hypertension in children after repair of coarctation by either construction of a subclavian flap or end-to-end anastamosis. The patients in both groups were studied a mean time of 13 years after surgery. Thus, we divided 43 children who had undergone surgical repair of coarctation, and who were not on antihypertensive therapy, into a group of 22 patients who had undergone subclavian flap repair, with a mean age of 14 plus or minus 2.6 years, and another group of 21 patients undergoing end-to-end anastomosis, with a mean age of 13.5 plus or minus 3.9 years. We examined blood pressure at rest and during exercise, along with the measurement of cardiac output using impedance cardiography, and during 24-hour ambulatory monitoring. We recorded systolic and diastolic blood pressures, pulse pressure, cardiac output and total peripheral vascular resistance at rest and at peak exercise. During ambulatory monitoring, we measured mean pressures over 24 hours, in daytime and nighttime, 24-hour pulse pressure, and 24-hour mean arterial pressure. Student's t test was used to judge significance, accepting this when p was less than 0.05. The group repaired using the subclavian flap showed significantly disadvantageous differences for diastolic blood pressure at rest, systolic blood pressure at peak exercise and for 24-hour systolic and diastolic blood pressure, 24-hour mean arterial pressure, and daytime and nighttime systolic blood pressure during ambulatory monitoring. Our findings suggest that, after repair using the subclavian flap in comparison to end-to-end anastomosis, patients show a higher incidence of late hypertension, both during exercise and ambulatory monitoring. The data indicate different residual aortic stiffnesses, these being lower after end-to-end anastomosis, which may be due to the greater resection of the abnormal aortic tissue when coarctation is repaired using the latter technique.

Significance of Heritability in Primary and Secondary Pediatric Hypertension

Patient weight and family history are significant risk factors for the development of hypertension in children. Multiple genetic factors have been identified in primary (essential) hypertension in adults; however, the delineation of genetic factors in the separate populations of children with primary or secondary hypertension are not well understood. Heritability is the proportion of observed variation in a particular trait that can be attributed to an inherited genetic factor in contrast to environmental factors. In the consideration of hypertension, heritability can be assessed in terms of an underlying continuous gradient of the liability for developing hypertension. With this assumption it is possible to compute heritability using hypertension incidence among relatives and described by Falconer. Heritability values range from 0 (no genetic contribution) to 1 (complete genetic contribution). The aim of this study was to determine the genetic contribution to primary and secondary hypertension in a pediatric population through heritability analysis. This was a retrospective case-control analysis of medical records of children (n=276) followed in the Pediatric Nephrology Clinic over a 4-year period from 1999 to 2002. There were 192 children and adolescents with primary hypertension (124 male, 68 female, age 0 to 21 years) and 84 children and adolescents with secondary hypertension (46 male, 38 female, age 0 to 21 years). Each hypertensive group served as the control for the other. Estimates of heritability were made using Falconer's method 2. The model assumes independence between the environment and genetic factors and that the joint distribution of liabilities between parent and child are normally distributed. Problems can arise from computing heritability due to dominance within loci, correlations between nongenetic familial effects, or the presence of a major gene. Of the children and adolescents with primary hypertension, 49% had parents with primary hypertension; and of the children and adolescents with secondary hypertension, 24% had parents with primary hypertension. Of the children and adolescents with primary hypertension, 10% had parents with secondary hypertension; and of the children and adolescents with secondary hypertension, 46% had parents with secondary hypertension. The estimated heritability for primary hypertension was 0.84 (SE=0.21). The estimated heritability for secondary hypertension was 1.14 (SE=0.21). As the value was >1, this indicates that the fit of the liability model is poor and that a few genes, or even one major gene, were significantly involved in the causes of secondary hypertension in the children and adolescents studied. The results suggest that primary and secondary hypertension do not share the same type of genetic profile. Primary hypertension in children and adolescents is likely due to a large number of additive contributions of genes, although a highly correlated environmental component can not be excluded. The continuous liability model is inappropriate for secondary hypertension because the estimate was substantially greater than one. This study supports the model that secondary hypertension in children and adolescents may be related to just a few genes.