Blood pressure in childhood. The National Health Examination Survey

Hypertension and correlates among Montenegrin schoolchildren-a cross-sectional study

OBJECTIVES

In one of the few national studies of children in a former Eastern bloc country emerging as a Western democracy and the first such study ever in Montenegro, this study establishes the prevalence and correlates of childhood hypertension (CH).

STUDY DESIGN

A cross-sectional national study.

METHODS

The study was conducted with 3254 children aged 7-13 years (50.3% male) from 39 elementary schools. We used a structured questionnaire to gather sociodemographic information as well as data on factors potentially related to CH. Children's nutritional status was assessed using the criteria of the International Obesity Task Force. Waist circumference was also measured. Blood pressure was measured in schools using an oscillometric monitor. CH was defined as an average systolic blood pressure and/or diastolic blood pressure greater than or equal to the 95th percentile for sex, age, and height.

RESULTS

The prevalence of CH was 10.4% with no differences between boys and girls. Multiple regression revealed that the odds for child hypertension were lowered by 10% for each year of age. On the other hand, rural environment and child obesity raised the odds of hypertension by 38% and 68%, respectively.

CONCLUSIONS

We found hypertension in one out of ten Montenegrin schoolchildren, with no gender differences. Obesity and rural areas may be unfriendly to children's blood pressure.

Blood pressure tables for Chinese adolescents: justification for incorporation of important influencing factors of height, age and sex in the tables

Background

Elevated blood pressure (BP) in childhood was a predictor of hypertension in adulthood and contributes to the current epidemic of cardiovascular disease. It is necessary to identify abnormal BP in children and adolescents with accurate BP tables based on several crucial factors. The purpose of this study was to identify the important influencing factors of BP of Chinese adolescents.

Methods

BP, height, and body weight were assessed in 32221 normal-weight Chinese adolescents aged 12–17 years. An equal number of 6815 subjects from boys and girls were individually matched by height and age to assess the independent effect of sex on BP; and an equal number of 1422 subjects from each of the age groups (12, 13, 14, 15, 16 and 17 years) were individually matched by sex and height to estimate the independent effect of age on BP. Height of each sex and age was divided into eight height groups - ~5^th, ~10^th, ~25^th, ~50^th, ~75^th, ~90^th, ~95^th, and 95^th ~ percentiles- and the Spearman’s correlation between height percentiles and BP was used to examine the independent effect of height on BP.

Results

Boys had higher systolic BP (SBP) and diastolic BP (DBP) than girls after controlling for age and height. BP increased with age after controlling for sex and height. In each age group, both SBP and DBP increased alongside increasing height in boys and girls.

Conclusions

Sex, age and height are all independent determinants for BP levels in Chinese adolescents. It is essential to incorporate these three factors for the establishment of the BP reference tables.

Explaining socioeconomic inequalities in childhood blood pressure and prehypertension: the ABCD study

Much remains to be understood about the socioeconomic inequalities in hypertension that continue to exist. We investigated the association of socioeconomic status with blood pressure and prehypertension in childhood. In a prospective cohort, 3024 five- to six-year-old children had blood pressure measurements and available information on potential explanatory factors, namely birth weight, gestational age, smoking during pregnancy, pregnancy-induced hypertension, familial hypertension, maternal body mass index, breastfeeding duration, domestic tobacco exposure, and body mass index. The systolic and diastolic blood pressures of children from mid-educated women were 1.0-mm Hg higher (95% CI, 0.4-1.7) and 0.9-mm Hg higher (95% CI, 0.3-1.4), and the blood pressures of children with low-educated women were 2.2-mm Hg higher (95% CI, 1.4-3.0) and 1.7-mm Hg higher (95% CI, 1.1-2.4) compared with children with high-educated women. Children with mid- (odds ratio, 1.50; 95% CI, 1.18-1.92) or low-educated mothers (odds ratio, 1.80; 95% CI, 1.35-2.42) were more likely to have prehypertension compared with children with high-educated mothers. Using path analyses, birth weight, breastfeeding duration, and body mass index were determined as having a role in the association of maternal education with offspring blood pressure and prehypertension. The socioeconomic gradient in hypertension appears to emerge from childhood as the results show a higher blood pressure and more prehypertension in children from lower socioeconomic status families. Socioeconomic disparities could be reduced by improving 3 factors in particular, namely birth weight, breastfeeding duration, and body mass index, but other factors might also play a role.

Community-based blood pressure measurement by non-health workers using electronic devices: a validation study

Introduction

Population monitoring and screening of blood pressure is an important part of any population health strategy. Qualified health workers are expensive and often unavailable for screening. Non-health workers with electronic blood pressure monitors are increasingly used in community-based research. This approach is unvalidated. In a poor, urban community we compared blood pressure measurements taken by non-health workers using electronic devices against qualified health workers using mercury sphygmomanometers.

Method

Fifty-six adult volunteers participated in the research. Data were collected by five qualified health workers, and six non-health workers. Participants were randomly allocated to have their blood pressure measured on four consecutive occasions by alternating a qualified health worker with a non-health worker. Descriptive statistics and graphs, and mixed effects linear models to account for the repeated measurement were used in the analysis.

Results

Blood pressure readings by non-health workers were more reliable than those taken by qualified health workers. There was no significant difference between the readings taken by qualified health workers and those taken by non-health workers for systolic blood pressure. Non-health workers were, on average, 5–7 mmHg lower in their measures of blood pressure than the qualified health workers (95%HPD: −2.9 to −10.0) for diastolic blood pressure.

Conclusion

The results provide empirical evidence that supports the practice of non-health workers using electronic devices for BP measurement in community-based research and screening. Non-health workers recorded blood pressures that differed from qualified health workers by no more than 10 mmHg. The approach is promising, but more research is needed to establish the generalisability of the results.

Clinical characteristics of 18-year-old men with elevated blood pressure

Twenty "hypertensive" 18-year-old men (systolic BP greater than or equal to 146 and/or diastolic BP greater than or equal to 90 mmHg) from the screening examinations of a military draught bureau were compared with 17 normotensive (systolic BP 124-131) and 12 hypotensive (systolic BP 100-106) subjects. The hypertensive subjects were on average taller, showed more often ECG evidence of sympathoadrenomedullary overactivity, tended to excrete more adrenaline in the urine during a standardized psychological stress test, had higher serum levels of sodium and potassium and reported more frequently family prevalence of hypertension than the normotensives and hypotensives. Non-participating subjects without verified hypertension had higher mean relative weight than any of the study groups. Only one hypertensive subject showed dilated pulmonary vessels on chest X-ray and borderline evidence of mild left ventricular hypertrophy. None of the hypertensive subjects showed evidence of decreased glomerular filtration rate or endocrine disorder. The subjects in both comparison groups showed frequently ECG evidence of parasympathetic activity. The hypotensive group had a lower average relative body weight than the other groups.

Blood pressure during adolescence: a study among Belgian adolescents selected from a high cardiovascular risk population

INTRODUCTION

The Belgian province of Luxembourg has a high incidence of cardiovascular (CV) disease according to the MONICA register. Surveys conducted in adults and children have also found high CV risk factor levels in this province.

DESIGN

cross-sectional study. OBJECTIVE OF THE PRESENT STUDY: To collect data about blood pressure (BP) and its determinants in adolescents from this high CV risk population and to analyse their relationship.

PARTICIPANTS

1526 adolescents (12-17 years) in 24 secondary schools of the province.

RESULTS

Mean systolic BP levels were 125 mm Hg (sd = 12 mm Hg) and 122 mm Hg (sd = 11 mm Hg) for boys and girls, respectively. Mean diastolic BP was equal to 74 mm Hg (sd = 10 mm Hg) in both genders. Systolic BP increased with age and differed significantly between genders from 15 years onwards. Body fatness indices increased with age except waist-to-hip ratio in girls and triceps skinfold in boys. Regression models including age, anthropometric indices and physical activity explained a small percentage of BP variance (for systolic BP, r2 = 0.21 and 0.12 for boys and girls, respectively). Weight was the first parameter related to BP in correlation and regression analyses.

CONCLUSIONS

This study showed high BP and body fatness indices in adolescents from a high CV risk population. The model under study showed a moderate relationship between body fatness and BP. This finding suggests other influences as a genetic component to account for the high levels observed.

Measurement of blood pressure in children: recommendations and perceptions on cuff selection

OBJECTIVE

. To review some of the recent recommendations on blood pressure (BP) cuff selection, including those by the Task Force and its update, and to survey the perceptions on cuff selection among practitioners.

METHODS

The study was conducted in two parts. In the first, we selected three brands of commonly used infant, child/pediatric, small adult, adult, and large adult BP cuffs. From the median width of each, we derived the required upper arm length (UAL) for the cuff to cover three quarters or two thirds of the UAL, and with the help of a published normal UAL at various ages, we matched the derived UAL with the corresponding age at the 50th percentile. Similarly, we derived the midupper arm circumference (UAC) so that the available cuffs would cover 40% of the UAC, and by using the published normal UAC at various ages, we matched the derived UAC with the corresponding age at the 50th percentile. The second part of the study involved a survey by multiple choice questionnaire mailed to 400 hospital- and office-based pediatricians, residents, and nurses at the Children's Hospital of Michigan. Included in the survey were questions about the age at which practitioners would choose the cuffs described above; the minimum age they would consider using an adult cuff in a pediatric patient with an average height and weight; selecting a cuff using UAL as a criterion; selecting a large versus a small cuff when the appropriate cuff size is not available; and the Task Force definition of hypertension.

RESULTS

Using three quarters of the UAL as a criterion, it seems that a large adult cuff should be appropriate for an average-size 6-year-old child and that using two thirds of UAL as a criterion, the cuff should be appropriate for an average-size 7- to 8-year-old child. Similarly, by using 40% of the mid-UAC as a criterion, an adult cuff would be of no use in an average pediatric patient at any age. Our survey revealed that 57% of practitioners would consider using a neonatal cuff for patients up to 1 month of age, 65% would use an infant cuff for those 1 year of age, 49% would use a child/pediatric cuff for those 5 years of age, and 84% would use a small adult cuff for those 10 years of age and older. Most (83%) of the practitioners would consider using an adult cuff in children 11 years of age and older. Practitioners are likely to use a smaller cuff than is appropriate by two thirds or three quarters of UAL criteria, and a larger cuff than is appropriate, particularly in older children, by 40% of UAC criteria. Using UAL as a criterion, a majority (59%) of practitioners use cuffs that cover two thirds of the distance between the axilla and the cubital fossa. Ninety-two percent of practitioners believe that a smaller cuff causes a moderate to significant increase in the BP reading, and 55% believe that a larger cuff causes a similar decrease in the BP reading. A significant number of practitioners (44%) did not know the Task Force definition of hypertension, including 42% of attendings, 44% of residents, and 50% of nurses.

CONCLUSIONS

The Task Force and the Working Group recommendations on BP cuff selection need to be reviewed. A new multicenter study, using uniform criteria for cuff selection, may be necessary to establish the accuracy of the published nomogram on normal BP in children. More awareness is required on part of practitioners of the current recommendations on BP measurement and the definition of hypertension. Finally, the labeling of BP cuffs as infant, pediatric, small adult, adult, and large adult is misleading, and such designations should be eliminated. Cuff sizes should be standardized, indicate bladder size, and be uniformly color-coded for convenience.

Central adiposity and hemodynamic functioning at rest and during stress in adolescents

OBJECTIVE

To examine the impact of central adiposity upon hemodynamic functioning at rest and during stress in adolescents.

DESIGN

Cross-sectional, correlational study.

SUBJECTS

46 White and 49 Black normotensive adolescents with family histories of essential hypertension.

MEASUREMENTS

Systolic and diastolic blood pressure (SBP, DBP), cardiac output and total peripheral resistance responses were assessed at rest, during postural change, video game challenge and forehead cold stimulation. Specific lower and higher waist-to-hip ratio (WHR) tertiles were created for each gender and then integrated for analyses. This resulted in a lower WHR tertile of 11 Whites and 21 Blacks and an upper WHR tertile of 15 Whites and 17 Blacks.

RESULTS

No differences in age, gender or ethnicity proportions were found between tertile groups (all P > 0.21). The upper WHR group showed greater body weight, waist and hip circumferences, body mass index (BMI), triceps skinfold and body surface area (all P < 0.001). Controlling for peripheral (that is, triceps skinfold) and overall (that is, BMI) adiposity, the upper WHR group exhibited greater SBP (that is, peak response minus mean pre-stressor level) to all three stressors and greater DBP reactivity to postural change and cold pressor (all P < 0.05).

CONCLUSION

Central adiposity appears to adversely influence hemodynamic functioning during adolescence. Underlying mechanisms responsible for these associations require exploration.

Percentiles for body mass index in U.S. children 5 to 17 years of age

OBJECTIVES

It has been recommended that body mass index (BMI) (weight in kilograms/height in meter2) be used routinely to evaluate obesity in children and adolescents. This report describes the distribution of BMI in children and adolescents in the United States.

METHODS

Standardized measurements of height and weight from 9 large epidemiologic studies including 66,772 children age 5 to 17 years were used to develop tables for the distributions of BMI that are age, race, and gender specific.

RESULTS

The mean BMI increases with age and is slightly higher for girls than boys. Mean BMI for black and Hispanic girls was noticeably higher than for white girls. The percentiles of BMI are consistently higher than those based on the NHANES I measures, particularly for the 95th percentile. The proportion of obese children compared with NHANES I standards is higher and is highest for Hispanic boys and black and Hispanic girls.

CONCLUSION

The tables and figures will allow pediatricians to determine the relative ranking of BMI for patients compared with values derived from a large sample of healthy children and adolescents. The identified gender and ethnic differences may be guides to understanding the cause and prevention of obesity.

Birth weight versus childhood growth as determinants of adult blood pressure

In older white American adults, recent retrospective studies have demonstrated a relationship between lower birth weight and hypertension. Black Americans have a higher occurrence of both lower birth weight and hypertension than do white Americans. To test the low birth weight-high blood pressure hypothesis, data from a prospective study (Perinatal Collaborative Project) were examined. The study followed a sample of 137 black Americans, with nine examinations. Data on birth weight, growth, and blood pressure from birth through 28.0+/-2.7 years were obtained longitudinally. Bivariate correlations among parameters were computed with the Pearson r. Birth weight and blood pressure at age 28 years are not correlated (Pearson r=.06). However, systolic blood pressures measured at 0.3 years and thereafter are correlated with adult systolic blood pressure. Also, weight at 0.3 years and body mass index at 7 years and thereafter are correlated with adult weight. Our data did not confirm the birth weight-blood pressure hypothesis. Rather, we detected significant correlations between preadult measurements of blood pressure and weight with adult measurements. These results indicate that in black Americans, childhood growth is a stronger determinant than intrauterine growth of adult blood pressure.

Life style as a blood pressure determinant

In Belgium, an affluent Western European country, participation in sports, alcohol intake, and living in a working class area were identified as the life style factors with the closest associations with the blood pressure level. Obesity was another important blood pressure correlate. Sodium intake, determined from the 24 h urinary output, and smoking were not associated with blood pressure. Controlled intervention studies have proven that weight reduction, endurance training and alcohol abstinence effectively reduce blood pressure. In the light of these intervention studies, the Belgian findings and the published work highlight the potential of preventive strategies aimed at these major life style factors.

Blood pressure in young blacks and whites: relevance of obesity and lifestyle factors in determining differences. The CARDIA Study. Coronary Artery Risk Development in Young Adults

BACKGROUND

Middle-aged black men and women have higher blood pressure, on average, than whites. However, this pattern is inconsistent in children and adolescents. This study explores how differences in lifestyle factors in young adulthood may influence blood pressure patterns in the two races.

METHODS AND RESULTS

The Coronary Artery Risk Development in Young Adults (CARDIA) study is an ongoing collaborative investigation of lifestyle and the evolution of cardiovascular disease risk factors in a random sample of young adults ages 18 to 30 years at baseline (1985 to 1986). Data from four examinations over 7 years were analyzed with the use of a method that simultaneously examined cross-sectional and longitudinal relationships of lifestyle factors and blood pressure. This study included 1154 black women, 853 black men, 1126 white women, and 1013 white men. Blacks had higher systolic blood pressure and diastolic blood pressure than whites at every examination. Racial differences were much greater in women than in men and increased over time. Within each sex-race group, average diastolic blood pressure over four examinations was positively associated with baseline age, body mass index, and alcohol intake and negatively associated with physical activity, cigarette use, and intake of potassium and protein. Longitudinal change in diastolic blood pressure was positively associated with changes in body mass index and alcohol intake. After adjustment for obesity and other lifestyle factors, black-white diastolic blood pressure differences were reduced substantially: 21% to 75% for men and 49% to 129% for women. Results for systolic blood pressure were similar.

CONCLUSIONS

Differences in obesity and other lifestyle factors in young adults largely explain the higher baseline blood pressure and greater increase over time of blacks relative to whites.

Correlates of blood pressure in Seventh-Day Adventist (SDA) and non-SDA adolescents

OBJECTIVE

This comparative study was designed to discover early determinants of systolic (S) and diastolic (D) blood pressure (BP) elevations in 138 Seventh-Day Adventist (SDA) and 89 non-SDA male and female adolescents (median age, 17 years) living at three residential secondary schools in North Carolina.

METHODS

Measurements were made of blood pressure, body weight, and height, and information was collected on lifestyle factors, dietary intake, and other behaviors, including exercise, religiosity, Type A behavior, and anger, by questionnaire. Multiple stepwise regression analyses were performed with BP, either SBP or DBP, as the independent variable.

RESULTS

A significant direct association was found only between body weight and BP, but weak associations were shown between BP and other variables, including exercise, diet, religiosity, Type A behavior, and anger. Male and female SDA students showed significantly higher SBPs and DBPs than did non-SDA adolescents though the differences were small (approximately 5 mm for each sex).

CONCLUSIONS

These findings suggest that the higher BP values of SDA adolescents, who were all practicing lacto-ovo-vegetarians, compared to similarly aged health-conscious non-SDAs, are determined more by eating behaviors that contribute to gains in body weight than by any other lifestyle variable. Furthermore, these data support the notion that the BP-protective effects of the vegetarian diet may not emerge in these SDA youth until early adulthood.

Ethnic differences in electrocardiographic left ventricular hypertrophy in young and middle-aged employed American men

In the United States population, black men have higher prevalence rates of electrocardiographic (ECG) high QRS voltage, more ST-segment and T-wave abnormalities, and more ECG left ventricular hypertrophy (LVH) than do white men. Reasons for these differences have not been fully elucidated. The prevalence rate of ECG LVH and associated characteristics were compared in black and white men in the Chicago Heart Association Detection Project in Industry population study. Data were from 1,391 black men and 19,126 white men (age range 20 to 64 years) employed by 84 Chicago organizations. ECG LVH was defined by the presence of both high QRS (Minnesota code 3.3) and ST-T abnormality (code 4.1-4.3 or 5.1-5.3). Black men had a significantly higher prevalence rate of ECG LVH than did white men in each 15-year age group (15.9 vs 2.4, 14.6 vs 2.8, and 35.7 vs 12.5/1,000 in the 20- to 34-, 35- to 49-, and 50-to 64-year age groups, respectively; p < 0.01 for each comparison). Multiple logistic regression analyses indicated that systolic blood pressure and age were associated positively with ECG LVH (p < 0.01) in both black and white men. Men with history of hypertension and receiving drug treatment had a greater likelihood of having ECG LVH than did those with history of hypertension but not receiving drug treatment, possibly because those with more severe hypertension were more likely to have been prescribed medication. Serum cholesterol, cigarettes smoked/day, 1-hour post-load plasma glucose and education were not consistently related to ECG LVH.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood pressure nomograms for children and adolescents, by height, sex, and age, in the United States

Because height is a more appropriate index of maturation than weight for use with normative blood pressure (BP) data, we developed normative BP levels for children, by sex, while accounting for age and height simultaneously. Eight U.S. studies used in the Report of the Second Task Force on Blood Pressure Control in Children and one additional study of BP in U.S. children were reanalyzed to develop age-sex-height-specific values for normative BP values among 56,108 children, aged 1 to 17 years, seen at 76,018 visits. Height percentiles were computed on the basis of standard National Center for Health Statistics growth charts. When height is taken into account, more short children (10th age-sex-specific height percentile) and fewer tall children (90th age-sex-specific height percentile) are likely to be classified as hypertensive than when the current age-sex-specific percentiles of BP alone are used. Tables are provided for boys and girls separately, by single year of age (1 to 17 years) and by the 90th and 95th percentiles of systolic blood pressure and diastolic blood pressure (fifth phase of Korotkoff sounds) for selected age-sex-specific height percentiles based on standard U.S. growth charts.

Hypertension in childhood and adolescence

Through the benefit of a large body of normative data on blood pressure throughout childhood, along with the clinical practice of regular blood pressure measurement in the young, mild elevation of blood pressure can be detected in the young. Unlike secondary hypertension in the young which is more severe, slight to mild elevations in blood pressure during childhood may be an early expression of essential hypertension. Mildly elevated blood pressure in the young is usually associated with other risk factors including obesity, family history of cardiovascular disease, and metabolic alterations in lipids and insulin. Environmental factors, which include health related behaviors can modulate the expression of the risk factors including elevated blood pressure. The extent to which the health behaviors of diet and exercise can be modified in the young may be important for risk factor intervention during the early phases of hypertension.

Longitudinal assessment of blood pressures in black and white children

The prevalence of hypertension is greater for blacks than whites. Whether black children have higher blood pressure than white children is less clear. We investigated this issue through a prospective longitudinal assessment of blood pressure in 345 white children and 164 black children. Each child had his or her blood pressure measured every 6 months for 2 to 5.5 years. The means for systolic and diastolic blood pressures for each individual were calculated, and the rate of change in blood pressure over time for each subject was estimated. The mean blood pressure and the mean rate were compared between gender-specific black and white groups. For both boys and girls, the mean systolic blood pressure was 2 mm Hg higher in black children than white children (P = .0008). Boys had a higher systolic blood pressure than girls (P = .0048). The mean diastolic blood pressure was 1.5 mm Hg higher in black children than in white children (P = .0270); no significant gender difference in diastolic blood pressure was observed. Age, weight, height, and body mass index were highly correlated with blood pressure. When accounting for these variables, for girls the racial difference in systolic blood pressure remained significant, whereas the difference in diastolic blood pressure in boys and girls was no longer significant. The rate of increase in blood pressure over time was significantly greater in blacks than whites: for systolic blood pressure, P = .0002, and for diastolic blood pressure, P = .009.(ABSTRACT TRUNCATED AT 250 WORDS)

Children's cardiovascular reactivity: stability of racial differences and relation to subsequent blood pressure over a one-year period

After measuring blood pressure and heart rate at rest and during a video game procedure in 477 children enrolled in 3rd grade, 434 (91%) children had these measurements repeated a year later in 4th grade. Black children demonstrated greater blood pressure and heart rate reactivity than White children in both years, and an increase in heart rate reactivity from 3rd to 4th grade. Gender effects were inconsistent. Systolic and diastolic blood pressures during the video game were more highly correlated from year-to-year than were the resting measures. Regression analysis indicated that systolic reactivity was significantly related to subsequent systolic pressure at rest, particularly among Black girls. Diastolic reactivity was associated with subsequent resting diastolic pressure only among White children. Associations between reactivity and future blood pressure were independent of initial resting blood pressure. This study suggests that cardiovascular reactivity to psychological stress may be one important factor in future level of blood pressure and that the increased heart rate reactivity of Black children may be associated with the prevalence of hypertension among Black adults.

Measures of body composition. Their relationship to blood pressure and use in epidemiologic research

The association between "overweight" and increased risk of high blood pressure has long been recognized. The quantification of overweight into various aspects of body composition and the relationships of these aspects to blood pressure remain important areas of current research. The manner in which adipose tissue is distributed over the body is proving to be another important risk factor. Methodologies for assessing body composition include a variety of approaches commonly used in epidemiologic studies, ranging from simple indices (e.g., body mass index) to estimation of total body fat mass from equations based on skinfolds and other anthropometry, to newer approaches incorporating bioelectric impedance. Refined laboratory methods for assessing body composition are important in the study of small groups and in the development of predictive equations. These refined methods include the traditional approaches of hydrostatic weighing and K40 determinations, as well as newer improvements on these techniques incorporating estimates of bone mineral content and total body water. Other new sophisticated methodologies include dual-energy x-ray absorptiometry and nuclear magnetic resonance imaging. The approach to assessing body composition may vary among age groups; methodologies applicable to children may not work for the elderly.

Effect of chronic sodium loading on cardiovascular response in young blacks and whites

The effect of long-term oral sodium loading on blood pressure and on stress-induced cardiovascular response was studied in normotensive and marginally hypertensive young adults. The 121 subjects, 18-23 years old, included 38 whites and 83 blacks. Blood pressure and heart rate response to the stress of mental arithmetic was measured before and after 14 days of sodium load, which consisted of 10 g NaCl/day added to the usual diet. A sodium-sensitive response to sodium load occurred in 18.4% of whites and 37.3% of blacks. Sodium-insensitive subjects had a higher rate of sodium excretion (p less than 0.001). Sodium-sensitive hypertensive subjects had a significantly greater weight gain (p less than 0.001). A significant correlation between blood pressure change and sodium excretion (r = -0.28, p less than 0.01) occurred in the sodium-sensitive group. The high sodium intake did not augment the blood pressure or heart rate response to the beta-adrenergic-mediated stimulus of mental arithmetic in the population when grouped by blood pressure, race, or sodium sensitivity. These results suggest that blood pressure increase in response to sodium load, particularly in blacks, is related to functional changes in peripheral vascular resistance.

Blood pressure trends associated with changes in height and weight from early adolescence to young adulthood

In children, blood pressure is more closely related to height and indices of maturation than to age. This study extends observations on the relationship between height, weight, maturation and blood pressure during early adolescence into young adulthood. Standardized measurements of blood pressure, height, and weight were initially obtained in all 14-15 year old adolescents (N = 304) in a rural Kentucky school system. Measurements were repeated 5 and 8 years later. Adolescents with relatively high blood pressures continued to have higher blood pressures as young adults. Increases in systolic and diastolic blood pressure over time were related to increases of relative weight in both sexes (p less than 0.0001 and p less than 0.005, respectively), and in males increases of systolic blood pressure were related to increases of height (p less than 0.005). However, males who attained their full height at younger ages had higher blood pressures both during adolescence and subsequently, as young adults. Thus blood pressure of young adults is related to blood pressure in adolescence, relative weight and change in relative weight since adolescence, and in males to age of maturation as determined by the age at which adult height is attained.

Aortic stiffness: a new Doppler echocardiographic measure predictive of systolic blood pressure in children

Aortic stiffness, the maximal frequency shift in the descending aorta divided by the Doppler acceleration time, was studied in 384 eleven year old twin children. The extent to which this measurement provided a prediction of systolic blood pressure that was independent of body size, heart rate, cardiac contractility and left ventricular mass was investigated. Aortic stiffness, after adjustment for height and weight, correlated significantly with systolic blood pressure (r = 0.22, p less than 0.01), but not with diastolic blood pressure. The short- (r = 0.82) and longer- (r = 0.68) term reproducibility of aortic stiffness was high. This measure appears to be a more powerful predictor of systolic blood pressure than is left ventricular mass. Aortic stiffness is a highly reproducible Doppler variable that may explain in part the contribution of the aortic wall elastic properties to the level of systolic blood pressure in preadolescent children at rest.

Body fat patterning and blood pressure in children and young adults. The Bogalusa Heart Study

The relationship of central body fat (measured by subscapular skinfold) and peripheral body fat (measured by triceps skinfold) to blood pressure was investigated in 3784 subjects aged 5 to 24 years old from the biracial community of Bogalusa, Louisiana. After adjustment for height, age, sex, and race, significant relationships were found for both central body fat (r = 0.19 and 0.14, p less than 0.0001) and peripheral body fat (r = 0.15 and 0.12; p less than 0.0001) with systolic and diastolic (fourth phase) blood pressure, respectively. However, the relationship between peripheral body fat and blood pressure, after controlling for the level of central body fat, was negligible (r = 0.00 and 0.01 for systolic and diastolic blood pressure, respectively). In contrast, the central body fat-blood pressure relationship remained statistically significant even after controlling for the peripheral body fat level. For central body fat, the partial correlations with systolic blood pressure were highest in young children (r = 0.15), dropped slightly during adolescence (r = 0.12), and became nonsignificant only in 18- to 24-year-old female subjects; correlations remained high in both black and white 18- to 24-year-old male subjects (r = 0.18 and 0.16, respectively). Mean levels of systolic blood pressure from the lowest to the highest quartile of central body fat ranged from 100.4 to 108.9 mm Hg. The adult hypertension-central body fat relationship, which has been shown by others, appears to exist in children. Continued efforts at early identification and prevention of obesity in children are warranted.

The cross-cultural study of U.S. and Greek adolescents: blood pressure data

Blood pressures (BP) were determined in 1409 boys aged 8-16 years at three one-year intervals in New York City (NYC) and in Greece, areas of high and low incidence of coronary heart disease (CHD), respectively. Non-Greek American boys had significantly lower systolic and diastolic BP than all the Greek boys from NYC and from Greece. The boys residing in Crete and in Athens had higher BP than all other cohorts. After covariance adjustment for height, ponderal index and age, significant differences among the cohorts showed the non-Greek American cohort to have the lowest and the Cretan cohorts the highest BP levels. The Cretans lead a lifestyle noted for the absence of other risk factors for CHD. Thus, while the incremental increase in blood pressure might have a corresponding increase in CHD risk among individuals, there are fewer individuals in Crete at elevated risk overall based on the CHD experience of the U.S. and Greece.

Sources of error in measurement of children's blood pressure in a large epidemiologic study: Bogalusa Heart Study

Accurate and reliable measurement of blood pressure is essential in the determination of early hypertensive disease. Multiple blood pressure measures were determined by well trained field observers on a large number of children representing a total pediatric community. Changes in children's blood pressure levels with multiple measurements, as well as differences between field observers, were examined. A random effects analysis of variance model was used to determine specific contributors to blood pressure variability in an epidemiologic survey of children. Observer differences were found to be the largest preventable contributor to blood pressure variation. In addition, systolic blood pressure levels decreased approx. 2.5 mmHg from the first to the third blood pressure station. More than 86% of systolic blood pressure readings and 90% of diastolic blood pressure readings by two different observers on the same child were within 15 mmHg. These data emphasize the importance of both adequate training of field observers and the use of replicate blood pressure measurements by multiple observers to determine blood pressure levels accurately in an epidemiologic survey.

Race and cardiovascular reactivity. A neglected relationship

The magnitude of the cardiovascular response to stress has been implicated in the pathogenesis of cardiovascular disease. Psychological stress procedures have received increased usage as an alternative to expensive physical (exercise) stress procedures. In the present investigation, 213 healthy, black or white, male or female children between the ages of 6 and 18 years were exposed to the psychological stress of a video game. The video game challenge was administered by a black or a white experimenter and was played under three levels of increasing stress, 1) personal challenge, 2) experimenter's challenge, and 3) experimenter's challenge accompanied by a financial incentive, while blood pressure and heart rate were monitored. Results indicated that the video games provoked significant and incremental cardiovascular reactivity across the games. Black children demonstrated significantly greater reactivity than white children; the racial difference was more reliably observed for systolic and diastolic blood pressure than for heart rate. Furthermore, the race of the experimenter exerted a significant effect and often interacted with the race of the child, such that greater reactivity occurred in same-race pairings than in mixed-race pairings. These results suggest that reactivity is affected by an individual's race and social milieu and that reactivity may be one mechanism responsible for the greater prevalence of hypertension among blacks.

Persistence of high diastolic blood pressure in thin children. The Bogalusa Heart Study

Relationships between initial anthropometric variables and subsequent diastolic blood pressure (fourth phase) were examined in children identified as being in the upper quintile for diastolic blood pressure at Year 1. Of 156 white children, aged 10 to 14 years, with diastolic blood pressure levels in the upper age-race-sex-specific quintile at Year 1, 38% remained in the upper quintile at Year 4. However, there was a definite trend for leaner children, defined by ponderosity (weight/height3) to remain in the highest diastolic blood pressure quintile (p less than 0.001). Of white children originally identified in the highest quintile for diastolic blood pressure and the lowest quintile for ponderosity (lean group), 67% (18 of 27) remained in the upper quintile at Year 4. In contrast, only 21% (11 of 52) of white children identified as being in the highest quintile for both diastolic blood pressure and ponderosity (obese group) at Year 1 were in the upper diastolic blood pressure quintile at Year 4. Similar results were seen in children examined 5 years later. Pearson correlation coefficients and linear regression analyses confirmed the negative relationship between initial ponderosity and subsequent diastolic blood pressure, especially in older children. A similar relationship was noted in black children. Potential differences in the etiological process of obesity-related and non-obesity-related high blood pressure were examined. These observations indicate that characteristics other than obesity can contribute to high blood pressure in late childhood.

Interpretation of children's blood pressure using a physiologic height correction

In a cross-sectional survey of 1834 black, Atlanta schoolchildren we corrected the customary blood pressure (BP) observations for the height of the arterial column extending from the BP cuff to the top (vertex) of the subject's head. Each cuff-to-vertex height was converted to its pressure equivalent in mmHg; then this pressure was subtracted from the observed BP to compute vertex-corrected BP values. The vertex-corrected mean arterial pressure (VMAP) ranged from 22.3 to 83.2 mmHg, but there was no estimated linear association between VMAP and age. For males, mean VMAP was 49.4 mmHg for ages 6-13 and 46.0 mmHg for ages 14-17. For females, mean VMAP was 50.2 mmHg for ages 6-17. Since VMAP appears to be independent of age in most of childhood, its use may simplify the development of pediatric BP reference values. VMAP can also serve as a non-invasive approximation of cerebral perfusion pressure. Investigators of primary hypertension may wish to use VMAP for comparing average BP levels between childhood groups which differ by potentially etiologic characteristics.

Pulse rate, blood pressure and body composition in black adolescents: the Philadelphia Blood Pressure Project

Patterns of pulse rate, blood pressure (BP), and body size and composition are investigated in a black urban sample of over 600 adolescents (aged 12-17) in Philadelphia as part of the Philadelphia Blood Pressure Project. Supine and seated pulse rates decline after the age of 13 in both males and females, and females have significantly higher pulse rates than males, ranging from 1.6 to 4.7 beats/30 sec higher depending upon chronological age and position. Seated pulse rates are consistently higher than supine in both sexes ranging from 1.3 to 2.9 beats/30 sec depending upon chronological age. Pulse rate and both systolic blood pressure (SBP) and diastolic phase IV blood pressure (DBP) show a positive association throughout adolescence for females (r = 0.16 SBP, r = 0.24 DBP) but not for males (r = -0.06 SBP, r = 0.06 DBP). Females in the highest diastolic IV blood pressure stratum (greater than 85%) maintain higher pulse rates throughout adolescence, while males with the highest DBP have higher pulse rates in early adolescence (ages 12-14) but lower pulse rates in later adolescence (ages 16 and 17). Females with the highest DBP also show consistently higher measures of relative fatness (triceps skinfolds) throughout adolescence. Males with the highest DBP have greater triceps skinfolds in early adolescence and lower triceps in later adolescence, a pattern similar to that shown for pulse rate. For DBP, triceps is significantly and positively associated with pulse rate in the upper DBP percentile group (p less than 0.05). Thus, females with the highest blood pressure during adolescence are characterized by higher pulse rate and greater fatness. Males show this same pattern in early adolescence; whereas, in contrast, the older adolescent males in our sample with the highest DBP are characterized by lower pulse rates, relatively decreased fatness, and increased muscularity. Our findings suggest that, at least in some older black male adolescents, a higher DBP may reflect a decrease in cardiac output as indicated by a lower pulse rate, or an increase in peripheral vascular resistance, possibly associated with relatively decreased fatness and increased muscle mass for size.

Racial contrasts of blood pressure levels in two southern, rural communities

Blood pressure and anthropometric measurements were obtained according to a standardized protocol in two biracial, rural, southern communities. Essentially, the same examination team and protocol were used in Franklinton and Bogalusa. No differences between the communities in mean height or weight (except for white boys) were observed. Blood pressure levels were 2-5 mm Hg higher in Franklinton, particularly in blacks ages 8-13 years. These differences could not be explained by differences in anthropometric measurements or observers. The difference may be due partly to the fact that larger numbers of students each morning were examined in Franklinton than Bogalusa in perhaps a more hurried environment. Most of the staff members, being from Bogalusa, were not familiar to the children in Franklinton (as they are in Bogalusa), and this may have created anxiety. The differences were small, however, when compared with differences observed among several populations using varying methods. Confirmation is given to the finding that height and weight, not age, are the strongest determinants of blood pressure level in growing children, giving a further clue toward development of an appropriate definition of hypertension in children.

Concurrent validity studies of blood pressure instrumentation. The Philadelphia Blood Pressure Project

There is increasing evidence that blood pressure (BP) screening during adolescence may detect early evidence of hypertensive disease. Choice of instrumentation becomes important to maximize the accuracy and interpretive value of several serial readings. We therefore conducted two studies of adolescents, comparing auscultatory (Baumanometer and Random-zero), ultrasonic (Arteriosonde 1216), and infrasonic (Physiometrics SR-2) devices. These instruments were compared serially (Study 1) for older adolescents (n = 48). The Baumanometer, Arteriosonde 1216, and Physiometrics SR-2 were compared both serially and simultaneously (Study 2) for younger and older adolescents (n = 24). In both studies, the order of device presentation was completely counterbalanced. In Study 1, reliability estimates were high (r greater than 0.65), with the exception of the Arteriosonde 1216 diastolic readings, and the Physiometrics SR-2 yielded significantly lower mean diastolic BP readings than the other devices. Diastolic Phase V readings taken with the Random-zero were significantly higher when the Random-zero was presented at the end of the sequence of instrument presentation. This order of presentation effect is probably attributable to the need for overinflation when using the Random-zero device and may cause an overestimation of diastolic BP in the young. In Study 2, again the Arteriosonde 1216 did not perform reliably in recording diastolic BP. Further, the Physiometrics SR-2 device, although reliable, yielded diastolic readings significantly lower (p less than 0.001) than diastolic Phase IV readings taken both serially and simultaneously.(ABSTRACT TRUNCATED AT 250 WORDS)

[Blood pressure, renin angiotensin aldosterone system and other cardiovascular risk factors in children of essential hypertensives (author's transl)]

In the present study, blood pressure, the renin angiotensin aldosterone system, and other cardiovascular risk factors, such as glucose, cholesterine, and triglycerides, were investigated in 294 offspring of essential hypertensives (5-34 years) and in 122 children of normotensive parents (5-34 years). Offspring of essential hypertensives showed statistically significant higher systolic and diastolic blood pressure values than those of normotensive parents (p less than 0.003, less than 0.005, respectively). Furthermore, in children of hypertensive parents a statistically significant higher body weight and body mass index than in controls could be observed (p less than 0.006, less than 0.001, respectively). With the exception of statistically significant, lower mean supine plasma aldosterone values (p less than 0.02) in children of hypertensive parents, no major differences between the two groups were seen in stimulated aldosterone, supine and stimulated plasma renin activity, and plasma cortisol. Furthermore, in the present study, 41 hypertensive parents, 65 (normotensive) spouses of hypertensives, and 47 (normotensive) parents of control children were investigated. As expected, hypertensive parents showed statistically significant higher blood pressure values than parents of control children and their spouses (p less than 0.001). Interestingly, hypertensive parents had not only a higher body mass index than control parents but also than their spouses (p less than 0.01 and less than 0.02, respectively). These findings support a genetic disposition as being the underlying cause of higher body weight in hypertensives and make it less probable that a higher food intake in hypertensive families is responsible for this phenomenon. The results of the present study indicate that early body weight control in children of hypertensive parents may be an important contribution to the prevention of hypertension.

Blood pressure variations across areas in the greater Stockholm region: analysis of 74,000 18-year-old men

74,000 18-year-old men who went through the medical examination for the military draft procedure in the greater Stockholm region during the years 1969-1978 were divided into 63 areas of residence. Means of systolic and diastolic blood pressures, as well as heart rate, height, muscle strength and reasoning test results varied significantly across areas. In a univariate analysis, significant correlations were found between high average systolic blood pressure in an area on one hand and low median income and high proportion of subjects on social welfare in the area on the other hand. In a multivariate analysis these associations were partly explained by a tendency of areas with relatively poor socioeconomic conditions to have high average relative weight, high mean muscle strength and poor average reasoning test results. All of these variables were associated with high average systolic blood pressure. The findings are discussed in relation to ecological mechanisms. Somatic and psychological development during childhood is associated with educational environment at school and leisure activities. Areas with poor socioeconomic conditions and high average systolic blood pressure were those which tended to have high rates of migration.