Sexual maturation and racial differences in blood pressure in girls: the National Heart, Lung, and Blood Institute Growth and Health Study

Association between pubertal development and elevated blood pressure in children

Blood pressure (BP) increased with age and height development, but little was known about the effect of pubertal development on blood pressure in children. A cross‐sectional study was performed among 4146 children aged 7–12 years old in China. Pubertal development was assessed based on breast stages and testicular volume. The associations of pubertal development with BP levels and the rate of elevated blood pressure (EBP) were quantified using multiple linear and logistic regressions. We found that pubertal developmental level was positively correlated with BP, and children who experienced puberty onset and early pubertal timing had higher BP levels and prevalence of EBP. After adjusting for covariates, children experienced puberty onset had 3.84 and 2.24 mmHg increase in systolic blood pressure and diastolic blood pressure, and 70%, 53%, and 62% increased odds of EBP, ESBP, and EDBP, respectively, compared with those without puberty onset. Similar results were observed for children who had early pubertal timing. The change of BP in puberty is greater and the association between pubertal development and BP is stronger in girls than boys. These findings suggested that pubertal development could be an important independent factor and one critical period for the EBP progress. Monitoring and management of pubertal development are necessary particularly among girls.

Differences in prevalence of prehypertension and hypertension in children and adolescents in the eastern, central and western regions of China from 1991-2011 and the associated risk factors

The present study aimed to estimate the differences in rates of prehypertension and hypertension in children and adolescents among three regions with different socioeconomic status in China, and explore the corresponding risk factors associated with prehypertension and hypertension to guide the prevention. Blood pressure measurements of 13 762 children and adolescents aged 6–17 years were obtained from a prospective national survey (the China Health and Nutrition Survey, 1991–2011). Prehypertension and hypertension were defined by age and gender, according to China’s standard criteria. Chi-square tests were used to compare the differences in the prevalence of prehypertension and hypertension among three regions. Trend chi-square tests were used to detect the trends in rates of prehypertension and hypertension over survey years. Logistic regression models were used to detect the potential risk factors of prehypertension and hypertension in children and adolescents. During the survey years, the overall prevalence of prehypertension and hypertension were 6.0% and 10.6%. The corresponding rates in the western region were lowest, but increased rapidly over the two decades (84.0% and 122.6% increases respectively, P<0.001). The overall hypertension rate remained high in the eastern region, despite the slower increase (24.2% increase). In the central region, although the prehypertension rate remained stable, the rate of hypertension had a 94.8% increase these years (P<0.0001). According to the results of logistic regression, age, body mass index (BMI) and waist/height ratio (WHtR) were associated with prehypertension and hypertension. Children and adolescents in the eastern region had the highest level of prehypertension and hypertension, while the rapid increase of blood pressure in the western and central regions were also supposed to concern. Improvement of the healthy lifestyle is urgent for prehypertension and hypertension prevention in children and adolescents.

Race and Sex Differences of Long-Term Blood Pressure Profiles From Childhood and Adult Hypertension: The Bogalusa Heart Study

This study aims to characterize longitudinal blood pressure (BP) trajectories from childhood in black-white and sex groups and examine the association between childhood level-independent trajectories of BP and adult hypertension. The longitudinal cohort consisted of 2732 adults who had body mass index and BP measured 4 to 15 times from childhood (4-19 years) to adulthood (20-51 years). Model-estimated levels and linear slopes of BP and body mass index at childhood age points were calculated at 1-year intervals using the growth curve parameters and their first derivatives, respectively. Linear and nonlinear curve parameters differed significantly between race-sex groups; BP levels showed race and sex differences 15 years of age onward. Hypertensives had higher long-term BP levels than normotensives in race-sex groups. Although linear and nonlinear slope parameters of BP were race and sex specific, they differed consistently, significantly between hypertension and normotension groups. BP trajectories during young adulthood (20-35 years) were significantly greater in hypertensives than in normotensives; however, the trajectories during middle-aged adulthood (36-51 years) were significantly smaller in hypertensives than in normotensives. Level-independent linear slopes of systolic BP showed significantly negative associations (odds ratio=0.50≈0.76; P<0.001) during prepuberty period (4-11 years) but significantly positive associations (odd ratio=1.44≈2.80, P<0.001) during the puberty period (13-19 years) with adult hypertension, adjusting for covariates. These associations were consistent across race-sex groups. These observations indicate that adult hypertension originates in childhood, with different longitudinal BP trajectory profiles during young and middle-aged adulthood in black-white and sex groups. Puberty is a crucial period for the development of hypertension in later life.

Sex-specific trajectories of systolic and diastolic blood pressure in youth

BACKGROUND AND OBJECTIVE

High blood pressure early in life is associated with cardiovascular disease morbidity and mortality in adulthood. The objective was to identify sex-specific trajectories of SBP and DBP from early adolescence to early adulthood and to assess the impact of modifiable factors on the trajectories, including BMI, smoking, alcohol use, physical activity, and screen-time.

METHODS

Data were drawn from four waves of a prospective investigation of 1294 youth aged 12-13 years at inception and followed until age 24 years. Group-based trajectory models were used to identify trajectories and assess the impact of modifiable factors in 403 men and 432 women.

RESULTS

Three SBP trajectories were identified in men [corresponding to low (43.2%), medium (45.2%), and high SBP (11.7%)] and women [corresponding to low (48.1%), medium (44.7%), and high SBP (7.2%)]. Similar results were observed for DBP in both sexes. BMI and smoking were associated with higher SBP and DBP values in most trajectory groups, whereas screen-time in both sexes and physical activity in women were associated with high SBP trajectories only.

CONCLUSION

There is heterogeneity in the sex-specific natural course of SBP and DBP in youth and in the magnitude of the effect of modifiable factors on SBP and DBP across trajectories. Distinguishing trajectories allows identification of subgroups at risk of hypertension and cardiovascular disease later in life and in addition can inform the design of targeted interventions to attenuate high SBP and DBP trajectories over time and maintain normal trajectories.

Racial Differences in Aortic Stiffness in Children

OBJECTIVE

To investigate racial differences in central blood pressure and vascular structure/function as subclinical markers of atherosclerotic cardiovascular disease in children.

STUDY DESIGN

This cross-sectional study recruited 54 African American children (18 female, 36 male; age 10.5 ± 0.9 years) and 54 white children (27 female, 26 male; age 10.8 ± 0.9 years) from the Syracuse City community as part of the Environmental Exposures and Child Health Outcomes study. Participants underwent blood lipid and vascular testing on 2 separate days. Carotid artery intima-media thickness and aortic stiffness were measured by ultrasonography and carotid-femoral pulse wave velocity, respectively. Blood pressure was assessed at the brachial artery and estimated in the carotid artery using applanation tonometry.

RESULTS

African American children had significantly higher pulse wave velocity (4.8 ± 0.8 m/s) compared with white children (4.2 ± 0.7 m/s; P < .05), which remained significant after adjustment for confounding variables including socioeconomic status. African American children had significantly higher intima-media thickness (African American 0.41 ± 0.06, white 0.39 ± 0.05 mm), and carotid systolic blood pressure (African American 106 ± 11, white 102 ± 8 mm Hg; P < .05) compared with white children, although these racial differences were no longer present after covariate adjustments for height.

CONCLUSIONS

Racial differences in aortic stiffness are present in childhood. Our findings suggest that racial differences in subclinical cardiovascular disease occur earlier than previously recognized.

Review: Obesity and cardiometabolic syndrome in children

The cardiometabolic syndrome is highly prevalent among overweight youth. The risk of developing the cardiometabolic syndrome is likely triggered or exacerbated by concurrent obesity, unhealthy lifestyle/eating habits, and hormonal changes (puberty). Current screening recommendations include measurement of blood pressure, fasting insulin and glucose, and total cholesterol. However, limiting assessments to these measures underestimates cardiometabolic risk in overweight youth, particularly minorities. Early identification of cardiometabolic risk in its incipient stages may justify early and more aggressive intervention to prevent progression and complications. This review provides rationale for additional assessments to determine cardiometabolic risk in overweight youth and recommends treatment options.

Gender differences in artery wall biomechanical properties throughout life

Elevated large artery stiffness and pulse pressure have emerged as important risk factors for cardiovascular disease. The genders differ in large artery biomechanical properties throughout the lifespan with females displaying higher stiffness than males during the prepubertal years and a dramatic increase after menopause. Males on the other hand experience an increase in arterial stiffness postpuberty and a linear increase thereafter, suggesting that females have intrinsically stiffer large arteries than males, but that such effects are mitigated by sex steroids during the reproductive years. This review discusses anthropometric and sex steroid influences on gender differences in large artery stiffness and pressure dynamics from childhood to senescence. In particular, the sex-specific effects of estrogen, progesterone and testosterone on vascular structure and function and how these influence arterial stiffness are explored. These factors may contribute in part to the observed gender differences in the pathophysiology and clinical manifestations of cardiovascular disease.

Trends in blood pressure and hypertension among Chinese children and adolescents: China Health and Nutrition Surveys 1991-2004

OBJECTIVE

To observe the trends in blood pressure (BP) and prevalence of hypertension among Chinese children and adolescents.

METHODS

Data were extracted from the China Health and Nutrition Survey conducted from 1991 to 2004; 8247 children and adolescents aged 6-17 years were selected for this study. Multivariate linear regression analysis and multivariate logistic regression analysis were performed to evaluate the secular trends in BP levels and prevalence of hypertension, respectively.

RESULTS

During the study period, there was an upward trend in BP in Chinese children and adolescents. After adjustment for gender, age and weight status, the prevalence of pre-hypertension and hypertension increased dramatically from 1991 to 2004, with average relative increases of 6.38% and 8.13% in children and adolescents, respectively. Overweight was strongly associated with pre-hypertension and hypertension in comparison with normal weight, with odds ratios (95% confidence intervals) of 2.21 (1.58-3.11) and 4.13 (3.32-5.13), respectively.

CONCLUSION

BP levels and prevalence of hypertension increased dramatically among Chinese children and adolescents from 1991 to 2004.

Pediatric hypertension update

PURPOSE OF REVIEW

The field of childhood hypertension has been changing rapidly since publication of the most recent consensus guidelines contained in the 2004 'Fourth Report'.

RECENT FINDINGS

Several epidemiologic studies have indicated that the prevalence of hypertension in children and adolescents is on the increase. A major factor behind this increase is the childhood obesity epidemic. There is substantial new information on the frequency of hypertensive target-organ damage in the young, including vascular, cardiac and renal effects. These data have led some authorities to recommend changes in how hypertension is evaluated and managed in the young.

SUMMARY

There has been significant new knowledge gained about many aspects of childhood hypertension over the past 5 years. Clinicians who care for children and adolescents with high blood pressure should familiarize themselves with these new data and incorporate them into their clinical decision-making.

Emergence of ethnic differences in blood pressure in adolescence: the determinants of adolescent social well-being and health study

The cause of ethnic differences in cardiovascular disease remains a scientific challenge. Blood pressure tracks from late childhood to adulthood. We examined ethnic differences in changes in blood pressure between early and late adolescence in the United Kingdom. Longitudinal measures of blood pressure, height, weight, leg length, smoking, and socioeconomic circumstances were obtained from London, United Kingdom, schoolchildren of White British (n=692), Black Caribbean (n=670), Black African (n=772), Indian (n=384), and Pakistani and Bangladeshi (n=402) ethnicity at 11 to 13 years and 14 to 16 years. Predicted age- and ethnic-specific means of blood pressure, adjusted for anthropometry and social exposures, were derived using mixed models. Among boys, systolic blood pressure did not differ by ethnicity at 12 years, but the greater increase among Black Africans than Whites led to higher systolic blood pressure at 16 years (+2.9 mm Hg). Among girls, ethnic differences in mean systolic blood pressure were not significant at any age, but while systolic blood pressure hardly changed with age among White girls, it increased among Black Caribbeans and Black Africans. Ethnic differences in diastolic blood pressure were more marked than those for systolic blood pressure. Body mass index, height, and leg length were independent predictors of blood pressure, with few ethnic-specific effects. Socioeconomic disadvantage had a disproportionate effect on blood pressure for girls in minority groups. The findings suggest that ethnic divergences in blood pressure begin in adolescence and are particularly striking for boys. They signal the need for early prevention of adverse cardiovascular disease risks in later life.

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

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

Trends of elevated blood pressure among children and adolescents: data from the National Health and Nutrition Examination Survey1988-2006

BACKGROUND

Elevated blood pressure (EBP) in children and adolescents increases future risk of cardiovascular disease. Among children and adolescents, increased weight is associated with EBP.

METHODS

National cross-sectional data for children and adolescents aged 8-17 years from the National Health and Nutrition Examination Surveys (NHANESs): 1988-1994, 1999-2002, and 2003-2006. The main outcome measures were EBP and pre-EBP estimates.

RESULTS

Overweight boys (odds ratio (OR) 1.54, confidence interval (CI) 1.11-2.13) and both obese boys and girls were significantly more likely to be classified as pre-EBP (boys, OR 2.81, CI 2.13-3.71; girls, OR 2.55, CI 1.75-3.73) and having EBP (boys aged 8-12 years, OR 6.06, CI 2.73-13.44, boys aged 13-17, OR 9.62 CI 4.86-19.06; girls, OR 2.33, CI 1.31-4.13) when compared to the reference weight and controlling for all other covariates.During 2003-2006, 13.6% (s.e. = 1.2) of boys aged 8-17 years and 5.7% (s.e. = 0.7) of the girls aged 8-17 years were classified as pre-EBP and 2.6% (s.e. = 0.5) of the boys aged 8-17 and 3.4% (s.e. = 0.7) of the girls aged 8-17 were having EBP. After controlling for age, race/ethnicity, and body mass index (BMI), girls only were significantly more likely to have EBP during 2003-2006 than during 1988-1994 (OR 2.17, CI 1.05-4.49). In contrast, adolescent boys aged 13-17 years were significantly less likely to be having EBP during 2003-2006 than during 1988-1994 (OR 0.32, CI 0.13-0.81).

CONCLUSIONS

Obesity is strongly, positively, and independently associated with EBP and pre-EBP among youths. However, controlling for all covariates including BMI, EBP has increased among girls but decreased among adolescent boys aged 13-17, during 2003-2006 when compared with 1988-1994.

Change of genetic determinants of left ventricular structure in adolescence: longitudinal evidence from the Georgia cardiovascular twin study

BACKGROUND

Genetic contribution to left ventricular (LV) structure is generally recognized, but whether and how this influence varies by ethnicity or with age is unknown.

METHODS

Participants were 517 European-American (EA) and African-American (AA) twin pairs (mean age: 14.6 +/- 3.0) at visit 1 and 422 EA and AA twin pairs at follow-up 4.1 years later. Echocardiograms were obtained on both visits. Data were analyzed using the structural equation modeling software Mx.

RESULTS

Body mass index (BMI) was a strong predictor for all LV measures at both visits 1 and 2, accounting for 3.5-24.2% of the total variance. Hemodynamics explained up to 4.5% additional LV measures variance. After adjusting for BMI, LV measures showed substantial heritability (range: 21-71%). Best-fitting longitudinal models revealed considerable novel genetic effects on the interventricular septum, posterior wall-, and relative wall thickness (RWT) (but not LV internal diameter), accounting for 32-41% of the phenotypic variance at visit 2, with no significant gender and ethnic effects. There was a gender difference for LV mass index in AAs (P < 0.01), with a significant influence of novel genetic effects in males (47%), but not in females. No gender difference was seen in EAs, with 34% of the phenotypic variance at visit 2 attributable to novel genetic effects.

CONCLUSIONS

The heritability of cardiac structure and geometry was equally substantial in both AAs and EAs. Significant novel genetic influences were detected for all measures but LV inner diameter and LV mass index in AA females. Further developmental genetic studies are warranted to elucidate the nature of the emerging gene effects during the transition from adolescence to adulthood.

Overweight, obesity and high blood pressure in an ethnically diverse sample of adolescents in Britain: the Medical Research Council DASH study

OBJECTIVES

To examine the impact of overweight on mean, high normal and high blood pressure in early adolescence, and how this relates to ethnicity and socio-economic status.

DESIGN

Cross-sectional study with anthropometric and blood pressure measurements.

SETTING

A total of 51 secondary schools in London.

SAMPLE

A total of 6407 subjects, 11-13 years of age, including 1204 White UK, 698 Other Whites, 911 Black Caribbeans, 1065 black Africans, 477 Indians and 611 Pakistanis/Bangladeshis.

MAIN OUTCOME MEASURES

Mean, high normal (gender, age and height-percentile-specific 90-94th percentile) and high (>/=95th percentile) blood pressure.

RESULTS

Based on the International Obesity Task Force age-specific thresholds, 19% of boys and 23% of girls were overweight, and 8% of each were obese. Overweight and obesity were associated with large increases in the prevalence of high normal and high blood pressures compared with those not overweight. The increases in the prevalence of high systolic pressure associated with overweight were as follows: boys, odds ratio 2.50 (95% confidence intervals 1.73-3.60) and girls 3.39 (2.36-4.85). Corresponding figures for obesity were: boys 4.31 (2.82-6.61) and girls 5.68 (3.61-8.95). Compared with their White British peers, obesity was associated with larger effects on blood pressure measures only among Indians, despite more overweight and obesity among black Caribbean girls and overweight among Black African girls. The effect of socio-economic status was inconsistent.

CONCLUSIONS

The tendency to high blood pressure among adult Black African origin populations was not evident at these ages. These results suggest that the rise in obesity in adolescence portends a rise in early onset of cardiovascular disease across ethnic groups, with Indians appearing to be more vulnerable.

Anthropometry and blood pressure differences in black Caribbean, African, South Asian and white adolescents: the MRC DASH study

OBJECTIVES

In this first large-scale study of ethnic differences in blood pressure (BP) among British adolescents, we examine the differences in BP levels in adolescence and the extent to which age, sex, body size and stage of maturation affect any observed differences.

METHOD

A total of 6365 11-13 year olds (including 1189 white, 907 black Caribbeans and 1056 black Africans, 473 Indians, 605 Pakistanis and Bangladeshis, and 548 of mixed ethnicity) had systolic blood pressure (SBP) and diastolic blood pressure (DBP), anthropometry and pubertal stage measured in 2003.

RESULTS

Compared with their white UK counterparts, black Caribbean and African boys were taller, and black Caribbean and African girls were taller, larger and matured earlier. Except for DBP among Indian girls, BP in minority groups was generally lower than in white UK children. Adjusted for age, height and body mass index, mean SBP was 109.1 mmHg (95% confidence interval 108.4, 109.8) and DBP 65.7 mmHg (65.2, 66.3) among white UK boys. Black Caribbean boys had lower SBP (-2.0; -3.2, -0.9 mmHg) and DBP (-1.5; -2.3, -0.6), and black African (-2.3; -3.4, -1.2) and mixed ethnicity (-1.6; -2.9, -0.3) boys had lower SBP. Adjusted SBP was 108.5 (107.8, 109.3) and DBP was 67.5 mmHg (66.9, 68.1) among white UK girls. Pakistani (-1.8; -3.2, -0.4) and black African (-1.1; -1.9, -0.3) girls had lower SBP and Indian girls (1.2; 0.1, 2.4) had higher DBP. Unlike African American girls, late puberty was not associated with higher BP in minority groups.

CONCLUSION

At these ages, the ethnic-specific patterns in BP in adulthood were not observed. Apart from higher DBP for Indian girls, BP in minority groups was generally lower than their white UK counterparts. Targeting intervention in adolescence may be a critical opportunity for preventing ethnic differences in BP in later life.

Birth weight, puberty, and systolic blood pressure in children and adolescents: a longitudinal analysis

We examined the association between birth weight and systolic blood pressure (SBP) from pre-puberty to late puberty in a cohort of American children. Ninety-eight children aged 4-12 years at baseline were followed annually for 2-6 years with at least two Tanner stages. Annual measures included SBP, age, gender, race, birth weight, Tanner stage, and body composition using dual-energy X-ray absorptiometry and computed tomography. Birth weight was inversely correlated with SBP in pre-pubertal children (r=-0.23, P<0.05), especially in white children. SBP persisted at a higher level from pre-puberty through late puberty among children with low birth weight (<2500 g). However, SBP significantly increased from pre-puberty to early or late puberty among children with high birth weight (>or=4000 g). After adjusting for visceral fat, one unit change of birth weight category was associated with a 2.6 mm Hg reduction in SBP (P<0.05), but this association was attenuated as puberty progressed. The changes in SBP across puberty followed different trajectories in children with low vs high birth weight. Attenuation in the association between birth weight and SBP from pre-puberty to late puberty may be influenced by sexual maturation.

Early menarche and the development of cardiovascular disease risk factors in adolescent girls: the Fels Longitudinal Study

The purpose of this study was to evaluate the influence of menarcheal age on changes in insulin, glucose, lipids, and blood pressure during adolescence and to assess whether body composition modifies this relationship. We examined 391 girls, a subset of Fels Longitudinal Study female participants (8-21 yr of age). Self-reported menarcheal age was classified based on the National Health and Nutrition Examination Survey III distribution, in which early menarche was at the 25th percentile or less (11.9 yr). Age at menarche was examined in relation to measures of body composition [e.g. fat-free mass (FFM) and percent body fat (PBF)], insulin resistance, blood pressure, and lipid profile. The effects of menarcheal age and body composition on cardiovascular disease risk factor changes were analyzed with serial data mixed models. Median menarcheal age was 12.7 yr (range, 9.8-17.0 yr), with 91 girls (23%) classified as early menarche. Girls with early menarche had more deleterious changes in insulin, glucose, blood pressure, FFM, and PBF levels than girls with average or late menarche. Menarcheal age adversely affected cardiovascular disease risk factor changes independent of age and changes in FFM or PBF. Girls with early menarche exhibited elevated blood pressure and glucose intolerance compared with later maturing girls, independent of body composition.

Fetal and childhood onset of adult cardiovascular diseases

Childhood onset of adult cardiovascular disease has become a significant public health problem. Whether genetic, environmental, or fetal influences are the primary culprits in the epidemic of the cardiovascular disease seen today remains unknown. The benefits of an overall physically active lifestyle that includes weight control, lower blood pressure, avoidance of tobacco use, and consistent exercise are clear and can impact the overall health of children and adolescents. Physicians who care for children and adolescents must begin to incorporate screening of adult cardiovascular disorders into their practice. Better understanding of the etiology of these disease states will bring with it enhanced preventive and targeted therapies.

Blood pressure levels in 7 to 14-year-old Belgrade children

The objective of the work was to study blood pressure and some anthropometric characteristics in children. The study design included the prevalence study at Belgrade, Serbia and Montenegro. The study comprised 1651 subjects (809 boys and 842 girls) aged 7-14 years, that is, 2.6% of all relevant population. The average levels of systolic and diastolic blood pressures (SBP and DBP) were 113.4/70.3 mmHg in boys and 114.6/71.1 mmHg in girls. High SBP was present in 4.7% of boys and in 5.3% of girls. High DBP was found in 5.6% of boys and in 4.8% of girls. According to multivariate regression analysis, in boys SBP and DBP were significantly associated with age, body mass index (BMI) and subscapular skinfold, SBP was also associated with body weight, and DBP with triceps skinfold. In girls, SBP was significantly related to BMI, suprailiac skinfold and body height, and DBP was significantly associated with BMI, suprailiac and subscapular skinfolds. The results of the present study support the opinion that BMI is a significant predictor of blood pressure in children and point out to suprailiac skinfold in girls as a possible predictor of blood pressure.

Body size, fat distribution, menarcheal age and blood pressure in 14-year-old girls

BACKGROUND

The relationships between body size and fatness and blood pressure are generally acknowledged. The majority of the few studies that have examined the effect of fat distribution and maturation rate on blood pressure have used secondary sex characteristics as the measure of maturity. The aim of the present study is to examine the associations between blood pressure and relative weight, fat distribution, recalled menarcheal age and occurrence of menstruation (yes/no) in a sample comprising of 1149 14-year-old girls.

METHODS

Systolic and diastolic blood pressure (DBP), height, weight and body circumferences were measured using standard protocols. Fatness was expressed as body mass index (BMI, kg/m2), whereas fat distribution was estimated by using waist-to-hip ratio. The girls' maturity status was assessed from exact recalled date of menarche. One-way analysis of covariance and multiple linear regression analyses were used to determine the strength of association among systolic blood pressure (SBP), DBP and BMI, menarcheal age and indices of fat distribution.

RESULTS AND CONCLUSION

Height and BMI are significantly associated with SBP. Relative weight is the most important factor related to SBP independently of chronological age and maturity status. Height and age at menarche are significantly associated with DBP. Height of 14-year-old girls shows the same strength of association with SBP and DBP, whereas maturity status negatively correlates with DBP. Fat distribution shows no effect on the level of DBP in girls.

Childhood obesity in Canada: a review of prevalence estimates and risk factors for cardiovascular diseases and type 2 diabetes

Childhood obesity in Canada has become increasingly prevalent over the past 2 decades. Despite inconsistencies regarding different anthropometric indicators, cut-offs, and reference populations, both regional and national investigations have revealed high numbers of overweight and obese children and adolescents. A number of risk factors and health consequences have been associated with increased levels of body fatness in youth. Specifically, risk factors for cardiovascular diseases (CVD) and type 2 diabetes are known to develop early in life and tend to emerge in clusters among overweight youngsters. Unhealthy lifestyle behaviours (i.e., physical inactivity), a genetic disposition, and a centralized body fat distribution, all contribute to increased risk. In order to prevent future generations of children from experiencing increased morbidity and mortality as overweight and obese adults, coordinated efforts at all levels (family, school, community, and government) must be established with a long-term commitment to promote healthy nutrition and physical activity behaviours in our youth.

Moderators of blood pressure development from childhood to adulthood: a 10-year longitudinal study

OBJECTIVE

To examine the effect of ethnicity on the development of blood pressure (BP) from childhood into early adulthood within the context of height, sex, adiposity, and socioeconomic status (SES).

STUDY DESIGN

Individual growth curves of systolic BP (SBP) and diastolic BP (DBP) were created for 745 black and white male and female youths, with annual assessments over a 10-year period (age range, 4.9-27.5 years).

RESULTS

Blacks had higher SBP levels (P <0.01) than whites, respectively. Moreover, black female subjects showed a greater SBP increase over time (P <.05) than white female subjects. Black male and female subjects also showed higher DBP levels (P <.001) than white male and female subjects, respectively, but the rate of change of DBP did not differ. Ethnic differences in BP trajectories persisted after adjusting for SES and/or changes in height and/or adiposity in both male and female subjects.

CONCLUSIONS

Ethnic differences in SBP become manifest in childhood in girls, in early adolescence in boys, and tend to increase with age. Ethnic differences in DBP become manifest in childhood in both boys and girls and remain stable over time. The ethnic differences cannot be entirely explained by individual differences in SES, growth, or adiposity. Identification of mechanisms responsible for increase of BP in childhood will improve prevention of hypertension in adulthood.

Chronic pain in a biracial population of young women

This study investigated dimensions of chronic pain and temporomandibular disorders (TMDs) in a census tract sampling of African-American and Caucasian young women enrolled (from racially congruent households) at ages 9-10 in the longitudinal multicenter National Heart Lung and Blood Institute's Growth and Health Study (NGHS). The present study, which examined participants at the California clinical NGHS center when they were 19-23 years old, investigates five commonly reported chronic pains: back, head, face/jaw, abdomen, and chest. Chronic pain grade (CPG) status based on pain self-reports (frequency, duration, severity, and interference with usual activities) is reported for each of the five pain sites. Results show that chronic pain is common in this population of young women, although based on the CPG severity scores, only a small percentage is dysfunctional. Racial differences were not found for back, head, abdomen or chest pains. However, significant racial differences were found regarding facial pain and symptoms related to TMDs above and beyond socioeconomic status (SES) (lifetime prevalence: adjusted odds ratio (aOR)=2.14 and 95% confidence interval (CI)=1.40-3.31; 6 month period prevalence: aOR=2.03 and 95% CI=1.16-3.64). Not only were facial pain and jaw symptoms reported more frequently by Caucasians compared to African-Americans controlling for SES, but they were also reported to have an earlier onset.

Persistent hypercholesterolemia is associated with the development of obesity among girls: the Bogalusa Heart Study

BACKGROUND

Obesity is associated with cardiovascular disease (CVD) risk factors. Cross-sectional data suggest that hypercholesterolemia is associated with the development of childhood obesity.

OBJECTIVE

The objective was to assess age-related changes in relative weight and the association between relative weight and CVD risk factors in hypercholesterolemic and nonhypercholesterolemic children who were nonobese at baseline.

DESIGN

Data on relative weight and CVD risk factors were extracted from the Bogalusa Heart Study for nonobese 5-6-y-old black and white hypercholesterolemic (LDL cholesterol > 75th percentile; n = 58) and nonhypercholesterolemic (LDL cholesterol < 60th percentile; n = 215) children (41% black, 52% girls) who were also assessed 3 and 6 y later. Changes in body mass index (BMI) and CVD risk factors were assessed as a function of age, sex, race, and cholesterol concentration.

RESULTS

BMI increased more in the hypercholesterolemic (n = 31) than in the nonhypercholesterolemic (n = 111) girls during the 6 y of follow-up but was not significantly different between hypercholesterolemic (n = 27) and nonhypercholesterolemic (n = 104) boys aged 5-12 y. Associations between BMI and the risk factors blood pressure, insulin, and blood lipids were observed to be stronger with increasing age and, in some cases, stronger in hypercholesterolemic children and girls.

CONCLUSIONS

Hypercholesterolemia is associated with increased relative weight in girls. The increased relative weight, even at an early age, is associated with a deleterious effect on blood lipids and other CVD risk factors in hypercholesterolemic children, although the strength of these associations is sex dependent.

Trunk fat and blood pressure in children through puberty

BACKGROUND

Fat distribution is well recognized as a cardiovascular risk factor in adults. The association between android fat distribution and cardiovascular risk factors, such as blood pressure (BP), was previously reported in an African-American and Caucasian pediatric population. The aim of the present study was to investigate the relationship between BP and body fat distribution in a large cross-sectional pediatric sample. The effects of race, sex, and puberty on this relationship were assessed.

METHODS AND RESULTS

BP was measured in 920 healthy children and adolescents (African-American, Asian, and Caucasian, ages 5 to 18 years). Fat distribution was determined by skinfold thickness and dual-energy X-ray absorptiometry (DXA). Pubertal status was assessed by the criteria of Tanner. Regression analysis was used to explore the association between BP and fat distribution. Significant positive relationships between systolic and diastolic BP and trunk fat adjusted for total fat were seen in boys at all pubertal stages in all 3 races by both DXA and skinfold measurements. In girls, trunk fat was not a significant predictor of BP.

CONCLUSIONS

Our results demonstrate a sex difference in the relationship between BP and trunk fat in that a significant positive relationship was present in boys only. These findings, based on 2 independent measures of fat distribution, may help identify the specific features of individuals at risk, allow earlier intervention, and suggest sex-specific determinants for BP.

Body mass index growth in a sample of U.S. children: repeated measures data analysis of the Minneapolis Children's Blood Pressure Study

Longitudinal assessments of the body mass index (BMI) in children and adolescents are limited. The purpose of the study was to describe the growth patterns of the BMI in children and young adults. Black and White children of Minneapolis Children's Blood Pressure Study (MCBPS) were 6 to 9 years old at entry and were followed for 12 years at 19 separate visits. Those with at least five visits (n = 1,302) were included for analysis, using non-linear mixed effects models in conjunction with the Gompertz curve. The growth patterns of four sex-ethnic groups were different at three levels: starting level (SL) (kg/m(2)), asymptote level (AL) (kg/m(2)), and peak growth age (PGA) (in years). In this context, SL is the average BMI level at age 6, AL is the average BMI level when growth diminishes, and PGA is the average age at which the rate of growth in the BMI peaks. The SL (16.3 +/- 0.1) for White males was significantly greater than SL in the other three sex-ethnic groups, among which there were no significant differences. There was a significant ethnic difference in AL between Black females (25.5 +/- 0.3) and White females (24.4 +/- 0.2) and a marginally significant difference in AL between Black females and Black males (24.4 +/- 0.3). For PGA, only sex differences were significant: Black females reached the peak at the earliest age at (11.5 +/- 0.1) years, followed by White females (11.7 +/- 0.1), Black males (12.6 +/- 0.1), and White males (12.8 +/- 0.1).

Strategies for combining and scaling sexual maturity indicators: the Heartfelt Study

PRIMARY OBJECTIVE

To identify the best variable or combination of sexual maturity variables to use in investigations of adolescent health, and explore possible re-scaling of five-stage sexual maturity stages into dummy variables' ('advanced'/'delayed').

RESEARCH DESIGN

Cross-sectional.

SUBJECTS

Tri-ethnic sample of 384 US adolescents 11-16 years of age (Heartfelt Study).

METHODS

Sexual maturity variables are genital. breast and pubic hair stages obtained by clinical examination by nurse practitioners, testes size, menarche and age at menarche.

RESULTS

Principal factor analysis of sexual maturity variables, height and age, revealed high commonality among the variables, as no more than a single factor appeared in 27 of 28 factor analyses (by sex and age groups). Genital stage (boys) and breast stage (girls) were most highly related to the first principal factor independent of age and ethnicity. ANOVA of 'key variables' indirectly reflecting endocrine function suggested that some stages could be combined.

CONCLUSIONS

A single variable should suffice to describe sexual maturity at the studied ages, or variables could be combined in a (unstandardized) sexual maturity index (SMI): SMI (Girls)=0.998 x BREAST+0.900 x PUBIC HAIR + 1.815 x YEARS SINCE MENARCHE. SMI (Boys)= 1.104 x GENITAL + 1.328 x PUBIC HAIR + 5.997 x TESTES SIZE (mL).

Anger expression, body fat, and blood pressure in adolescents: Project HeartBeat!

This study explores the potential influence of growth, body/composition, and sexual maturity on the relation of anger expression and blood pressure in adolescents. Baseline data from Project HeartBeat! (82 boys and 85 girls, 14 years of age) examined the ability of anger expression (STAXI scale) to predict blood pressure, after controlling for the effects of ethnicity (African-American/ non-African-American), height, weight, percentage body fat, and sexual maturity. Blood pressures were unrelated to anger expression in models that included the above developmental variables. However, girls scoring high on healthy anger expression ("anger-control") had significantly lower levels of percentage body fat (P = 0.015) independent of the above factors. The literature suggests that body fat or body mass is often, though not unanimously, associated with unhealthy forms of anger expression in adolescents. Research is required into the biological, social, and behavioral origins of the association between body fat and anger expression. Height and sexual maturity, virtually ignored in this literature, should be included in future research.

Blood pressure and sexual maturity in adolescents: the Heartfelt Study

This study investigates sexual maturity as a predictor of resting blood pressures independent of other known predictors, in 179 boys and 204 girls 11-16 years of age from the Heartfelt Study. The sample included youth of African (n = 140), Mexican (n = 117), and European and "other" (n = 126) backgrounds. Sexual maturity was assessed during clinical examination of three standard indicators for each sex. Systolic and diastolic blood pressures were higher in children of maturity stages IV and V, compared to stages I-III, in each gender/ethnic group (P < 0.01 in almost all groups). Boys and girls advanced in sexual maturity for their age group, had significantly higher systolic blood pressures (but not diastolic) than the less advanced in linear models that included height, body mass index (BMI), ethnicity, and age as co-predictors. Diastolic blood pressures were predicted by height in boys and by age and the BMI in girls. This analysis, using a very conservative approach, suggests that sexual maturity provides important and independent information on systolic blood pressure in adolescents. Further investigation of its role in 24-hr blood pressures and in blood pressures taken during physical and emotional stress, is recommended.

Racial differences in accuracy of self-assessment of sexual maturation among young black and white girls

PURPOSE

To examine the validity of maturation self-assessments and to investigate the association between race and validity of self-assessments among young black and white girls.

METHODS

Self-assessments and examiner-assessments of areolar and pubic hair development using line drawings were compared at three visits among a cohort of 11- to 14-year-old girls enrolled in the National Heart, Lung, and Blood Institute's Growth and Health Study. Accuracy rates and kappa coefficients were calculated to measure the agreement between girls and examiners. Logistic regression models were used to assess the racial differences in the accuracy of self-assessments while adjusting for possible confounders.

RESULTS

Fair to moderate agreement was found between self- and examiner-assessments (areolar self-assessments: adjusted accuracy rates: 60.7-69.9%, kappa: 0.32-0.51; pubic hair self-assessments: adjusted accuracy rates: 57.9-70.7%, kappa: 0.36-0.55). While there were indications of racial differences in the ability to perform self-assessment with black girls tending to self-assess less accurately, most of the differences disappeared after adjusting for nurse-assessed stage.

CONCLUSIONS

These findings suggest that self-assessment can substitute for examiner evaluations only when crude estimates of maturation are needed. However, when accurate maturation stage data are required, examiner-assessments are necessary. Because black girls are usually more pubertally advanced and tend to underestimate their development, the value of self-assessment is questionable for assessing populations with young black and white girls. Use of self-assessment might present biased estimates of maturation and confound research findings.

Short stature and hypertension in the city of Rio de Janeiro, Brazil

OBJECTIVE

Stature is a powerful indicator of poor nutrition early in life in nations where undernutrition is a public health problem. Hypertension in adults has been associated with factors present early in life such as low birth weight. We tested the hypothesis that short stature is associated with hypertension among adults.

DESIGN AND SETTING

A household survey of representative adults in Rio de Janeiro city, Brazil was carried out in 1996.

SUBJECTS

Blood pressure and anthropometric measures were collected from 2802 adults in their own households. Prevalence estimates and modelling incorporated the sample design and weights.

RESULTS

Age-adjusted prevalence of hypertension for both sexes was lower in the third quartile of stature distribution. In women, but not in men, the odds ratio comparing the first quartile of stature with the fourth quartile was statistically significant with an odds ratio of 1.68 (95%CI 1.02-2.76). Adjusting for known risk factors for hypertension such as age, income, smoking, sodium and alcohol intake and race, the association among women, comparing the first with the fourth quartile for stature, was 1.84 (95%CI 1.03-3.30). With further adjustment for residual of weight on height the ratio reduced to 1.76 (95% CI 0.97-3.19, P value of trend = 0.03). Systolic blood pressure showed a U-shaped association with quartiles of stature, mainly among women, with a beta-coefficient significantly lower at the third quartile.

CONCLUSIONS

This association of stature with hypertension supports the theory of an important ontogenetic dependence of adult blood pressure, at least among women.

Childhood hypertension. An update on etiology, diagnosis, and treatment

In the general population, an estimated 70% or more of premature morbidity can be attributed to tobacco use, undertreatment of hypertension, and obesity. From a public health perspective, health-related behaviors that reduce the risk for cardiovascular disease should be encouraged for all children and their families. Pediatricians are obligated to accurately and frequently monitor patients' blood pressures. When discovered, elevated blood pressure should be appropriately investigated, with the evaluation being tailored to the age of the child and to the severity of the blood pressure elevation. Investigation should focus on not only a search for a cause but also target organ effects. Timely recognition of abnormal blood pressure and appropriate interventions are necessary to affect the future development of cardiovascular and renal morbidity and mortality.

Association of body fat distribution and cardiovascular risk factors in children and adolescents

BACKGROUND

Obesity is associated with increased risk of cardiovascular disease in adults and less favorable cardiovascular risk factor status in children and adolescents. In adults, fat distribution has been shown to be related to lipid and lipoprotein concentrations, blood pressure levels, and left ventricular mass. These relationships have not been extensively studied in young subjects.

METHODS AND RESULTS

This was a cross-sectional study of 127 children and adolescents 9 to 17 years of age. Dual-energy x-ray absorptiometry was used to measure total and regional fat mass. The dependent variables were fasting lipid and lipoprotein concentrations, systolic and diastolic blood pressures, and left ventricular mass. There were significant (P<0.05) univariate correlations between fat distribution and log triglycerides (r=0.27), log HDL cholesterol (r=-0.23), systolic blood pressure (r=0.26), and left ventricular mass (r=0.37). Multiple regression analysis showed that the significant independent correlates for triglycerides and HDL cholesterol were age and fat distribution; for systolic blood pressure, height and fat distribution; and for left ventricular mass, height, race, sex, and fat distribution.

CONCLUSIONS

These results demonstrate that fat distribution is a more important independent correlate of cardiovascular risk factors than percent body fat in children and adolescents. Greater deposition of central fat (an android fat pattern) is associated with less favorable plasma lipid and lipoprotein concentrations, blood pressure, and left ventricular mass.

Age-related changes in cardiovascular disease risk factors of hypercholesterolemic children

OBJECTIVE

To describe the age-related changes in cardiovascular disease risk factors in young, hypercholesterolemic (HC) children.

METHODS

Hypercholesterolemic (n = 227) and nonhypercholesterolemic (NHC) (n = 80) children between the ages of 4 and 10 years were identified. Height, weight, skin-fold and blood pressure measurements, and total cholesterol levels were measured. The HC group also had insulin levels evaluated. The groups were compared by analysis of variance. Simple Spearman correlations evaluated the associations between factors within each group.

RESULTS

The HC and NHC groups had similar mean ages, heights, and weights, both contained 51% girls, and all were white subjects. Percent weight-for-height median, and biceps, triceps, suprailiac and subscapular skin-fold measurements were all larger for the HC group. A significant age interaction demonstrated that the HC group's larger suprailiac and sum of skin-fold measures were expressed in the 8.0- to 9.9-year-old children, but not the 4.0- to 5.9-year-olds. For both groups, systolic blood pressure was associated with the measures of adiposity. For the HC group, insulin levels were also associated with adiposity.

CONCLUSIONS

These results suggest that: (1) children with HC have greater body fat, (2) the expression of the hypercholesterolemia precedes the expression of increased body fat, (3) body fat increases with age, and (4) altered insulin and blood pressure levels are expressed in association with the increased body fat in children with HC. Confirmation with longitudinal data is necessary.

Prediction of left ventricular mass in youth with family histories of essential hypertension

To determine predictors of left ventricular mass (LVM) and hypertrophy (LVH), 56 black and 30 white normotensive healthy youths (mean age 12.6 +/- 2.3 years at initial visit) were studied twice, 2.5 years apart. During the initial visit, anthropometric variables and hemodynamics were measured at rest and before, during, and after 4 physical and behavioral stressors. 2-D directed M-mode echocardiography was performed to derive LVM. Hierarchical multiple regression analyses indicated that follow-up LVM was predicted by initial LVM, weight, height (ht), and gender (males > females; total model R2 = 0.77, P < 0.0001). Predictors of LVM/ht2.7 were initial LVM/ht2.7, weight, ethnicity (blacks > whites), and the aggregate index of blood pressure reactivity (total model R2 = 0.66, P < 0.0001). Youth with LVH at follow-up were taller, heavier, and exhibited greater blood pressure reactivity at initial evaluation. These findings are important since interventional strategies can be developed that target obesity and exaggerated reactivity to stress.

Prediction of resting cardiovascular functioning in youth with family histories of essential hypertension: a 5-year follow-up

Two hundred forty-six children (96 Whites, of whom 51 were males; 150 African- Americans, of whom 69 were males) with a familial history of essential hypertension (EH) were re-evaluated 5 years after an initial evaluation. During the initial visit anthropometric, demographic, and resting cardiovascular (CV) parameters (designated initial baseline levels) were assessed. These CV parameters (systolic and diastolic blood pressure [BP], heart rate, cardiac output index [CI], and total peripheral resistance index [TPRI] were also measured during postural challenge, a video game challenge, and a cold pressor task. At follow-up, resting CV parameters were again evaluated, and designated as follow-up resting levels. Moderate temporal stability (r range = .43-.56) was observed for all resting CV parameters. Mean stress responses for each CV parameter for all 3 stressors during the initial visit were positively related to the respective CV follow-up resting level. BP stress responses to postural change and video game challenge to be significant independent predictors of future resting BP after controlling for standard EH risk factors. Follow-up resting CI was not predicted by any stress responses, whereas follow-up resting TPRI was predicted by TPRI responses to the video game after controlling for standard Eh risk factors. These results contrast with those from an earlier 1-year follow-up, where stress responses for neither CI nor TPRI predicted follow-up resting levels. It appears that, as children get older, TPRI stress responses play a stronger role in vasoconstrictive function.