Primary Prevention of Cardiovascular Disease in Nursing Practice: Focus on Children and Youth

Abstract

HomeCirculationVol. 116, No. 3Primary Prevention of Cardiovascular Disease in Nursing Practice: Focus on Children and Youth Free AccessReview ArticlePDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toFree AccessReview ArticlePDF/EPUBPrimary Prevention of Cardiovascular Disease in Nursing Practice: Focus on Children and YouthA Scientific Statement From the American Heart Association Committee on Atherosclerosis, Hypertension, and Obesity in Youth of the Council on Cardiovascular Disease in the Young, Council on Cardiovascular Nursing, Council on Epidemiology and Prevention, and Council on Nutrition, Physical Activity, and Metabolism Laura L. Hayman, Janet C. Meininger, Stephen R. Daniels, Brian W. McCrindle, Liz Helden, Joyce Ross, Barbara A. Dennison, Julia Steinberger and Christine L. Williams Laura L. HaymanLaura L. Hayman Search for more papers by this author , Janet C. MeiningerJanet C. Meininger Search for more papers by this author , Stephen R. DanielsStephen R. Daniels Search for more papers by this author , Brian W. McCrindleBrian W. McCrindle Search for more papers by this author , Liz HeldenLiz Helden Search for more papers by this author , Joyce RossJoyce Ross Search for more papers by this author , Barbara A. DennisonBarbara A. Dennison Search for more papers by this author , Julia SteinbergerJulia Steinberger Search for more papers by this author and Christine L. WilliamsChristine L. Williams Search for more papers by this author Originally published25 Jun 2007https://doi.org/10.1161/CIRCULATIONAHA.107.184595Circulation. 2007;116:344–357Other version(s) of this articleYou are viewing the most recent version of this article. Previous versions: June 25, 2007: Previous Version 1 Cardiovascular disease (CVD) is a leading cause of morbidity and premature mortality in women and men in the United States, most of the industrialized world, and many developing countries.1 Data accumulated over the past 3 decades indicate that atherosclerotic-CVD processes begin early in childhood and are influenced over the life course by genetic and potentially modifiable risk factors and environmental exposures. Taken together, these data provide compelling evidence for primary prevention of CVD beginning early in childhood. Within the pediatric healthcare community, this evidence has prompted and informed the development of science-based guidelines with recommendations for individual/high-risk and population-based approaches to primary prevention of CVD in children and youth. The purpose of this statement is to provide an overview of the evidence and current science-based recommendations and to emphasize the role of advanced practice nurses in the implementation of strategies consistent with population-based and individual/high-risk approaches to CVD prevention in children and youth.Evidence for CVD Prevention in ChildhoodEvidence-based guidelines for primary and secondary prevention of CVD in adults are informed by the results of randomized controlled trials. The existing evidence (discussed below) argues convincingly for prevention of CVD beginning early in childhood. It is noteworthy that data from randomized controlled trials documenting the effect of risk reduction in childhood on the development of CVD in adulthood are nonexistent. Similarly, no long-term longitudinal studies have been conducted to determine the absolute levels of risk factors measured in childhood that predict CVD in adult life. However, evidence from laboratory, clinical, and epidemiological studies supports the need for primary prevention of CVD beginning early in life and has prompted and informed existing guidelines for children and adolescents.Laboratory/Pathology and In Vivo/Clinical StudiesAutopsy studies conducted as part of the Bogalusa Heart Study2,3 and the Pathobiological Determinants of Atherosclerosis in Youth (PDAY) Study4,5 demonstrate significant positive associations between potentially modifiable CVD risk factors and the presence and extent of atherosclerotic lesions in the aorta and coronary arteries.2–5 In the pathology component of the Bogalusa Heart Study, a long-term epidemiological study of risk factors for CVD in a biracial (black-white) population, risk factors were measured in free-living, healthy children and adolescents before death from non-CVD causes.2,3 The PDAY study quantified risk factors by analyses of postmortem blood samples obtained at autopsy from ≈3000 persons 15 to 34 years of age who died from external causes, including accidents and homicides.4,5 Findings from PDAY4,5 and Bogalusa2,3 confirmed the positive associations between modifiable risk factors, including hypertension, tobacco use, obesity, atherogenic lipids (non–high-density lipoprotein cholesterol [HDL-C]), and the presence and extent of arterial lesions and the negative association of cardioprotective HDL-C with these lesions.2–5 More recently, noninvasive imaging has been used to examine the association of risk factors for CVD and vascular structure and function in childhood and adolescence and atherosclerosis in young adult life. Investigators from the Muscatine Study, a landmark longitudinal, observational study of CVD risk factors in children and youth, used carotid ultrasound in adults 33 to 42 years of age and found that carotid intima-media thickness was positively associated with levels of total serum cholesterol and body mass index (BMI) measured in childhood.6 Similar results were observed in Bogalusa: childhood low-density lipoprotein cholesterol (LDL-C) level and BMI predicted increased carotid intima-media thickness in adulthood.7 Results from the Young Finns Study reaffirm the link between risk factor exposures (including LDL-C, BMI, cigarette smoking, and systolic blood pressure [SBP]) in 12- to 18-year-old adolescents and preclinical atherosclerosis in adulthood.8 Results from this population-based prospective cohort study of 2229 young adults 24 to 39 years of age are noteworthy because risk factors present in adolescence predicted adult common carotid intima-media thickness independently of contemporaneous risk factors.8 Data from other noninvasive studies of adolescents and young adults are consistent with these results indicating that intraindividual clustering of multiple risk factors adversely affects carotid intima-media thickness during these developmental periods.9,10Taken together, the results of laboratory/pathology studies and more recent noninvasive studies provide convincing evidence of the link between established potentially modifiable risk factors and accelerated atherosclerotic processes in adolescence and adulthood and support the need for primary prevention beginning early in life.Epidemiological StudiesSeveral sources, including the National Health and Nutrition Examination Surveys (NHANES),11 the Centers for Disease Control and Prevention–Youth Risk Behavior Surveillance Surveys (CDC-YRBSS),12 the National Heart, Lung, and Blood Institute (NHLBI),13 and the American Heart Association (AHA),1 provide nationally representative data on the distribution, prevalence and trends, and tracking of major risk factors and CVD-related health behaviors in children and youth. Data on potentially modifiable risk factors and behaviors, which are essential for the development of both individual and public health approaches to primary prevention, are presented below.Lipids and LipoproteinsPopulation-based data from the Lipid Research Clinics indicate that serum lipids and lipoproteins increase throughout the first 2 years of life and reach young adult levels by 2 years of age.14 Partly on the basis of these observations of non-Hispanic white and black males and females, the National Cholesterol Education Program15 issued the first guidelines for assessing the lipid profile and recommended selective screening for high-risk children (as defined by family history of premature CHD or parental dyslipidemia) after 2 years of age.Population-based data from NHANES III (1988–1994) indicate that among children and adolescents (4 to 19 years old), the mean total cholesterol (TC) was 165 mg/dL. The mean age-specific values for TC peaked at 171 mg/dL just before puberty at 9 to 11 years of age and decreased thereafter.11 Females had significantly higher mean TC and LDL-C than males. Children and adolescents classified as non-Hispanic black had higher LDL-C and cardioprotective HDL-C compared with those classified as non-Hispanic white or Mexican American.11 Approximately 10% of adolescents (12 to 19 years old) had TC levels >200 mg/dL. An analysis of time trends for adolescents 12 to 17 years of age revealed a decline in mean TC of 7 mg/dL from 1966–1970 to the 1988–1994 survey.11 A similar but greater decline has been observed in adults, providing evidence of a strong prevention effect in the United States from 1959 to 1994.16 However, data from NHANES 1999–2000 indicate that mean levels of TC for children and adolescents (4 to 17 years old) have remained relatively unchanged since NHANES III.17 The Figure illustrates trends in mean TC observed in adolescents (12 to 17 years old) in the NHANES surveys. Download figureDownload PowerPointFigure. Trends in mean total blood cholesterol among adolescents 12 to 17 years of age by sex, race, and survey. NHES indicates National Health Examination Surveys.Although population-based prevention efforts aim to lower the distribution of TC and LDL-C for all children and adolescents, cut points for acceptable, borderline, and high levels have been established for assessment of individuals between the ages of 2 and 19 years as follows: acceptable (TC <170 mg/dL; LDL-C <110 mg/dL); borderline (TC 170 to 199 mg/dL; LDL-C 110 to 129 mg/dL); and high (TC ≥200 mg/dL; LDL-C ≥130 mg/dL).15 Baseline data (collected in 1991) in the Child and Adolescent Trial for Cardiovascular Health (CATCH) indicated that 13.3% of children in the fourth grade in 4 geographic areas in the United States had TC levels ≥200 mg/dL, with a higher percentage of girls (15.6%) than boys (11.1%) at this high level. A higher prevalence of elevated TC was observed for African American (17.4%) than Anglo-American (12.5%) or Latino (13.2%) subjects.18 A similar overall percentage (12.6%) was observed for 8- to 10-year-old subjects in the Cardiovascular Health in Children (CHIC) baseline study (conducted in the early 1990s) in North Carolina; however, gender differences were not pronounced. The CHIC study confirmed a higher percentage of African American children (18.7%) with high TC compared with Anglo-American children (11%) and others (11.8).19Examining gender and ethnic/racial group differences in lipids and lipoproteins across broader age ranges is more complex. Longitudinal follow-up of children and adolescents in Project HeartBeat! in Texas demonstrated that development has a profound impact on TC values and that these developmental patterns are different for males and females.20 Recent longitudinal evidence from 2 biracial cohort studies is consistent with these observations indicating that pubertal stage affects estimated prevalence of dyslipidemia as defined by current single cut points.21 Age-gender patterns are further complicated by the fact that African American children have, on average, an earlier onset of sexual maturation than other racial/ethnic groups in the United States.22Taken together, these observations underscore the need to reexamine current recommendations for assessment and management of the lipid profile in children and adolescents. Attention to the documented influences of gender, race/ethnicity, and sexual maturation on lipids and lipoproteins is likely to increase the sensitivity and specificity of screening and improve management of dyslipidemia as part of CVD risk reduction for children and youth.Tracking of lipids and lipoproteins, particularly TC and LDL-C from childhood to young adulthood, has been observed in males and females from diverse racial/ethnic groups and is particularly evident in the upper and lower extremes of the distribution. In the Muscatine Study, 75% of children who were 5 to 18 years of age at baseline and had TC levels greater than the 90th percentile had elevated TC (≥200 mg/dL) at 20 to 25 years of age.23,24 Bogalusa data indicate that ≈70% of children with elevated TC in childhood persisted with elevated levels in young adulthood.25 Tracking, maintenance of percentile rank over time, is relevant to primary prevention because of the potential for identifying children at risk for future CVD.Blood PressureCompared with NHANES III (1988–1994),26 results from the most recent survey (1999–2000) of 5582 black, Hispanic, and white children 8 to 17 years of age indicate substantial increases in SBP and diastolic blood pressure (DBP) for all age, race/ethnic, and gender subgroups examined.27 In NHANES III, children’s mean SBP was 104.6 mm Hg, and mean DBP was 58.4 mm Hg.26 In the most recent survey, children’s mean SBP was 106 mm Hg, and mean DBP was 61.7 mm Hg.27 Adjustment for the BMI distribution in 1988–1994 and 1999–2000 reduced the increases in SBP and DBP by 29% and 12%, respectively.27 These results suggest that increases in BP in US children and youth are partially attributable to the increases in the prevalence of overweight. Other data underscore the clinical significance of these adverse trends indicating that, for each increment of 1 to 2 mm Hg in SBP, children have a 10% greater risk of developing hypertension in adulthood.28 Additionally, modest elevations in BP levels in childhood have an adverse effect on vascular structure and function, with target organ damage (ie, left ventricular hypertrophy) documented in hypertensive children and adolescents.29,30Although African American adults have significantly higher levels of blood pressure (BP) and higher prevalence and mortality from CVD, ethnic group differences in BP among children and adolescents are not evident in all studies and when present have produced conflicting results.31 Detailed studies with ambulatory BP monitoring indicate that differences between African and European American adolescents in levels and diurnal patterns of BP are evident, but some of these differences are accounted for by other variables such as body size, sexual maturation, and socioeconomic status.32,33 Few studies have included adequate numbers of Hispanic American children and adolescents to allow for subgroup analysis. An exception is a study of 7207 children 5 to 17 years of age that included Mexican American (58.2%), African American (13.2%), and non-Hispanic white children (28.3%).34 There were no consistently significant differences in SBP or DBP across ethnic/racial groups.34 Recent NHANES data, however, indicate slightly higher levels of BP among Mexican American youth (8 to 17 years of age) compared with their non-Hispanic white counterparts.27 Analysis of pooled data from large national studies in the United States revealed an interaction between BMI and ethnic group; these interactions were different for SBP and DBP and not consistent across age and gender groups. In general, at lower levels of BMI, black youth had higher SBP and DBP, whereas at higher levels of BMI, white youths had higher SBP and DBP.31Tracking of BP during childhood and adolescence and from childhood to adulthood tends to be weaker and more disparate for BP than for other risk factors for CVD, largely because of the inherent variability of BP. Nevertheless, elevated BP in childhood predicted hypertension in young adulthood for participants in the Bogalusa Heart Study.35 Similarly, with the use of data from an East Boston cohort and by averaging BP measurements over several years during childhood, tracking correlations for SBP were 0.55 in boys and 0.66 in girls, and for DBP, were 0.47 for boys and 0.57 for girls.36Although not common in children, primary hypertension has been observed, is usually characterized by mild or stage 1 hypertension, and is often associated with family history of this risk factor and/or CVD.29,37 As documented in the most recent NHANES,27 overweight and obesity are positively associated with elevated BP levels in childhood and adolescence. Data from school health screening programs indicate a progressive increase in the prevalence of hypertension with increases in BMI.38 Intraindividual clustering of CVD risk factors, including low HDL-C, elevated triglycerides, hyperinsulinemia, and truncal obesity, has been observed in children with elevated BP.39–42Collectively, these results have informed recent guidelines for clinical practice that place emphasis on comprehensive assessment of the CVD risk factor profile in children and youth with elevated levels of SBP and/or DBP.42 These guidelines, the Fourth Report on the Diagnosis, Evaluation, and Treatment of High Blood Pressure in Children and Adolescents, were published in 2004.42 They also recommend that children ≥3 years of age have their BP measured when seen in a medical setting. Correct methods of measurement are described in this report along with recommended dimensions for BP cuff bladders.42 Assessing whether a BP level of a child is elevated is difficult in that the standards for SBP and DBP are specific for age, gender, and percentile of height. Interpretation is facilitated by free software available from the NHLBI, which can be downloaded to a personal digital device.43 Assessment of BP in children is further complicated by the necessity of confirming an elevated BP on multiple occasions before characterizing a child as having hypertension.42BMI, Adiposity, and Related ComorbiditiesFor children in the United States, the CDC age- and genderspecific nomograms are used to monitor patterns of growth and define overweight and obesity.44 On the basis of cross-sectional data from sequential measurements of representative samples of US children, cut points (by age and gender) are defined as follows: normal weight (BMI percentile >5th and <85th); at risk for overweight (BMI percentile between 85th and 95th); and overweight (BMI percentile ≥95th).44,45 It is noteworthy that some recent reports, including a report issued by the Institute of Medicine, classify children with BMI ≥95th percentile as obese.46Recognized as a major risk factor for CVD in adulthood, overweight and obesity in children and adolescents in the United States (and globally) have become major public health challenges.47–49 With overweight defined as a BMI for age and gender ≥95th percentile, data from the most recent NHANES (2003–2004) indicate that 17.4% of adolescents (12 to 19 years old) and 18.8% of children (6 to 11 years old) are overweight.49 During 1999–2004, significant time trends were also observed for male and female children and adolescents, with increases in overweight prevalence from 13.8% to 16.0% and from 14.0% to 18.2% in female and male children and adolescents, respectively. As illustrated in Table 1, across the past 3 NHANES reports and consistent with other data, higher prevalence of excess BMI has been observed in non-Hispanic black and Mexican American children and adolescents compared with their non-Hispanic white counterparts.49TABLE 1. Percentage of Children and Adolescents Who Are Overweight*Age, yRace/EthnicityNHANES Examination Year1971–19741976–19801988–19941999–2002†2003–2004†*Overweight is defined as a BMI for age and sex greater than or equal to the 95th percentile. For all years except 2003–2004, adolescents were also coded as overweight if their BMI was ≥30 kg/m2, even if it was below the 95th percentile.†Data derived with permission from Ogden et al.49‡Age range is 12–19 years for 2003–2004.6–11Non-Hispanic white4%6%11%13%18%Non-Hispanic black4%9%15%20%22%Mexican American6%11%17%22%22%12–17‡Non-Hispanic white6%4%11%13%17%Non-Hispanic black8%8%13%22%22%Mexican American9%8%14%25%16%Particularly important from a CVD prevention perspective are the documented comorbidities associated with overweight in children, including atherogenic dyslipidemia, hypertension, left ventricular hypertrophy, insulin resistance, and the clustering and tracking of risk factors recognized as metabolic syndrome in adults.50–56 Although controversy exists regarding the specific components, cut points, and clinical utility of defining metabolic syndrome in children and youth, studies have estimated prevalence rates using Adult Treatment Panel III criteria adapted for pediatric populations. Accordingly, a report from NHANES III estimated that 1 million US adolescents meet the criteria for metabolic syndrome, with an estimated population prevalence of 4%.52 In overweight children and youth, prevalence estimates range from 30% to 50%.52,53,55With the use of the Adult Treatment Panel III criteria, a recent longitudinal assessment of predictors of metabolic syndrome in black and white females (18 to 19 years old) from the NHLBI Growth and Health Study indicated a prevalence of 3.5% and 2.4% in black and white females, respectively, in adolescence.57 Results of multivariate analysis indicated that central adiposity, as measured by waist circumference at baseline (9 to 10 years of age), was a significant predictor of metabolic syndrome. Racial differences in prevalence of components of metabolic syndrome were observed; increases in body size, central adiposity, and SBP and DBP in black females exceeded those observed in white females.57 However, the increase in insulin sensitivity (as defined by homeostasis model assessment–insulin resistance scores), consistent with completion of puberty, reduced the risk of metabolic syndrome. Racial differences in triglyceride levels were observed, with considerable increases from baseline noted in white females only. The contribution of adverse levels of triglycerides as a defining component of metabolic syndrome was less in black females than in their white counterparts. Patterns observed in adiposity-triglyceride associations at follow-up (18 to 19 years of age) suggest racial differences in triglyceride metabolism and warrant further research.57Paralleling the increases observed in the prevalence of overweight/obesity is the increase in type 2 diabetes mellitus in youth. A recent report that combined results from population-based studies and clinical case series conducted in North America, Europe, and the Asian-Pacific region documents a global spread of type 2 diabetes mellitus.58 Although type 2 diabetes mellitus accounted for ≈3% of incident cases of diabetes in youth in 1990, combined results from this report indicate that 45% of new cases of diabetes in youth are type 2 diabetes mellitus.58 The patterns and trends observed (by geographic region, ethnicity, and culture) suggest that attention to the epidemiology of this chronic condition in adults may assist in predicting incident type 2 diabetes mellitus in youth. Limitations in differential diagnosis and classification (type 1 versus type 2 diabetes mellitus) notwithstanding,58 results are consistent with obesity–type 2 diabetes mellitus associations documented in other clinical and population-based studies.59,60Taken together, these results suggest the potential for manifest CVD earlier in adult life for our current generation of children and youth and underscore the critical importance of primary prevention of overweight/obesity as part of a comprehensive profile approach to cardiovascular health and CVD risk reduction in childhood. They also suggest the need for increased attention to ethnic, cultural, and gender-related factors and issues in tailoring individual approaches to preventive interventions.Health BehaviorsThe cornerstone of cardiovascular health promotion and risk reduction in childhood and adolescence is healthy lifestyle behaviors and therapeutic lifestyle change. Recent population-based prevalence and trend data on health behaviors central to current recommendations, however, provide cause for concern. Although some positive trends have been observed in tobacco use, a recent (2006) report from the Office of National Drug Control Policy indicated that 730 000 adolescent girls and 565 000 adolescent boys in the United States initiated cigarette smoking in 2004.61 Early adolescence is recognized as a critical period for smoking initiation; ≈80% of persons who use tobacco begin before the age of 18 years.61,62Data from CDC-YRBSS for 2003 indicate that 30.3% of male high school students and 24.6% of female students use tobacco.63 A very recent report from CDC-YRBSS indicates that the prevalence of lifetime, current, and frequent cigarette use among high school students remains basically unchanged from 2003 to 2005.64,65 Several surveys of adolescents in the United States indicate racial/ethnic and gender differences in patterns of tobacco use. A consistent observation across recent CDC and NHANES surveys is higher prevalence of tobacco use for non-Hispanic whites compared with their non-Hispanic black and Hispanic counterparts.63–65 Among high school students, CDC data indicate a higher percentage of current cigarette use among black males (19.3%) than black females (10.8%).63 This survey, based on 2003 data, also indicated high prevalence (26.6%) of current smoking in non-Hispanic white females.63 Data from the most recent survey indicate persistence in gender and ethnic differences in current cigarette use, with no significant changes observed except for black males, whose current use declined from 19.3% to 14.0%.65 Socioeconomic status emerged as an important predictor of tobacco use in the analysis of Winkleby et al66 of NHANES data, with higher prevalence observed among youth of lower socioeconomic status.Although the determinants of smoking initiation in youth are multifaceted and include individual and familial factors, the role of broader socioecological influences and multilevel policies cannot be overemphasized. For example, statewide tobacco control programs have been instrumental in preventing smoking initiation. In California, where intense tobacco control and prevention programs were implemented in 1990, the proportion of 12- to 17-year-old persons who reported never smoking increased from 60% of males and 66% of females in 1990 to 70% of both males and females in 1999. From 2002 to 2004, however, overall statewide spending on tobacco prevention and control programs declined by 28% in the United States.67 Program cuts exceeded 75% in some states, including Minnesota, where reductions were associated with decreased awareness of the antitobacco campaign and a substantial increase in smoking susceptibility in youth.68As emphasized in pediatric guidelines for cardiovascular health and CVD risk reduction, patterns of dietary intake and physical activity for a majority of children and adolescents are not meeting current recommendations.65,69–71 Data indicate adverse trends in food consumption, particularly among older school-aged children and adolescents.65,72–74 These trends include reduction of high-fiber fruits and vegetables and dairy products consumed and increased consumption of nutrient-poor foods and sweetened beverages and increased percentage of total calories from snacks.65,72–74 In adolescents, these changes in dietary patterns have resulted in median intakes below the recommended values of several micronutrients, including calcium and potassium, and sodium intakes that are well above recommended levels.63,65,74 Data from the US Department of Agriculture (2005) also document dietary deficiencies (in male and female children and adolescents) in micronutrients necessary for healthy immune and metabolic functions, including magnesium, iron, zinc, and vitamins B6, C, D, and E.71Similarly, adverse trends in physical education and patterns of leisure-time physical activity have been documented, particularly among adolescent girls. Recent (2005) data from the CDC indicate that only 54.2% of students nationwide are enrolled in physical education classes on 1 or more days of an average school week, and 33.0% are enrolled in daily physical education.65 Nationwide, 35.8% of students reported the recommended levels of moderate to vigorous physical activity of at least 60 minutes per day on at least 5 days per week.65 The prevalence of meeting this recommendation was higher among male (43.8%) than female (27.8%) students and lowest in black females (21.3%).65 Consistent with results from the CDC,65 a population-based study of black and white girls documented substantial declines in leisure-time physical activity throughout adolescence; by age 18 or 19 years, 56% of black girls and 31% of white girls reported no habitual recreational activity.75Sedentary behaviors such as television viewing are considered risk factors for obesity in children and adolescents. On the basis of data linking these sedentary behaviors with overweight in childhood and adolescence and data indicating that reduction in viewing time can be an effective strategy for improving weight status,76–78 current recommendations limit television viewing (and other sedentary behaviors) to <2 hours per day.79 Current national estimates, however, indicate that 37.2% of students watched television at least 3 hours per day on an average school day.65 The prevalence of this behavior was higher among black (64.1%) than white (29.2%) and Hispanic students (45.8%).65 As discussed below, these health behavior data support the need for population-based as well as individual approaches to cardiovascular health promotion and CVD risk reduction in children and adolescents.Promoting Cardiovascular Health and Reducing Risk for CVD in Children and YouthBackgroundPrimary prevention of CVD beginning in childhood includes and encompasses both cardiovascular health promotion and reduction of es