Pediatric Antecedents of Adult Cardiovascular Disease — Awareness and Intervention
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《新英格兰医药杂志》
Hypertension, which is common among adults in the United States, has for several decades been recognized as a cardiovascular risk factor. Since blood pressure tends to "track" along the same percentile throughout life, children with higher blood pressures are more likely to become adults with hypertension. Therefore, the early recognition of the seeds of hypertension is crucial for introducing early interventions and reducing cardiovascular morbidity and mortality among adults. The potential benefits of initiatives targeting such early recognition are obvious.
One such initiative, Healthy People 2010, has been launched by the U.S. government with the declared "overarching goals" of increasing the quality and duration of healthy life and eliminating disparities in health. The prevention of cardiovascular diseases is targeted specifically, since a large segment of the adult population has hypertension and is consequently at risk for serious disease. As part of the mechanism to achieve the stated goals, the government has developed a network of Cardiovascular Disease Enhanced Dissemination and Utilization Centers, created as performance-based projects with the dual aim of educating high-risk communities and promoting heart-healthy behavior in these communities. These centers will use scientifically based information obtained from the National Heart, Lung, and Blood Institute to raise awareness on the part of the public and practitioners of the implications of cardiovascular disease.
Children's health is another focus of the Healthy People 2010 initiative. It is now widely accepted that cardiovascular health — or the lack thereof — originates in childhood. Yet the best way to target children at risk remains incompletely defined. At the time of the first Healthy People initiative in 1980, the measurement of children's blood pressure was not routine. Today, nearly all primary care physicians measure blood pressure in children — a distinct improvement from even a decade ago. Nevertheless, many physicians are still not familiar with the best way to evaluate and treat children with high blood pressure. The National High Blood Pressure Education Program Working Group on Children and Adolescents published a first "Task Force Report on Blood Pressure Control in Children" in 1977,1 and updates appeared in 19872 and 1996.3 This month, the fourth such report was presented at the national meeting of the Pediatric Academic Societies and is being presented today to the American Society of Hypertension. The new report calls attention to the role of hypertension in the current epidemic of obesity and the metabolic syndrome (obesity, insulin resistance, dyslipidemia, and hypertension) in the young and underscores the need for intervention.
Over the past two decades, a large national database has been developed in order to define normative blood-pressure levels throughout childhood. Since we now understand what constitutes "normal" blood pressure in children of different ages, we can more easily recognize abnormal blood pressures. The availability of these data for children has permitted the earlier detection of primary hypertension and has made it easier to identify children at risk. The newest report contains added data from the National Health and Nutrition Examination Survey conducted in 1999 and 2000, and the blood-pressure data have therefore been reexamined.1,2,3
The 1996 task force report defined normal blood pressure in children 18 years of age or younger as systolic and diastolic blood pressures below the 90th percentile for age, sex, and height. It defined high-normal blood pressure as a systolic or diastolic pressure between the 90th and 95th percentiles3 and frank hypertension as a blood pressure above the 95th percentile as measured on three separate occasions. The 2004 update has revised these definitions, in concert with the new guidelines for adults that were issued last year in the seventh report of the Joint National Committee on Prevention, Detection, Evaluation and Treatment of High Blood Pressure.4 That report pointed to epidemiologic research in adults indicating that for every increment of 20 mm Hg in systolic blood pressure and 10 mm Hg in diastolic blood pressure starting at 115/75 mm Hg, there is a doubling of the risk of cardiovascular disease.
In addition to making recommendations for treating frank hypertension, the report of the Joint National Committee introduced a new concept, prehypertension, defined as a systolic blood pressure of 120 to 139 mm Hg or a diastolic blood pressure of 80 to 89 mm Hg. The report noted that health-promoting lifestyle modifications were indicated for anyone with prehypertension. The new pediatric update also provides recommendations for treating frank hypertension; in addition, it suggests that children with a systolic or diastolic blood pressure between the 90th and 95th percentiles be considered to have prehypertension — a move that gives considerable weight to the observation that many children with "high-normal" blood pressure may, in the absence of interventions, go on to become frankly hypertensive. The new working group report considers children whose blood pressure lies above the 95th percentile to have hypertension and suggests that any adolescent with a blood pressure above 120/80 mm Hg (the threshold for prehypertension in adults) be considered at least prehypertensive, regardless of his or her age.
Is it wise to label a child or teenager "prehypertensive"? The intent of the Working Group, which used evidence-based data in writing its report, is that the label serve as a signal to institute healthful lifestyle changes that might avert future cardiovascular disease. It is now feasible to assess early target-organ damage that occurs in the presence of elevated blood pressure. The new guidelines suggest ways of assessing end-organ damage and provide a rationale for its early identification and treatment. When frank hypertension is present, current therapies can be more focused for children than was previously the case. Since the passage of the Food and Drug Administration Modernization Act, which called for clinical trials involving children, data have become available to guide the pediatric use of several antihypertensive medications, including information on appropriate doses, pharmacokinetics, effectiveness, and safety. The new report also points out that disordered sleep has been linked to hypertension, and recommendations regarding assessment for sleep disturbances have been added to the suggested evaluation of pediatric hypertension.
The new normative data, presented in tables in the report, include the 50th and 99th percentiles, as well as the previously available 90th and 95th percentiles, for blood pressure at different ages (see Figure). The Working Group recommends that blood pressure be measured in all children older than three years of age whenever they present in health care settings. In addition, it recommends the measurement of blood pressure in children younger than three years who were preterm infants, had a low birth weight, or had a rocky perinatal course involving a prolonged hospital stay, as well as in children who have congenital heart disease or renal disease, who are receiving medications that might increase their blood pressure, or who have any other condition that might lead to high blood pressure.
Figure. Determining Whether a Child's Blood Pressure Is Normal.
The child's height and blood pressure (BP) are measured, and the growth charts and tables from the Task Force report are used. In this example, one four-year-old boy is 43.0 in. (109.2 cm) tall (95th percentile, yellow dot). As the yellow column of the table shows, for this boy, a blood pressure of 106/66 mm Hg would be in the normal range — between the 50th and 90th percentiles. In contrast, another four-year-old boy is 37.5 in. (95.2 cm) tall (5th percentile, blue dot); for him, a blood pressure of 106/66 mm Hg would be at the 95th percentile, which would be categorized as hypertensive.
Will the new report be helpful for our national health? The hope of the Working Group is that it will constitute a call to action.
Source Information
Dr. Ingelfinger is a member of the Working Group that has compiled the new update.
References
Blumenthal S, Epps RP, Heavenrich R, et al. Report of the task force on blood pressure control in children. Pediatrics 1977;59:Suppl:797-820.
Task Force on Blood Pressure Control in Children. Report of the Second Task Force on Blood Pressure Control in Children -- 1987. Pediatrics 1987;79:1-25.
National High Blood Pressure Education Program Working Group on Hypertension Control in Children and Adolescents. Update on the 1987 Task Force Report on High Blood Pressure in Children and Adolescents: a working group report from the National High Blood Pressure Education Program. Pediatrics 1996;98:649-658.
Chobanian AV, Bakris GL, Black HR, et al. The seventh report of the Joint National Committee on Prevention, Detection, Evaluation and Treatment of High Blood Pressure: the JNC 7 report. JAMA 2003;289:2560-2572.(Julie R. Ingelfinger, M.D)
One such initiative, Healthy People 2010, has been launched by the U.S. government with the declared "overarching goals" of increasing the quality and duration of healthy life and eliminating disparities in health. The prevention of cardiovascular diseases is targeted specifically, since a large segment of the adult population has hypertension and is consequently at risk for serious disease. As part of the mechanism to achieve the stated goals, the government has developed a network of Cardiovascular Disease Enhanced Dissemination and Utilization Centers, created as performance-based projects with the dual aim of educating high-risk communities and promoting heart-healthy behavior in these communities. These centers will use scientifically based information obtained from the National Heart, Lung, and Blood Institute to raise awareness on the part of the public and practitioners of the implications of cardiovascular disease.
Children's health is another focus of the Healthy People 2010 initiative. It is now widely accepted that cardiovascular health — or the lack thereof — originates in childhood. Yet the best way to target children at risk remains incompletely defined. At the time of the first Healthy People initiative in 1980, the measurement of children's blood pressure was not routine. Today, nearly all primary care physicians measure blood pressure in children — a distinct improvement from even a decade ago. Nevertheless, many physicians are still not familiar with the best way to evaluate and treat children with high blood pressure. The National High Blood Pressure Education Program Working Group on Children and Adolescents published a first "Task Force Report on Blood Pressure Control in Children" in 1977,1 and updates appeared in 19872 and 1996.3 This month, the fourth such report was presented at the national meeting of the Pediatric Academic Societies and is being presented today to the American Society of Hypertension. The new report calls attention to the role of hypertension in the current epidemic of obesity and the metabolic syndrome (obesity, insulin resistance, dyslipidemia, and hypertension) in the young and underscores the need for intervention.
Over the past two decades, a large national database has been developed in order to define normative blood-pressure levels throughout childhood. Since we now understand what constitutes "normal" blood pressure in children of different ages, we can more easily recognize abnormal blood pressures. The availability of these data for children has permitted the earlier detection of primary hypertension and has made it easier to identify children at risk. The newest report contains added data from the National Health and Nutrition Examination Survey conducted in 1999 and 2000, and the blood-pressure data have therefore been reexamined.1,2,3
The 1996 task force report defined normal blood pressure in children 18 years of age or younger as systolic and diastolic blood pressures below the 90th percentile for age, sex, and height. It defined high-normal blood pressure as a systolic or diastolic pressure between the 90th and 95th percentiles3 and frank hypertension as a blood pressure above the 95th percentile as measured on three separate occasions. The 2004 update has revised these definitions, in concert with the new guidelines for adults that were issued last year in the seventh report of the Joint National Committee on Prevention, Detection, Evaluation and Treatment of High Blood Pressure.4 That report pointed to epidemiologic research in adults indicating that for every increment of 20 mm Hg in systolic blood pressure and 10 mm Hg in diastolic blood pressure starting at 115/75 mm Hg, there is a doubling of the risk of cardiovascular disease.
In addition to making recommendations for treating frank hypertension, the report of the Joint National Committee introduced a new concept, prehypertension, defined as a systolic blood pressure of 120 to 139 mm Hg or a diastolic blood pressure of 80 to 89 mm Hg. The report noted that health-promoting lifestyle modifications were indicated for anyone with prehypertension. The new pediatric update also provides recommendations for treating frank hypertension; in addition, it suggests that children with a systolic or diastolic blood pressure between the 90th and 95th percentiles be considered to have prehypertension — a move that gives considerable weight to the observation that many children with "high-normal" blood pressure may, in the absence of interventions, go on to become frankly hypertensive. The new working group report considers children whose blood pressure lies above the 95th percentile to have hypertension and suggests that any adolescent with a blood pressure above 120/80 mm Hg (the threshold for prehypertension in adults) be considered at least prehypertensive, regardless of his or her age.
Is it wise to label a child or teenager "prehypertensive"? The intent of the Working Group, which used evidence-based data in writing its report, is that the label serve as a signal to institute healthful lifestyle changes that might avert future cardiovascular disease. It is now feasible to assess early target-organ damage that occurs in the presence of elevated blood pressure. The new guidelines suggest ways of assessing end-organ damage and provide a rationale for its early identification and treatment. When frank hypertension is present, current therapies can be more focused for children than was previously the case. Since the passage of the Food and Drug Administration Modernization Act, which called for clinical trials involving children, data have become available to guide the pediatric use of several antihypertensive medications, including information on appropriate doses, pharmacokinetics, effectiveness, and safety. The new report also points out that disordered sleep has been linked to hypertension, and recommendations regarding assessment for sleep disturbances have been added to the suggested evaluation of pediatric hypertension.
The new normative data, presented in tables in the report, include the 50th and 99th percentiles, as well as the previously available 90th and 95th percentiles, for blood pressure at different ages (see Figure). The Working Group recommends that blood pressure be measured in all children older than three years of age whenever they present in health care settings. In addition, it recommends the measurement of blood pressure in children younger than three years who were preterm infants, had a low birth weight, or had a rocky perinatal course involving a prolonged hospital stay, as well as in children who have congenital heart disease or renal disease, who are receiving medications that might increase their blood pressure, or who have any other condition that might lead to high blood pressure.
Figure. Determining Whether a Child's Blood Pressure Is Normal.
The child's height and blood pressure (BP) are measured, and the growth charts and tables from the Task Force report are used. In this example, one four-year-old boy is 43.0 in. (109.2 cm) tall (95th percentile, yellow dot). As the yellow column of the table shows, for this boy, a blood pressure of 106/66 mm Hg would be in the normal range — between the 50th and 90th percentiles. In contrast, another four-year-old boy is 37.5 in. (95.2 cm) tall (5th percentile, blue dot); for him, a blood pressure of 106/66 mm Hg would be at the 95th percentile, which would be categorized as hypertensive.
Will the new report be helpful for our national health? The hope of the Working Group is that it will constitute a call to action.
Source Information
Dr. Ingelfinger is a member of the Working Group that has compiled the new update.
References
Blumenthal S, Epps RP, Heavenrich R, et al. Report of the task force on blood pressure control in children. Pediatrics 1977;59:Suppl:797-820.
Task Force on Blood Pressure Control in Children. Report of the Second Task Force on Blood Pressure Control in Children -- 1987. Pediatrics 1987;79:1-25.
National High Blood Pressure Education Program Working Group on Hypertension Control in Children and Adolescents. Update on the 1987 Task Force Report on High Blood Pressure in Children and Adolescents: a working group report from the National High Blood Pressure Education Program. Pediatrics 1996;98:649-658.
Chobanian AV, Bakris GL, Black HR, et al. The seventh report of the Joint National Committee on Prevention, Detection, Evaluation and Treatment of High Blood Pressure: the JNC 7 report. JAMA 2003;289:2560-2572.(Julie R. Ingelfinger, M.D)