High Blood Pressure in Children and Adolescents: To Treat or Not to Treat Is Not the Question
George A. Mensah, MD, National Center for Chronic Disease Prevention and Health Promotion, Centers for Disease Control and Prevention, Mailstop K-40, 4770 Buford Highway NE, Atlanta, GA 30341-3717
High blood pressure is an independent risk factor for stroke, myocardial infarction, cardiac and renal failure, and all-cause mortality in adults.1 Although these sequelae are uncommon in children and adolescents, their antecedents clearly begin in youth. For example, left ventricular hypertrophy is seen in 40% to 45% of children and adolescents with persistent primary hypertension or prehypertension.2,3 Compelling data from the Muscatine Study,4,5 the Bogalusa Heart Study,6,7 and the Pathobiological Determinants of Atherosclerosis in Youth study8,9 report that target organ damage and pathologic evidence of premature coronary and aortic atherosclerosis in youth are associated with elevated blood pressure.
In addition, high blood pressure in children and adolescents also begets hypertension in adults. Sun and associates10 reported that elevated systolic blood pressure in childhood predicted development of adult hypertension and the metabolic syndrome later in life. The Muscatine Study also showed that adult blood pressure was correlated with childhood blood pressure, body size, and changes in ponderosity from childhood to adult life.11 Although treating and controlling high blood pressure in children and adolescents is important, preventing the development of hypertension and its attendant risk factors in the first place is even more important. Recent trends, however, suggest that the prevalence of high blood pressure is on the rise.
A Rising Prevalence of High Blood Pressure in Children and Adolescents
Until recently, the prevalence of hypertension was generally assumed to be relatively low in children and adolescents. In fact, limited national data on children and adolescents enrolled in the earliest National Health and Nutrition Examination Survey showed a decreasing trend in the prevalence of high blood pressure, but more recent survey results demonstrate a worrisome observation.12,13 Several large population-based studies from the United States provide consistent evidence that the prevalence of high blood pressure in children has increased since the late 1980s. Trends in blood pressure levels and the prevalence of hypertension and prehypertension that had been downward from 1963 to 1988 have turned upward and are now increasing, coincident with the rising prevalence of obesity.12 Some of this increase may, however, be the result of more accurate reporting. In addition, racial, ethnic, and sex disparities in these trends have appeared recently for the first time, with the greatest burden in non-Hispanic black and Mexican American children and in boys compared with girls.12 Obesity is considered to be an important cause of the rising prevalence of high blood pressure in children and adolescents.12,13
Our clinical and public health strategy for addressing this rising tide of hypertension in children cannot be based predominantly on drug treatment for a variety of reasons. First, only a few drugs carry a US Food and Drug Administration indication for use in children. One recent study reported that 50% of all index antihypertensive prescription claims in a national sample of outpatient claims of persons aged 18 years or younger enrolled in private, employer-sponsored health plans were off-label, based on minimum age criteria.14
Second, recent studies suggest that although most pediatricians begin blood pressure measurement at age 3, 82% refer their hypertensive patients to a specialist.15 Approximately 40% of pediatricians apparently feel uncomfortable evaluating and treating hypertension in children.15 In one medical record review of persons aged 18 years or younger with primary hypertension seen in pediatric cardiology or pediatric nephrology clinics at an academic center, only 1 in 3 children with stage 2 hypertension received appropriate antihypertensive therapy from either subspecialty.14 While medical management was generally consistent with established guidelines, the initiation of appropriate antihypertensive drugs for children with the greatest severity of hypertension was equally poor with both subspecialties.14
Third, issues of safety persist, especially for very young children in whom the initiation of antihypertensive drug therapy may represent a lifelong commitment to treatment with ≥1 antihypertensive drug, often used off-label. In addition, the detection of hypertension, even when established and persistent, is fraught with many technical challenges. As a result of these concerns and challenges, a renewed commitment must be made to create a comprehensive strategy to prevent hypertension through the prevention and control of the major determinants of high blood pressure in children and adolescents. Some children will definitely need drug treatment in accordance with established clinical guidelines, but all children and adolescents will benefit from prevention.
Preventing the Causes of Primary Hypertension in Children and Adolescents
From a public health perspective, the major preventable causes of hypertension in children include obesity, physical inactivity, poor nutrition, and dietary sodium intake. In addition, low birth weight and lack of breastfeeding (because of its impact on obesity) are also preventable causes. Although family history, race, ethnicity, and sex are important in a variety of public health settings for the prevention of hypertension, they themselves are not preventable causes and therefore not discussed here. Similarly, certain monogenic disorders, renal parenchymal disorders, renovascular disease, neurologic diseases, and endocrine disorders are also not discussed here because they are recognized causes of secondary hypertension, especially in children and adolescents.
Among the preventable causes of primary hypertension, obesity, physical inactivity, and poor nutrition in children and adolescents command the highest priority because of their association with the increasing prevalence of hypertension and their strong relationship with the development of other cardiovascular risk factors. Although the evidence is not perfect, the short-term benefits of weight loss on blood pressure reduction in children, especially when achieved through a combination of calorie restriction and increased physical activity, have been demonstrated in both observational and interventional studies.16–18 The beneficial effect of modest salt reduction in lowering systolic blood pressure has also been reported in a recent meta-analysis of controlled trials in children.19 The Institute of Medicine (IOM) recently established an ad hoc committee to examine the primary sources of sodium in the US population overall and by life stage, sex, and ethnicity and to explore various options for reducing dietary sodium intake to levels recommended in national guidelines.20
Several health professional associations, federal agencies and departments, and the IOM have provided guidelines and frameworks that can help make a difference in halting and reversing the adverse trends in obesity and rising blood pressure in children.21–24 A coordinated broad-spectrum approach that calls on multiple sectors to work together on strategies tailored for schools (including the preschool and after-school program settings), families, communities, and work site settings will be invaluable.
The food and beverage industry is a crucial sector for the success of these programs. As recently pointed out by the IOM, “The food and beverage companies, restaurants, and marketers have underutilized potential to devote creativity and resources to develop and promote food, beverages, and meals that support healthful diets for children and youth.”25 From the quality and type of foods and beverages sold in vending machines on school campuses to the sodium content of processed foods, this sector can simultaneously address the poor nutrition and the dietary sodium consumption that are important determinants of hypertension. However, sustained, multisectoral, and integrated efforts that include industry leadership, initiative, and creativity will be required.25 In addition, parental control over screen time (including the hours children spend watching television or playing video games), healthy food choices, and participation in physical activity will be important.
A Call for Action
In light of the national population-based data on blood pressure trends in children and adolescents, a biomedical strategy that focuses on drug treatment is important but not enough. Rather, a comprehensive socioecologic model must be used to explore the underlying social and environmental determinants of the rising trends in high blood pressure prevalence; the goal should be to identify actionable levers for prevention. For example, the complex relations between blood pressure and rising trends in obesity and overweight, physical inactivity, poor nutrition, and dietary salt intake must be explored. However, effective action must not await definitive evidence from perfectly designed trials.
Many lessons can be learned from completed studies, such as the Child and Adolescent Trial for Cardiovascular Health,26 the largest school-based field trial ever sponsored by the National Institutes of Health, and the VERB campaign from the Centers for Disease Control and Prevention.27 Other tools, resources, and initiatives from other federal agencies and the IOM can be used to create multilevel health promotion programs to improve physical activity, nutrition, and ideal weight as strategies for the prevention of high blood pressure in children and adolescents in the United States (Table). Policy, legislative, and systems-level changes regarding nutrition and physical activity within school systems, day care centers, and nurseries can play a crucial role in stemming the epidemic of obesity and in preventing the development of prehypertension and hypertension.
The time has come for hypertension specialists to join forces with pediatricians, family physicians, obstetricians, gynecologists, nutritionists, physical education specialists, school principals, teachers, parents, and policy makers at the national, state, and local levels to address the prevention of high blood pressure in children. For primary hypertension in children and adolescents, the questions we ponder must go beyond whom to treat and how to treat and increasingly must include how to prevent because for the vast majority of children, an ounce of prevention must be certainly better than a pound of cure!
Disclaimer: The findings and conclusions in this editorial are those of the author and do not necessarily represent the official position of the Centers for Disease Control and Prevention.
Acknowledgement: This editorial is based on the 2008 Dr William McBride Memorial Lecture presented at the 15th Anniversary Scientific Session of the Consortium of the Southeastern Hypertension Control.