Primary Prevention of Hypertension: Clinical and Public Health Advisory from the National High Blood Pressure Education Program

Full text

Originally published by the National Heart, Lung, and Blood Institute (NIH Publication No. 02-5076). U.S. government work, public domain. Reproduced as archived reference, not current guidance.

U.S. DEPARTMENT OF HEALTH AND

Primary Prevention of Hypertension:

Clinical and Public Health

Advisory from the National

High Blood Pressure

Education Program

HUMAN SERVICES

Primary Prevention of Hypertension:

Clinical and Public Health

Advisory from the National

High Blood Pressure

Education Program

National Institutes

of Health

National Heart, Lung,

and Blood Institute

National High Blood Pressure

Education Program

NO. 02-5076

NOVEMBER 2002

Contents

PRIMARY PREVENTION OF HYPERTENSION CLINICAL AND PUBLIC HEALTH ADVISORY

FROM THE NATIONAL HIGH BLOOD PRESSURE EDUCATION PROGRAM

The Working Group

THE NATIONAL HIGH BLOOD PRESSURE EDUCATION PROGRAM COORDINATING

COMMITTEE MEMBER ORGANIZATIONS

FOREWORD

BACKGROUND

Method of guideline development

Evidence of classifications

LIFETIME BURDEN OF ELEVATED BLOOD PRESSURE

APPROACHES TO PRIMARY PREVENTION OF HYPERTENSION

Population-based strategy

Intensive targeted strategy

INTERVENTIONS WITH DOCUMENTED EFFICACY

Weight loss

Dietary sodium reduction

Increased physical activity

Moderation of alcohol consumption

Potassium supplementation

Modification of whole diets

INTERVENTIONS WITH UNCERTAIN OR LESS PROVEN EFFICACY

Calcium supplementation

Fish oil supplementation

Herbal or botanical dietary supplements

PRIMARY PREVENTION IN CHILDREN

ADDITIONAL RESEARCH

BARRIERS TO IMPROVEMENT

SUMMARY

REFERENCES

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PRIMARY PREVENTION OF HYPERTENSION CLINICAL AND PUBLIC HEALTH ADVISORY FROM THE NATIONAL HIGH BLOOD PRESSURE EDUCATION PROGRAM

The Working Group

COCHAIR

Paul K. Whelton, M.D., M.Sc. Senior Vice President for Health Sciences Professor of Epidemiology and Medicine Tulane University Health Sciences Center New Orleans, LA

COCHAIR

Jiang He, M.D., Ph.D. Associate Professor of Epidemiology and Medicine Department of Epidemiology Tulane University School of Public Health and Tropical Medicine New Orleans, LA

Lawrence J. Appel, M.D., M.P.H. Professor of Medicine Epidemiology and International Health Johns Hopkins Medical Institutions Baltimore, MD

Jeffrey A. Cutler, M.D., M.P.H. Senior Scientific Advisor Division of Epidemiology and Clinical Applications National Heart, Lung, and Blood Institute National Institutes of Health Bethesda, MD

Stephen Havas, M.D., M.P.H., M.S. Professor Department of Epidemiology and Preventive Medicine University of Maryland School of Medicine Baltimore, MD

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Theodore A. Kotchen, M.D. Professor of Medicine Associate Dean for Clinical Research Medical College of Wisconsin Milwaukee, WI

Edward J. Roccella, Ph.D., M.P.H. Coordinator National High Blood Pressure Education Program Office of Prevention, Education, and Control National Heart, Lung, and Blood Institute National Institutes of Health Bethesda, MD

Ron Stout, M.D., M.P.H. Associate Director, Medical, Health Care The Procter and Gamble Company Health Care Research Center Mason, OH

Carlos Vallbona, M.D. Distinguished Service Professor Department of Family and Community Medicine Baylor College of Medicine Houston, TX

Mary C. Winston, Ed.D., R.D. Senior Science Consultant American Heart Association Dallas, TX

STAFF

Joanne Karimbakas, M.S., R.D. National High Blood Pressure Education Program Partnership Leader American Institutes for Research Prospect Center Silver Spring, MD

THE NATIONAL HIGH BLOOD PRESSURE EDUCATION PROGRAM COORDINATING COMMITTEE MEMBER ORGANIZATIONS

Coordinating Committee includes representatives from the following member organizations:

American Academy of Family Physicians

American Academy of Insurance Medicine

American Academy of Neurology

American Academy of Ophthalmology

American Academy of Physician Assistants

American Association of Occupational Health Nurses

American College of Cardiology

American College of Chest Physicians

American College of Occupational and Environmental Medicine

American College of Physicians— American Society of Internal Medicine

American College of Preventive Medicine

American Dental Association

American Diabetes Association

American Dietetic Association

American Heart Association

American Hospital Association

American Medical Association

American Nurses Association

American Optometric Association

American Osteopathic Association

American Pharmaceutical Association

American Podiatric Medical Association

American Public Health Association

American Red Cross

American Society of Health-System Pharmacists

American Society of Hypertension

Association of Black Cardiologists

Citizens for Public Action on High Blood Pressure and Cholesterol, Inc.

International Society on Hypertension in Blacks

National Black Nurses Association, Inc.

National Hypertension Association, Inc.

National Kidney Foundation, Inc.

National Medical Association

National Optometric Association

National Stroke Association

NHLBI Ad Hoc Committee on Minority Populations

Society of Geriatric Cardiology

Society for Nutrition Education

Federal Agencies:

Agency for Healthcare Research and Quality

Centers for Medicare and Medicaid Services

Department of Veterans Affairs

Health Resources and Services Administration

National Center for Health Statistics, Centers for Disease Control and Prevention

National Heart, Lung, and Blood Institute

National Institute of Diabetes and Digestive and Kidney Diseases

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Foreword

As part of its mission to translate research results into practice, the National High Blood Pressure Education Program (NHBPEP) Coordinating Committee develops guidelines, advisories, and statements for the clinical and public health community.

Its first statement on the primary prevention of hypertension was published in 1993. Since then, additional evidence supporting those recommendations has emerged.

A distinguished panel reviewed the scientific literature and worked with the NHBPEP Coordinating Committee to develop this new advisory, which updates the 1993 National High Blood Pressure Education Program Working Group Report on Primary Prevention of Hypertension. The new statement recommends prevention of hypertension through both a population-based strategy and an intensive strategy focused on individuals at high risk for hypertension.

These two strategies are complementary and emphasize six approaches: Engage in moderate physical activity; maintain normal body weight; limit alcohol consumption; reduce sodium intake; maintain adequate intake of potassium; and consume a diet rich in fruits, vegetables, and lowfat dairy products and reduced in saturated and total fat. Applying these approaches can prevent blood pressure from rising in the general population and can lower blood pressure in persons with high normal blood pressure or hypertension.

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Drs. Whelton and He are to be congratulated for coordinating the efforts of updating the advisory to reflect the latest scientific information on preventing and managing elevated blood pressure, which remains an important public health imperative.

Claude Lenfant, M.D.

Director National Heart, Lung, and Blood Institute and

Chair National High Blood Pressure Education Program Coordinating Committee

Background

A direct positive relationship between blood pressure and cardiovascular risk has long been recognized. This relationship is strong, continuous, graded, consistent, independent, predictive, and etiologically significant for those with and without coronary heart

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disease (CHD); it has been identified in both men and women, younger and older adults, different racial and ethnic groups, and different countries; and applies to those with high-normal blood pressure

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as well as those with hypertension.

Despite progress in prevention, detection, treatment and control of high blood pressure, hypertension remains an important public health problem. Based on the Third National Health and Nutrition Examination Survey (NHANES III), approximately 43 million noninstitutionalized U.S. adults, 18 years of age or older, met the criteria for diagnosis of hypertension (systolic blood pressure ≥ 140 mmHg or diastolic blood pressure ≥ 90 mmHg, or taking antihypertensive medication) recommended in The Sixth Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment

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of High Blood Pressure ( JNC VI). Almost 13 million additional persons had been diagnosed as having hypertension by a health care professional but did not meet the previously mentioned JNC VI

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criteria. Approximately 20 million of the estimated 43 million persons with hypertension were not being treated with antihypertensive medication, and almost 12 million of the nearly 23 million for whom such medication was being prescribed had

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inadequately controlled hypertension. More than 23 million adults had high-normal blood pressure (130–139 mmHg systolic or 85–89 mmHg

diastolic), and almost 38 million had normal but above optimal blood pressure levels (120–129 mmHg systolic or 80–84 mmHg diastolic).

Primary prevention of hypertension provides an opportunity to interrupt and prevent the continuing costly cycle of managing hypertension and its

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complications. The purpose of this article is to update the 1993 National High Blood Pressure Education Program Working Group Report on Primary

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Prevention of Hypertension and to address the public health challenges of hypertension described

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in the JNC VI report.

METHOD OF GUIDELINE DEVELOPMENT

The National High Blood Pressure Education Program (NHBPEP) Coordinating Committee consists of representatives from 38 national professional, public, and voluntary health organizations and seven Federal agencies. As part of the mission to translate research results into practice, the NHBPEP Coordinating Committee develops guidelines, advisories, and statements for the clinical and public health communities. Since the first statement on the primary prevention of hypertension

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was published in 1993, new and further evidence supporting those recommendations has emerged.

The National Heart, Lung, and Blood Institute (NHLBI) staff identified research suggesting the need to update the NHBPEP 1993 report. The chair of the NHBPEP Coordinating Committee appointed cochairs and additional members to

serve as a working group on behalf of the Coordinating Committee.

To assist the cochairs, NHLBI staff conducted a MEDLINE search of the English-language, peerreviewed scientific literature since 1993 through 2002 using key Medical Subject Headings (MeSH) terms hypertension, blood pressure, primary prevention, exercise, weight loss, alcohol drinking, diet sodium-restricted, dietary potassium, and diet.

The cochairs reviewed the MEDLINE search results, identified new areas to be addressed, and, with the assistance of NHLBI staff, developed an outline and subsequently assembled a working draft of the document. The draft document was distributed to the members of the working group for additions and modifications.

Thereafter, the additions and modifications were tabulated and discussed via teleconferencing and electronic mail. This process continued among members of the working group, NHLBI staff, and cochairs in a reiterative fashion. The cochairs adjudicated differences of opinions. The assembled document was mailed to the working group members for their final comments. The cochairs then revised the document and forwarded it to the entire Coordinating Committee for review and comment.

A working group member presented the report to the entire NHBPEP Coordinating Committee at their February 2002 meeting, and they provided oral and written comments to be included in the document. Two meetings of NHLBI staff and the cochairs were held to address and incorporate the Coordinating Committee comments. Thereafter, the penultimate draft of the report was prepared and sent to the Coordinating Committee, who unanimously voted to approve it.

The development of this report was funded entirely by the NHLBI. The members of the working group, NHBPEP Coordinating Committee, and reviewers served as volunteers without remuneration.

EVIDENCE OF CLASSIFICATIONS

The studies that provided evidence supporting the recommendations of this report were classified and reviewed by the staff, cochairs, and working group members. The scheme used for classification of the evidence is adapted from Last and Abramson.

M Meta-analysis; use of statistical methods to combine the results from clinical trials

Ra Randomized controlled trials; also known as experimental studies

Re Retrospective analysis; also known as case-control studies

F Prospective study; also known as cohort studies, including historical or prospective followup studies

X Cross-sectional survey; also known as prevalence studies

Pr Previous review or position statements

C Clinical interventions (nonrandomized)

These symbols are appended to the citations in the text and reference list.

Lifetime Burden of Elevated Blood Pressure

Age-related increase in blood pressure is a typical occurrence in most but not all populations. Accordingly, the prevalence of hypertension increases with increasing age, such that more than one of every two adults older than 60 years of age has

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hypertension. Experience in the Framingham Heart Study suggests that the residual lifetime risk for hypertension is 90 percent and the probability of receiving antihypertensive medication is 60 percent

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for middle-aged and elderly individuals. High blood pressure increases morbidity and mortality from CHD, stroke, congestive heart failure, and end-

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stage renal disease. There is no convincing evidence of a J-shaped relationship or a “threshold” below which the relationship between level of blood pressure and risk of cardiovascular and renal diseases

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is not observed. The association of systolic blood pressure with risk of cardiovascular and renal diseases is stronger than the corresponding relationship

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for diastolic blood pressure. In light of such knowledge, this advisory is primarily focused on systolic blood pressure.

High blood pressure is only one of several proven major modifiable risk factors for cardiovascular disease (CVD). In combination, these factors provide a powerful basis for predicting risk and preventing cardiovascular complications in the general population. A recent report of large cohort studies conducted in 366,559 young and middle-aged men and

women indicated that persons with a low CVD-risk profile (serum cholesterol level <200 mg/dL [5.18 mmol/L], blood pressure ≤ 120/80 mmHg, and no current cigarette smoking) have a 72 percent to 85 percent lower mortality from CVD and a 40 percent to 58 percent lower mortality from all causes compared with persons who have one or

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more of three modifiable cardiovascular risk factors. The estimated greater life expectancy for the low-risk group ranged from 5.8 to 9.5 years. Computer programs and risk-calculating charts are available to assist clinicians and public health workers in determining

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risk (http://www.nhlbi.nih.gov).

Approaches to Primary Prevention

3 of Hypertension

Hypertension can be prevented by complementary application of strategies that target the general population and individuals and groups at higher risk for high blood pressure. Lifestyle interventions are more likely to be successful and the absolute reductions in risk of hypertension are likely to be greater when targeted in persons who are older and those who have a higher risk of developing hypertension compared with their counterparts who are younger or have a lower risk. However, prevention strategies applied early in life provide the greatest long-term potential for avoiding the precursors that lead to hypertension and elevated blood pressure levels and for reducing the overall burden of blood pressure related complications in the community.

POPULATION-BASED STRATEGY

A population-based approach aimed at achieving a downward shift in the distribution of blood pressure in the general population is an important component for any comprehensive plan to prevent hypertension. As shown in the Figure on the next page, a small decrement in the distribution of systolic blood pressure is likely to result in a substantial reduction

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in the burden of blood pressure-related illness.

The greatest long-term potential for avoiding hyper- tension is to apply prevention strategies early in life.

In an analysis based on Framingham Heart Study experience, Cook et al. concluded that a 2 mmHg reduction in the population average of diastolic blood pressure for white U.S. residents 35 to 64 years of age would result in a 17 percent decrease in the prevalence of hypertension, a 14 percent reduction in the risk of stroke and transient ischemic attacks, and a 6 percent reduction in

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the risk of CHD. Public health approaches, such as lowering sodium content or caloric density in the food supply, and providing attractive, safe, and convenient opportunities for exercise are ideal population-based approaches for reduction of average blood pressure in the community. Enhancing access to appropriate facilities (parks, walking trails, bike paths) and to effective behavior change models is a useful strategy for increasing physical activity in the general population.

INTENSIVE TARGETED STRATEGY

More intensive targeted approaches, aimed at achieving a greater reduction in blood pressure in those who are most likely to develop hypertension, complement the previously mentioned populationbased strategies for prevention of hypertension. Groups at high risk for hypertension include those with a high-normal blood pressure, a family history of hypertension, African American (black) ancestry,

overweight or obesity, a sedentary lifestyle, excess intake of dietary sodium and/or insufficient intake of potassium, and/or excess consumption of alcohol. Contexts in which intensive targeted interventions can be conducted to prevent hypertension in African Americans and older Americans include not only health care settings but also senior centers and faith-based organizations that have blood pressure screening and referral programs.

FIGURE: Systolic Blood Pressure Distributions

After intervention

Prevalence, %

Reduction in BP

Blood pressure, mmHg

Reduction in BP

(mmHg)

Stamler R. Hypertension. 1991;17(Suppl 1):I16–20.

Reducing the average diastolic blood pressure in the U.S. population by 2 mmHg would result in a 17 percent decrease in the prevalence of hypertension…

Before intervention

% Reduction in Mortality

Interventions With Documented Efficacy

The 1993 recommendations included weight loss, reduced intake of dietary sodium, moderation in alcohol consumption, and increased physical activity as the best proven interventions for prevention of hypertension. Since then, further evidence in support of these recommendations has emerged. In addition, potassium supplementation and modification of eating patterns has been shown to be beneficial in prevention of hypertension. Brief descriptions of the six recommended lifestyles with proven efficacy for prevention of hypertension are presented in the Box on page 9. A summary of selected intervention efficacy experience published since 1993 is presented in the following sections.

WEIGHT LOSS

A comprehensive review of the evidence supporting the value of modest reductions in body weight is provided in the Clinical Guidelines for the Identification, Evaluation, and Treatment of Overweight and Obesity

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in Adults. He et al. reported on the experience of 181 normotensive persons who had participated in

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Phase I of the Trials of Hypertension Prevention. During their initial 18 months of active intervention

A sustained weight loss of 9.7 lb (4.4kg) or more can reduce systolic and diastolic blood pressure by 5.0 and 7.0 mmHg, respectively.

those assigned to the weight loss group reduced their body weight by 7.7 lb (3.5 kg) and their systolic and diastolic blood pressures by 5.8 and 3.2 mmHg, respectively. After 7 years of followup, the incidence of hypertension was 18.9 percent in the weight loss group and 40.5 percent in the control group. These findings suggest that weight loss interventions produce benefits that persist long after the cessation of the active intervention. In phase II of the Trials of Hypertension Prevention, the 595 participants assigned to a weight loss counseling intervention experienced a 21 percent reduction in incidence compared with 596 counterparts assigned

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to usual care. Weight loss participants who were able to lose 9.7 lb (4.4 kg) or more and to sustain this weight loss through the 36 month period of followup experienced average reduction in systolic and diastolic

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blood pressure of 5.0 and 7.0 mmHg, respectively.

DIETARY SODIUM REDUCTION

At least three meta-analysis of the efficacy of reduced sodium intake in lowering blood pressure

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have been published since 1993. In all three reports, sodium reduction was associated with a small but significant reduction in systolic blood pressure in normotensive persons. ln a meta-analysis of 12 randomized controlled trials conducted in 1,689 normotensive participants, Cutler and colleagues estimated that an average reduction of 77 mmol/d in dietary intake of sodium resulted in a 1.9 mmHg (95 percent confidence interval [CI], 1.2–2.6 mmHg) decrement in systolic blood pressure and a 1.1 mmHg (95 percent CI, 0.6 –1.6 mmHg)

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decline in diastolic blood pressure.

In a randomized controlled trial (Dietary Approaches to Stop Hypertension [DASH]-Sodium Trial) conducted in 412 persons with an average systolic blood pressure of 120 to 159 mmHg and an average diastolic blood pressure of 80 to 95 mmHg, a reduction in sodium intake from a high level (mean urinary sodium excretion, 142 mmol/d) to an intermediate level (mean urinary sodium excretion, 107 mmol/d) reduced systolic blood pressure by 2.1 mmHg (P<.001) during consumption of a usual American control diet and by 1.3 mmHg (P=.03) during consumption of a DASH diet that was high in fruits and

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vegetables and lowfat dairy products. Reducing sodium intake from the intermediate level to a lower level (mean urinary sodium excretion, 65 mmol/d) resulted in an additional reduction in systolic blood pressure of 4.6 mmHg during consumption of the control diet (P<.001) and 1.7 mmHg reduction during consumption of the DASH diet (P<.01). The effects of sodium reduction were greater for those who ate the typical American diet, compared with

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those on the DASH diet. These findings are consistent with current national recommendations for a moderately low intake of dietary sodium (no more than 100 mmol/d: approximately <6 g of sodium chloride or <2.4 g of sodium per day) by

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all Americans and suggest that an even lower level of dietary sodium intake may result in a greater reduction in blood pressure.

In a large, long-term community-based randomized controlled trial, Whelton et al. reported that a moderate reduction of dietary sodium intake resulted in an additional 4.3 mmHg reduction in systolic blood pressure among older persons with hypertension whose blood pressures were already well controlled by a single antihypertensive

The upper limit of dietary sodium intake is 2,400 mg per day.

Lower intake of dietary sodium reduces the risk of cardiovascular disease, especially in those who are also overweight.

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medication. For those assigned to a combined sodium reduction and weight loss intervention, the corresponding additional reduction in systolic blood pressure was 5.5 mmHg. The need for antihypertensive medication during a subsequent 18 month period of followup was reduced by 31 percent and 53 percent in those assigned to sodium reduction and combined sodium reduction and weight loss, respectively. Although not directly relevant to prevention of hypertension, the results of this trial provide additional evidence in support of the role of weight loss and moderate sodium reduction as means to reduce blood pressure, even for persons who have been taking antihypertensive medication.

In the NHANES I Epidemiologic Follow-up Study, He et al. reported that a 100 mmol higher level of sodium intake in overweight persons was associated with a 32 percent increase in stroke incidence, a 89 percent increase in stroke mortality, a 44 percent increase in CHD mortality, a 61 percent increase in CVD mortality, and a 39 percent increase in

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mortality from all causes. In Finland in a prospective population-based cohort study conducted in 1,173 men and 1,263 women 25 to 64 years of age, the hazard ratios for CHD, CVD, and all-cause mortality, associated with a 100 mmol higher level of

24 h urinary sodium excretion, were 1.51 (95 percent CI, 1.14–2.00), 1.45 (95 percent CI, 1.14–1.84),

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and 1.26 (95 percent CI, 1.06 –1.50), respectively. There was a significant interaction between sodium excretion and body mass index for cardiovascular and total mortality, with sodium being a stronger predictor of mortality in men who were overweight. These data support the premise that a lower intake of dietary sodium reduces the risk of subsequent CVD, especially in those who are also overweight.

INCREASED PHYSICAL ACTIVITY

A meta-analysis by Whelton et al. in which the experience of 1,108 normotensive persons enrolled in 27 randomized controlled trials was included, identified a 4.04 mmHg (95 percent CI, 2.75–5.32) reduction in systolic blood pressure in those assigned to aerobic exercise compared with the control

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group. The magnitude of the intervention effect appears to be independent of the intensity of the exercise program. In the Physical Activity and Health: A Report of the Surgeon General it is recommended that persons exercise for at least 30 minutes on most, if

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not all, days of the week.

MODERATION OF ALCOHOL CONSUMPTION

In a meta-analysis of 15 randomized controlled trials, Xin et al. reported that decreased consumption of alcohol (the median reduction in self-reported consumption of alcohol was 76 percent, with a range from 16 percent to 100 percent) was associated with a reduction in blood pressure, and that the relationship between reduction in mean percentage of alcohol and decline in blood pressure was

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dose-dependent. Pooling of the experience

It is recommended that persons exercise for at least 30 minutes on most, if not all, days of the week.

Potassium supplementation lowers blood pressure in both hypertensive and normotensive persons.

of 269 normotensive participants enrolled in 6 randomized controlled trials identified a reduced consumption of alcohol as being associated with a 3.56 mmHg (95 percent CI, 2.51– 4.61) lower level of systolic blood pressure and a 1.80 mmHg (95 percent CI, 0.58–3.03) lower level of diastolic

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blood pressure. Therefore, it is recommended that alcohol consumption be limited to no more than 1 oz (30 mL) ethanol (e.g., 24 oz [720 mL] beer, 10 oz [300 mL] wine, or 2 oz [60 mL] 100-proof whiskey) per day in most men and to no more than 0.5 oz (15 mL) ethanol per day in women and lighter weight persons.

POTASSIUM SUPPLEMENTATION

Clinical trials and meta-analysis indicate that potassium supplementation lowers blood pressure in both hypertensive and normotensive persons. In a meta-analysis of the results from 12 trials with 1,049 normotensive participants, Whelton et al. reported that potassium supplementation (median, 75 mmol/d) lowered systolic blood pressure by 1.8 mmHg (95 percent CI, 0.6–2.9) and diastolic blood pressure by 1.0 mmHg (95 percent

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CI, 0.0–2.1). The effects of potassium supplementation appeared greater in those with higher levels of sodium intake.

MODIFICATION OF WHOLE DIETS

The DASH and DASH-Sodium trials used dietary interventions that incorporated several nutritional

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recommendations for lowering blood pressure. In the 8 week DASH trial, study participants with a systolic blood pressure less than 160 mmHg and a diastolic blood pressure between 80 and 95 mmHg

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were randomly assigned to one of the following diet groups: (1) a control diet that was low in fruits, vegetables, and dairy products, with a fat content typical of the average diet in the United States, (2) a similar diet that was rich in fruits and vegetables, or (3) a

level of urinary sodium excretion (141 mmol/d). A significant reduction in diastolic blood pressure was also observed. Furthermore, the beneficial effects of the DASH diet and the DASH diet with reduced sodium occurred broadly in all major subgroups of 36Ra

DASH diet that was rich in fruits, vegetables and the population. low-fat dairy products but reduced in saturated and total fat. Among the 326 normotensive DASH participants (blood pressure <140/90 mmHg), the DASH diet reduced systolic blood pressure by

34Ra The beneficial effects of the

3.5 mmHg (P<.001). In a subsequent DASH-

Sodium study, normotensive persons assigned to low sodium DASH diet

the DASH diet and a low level of urinary sodium

occurred in all major sub-

excretion (67 mmol/d) reduced their systolic blood

pressure by 7.1 mmHg (7.2 mmHg for blacks and groups of the population.

6.9 mmHg for others) compared with counterparts who were assigned to the control diet and a high

Lifestyle Modifications for Primary Prevention of Hypertension

1. Engage in regular aerobic physical activity such as brisk walking (at least 30 minutes per day, most days of the week).
2. Maintain normal body weight for adults (body mass index 18.5 – 24.9 kg/m ).
3. Limit alcohol consumption to no more than 1 oz (30 mL) ethanol (e.g., 24 oz [720 mL] of beer, 10 oz [300 mL] of wine, or 2 oz [60 mL] 100-proof whiskey) per day in most men and to no more than 0.5 oz (15 mL) of ethanol per day in women and lighter weight persons.
4. Reduce dietary sodium intake to no more than 100 mmol per day (approximately 2.4 g of sodium or 6 g of sodium chloride).
5. Maintain adequate intake of dietary potassium (more than 90 mmol [3,500 mg] per day).
6. Consume a diet that is rich in fruits and vegetables and in lowfat dairy products with a reduced content of saturated and total fat (Dietary Approaches to Stop Hypertension [DASH] eating plan).

Interventions With Uncertain

5 or Less Proven Efficacy

CALCIUM SUPPLEMENTATION

Consistent with previous observations, a recent metaanalysis of randomized controlled clinical trials suggests that calcium supplementation results in only a small

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reduction in blood pressure. This effect has only been observed in those with hypertension. However, for general health, it is prudent to recommend adequate calcium intake as a component of any

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diet (1,000–1,200 mg/d for adults).

FISH OIL SUPPLEMENTATION

Two meta-analysis of clinical trials indicate that supplementation with relatively high doses of omega-3 polyunsaturated fatty acids (omega-3 PUFA) lowers blood pressure in hypertensive patients, especially

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in those with untreated hypertension. In normotensive persons, however, the effect seems to be small. For example, in a pooled analysis of 11 trials with 728 normotensive participants, Appel et al. reported that fish oil supplementation (3.4 g/d) lowered systolic blood pressure by only 1.0 mmHg (95 percent CI, 0.0–2.0) and diastolic blood pressure

Health care professionals should ask their patients about the use of herbal products and consider the possibility of herb drug interactions.

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by 0.5 mmHg (95 percent CI, –0.2–1.2). Adverse effects, including eructation and a fishy taste, were more common in those assigned to fish oil capsules than in their controls. Although evidence for a blood pressure-lowering effect of fish oil is modest, observational epidemiological studies and clinical trials have suggested that an increased intake of fish oil

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may reduce the risk of CHD and stroke.

HERBAL OR BOTANICAL DIETARY SUPPLEMENTS

There has been considerable increase in the use of herbal products in the United States. Results from the 1998–1999 Slone Survey indicated that about 14 percent of U.S. adults were taking herbal prod-

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ucts. The 10 most commonly used herbal products are ginseng, Ginko biloba extract, Allium sativum, glucosamine, St. John’s wort, Echinacea augustifolia,

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lecithin, chondroitin, creatine, and Serenoa repens. Dietary supplements including herbals do not undergo the same stringent regulatory approval process as drugs. Food and drug laws do not require demonstration of safety and efficacy to support legal marketing of dietary supplements. There is a lack of standardization among brands of supplements, and the bioactive ingredient of products can vary widely.

Few clinical trial reports are available to support the use of herbal and botanical supplements in the prevention or treatment of high blood pressure or heart disease. At a minimum, health care professionals should ask their patients about the use of herbal products and consider the possibility of herb-drug interactions.

Primary Prevention in Children

There is ample evidence that hypertension begins in childhood. Children with higher than average blood pressure levels early in life are more likely to develop hypertension later in life. Efforts to prevent blood pressure from increasing in childhood are prudent and best accomplished by application of the same lifestyle approaches used to prevent and treat

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hypertension in adults.

Accordingly, school administrators are encouraged to examine their lunch menus and promote the use of heart healthy foods. Parents are encouraged to read food labels and make wise choices for lunches prepared at home. In addition, school curricula should include health education programs that promote

High blood pressure preven- tion and treatment should encourage lifestyle changes in children, as well as adults.

increased physical activity and other healthy lifestyles aimed at prevention of cardiovascular and other chronic diseases.

Additional Research

Further strengthening of the science that underpins strategies for implementation and maintenance of hypertension prevention strategies is warranted.

Some of the most pressing needs include:

(1) attaining a better understanding of physical and behavioral factors that influence blood pressure during growth and development, (2) gaining additional knowledge of the efficacy and effectiveness of specific dietary interventions, such as increased dietary protein or dietary fiber intake, and other modifications of whole diets in the prevention of hypertension, (3) testing alternative strategies for implementation of nonpharmacologic interventions, including nutrition education, in clinical and community settings,

(4) enhancing the capacity to change general environmental exposures to diet and exercise in a favorable manner, by working with the food industry and planning agencies, (5) identifying and testing culturally specific approaches for hypertension prevention, (6) maintaining a strong program of behaviorally focused research to strengthen the empirical base of educational interventions, and (7) characterizing phenotypic and genetic predictors of response to interventions for prevention of hypertension in an individual and/or group.

Barriers to Improvement

Cultural norms, insufficient attention to health education and lack of referral to registered dietitians, economic disincentives to healthier lifestyles, lack of reimbursement for hypertension prevention counseling services by third-party payers, and other barriers to prevention of hypertension continue to impede progress. For example, economic disincentives to healthier lifestyles include higher prices for low sodium products and lower unit pricing for larger portions. To overcome this barrier, professional associations and policy developers should work with the food industry to increase availability of lower sodium food products and to provide educational

programs for consumers regarding portion size and heart healthy food choices. In addition, insufficient attention to health education, including nutrition education, by health care providers, school systems, and public health and voluntary associations is an impediment to progress.

Summary

A combination of increased physical activity, moderation in alcohol intake, and consumption of an eating plan that is lower in sodium content and higher in fruits, vegetables and lowfat dairy products than the average American diet represents the best approach for preventing high blood pressure in the general population and in high risk groups. The demonstrated reductions in blood pressure using lifestyle changes can be as large as those seen in drug studies, occur in virtually all subgroups of the population, and can be sustained over a long period of time (more than 3 years). Additional education of health care professionals and the general public, enhanced means of support for those attempting to change their lifestyles, and policies aimed at reducing the burden in complying with the recommendations for nonpharmacologic reductions in blood pressure are essential elements for any national program aimed at prevention of hypertension. Given that sodium added during processing of foods accounts for approximately three quarters of an individual’s total sodium intake, any meaningful reduction in sodium intake is predicated on a

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decrease in dietary sodium from food sources. This could be achieved by gradually reducing the amount of sodium added during processing and by greater availability and promotion of foods with a lower sodium content. Reduction in discretionary salt intake at the table and during cooking is desirable but unlikely to have a major impact on dietary sodium intake in most persons. Despite the acknowledged challenges to implementing these recommendations, the potential for health benefits makes continued efforts to achieve prevention of hypertension an important national objective.

REFERENCE LIST

1. Stamler J, Stamler R, Neaton JD. Blood pressure, systolic and diastolic, and cardiovascular risks. U.S. population data. Arch Intern Med. 1993;153(5):598– 615. F
2. Flack JM, Neaton J, Grimm R Jr, et al. For the Multiple Risk Factor Intervention Trial Research Group. Blood pressure and mortality among men with prior myocardial infarction. Circulation. 1995;92(9):2437– 45. F
3. Vasan RS, Larson MG, Leip EP, et al. Impact of high-normal blood pressure on the risk of cardiovascular disease. N Engl J Med. 2001;345(18):1291–7. F
4. Wolz M, Cutler J, Roccella EJ, Rohde F, Thomas T, Burt V. Statement from the National High Blood Pressure Education Program: prevalence of hypertension. Am J Hypertens. 2000;13:103– 4. X
5. Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure. The sixth report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure. Arch Intern Med. 1997;157(21):2413– 46. Pr
6. Burt VL, Whelton P, Roccella EJ, et al. Prevalence of hypertension in the U.S. adult population. Results from the Third National Health and Nutrition Examination Survey, 1988–1991. Hypertension. 1995;25(3):305–13. X
7. National High Blood Pressure Education Program Working Group. National High Blood Pressure Education Program Working Group report on primary prevention of hypertension. Arch Intern Med. 1993;153(2):186–208. Pr
8. Last JM, Abramson JH, eds. A dictionary of epidemiology. 3rd ed. New York, NY: Oxford University Press, 1995.
9. Vasan RS, Beiser A, Seshadri S, et al. Residual lifetime risk for developing hypertension in middle-aged women and men: The Framingham Heart Study. JAMA. 2002;287:1003–10. F
10. Levy D, Larson MG, Vasan RS, Kannel WB, Ho KK. The progression from hypertension to congestive heart failure. JAMA. 1996;275(20):1557– 62. F
11. Klag MJ, Whelton PK, Randall BL, et al. Blood pressure and end-stage renal disease in men. N Engl J Med. 1996;334(1):13–8. F
12. Whelton PK. Epidemiology of hypertension. Lancet. 1994;344(8915):101– 6. Pr
13. He J, Whelton PK. Elevated systolic blood pressure as a risk factor for cardiovascular and renal disease. J Hypertens. 1999;17(Suppl 2):S7– S13. M
14. Stamler J, Stamler R, Neaton JD, et al. Low risk-factor profile and long-term cardiovascular and noncardiovascular mortality and life expectancy: findings for 5 large cohorts of young adult and middle-aged men and women. JAMA. 1999;282(21):2012–8. F
15. Pocock SJ, McCormack V, Gueyffier F, Boutitie F, Fagard RH, Boissel J-P. On behalf of the INDANA Project Steering Committee. A score for predicting risk of death from cardiovascular disease in adults with raised blood pressure, based on individual patient data from randomized controlled trials. BMJ. 2001;323(7304):75–81. M
16. Stamler R. Implications of the INTERSALT study. Hypertension. 1991;17(Suppl 1):I16–I20. Pr
17. Cook NR, Cohen J, Hebert PR, Taylor JO, Hennekens CH. Implications of small reductions in diastolic blood pressure for primary prevention. Arch Intern Med. 1995;155(7):701– 9. F
18. U.S. Department of Health and Human Services. National Heart, Lung, and Blood Institute. Hearts N’ Parks. Available at http://www.nhlbi.nih.gov/health/prof/heart/ obesity/hrt_n_pk/index.htm. Accessed August 8, 2002.
19. Clinical Guidelines on the Identification, Evaluation, and Treatment of Overweight and Obesity in Adults—The Evidence Report. National Institutes of Health. Obes Res. 1998;6(Suppl 2):51S–209S. Pr
20. He J, Whelton PK, Appel LJ, Charleston J, Klag MJ. Long-term effects of weight loss and dietary sodium reduction on incidence of hypertension. Hypertension. 2000;35(2):544–9. F
21. Trials of Hypertension Prevention Collaborative Research Group. Effects of weight loss and sodium reduction intervention on blood pressure and hypertension incidence in overweight people with high-normal blood pressure. The Trials of Hypertension Prevention, phase II. Arch Intern Med. 1997;157(6):657– 67. Ra
22. Stevens VJ, Obarzanek E, Cook NR, et al. For the Trials of Hypertension Prevention Research Group. Long-term weight loss and changes in blood pressure: results of the Trials of Hypertension Prevention, Phase II. Ann Intern Med. 2001;134(1):1–11. Ra
23. Cutler JA, Follmann D, Allender PS. Randomized trials of sodium reduction: an overview. Am J Clin Nutr. 1997;65(Suppl 2):643S –51S. M
24. Graudal NA, Galloe AM, Garred P. Effects of sodium restriction on blood pressure, renin, aldosterone, catecholamines, cholesterols, and triglyceride: a meta-analysis. JAMA. 1998;279(17):1383–91. M
25. Midgley JP, Matthew AG, Greenwood CM, Logan AG. Effect of reduced dietary sodium on blood pressure: a meta-analysis of randomized controlled trials. JAMA. 1996;275(20):1590–7. M
26. Sacks FM, Svetkey LP, Vollmer WM, et al. For the DASH-Sodium Collaborative Research Group. Effects on blood pressure of reduced dietary sodium and the Dietary Approaches to Stop Hypertension (DASH) diet. N Engl J Med. 2001;344(1):3–10. Ra
27. Whelton PK, Appel LJ, Espeland MA, et al. For the TONE Collaborative Research Group. Sodium reduction and weight loss in the treatment of hypertension in older persons: a randomized controlled trial of nonpharmacologic interventions in the elderly (TONE). JAMA. 1998;279(11):839– 46 [Erratum, JAMA 1998:279(24):1954]. Ra
28. He J, Ogden LG, Vupputuri S, Bazzano LA, Loria C, Whelton PK. Dietary sodium intake and subsequent risk of cardiovascular disease in overweight adults. JAMA. 1999;282(21):2027–34. F
29. Tuomilehto J, Jousilahti P, Rastenyte D, et al. Urinary sodium excretion and cardiovascular mortality in Finland: a prospective study. Lancet. 2001;357(9259):848–51. F
30. Whelton SP, Chin A, Xin X, He J. Effect of aerobic exercise on blood pressure: a meta-analysis of randomized, controlled trials. Ann Intern Med. 2002;136(7):493–503. M
31. U.S. Department of Health and Human Services. Physical Activity and Health: A Report of the Surgeon General. Atlanta, GA: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Center for Chronic Disease Prevention and Health Promotion, 1996:28. Pr
32. Xin X, He J, Frontini MG, Ogden LG, Motsamai OI, Whelton PK. Effects of alcohol reduction on blood pressure: a meta-analysis of randomized controlled trials. Hypertension. 2001;38(5):1112–7. M
33. Whelton PK, He J, Cutler JA, et al. Effects of oral potassium on blood pressure. Meta-analysis of randomized controlled clinical trials. JAMA. 1997;277(20):1624–32. M
34. Appel LJ, Moore TJ, Obarzanek E, et al. For the DASH Collaborative Research Group. A clinical trial of the effects of dietary patterns on blood pressure. N Engl J Med. 1997;336(16):1117–24. Ra
35. U.S. Department of Health and Human Services. National Heart, Lung, and Blood Institute. Your guide to lowering high blood pressure. Available at http://www.nhlbi.nih.gov/hbp/prevent/prevent.htm. Accessed April 9, 2002.
36. Vollmer WM, Sacks FM, Ard J, et al. For the DASH-Sodium Trial Collaborative Research Group. Effects of diet and sodium intake on blood pressure: subgroup analysis of the DASH-Sodium Trial. Ann Intern Med. 2001;135(12):1019–28. Ra
37. Griffith LE, Guyatt GH, Cook RJ, Bucher HC, Cook DJ. The influence of dietary and nondietary calcium supplementation on blood pressure: an updated metaanalysis of randomized controlled trials. Am J Hypertens. 1999;12(1):84–92. M
38. Institute of Medicine. Dietary Reference Intakes for Calcium, Phosphorus, Magnesium, Vitamin D, and Fluoride. Washington, DC: National Academy Press, 1997; 106–17. Pr
39. Appel LJ, Miller ER III, Seidler AJ, Whelton PK. Does supplementation of diet with ‘fish oil’ reduce blood pressure? A meta-analysis of controlled clinical trials. Arch Intern Med. 1993;153(12):1429–38. M
40. Morris MC, Sacks F, Rosner B. Does fish oil lower blood pressure? A meta-analysis of controlled trials. Circulation. 1993;88(2):523–33. M
41. Dehmer GJ, Popma JJ, van den Berg EK, et al. Reduction in the rate of early restenosis after coronary angioplasty by a diet supplemented with n-3 fatty acids. N Engl J Med. 1988;319(12):733– 40. Ra
42. Ascherio A, Rimm EB, Stampfer MJ, Giovannucci EL, Willett WC. Dietary intake of marine n-3 fatty acids, fish intake, and the risk of coronary disease among men. N Engl J Med. 1995;332(15):977–82. F
43. Kaufman DW, Kelly JP, Rosenberg L, Anderson TE, Mitchell AA. Recent patterns of medication use in the ambulatory adult population of the United States. The Slone Survey. JAMA. 2002;287(3):337– 44. X
44. 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;98:649–58. Pr
45. Mattes RD, Donnelly D. Relative contributions of dietary sodium sources. J Am Coll Nutr. 1991;10(4):383–93. F

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NIH Publication No. 02-5076 November 2002