Coronary heart disease is still the leading cause of morbidity and mortality in the United States, despite recent declines in the incidence of and the death rate from this disease.1 Although the incidence and mortality rate have decreased, the absolute prevalence of coronary heart disease has increased, which implies a future increase in the financial burden associated with this disease and raises the possibility that age-adjusted death rates from coronary artery disease may start to rise again as the number of persons who are at risk for death from this disease continues to increase.2
Risk factors for cardiovascular disease may be directly causative, may be secondary manifestations of a more basic underlying metabolic abnormality or may represent early symptoms of the disease. In adults, several risk factors are associated with an increased incidence of cardiovascular disease, including cigarette smoking, hypertension, dyslipidemia, diabetes mellitus, obesity, a sedentary lifestyle and poor nutrition. The effects of risk factors in adults are additive: the greater the number of high-risk factors present, the greater the risk of cardiovascular disease.3
These risk factors often have their roots in childhood.4,5 Primary prevention and intervention through risk factor modification can be effective in childhood. Although the expense and the duration of follow-up prohibit longitudinal studies to document that altering cardiovascular risk factors in childhood will reduce morbidity and mortality from this disease in adulthood, it is intuitive to suppose that risk factor modification early in life will have a positive impact.
Specific Risk Factors
Tobacco use is the single most preventable cause of death and disease in Americans.6 Every day more than 3,000 adolescents in the United States use tobacco for the first time.6 More than 8.5 million adolescents between the ages of 12 and 17 years, representing 42 percent of this age group, have tried cigarette smoking, and 11 percent of high school seniors smoke at least 10 cigarettes daily.7 The mean age of initial tobacco use is 10.7 years for boys and 11.4 years for girls. Compared with boys, girls tend to have a more difficult time quitting.8 Regular use of alcohol and cocaine has declined in high school seniors, whereas regular use of cigarettes has remained unchanged.9 Adolescents are clearly the group at greatest risk of beginning smoking. Adolescents more often perceive smoking as having an immediate positive consequence. Smoking is an activity that can make adolescents feel accepted in their peer groups and appear “more mature”. Peer influence seems to be the most important factor in the initiation of smoking, and the ability to say “no” to peer pressure appears to be a critical point. Because adolescents smoke cigarettes for a particular reason (to fit into a group, to lose weight, to appear older, etc.), in their minds, smoking serves an important function.
Paying attention to the adolescent needs that smoking can fulfill can help the physician encourage alternate behaviors. For example, pointing out some of the consequences of smoking, such as having bad breath, smelling like smoke and having nicotine stains on the fingers and teeth, may cause concern for self-conscious adolescents.
The use of nicotine patches seems to be safe in adolescent smokers,10 although placebo-controlled trials are needed to establish the efficacy of the different nicotine delivery systems in this population.
Intervention for hypertension in childhood is reserved for children whose blood pressure is consistently high and for those with significant secondary hypertension.11 Tables are available that provide blood pressure values for the 90th and 95th percentiles based on the child's age, gender and height.11 (For tables showing the 90th and 95th percentiles for blood pressure in boys and girls ages one to 17 years, see “Special Medical Reports” in the May 1, 1997, issue of American Family Physician, pages 2341–2.)
Patients with a blood pressure in the 95th percentile should be evaluated, and patients whose blood pressure consistently stays in the 95th percentile or higher should be treated.11,12 As a general rule, evaluation should be conducted if the blood pressure is 110/70 mm Hg or higher in children five years of age, 120/80 mm Hg or higher in children five to 10 years of age and 130/80 mm Hg or higher in children 10 to 15 years of age. Because obesity in childhood and the development of obesity in adolescence are strongly related to hypertension in adulthood, weight control and both prevention of obesity and encouragement of a physically active lifestyle are important, beginning in childhood.
Data on the relationship between dietary sodium and blood pressure are mainly based on adult populations. Significant correlations have not been shown between sodium intake and blood pressure in children and adolescents. However, the usual dietary intake of sodium in children and adolescents well exceeds nutritional requirements, and current dietary patterns suggest that sodium consumption among the young may be increasing. In addition, certain groups of adolescents demonstrate blood pressure sensitivity to sodium. It is unlikely that sodium contributes to the development of hypertension as an isolated factor, but blood pressure sensitivity to sodium may have an association with race, family history and obesity. These dietary issues need to be investigated in prospective studies of children as well as adults.13
The Second Task Force on Hypertension in Children developed guidelines for the use of antihypertensive drugs in childhood. Antihypertensive therapy is warranted to reduce the blood pressure to below the 95th percentile.11 Diuretics and beta-adrenergic blockers have been used in the treatment of hypertension in children and adolescents. In addition, angiotensin-converting enzyme (ACE) inhibitors are effective in children and can be useful in newborns and young infants. Calcium channel blockers have also been used in children. The dosages recommended for children are different from those used in adults.11
Physical inactivity is an independent risk factor for cardiovascular disease, as well as for high blood pressure, high cholesterol levels and obesity. Among adults, higher levels of physical activity are associated with a reduced incidence of coronary artery disease and hypertension.14
Schools can serve as a community resource for programs to increase physical activity in children and adolescents, particularly given the urgent need for the development of strategies that would encourage affected adolescents to become more active. While a formal exercise program may be helpful, it may not be effective in most adolescents. However, even small increases in daily activity can help young people maintain optimal weight. Children and adolescents can be encouraged to walk or ride their bikes, to stand while talking on the telephone and to take stairs rather than elevators or escalators when possible.
The physical activities that children engage in should be appropriate for all skill levels and not be limited to competitive sports or physical education classes. The activities should appeal to girls as well as boys and to children from diverse backgrounds. Skill sports such as football should not be their sole opportunity to be physically active. Life-long participation in sport activities should be encouraged.
The number of children who are obese is increasing in the United States. Approximately 21 percent of 12- to 17-year-old adolescents are obese, up from 15 percent in the 1960s, and about 23 percent of six- to 11-year-old children are obese, compared with 15 percent in the 1960s.15 Overweight young people, particularly those who are older, tend to remain overweight and, in general, have a 1.5- to 2.0-fold increase in the risk of being overweight as adults.15 The increased prevalence of obesity in early life indicates a need for primary prevention.
Recommendations for weight maintenance and reduction in children should include regular physical activity and careful attention to diet to avoid excessive calorie intake. Factors predictive of successful weight-loss programs in children include frequent intervention visits, the inclusion of parents and other family members in the program, strong support for dietary intervention from family members responsible for food preparation and a prescription for regular exercise.
Cholesterol elevation seldom occurs in isolation except in persons with familial hypercholesterolemia. Elevated cholesterol levels early in life play a role in the development of adult atherosclerosis, and reducing cholesterol levels in children and adolescents will be beneficial in reducing the risk of atherosclerosis.5
Table 1 lists the total cholesterol and low-density lipoprotein (LDL) cholesterol values that are acceptable, borderline and high in children from families with a history of hypercholesterolemia or premature cardiovascular disease. A complete evaluation should be performed in patients whose levels fall into the borderline and high levels. A child, regardless of family history, who has a total cholesterol level greater than 200 mg per dL (5.15 mmol per L) or an LDL cholesterol level greater than 130 mg per dL (3.35 mmol per L) should be evaluated.
|Category||Total cholesterol, mg per dL (mmol per L)||LDL cholesterol, mg per dL (mmol per L)|
|Acceptable||< 170 (< 4.40)||< 110 (< 2.85)|
|Borderline high||170 to 199 (4.40 to 5.15)||110 to 129 (2.85 to 3.35)|
|High||≥ 200 (≥ 5.15)||≥ 130 (≥ 3.35)|
Compared with their counterparts in other countries, American children and adolescents have higher cholesterol levels and higher intakes of saturated fatty acids and cholesterol. Furthermore, autopsy studies demonstrate that early coronary atherosclerosis or precursors of atherosclerosis often begin in childhood and adolescence and are related to the total cholesterol and LDL cholesterol levels and to smoking.16
The management of a child with an elevated cholesterol level begins with a complete nutrition evaluation and counseling. Children at highest risk for the development of accelerated atherosclerosis should be identified by performing cholesterol screening in children who have a parent or grandparent with a history of myocardial infarction, angina pectoris, peripheral vascular disease, cerebrovascular disease or sudden death. Such screening should also be performed in children who have a parent with a cholesterol level greater than 240 mg per dL (6.20 mmol per L). In addition, cholesterol screening may be considered in children and adolescents whose parental history is unobtainable, particularly if other cardiovascular risk factors are present.17
The National Cholesterol Education Program report on blood cholesterol levels in children and adolescents5 recommends drug therapy for children 10 years of age or older if an adequate trial of dietary therapy fails to reduce the LDL cholesterol level to 190 mg per dL (4.90 mmol per L) or lower. In children with a positive family history or two other risk factors, drug therapy is recommended if the LDL cholesterol level remains above 160 mg per dL (4.15 mmol per L) despite a trial of dietary therapy.
Bile acid sequestrants are the class of agents currently used for the treatment of hypercholesterolemia and LDL cholesterol elevation in children and adolescents. Nicotinic acid has also been used with some success. Recently, HMG–CoA reductase inhibitors have been found to be safe in children with familial hypercholesterolemia.18
To improve the eating habits of children, the entire family must become involved in the change to healthy eating and knowledgeable about nutrition and the benefits of good nutrition. Nutrition counseling is the first step in the treatment of a child or adolescent who is at risk, unless the patient is smoking, in which case smoking cessation may be the first step in risk modification. Nutritionists from the local hospital may be a resource for nutrition counseling, and nutrition information is readily available from the American Heart Association, the American Dietetic Association and other sources.
Children and their parents can be given some basic tips on ways to reduce their fat intake. For example, low-fat and nonfat dairy products can replace common sources of dietary fat, such as cheese, ice cream, butter and whole milk. Fruits and vegetables can replace the fatty snack foods commonly consumed after school or in lunches. Dietary fat intake can also be reduced by eliminating prepared meats such as bologna, pepperoni, sausage and canned ham. When eating at a fast-food restaurant, the healthier items on the menu can be selected instead of the high-fat foods. For example, a regular hamburger can be ordered instead of a double cheeseburger, a small salad can replace french fries and a diet drink can be selected instead of a milk shake. A vegetarian pizza can be eaten instead of a sausage or pepperoni pizza.
Elevated levels of plasma insulin are common in adults and are often associated with coronary artery disease. Cross-sectional studies in both children and adults have shown that hyperinsulinemia is associated with an adverse pattern of cardiovascular risk factors that include obesity, dyslipidemia and hypertension. The clustering of these risk factors along with hyperinsulinemia in adults is called syndrome X. Elevated insulin levels in childhood persist into adulthood, resulting in a clinically relevant adverse cardiovascular risk profile in young adults. More research is needed to determine when intervention should be initiated.19
Recent studies have shown that moderate elevation of plasma homocysteine is an independent risk factor for cardiovascular disease. As is the case in adults with hyperlipidemia or vascular disease, it has also been suggested that homocysteine levels should be determined in children with a family history of familial hyperlipidemia.20 Dietary recommendations for patients with homocysteinemia include not only fat restriction but also increased intake of foods such as fresh fruits and vegetables that contain nutrients associated with homocysteine metabolism. Folate supplementation is also useful.20 However, studies that corroborate the need for routine screening and treatment of homocysteinemia are not yet available.
Counseling the At-risk Family About Cardiovascular Health
If risk factors for cardiovascular disease are altered early in a child's life, it is likely that the onset of coronary artery disease will be delayed, if not prevented. The family physician has an obligation to counsel at-risk families about the need to make lifestyle changes to modify their cardiovascular profiles. The American Heart Association's cardiovascular health schedule for children is a useful guide for incorporating advice about risk factor modification into routine visits for well-child care (Table 2).21
When a child at risk of cardiovascular disease is identified, a counseling session with the entire family may be the most effective way to initiate intervention to reduce both the child's and the family's risk factors for cardiovascular disease. All family members should attend this 30- to 60-minute session. Before the counseling session, the parents can complete a family history questionnaire that focuses on the risk factors for cardiovascular disease (Figure 1). Having this questionnaire completed before the session can save valuable time. Often the parents do not know their own cholesterol status, which may necessitate cholesterol screening in the parents.22
The patient and parents should compile a three-day diet diary that includes all of the foods eaten both at home and away from home. The diary should provide details about the quantity of food and how it was prepared. Ideally, the diet diary should be completed before the counseling session. A nutritionist or dietitian may be consulted to analyze the diet diary to determine the total caloric intake, the percentage of calories from total fat and saturated fat, and the total cholesterol intake. All of the information about the family history, current eating habits and the parents' cholesterol status can be gathered before a counseling session to discuss the family's cardiovascular health. The counseling session should be individualized for each particular family. Some families will require a longer discussion on nutrition and a shorter discussion on physical activity. Others will need guidance on smoking cessation or increased physical activity, etc. Nutrition should be reviewed in detail by a nutritionist. Depending on scheduling factors, the nutritionist may be present at the session with the family and physician, or a separate session may be arranged with the nutritionist. At the conclusion of the counseling session, the family should be given written, age-specific material regarding lifestyle changes for reducing the risk factors for cardiovascular disease.
Selection of a healthy diet is the first step in controlling cholesterol, hypertension and obesity. But a nutrition plan is certain to fail if favorite foods are forbidden. The diet should be moderated, not restricted. An occasional dish of ice cream is all right, as long as it is truly occasional. Snack foods are generally acceptable, but the type of snack food should be carefully selected. The diet should contain an abundance of fruits and vegetables, and high-fat or high-carbohydrate snacks should rarely be eaten. In addition, the parents should be advised that food is an inappropriate reward. Too often, high-fat, high-sugar foods are used to reward a child's good behavior.
It may be helpful for the parents to purchase a book that provides information about the nutritional content of fast foods. Such a guide can help the child and the other family members make healthy choices when eating out. In addition, the child should accompany the parents to the grocery store and be allowed to make appropriate selections that are within the nutrition guidelines for the family. This type of involvement will help increase the patient's compliance in adhering to the desired guidelines.
The physician should anticipate the barriers to acceptance of this information. One comment that is often made is “My grandfather ate four eggs every day and had chicken fried steak for lunch with two pieces of pie, and he lived until he was 90.” An appropriate reply might be, “Yes, but your grandfather probably lived a much more active life. He may have engaged in manual labor for 12 to 14 hours a day.”
Follow-up can be useful in helping to underscore the need for the child and the rest of the family to change their lifestyles to reduce the risk of cardiovascular disease. A follow-up phone call can serve as a reminder of the information provided in the session, and a personal postcard or letter from the physician is often a powerful tool for convincing the patient and the family that risk factor modification is an important way to forestall the development of cardiovascular disease in adulthood.