“Risk Factors” in Coronary Heart DiseaseA Childhood Concern I. Hunter Crittenden, MD
INTRODUCTION Ischemic coronary heart disease is pandemic in the westernized industrialized adult population of the world. Cardiovascular complications resulting from atherosclerosis account for more than one-half of all deaths in the United States. ’ Approximately one-third of the men in our country will have suffered from coronary heart disease by the age of Open heart surgery for coronary artery bypass has become one of the largest businesses of our nation. Estimated annual costs for care of cardiovascular disease exceeds 26 billion dollars. If inroads into this staggering social problem are to be made, it must be by primary attention toward prevention. The genesis of the atherosclerotic lesion appears to begin in childhood. Efforts to prevent or retard this process should therefore be directed at children since substantial and potentially irreversible damage may already exist by the third or fourth decade of life before any symptoms have occurred. These lesions appear to progress through a series of linked steps: (1) Development of arterial fatty streaks. (2) Formation of fibrous plaques. (3) Development of complicated fibrotic and calcific mature atherosclerotic lesions. (4) Clinical atherosclerotic cardiovascular disease. Fatty streaks appear by the third to fifth month of age and increase in number during the first 20 years.’ Some resorb while other may progress to fibrous plaques. Fatty streaks per se may be normal. Fibrous plaques often appear by the second and third decade. Military casualty autopsy studies have shown that 45%-75% of young American men have a considerable amount of coronary and aortic fibrous plaques in the second, third and fourth decade of life?’ These data suggest that half of young American men are already predisposed to atherosclerotic cardiovascular disease by the end of their second or third decade. Atherosclerosis is probably a complex multi-factoral disease which is incompletely understood at this time. The well-known “risk factors” may not represent etiologic factors but may well be critical links in a pathologic sequence. Of particular importance is the fact that societies with a different life style, in particular dietary habits with lower saturated fat and cholesterol 210
THE JOURNAL OF SCHOOL HEALTH
intake, have a much lower incidence of this disease. There are a number of so called “risk factors” associated with an increase in the incidence of atherosclerosis; the greater their number, the more apt is the individual eventually to manifest its complications. Age, sex, race and diabetes mellitus are all factors which correlate with the incidence of atherosclerosis over which we have little control. Other identifiable “risk factors,” however, can be influenced by an alteration of life style and are the concern of this report. It is probable that modification of known “risk factors” may retard or reverse the development of atherosclerosis; and if such preventative measures are possible, they should begin early in childhood when the disease is beginning. The great attention and costs now being directed to adults with symptomatic disease is in a sense “after the fact.’’ RISK FACTORS Smoking Smoking is the single most preventable cause of cardiovascular disease, chronic obstructive pulmonary disease and cancer. The risk of cardiovascular disease increases in proportion to the number of cigarettes smoked and the duration of exposure to the habit. It is estimated that cigarette smoking is responsible for 325,000 premature deaths each year. Total mortality is 1.6 times higher in cigarette smokers than among nonsmokers.’’ The effect of cigarette smoking on cardiovascular disease risk is independent of other major “risk factors” and this risk is greatly aggravated when such factors as high blood pressure, high blood cholesterol or diabetes mellitus are present. ’ I There has been an alarming recent increase in smoking among teenagers, especially girls.’* Vigorous efforts should be made to prevent children from taking up the cigarette habit. Elevated Serum Cholesterol Elevated serum cholesterol has the highest single correlation with the risk of major coronary artery disease.13 Average values in our population tend to be much higher than in populations where there is a low incidence of atherosclerosis. No population whose diet is low in saturated fats and cholesterol has a high APRIL 1979
incidence of coronary artery disease. Ideal values for serum cholesterols are not critically defined for children, but values above 190 to 200 mg. Vo are almost certainly excessive for adolescents, while levels of 160 to 170 may be abnormal for infants and children.“ Studies of U.S. school-age children from 6 to 16 years have shown that 10% to 20% have serum cholesterol levels above 200 mg. Yo. Children from underdeveloped, nonindustrialized and rural populations usually have levels 40 to 50 mg. 9’0 10wer.~The incidence of atherosclerotic cardiovascular disease statistically correlates with these findings even though there is no conclusive proof that dietary restriction reduces the incidence of coronary heart disease. The highest priority and most fruitful areas of case finding of hypercholesterolemia will be in those children where there is a strong family history of early atherosclerotic heart disease. There should be a heightened sensitivity to the need to take a detailed and on-going history of such events in the family. Nearly one-third of the offspring of parents who have suffered myocardial infarction under the age of 50 will have hyperlipoproteinemia. Is Cholesterol is carried in the blood by lipoproteins, principally low density lipoproteins (LDL), and to a lesser degree high density lipoproteins (HDL). LDL cholesterol significantly and independently relates to risk of coronary disease while HDL cholesterol inversely relates to its development.*6 This apparent protective role of HDL appears to be important and may be a valuable indicator of risk but in no way invalidates the extensive evidence of the critical role of LDL in human atherogenesis. The significant relationship of LDL level to risk for both younger and older persons, male and female, is well established. The relationship of plasma total cholesterol to risk has been consistently shown in study after study. ” The “average American diet” is athetogenic while the “prudent diet” is markedly less so, and preliminary reports show a reversal of lesions in the Rhesus monkey with a change to the “prudent diet.” 18 It is recommended, therefore, that modest shifts in our dietary pattern be made now for the general population in the hopes of achieving optimal benefit for children over their lifetime. These changes will require some reduction in saturated fats and cholesterol foods which are of animal origin (meat, eggs and dairy products). These reductions should be replaced by foods low in cholesterol and saturated fats such as fish, poultry, lean meat, fruits, vegetables and cereal grains. High fat content products such as sausage and luncheon meats, “premium” fat marbled meats, milk and milk products (skim milk excepted), eggs, and pastries made with butter will have to be de-emphasized. Inasmuch as eating habits and food preferences are established in very early childhood, these modifications may best be APRIL 1979
achieved by the young family. It is imperative that the principles of good nutrition be followed in any dietary change. Details of a “prudent diet” are available from the American Heart Association. High Blood Pressure High blood pressure has been well-defined as an atherogenic “risk factor” in the adult population. The evidence linking hypertension in childhood with the later development of atherosclerosis is less complete than that for hyperlipidemia, but many children have blood pressures that are high even by adult standards. Rank order of blood pressure is maintained less well through childhood than rank order of plasma cholesterol concentration, though children with elevated levels are likely to become hypertensive as adults. l9 HBP measurements should begin by the third year of life and be repeated on each general examination thereafter. Emphasis should be given to proper technique of taking blood pressure in children (cuff size, et cetera). A causal relationship in man between sodium intake and hypertension has not been firmly established, but there is increasing evidence that current levels of sodium intake in the United States contribute as one of the multiple factors in the etiology of hypertension. Studies suggest that it is prudent to avoid excessive sodium in the diet.m Obesity Obesity is a less clearly defined “risk factor” other than its relationship with high blood pressure and hyperlipidemia. 21 This relationship, however, is sufficient to use every effort to curtail this increasingly common condition by diet and physical activity. Obesity tends to be a “family affair” necessitating efforts directed toward the family unit. Exercise There is no clear proof that regular exercise will prevent atherosclerosis; but it does induce a number of physiologic changes seen as “favorable,” including the potential to minimize obesity and improve a sense of well-being, and would thus seem to be desirable. CONCLUSION We are currently faced with the fact of an “epidemic” of atherosclerotic cardiovascular disease, substantial dietary hypercholesterolemia in children, and inadequate evidence to conclude that dietary alteration might reduce risk potential in the pediatric population. The nature of coronary heart disease is such that prevention is the primary means by which a reduction in morbidity and mortality will be realized. As a consequence, it appears prudent, based on existing evidence, for the American people to follow a diet aimed at lowering serum lipid concentration. For most individuals, this can be achieved by lowering intake of THE JOURNAL OF SCHOOL HEALTH
211
calories, cholesterol and saturated fats. Maximum benefit will be achieved by adoption in early childhood with particular emphasis on those families with a history of early coronary heart disease. Every effort should be made to discourage children from beginning to smoke and to encourage individuals who now smoke to stop. High blood pressure should be detected early in life, observed at routine intervals, and controlled when indicated. Obesity should be discouraged and alleviated by proper diet and exercise. A major challenge to professionals in the health field, and in particular to health educators, is to develop techniques of education that will effectively modify behavior to allow young people to accept and adopt these principles of healthful living. REFERENCES 1. National Heart and Lung Institute Task Force on Arteriosclerosis: Arteriosclerosis. Vol 2, DHEW Pub. No. (NIH) 72-219. June 1971. 2. American Heart Association, Los Angeles Affiliate: Symposium
on the pediatrician’s obligation in the atherosclerosis epidemic. February 8, 1976. 3. American Heart Association: Heart Facts, 1976. 4. Glueck CJ, et al: Hypercholesterolemia and hypertriglyceridemia in children. Am J Dk Child 128:569-577, 1974. 5. Holman RL, et al: The natural history of atherosclerosis: the early aortic lesions as seen in New Orleans in the middle of the 20th century. Am J Pathol34:209-235, 1958. 6. Enos WF, Holmes RH, Beyer J: Coronary disease among United States soldiers killed in action in Korea. JAMA 153:1090-1093, 1953. 7. McNamara JJ. et al; Coronary artery disease in combat casualties in Vietnam. JAMA 216:1185-1187, 1971. 8. Atherosclerosis Study Group/Epidemiology Study Group, InterSociety Commission for Heart Disease Resources: Primary prevention of the atherosclerotic diseases. Circulation 42:ASS-A95, 1970. 9. American Heart Association: Report of the ad hoc committee on cigarette smoking and cardiovascular diseases for health professionals, AHA, 1977.
10. Feinleib M, Williams RR: Relative risks of myocardial infarction, cardiovascular disease and peripheral vascular disease by type of smoking. In: Proceeding of the 3rd World Confemnce on Smoking and Health 1:243-256, DHEW Pub. No. (NIH) 76-1221, 1975. 11. Proceedings of the 3rd World Corlference on Smoking and Health. DHEW Pub. No. (NIH) 76-1221, 1975. 12. Teenage Smoking, National Patterns of Cigarette Smoking, Ages 12-18 in 1972 and 1974. DHEW Pub. No. (NIH) 76-931, 1976. 13. American Heart Association: The value and safety of diet modification to control hyperlipidemia in childhood and adolescence. Circulation 58:381A, 1978. 14. California Society of Pediatric Cardiology, California Heart Association: Atherosclerosis prevention in children. West J Med 122355-356, April 1975. 15. Giueck CJ, et al: Hyperlipemia in progency of parents with myocardial infarction before age 50. Am J Dis Child 127:70-75, January 1974. 16. Kannel WB: A new viewpoint on cholesterol. Primary Cardiology, Sept 1978. 17. Stamler J: Lifestyles, major risk factors, proof and public policy. Circulation 58(1):3-19, July 1978. 18. Wissler RW: Development of the atherosclerotic plaque. Hospital Practice 8:61-72, 1973. 19. Clarke WR, et al: Tracking of blood lipids and blood pressures in school-age children: the muscatine study. Circulation 58(4):626634, Oct 1978. 20. American Heart Association Committee on Nutrition: Diet and Coronary heart disease. Circulation 58(4):762A, 1978. 21. Ashley FW,Kannel WB: Relation of weight change to changes in atherogenic traits: the Framingham study. J Chronic Dis 27:103-114, 1974.
Hunter Crittenden, MD, is assistant clinical professor, UCLA Medical School Director, Heart Cath Lab, St. Bernardino Hospital, San Bernardino, CA 92408; AHA Subcommittee on Heart Health Education in the Young.
NEW ASHA COMMIlTEE ON AGING Anyone interested in serving on the new ASHA Study Committee on Aging should contact John Gay, EdD, Health Science Department, Towson State University, Towson, MD 21204. Summer Courses for College Credit University of Arizona
Aspects of care for school-age children and physically or emotionally and mentally handicapped children will be studied in a 2 unit course entitled “The Developmentally Disabled Child,” June 18-29, 1979. The fee is approximately $30/credit hour. A 3-unit course, “School Nurse Practice,” will deal with the analysis and application of the nursing process within a school system. The course is being offered July 9-27 for approximately $30/credit hour. For further information, write: Mary Jane Welty, Associate Dean for Continuing Education, College of Nursing, The University of Arizona, Tucson, AZ 85721. 212
THE JOURNAL OF SCHOOL HEALTH
APRIL 1979
INTRODUCTION Ischemic coronary heart disease is pandemic in the westernized industrialized adult population of the world. Cardiovascular complications resulting from atherosclerosis account for more than one-half of all deaths in the United States. ’ Approximately one-third of the men in our country will have suffered from coronary heart disease by the age of Open heart surgery for coronary artery bypass has become one of the largest businesses of our nation. Estimated annual costs for care of cardiovascular disease exceeds 26 billion dollars. If inroads into this staggering social problem are to be made, it must be by primary attention toward prevention. The genesis of the atherosclerotic lesion appears to begin in childhood. Efforts to prevent or retard this process should therefore be directed at children since substantial and potentially irreversible damage may already exist by the third or fourth decade of life before any symptoms have occurred. These lesions appear to progress through a series of linked steps: (1) Development of arterial fatty streaks. (2) Formation of fibrous plaques. (3) Development of complicated fibrotic and calcific mature atherosclerotic lesions. (4) Clinical atherosclerotic cardiovascular disease. Fatty streaks appear by the third to fifth month of age and increase in number during the first 20 years.’ Some resorb while other may progress to fibrous plaques. Fatty streaks per se may be normal. Fibrous plaques often appear by the second and third decade. Military casualty autopsy studies have shown that 45%-75% of young American men have a considerable amount of coronary and aortic fibrous plaques in the second, third and fourth decade of life?’ These data suggest that half of young American men are already predisposed to atherosclerotic cardiovascular disease by the end of their second or third decade. Atherosclerosis is probably a complex multi-factoral disease which is incompletely understood at this time. The well-known “risk factors” may not represent etiologic factors but may well be critical links in a pathologic sequence. Of particular importance is the fact that societies with a different life style, in particular dietary habits with lower saturated fat and cholesterol 210
THE JOURNAL OF SCHOOL HEALTH
intake, have a much lower incidence of this disease. There are a number of so called “risk factors” associated with an increase in the incidence of atherosclerosis; the greater their number, the more apt is the individual eventually to manifest its complications. Age, sex, race and diabetes mellitus are all factors which correlate with the incidence of atherosclerosis over which we have little control. Other identifiable “risk factors,” however, can be influenced by an alteration of life style and are the concern of this report. It is probable that modification of known “risk factors” may retard or reverse the development of atherosclerosis; and if such preventative measures are possible, they should begin early in childhood when the disease is beginning. The great attention and costs now being directed to adults with symptomatic disease is in a sense “after the fact.’’ RISK FACTORS Smoking Smoking is the single most preventable cause of cardiovascular disease, chronic obstructive pulmonary disease and cancer. The risk of cardiovascular disease increases in proportion to the number of cigarettes smoked and the duration of exposure to the habit. It is estimated that cigarette smoking is responsible for 325,000 premature deaths each year. Total mortality is 1.6 times higher in cigarette smokers than among nonsmokers.’’ The effect of cigarette smoking on cardiovascular disease risk is independent of other major “risk factors” and this risk is greatly aggravated when such factors as high blood pressure, high blood cholesterol or diabetes mellitus are present. ’ I There has been an alarming recent increase in smoking among teenagers, especially girls.’* Vigorous efforts should be made to prevent children from taking up the cigarette habit. Elevated Serum Cholesterol Elevated serum cholesterol has the highest single correlation with the risk of major coronary artery disease.13 Average values in our population tend to be much higher than in populations where there is a low incidence of atherosclerosis. No population whose diet is low in saturated fats and cholesterol has a high APRIL 1979
incidence of coronary artery disease. Ideal values for serum cholesterols are not critically defined for children, but values above 190 to 200 mg. Vo are almost certainly excessive for adolescents, while levels of 160 to 170 may be abnormal for infants and children.“ Studies of U.S. school-age children from 6 to 16 years have shown that 10% to 20% have serum cholesterol levels above 200 mg. Yo. Children from underdeveloped, nonindustrialized and rural populations usually have levels 40 to 50 mg. 9’0 10wer.~The incidence of atherosclerotic cardiovascular disease statistically correlates with these findings even though there is no conclusive proof that dietary restriction reduces the incidence of coronary heart disease. The highest priority and most fruitful areas of case finding of hypercholesterolemia will be in those children where there is a strong family history of early atherosclerotic heart disease. There should be a heightened sensitivity to the need to take a detailed and on-going history of such events in the family. Nearly one-third of the offspring of parents who have suffered myocardial infarction under the age of 50 will have hyperlipoproteinemia. Is Cholesterol is carried in the blood by lipoproteins, principally low density lipoproteins (LDL), and to a lesser degree high density lipoproteins (HDL). LDL cholesterol significantly and independently relates to risk of coronary disease while HDL cholesterol inversely relates to its development.*6 This apparent protective role of HDL appears to be important and may be a valuable indicator of risk but in no way invalidates the extensive evidence of the critical role of LDL in human atherogenesis. The significant relationship of LDL level to risk for both younger and older persons, male and female, is well established. The relationship of plasma total cholesterol to risk has been consistently shown in study after study. ” The “average American diet” is athetogenic while the “prudent diet” is markedly less so, and preliminary reports show a reversal of lesions in the Rhesus monkey with a change to the “prudent diet.” 18 It is recommended, therefore, that modest shifts in our dietary pattern be made now for the general population in the hopes of achieving optimal benefit for children over their lifetime. These changes will require some reduction in saturated fats and cholesterol foods which are of animal origin (meat, eggs and dairy products). These reductions should be replaced by foods low in cholesterol and saturated fats such as fish, poultry, lean meat, fruits, vegetables and cereal grains. High fat content products such as sausage and luncheon meats, “premium” fat marbled meats, milk and milk products (skim milk excepted), eggs, and pastries made with butter will have to be de-emphasized. Inasmuch as eating habits and food preferences are established in very early childhood, these modifications may best be APRIL 1979
achieved by the young family. It is imperative that the principles of good nutrition be followed in any dietary change. Details of a “prudent diet” are available from the American Heart Association. High Blood Pressure High blood pressure has been well-defined as an atherogenic “risk factor” in the adult population. The evidence linking hypertension in childhood with the later development of atherosclerosis is less complete than that for hyperlipidemia, but many children have blood pressures that are high even by adult standards. Rank order of blood pressure is maintained less well through childhood than rank order of plasma cholesterol concentration, though children with elevated levels are likely to become hypertensive as adults. l9 HBP measurements should begin by the third year of life and be repeated on each general examination thereafter. Emphasis should be given to proper technique of taking blood pressure in children (cuff size, et cetera). A causal relationship in man between sodium intake and hypertension has not been firmly established, but there is increasing evidence that current levels of sodium intake in the United States contribute as one of the multiple factors in the etiology of hypertension. Studies suggest that it is prudent to avoid excessive sodium in the diet.m Obesity Obesity is a less clearly defined “risk factor” other than its relationship with high blood pressure and hyperlipidemia. 21 This relationship, however, is sufficient to use every effort to curtail this increasingly common condition by diet and physical activity. Obesity tends to be a “family affair” necessitating efforts directed toward the family unit. Exercise There is no clear proof that regular exercise will prevent atherosclerosis; but it does induce a number of physiologic changes seen as “favorable,” including the potential to minimize obesity and improve a sense of well-being, and would thus seem to be desirable. CONCLUSION We are currently faced with the fact of an “epidemic” of atherosclerotic cardiovascular disease, substantial dietary hypercholesterolemia in children, and inadequate evidence to conclude that dietary alteration might reduce risk potential in the pediatric population. The nature of coronary heart disease is such that prevention is the primary means by which a reduction in morbidity and mortality will be realized. As a consequence, it appears prudent, based on existing evidence, for the American people to follow a diet aimed at lowering serum lipid concentration. For most individuals, this can be achieved by lowering intake of THE JOURNAL OF SCHOOL HEALTH
211
calories, cholesterol and saturated fats. Maximum benefit will be achieved by adoption in early childhood with particular emphasis on those families with a history of early coronary heart disease. Every effort should be made to discourage children from beginning to smoke and to encourage individuals who now smoke to stop. High blood pressure should be detected early in life, observed at routine intervals, and controlled when indicated. Obesity should be discouraged and alleviated by proper diet and exercise. A major challenge to professionals in the health field, and in particular to health educators, is to develop techniques of education that will effectively modify behavior to allow young people to accept and adopt these principles of healthful living. REFERENCES 1. National Heart and Lung Institute Task Force on Arteriosclerosis: Arteriosclerosis. Vol 2, DHEW Pub. No. (NIH) 72-219. June 1971. 2. American Heart Association, Los Angeles Affiliate: Symposium
on the pediatrician’s obligation in the atherosclerosis epidemic. February 8, 1976. 3. American Heart Association: Heart Facts, 1976. 4. Glueck CJ, et al: Hypercholesterolemia and hypertriglyceridemia in children. Am J Dk Child 128:569-577, 1974. 5. Holman RL, et al: The natural history of atherosclerosis: the early aortic lesions as seen in New Orleans in the middle of the 20th century. Am J Pathol34:209-235, 1958. 6. Enos WF, Holmes RH, Beyer J: Coronary disease among United States soldiers killed in action in Korea. JAMA 153:1090-1093, 1953. 7. McNamara JJ. et al; Coronary artery disease in combat casualties in Vietnam. JAMA 216:1185-1187, 1971. 8. Atherosclerosis Study Group/Epidemiology Study Group, InterSociety Commission for Heart Disease Resources: Primary prevention of the atherosclerotic diseases. Circulation 42:ASS-A95, 1970. 9. American Heart Association: Report of the ad hoc committee on cigarette smoking and cardiovascular diseases for health professionals, AHA, 1977.
10. Feinleib M, Williams RR: Relative risks of myocardial infarction, cardiovascular disease and peripheral vascular disease by type of smoking. In: Proceeding of the 3rd World Confemnce on Smoking and Health 1:243-256, DHEW Pub. No. (NIH) 76-1221, 1975. 11. Proceedings of the 3rd World Corlference on Smoking and Health. DHEW Pub. No. (NIH) 76-1221, 1975. 12. Teenage Smoking, National Patterns of Cigarette Smoking, Ages 12-18 in 1972 and 1974. DHEW Pub. No. (NIH) 76-931, 1976. 13. American Heart Association: The value and safety of diet modification to control hyperlipidemia in childhood and adolescence. Circulation 58:381A, 1978. 14. California Society of Pediatric Cardiology, California Heart Association: Atherosclerosis prevention in children. West J Med 122355-356, April 1975. 15. Giueck CJ, et al: Hyperlipemia in progency of parents with myocardial infarction before age 50. Am J Dis Child 127:70-75, January 1974. 16. Kannel WB: A new viewpoint on cholesterol. Primary Cardiology, Sept 1978. 17. Stamler J: Lifestyles, major risk factors, proof and public policy. Circulation 58(1):3-19, July 1978. 18. Wissler RW: Development of the atherosclerotic plaque. Hospital Practice 8:61-72, 1973. 19. Clarke WR, et al: Tracking of blood lipids and blood pressures in school-age children: the muscatine study. Circulation 58(4):626634, Oct 1978. 20. American Heart Association Committee on Nutrition: Diet and Coronary heart disease. Circulation 58(4):762A, 1978. 21. Ashley FW,Kannel WB: Relation of weight change to changes in atherogenic traits: the Framingham study. J Chronic Dis 27:103-114, 1974.
Hunter Crittenden, MD, is assistant clinical professor, UCLA Medical School Director, Heart Cath Lab, St. Bernardino Hospital, San Bernardino, CA 92408; AHA Subcommittee on Heart Health Education in the Young.
NEW ASHA COMMIlTEE ON AGING Anyone interested in serving on the new ASHA Study Committee on Aging should contact John Gay, EdD, Health Science Department, Towson State University, Towson, MD 21204. Summer Courses for College Credit University of Arizona
Aspects of care for school-age children and physically or emotionally and mentally handicapped children will be studied in a 2 unit course entitled “The Developmentally Disabled Child,” June 18-29, 1979. The fee is approximately $30/credit hour. A 3-unit course, “School Nurse Practice,” will deal with the analysis and application of the nursing process within a school system. The course is being offered July 9-27 for approximately $30/credit hour. For further information, write: Mary Jane Welty, Associate Dean for Continuing Education, College of Nursing, The University of Arizona, Tucson, AZ 85721. 212
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APRIL 1979
