Dietary Risk Assessment for Cardiovascular Disease Among Central Maine Adolescents Adrienne A. White, Dorothy J. Klimis-Tavantzis
ABSTRACT: Dietary risk for cardiovascular disease was assessed in 97 adolescents enrolled in health classes in two high schools in rural, central Maine, using three-day food records and written questionnaires of selfperceived food practices and cardiovascular nutrition knowledge. Mean percent of kilocalories from fat was 36% f o r both males and females. Compared to American Heart Association guidelines. 80% males and 73% females had more than 30% kilocalories from fat; 37% males and 16% females had dietary cholesterol intakes above 300 milligrams. More than 50% of males but less than 25% of females had sodium intakes greater than 3,wO milligrams. Mean dietary fiber intake of females (6 f 4 grams) was significantly lower than the fiber intake of males (I1 f 8 grams). During adolescence, greater emphasis should be placed on modifying food behaviors that may be detrimental to heart health if continued into adulthood. Individualization provided within nutrition education curricula is necessary to meet the needs presented by differences in gender and variation among adolescents. ( J Sch Health. 1992;62(9):428-432)
H
igh blood cholesterol is a major risk factor in developing cardiovascular disease (CVD), a leading cause of mortality and morbidity in the American population. The Population Panel of the National Cholesterol Education Program' and the Expert Panel on Blood Cholesterol Levels in Children and Adolescents* reported that cholesterol lowering strategies are needed for all healthy Americans over age two.' More healthful food choices, such as reducing total fat, saturated fat, and cholesterol, and increasing complex carbohydrates, are seen as the primary means of achieving reduced blood cholesterol among the general population. The need exists for early dietary intervention since habits begun in childhood are likely to continue into adulthood. Targeting adolescents is especially critical because it is developmentally appropriate for them to make independent food choices. Schools offer the environment for adolescents to link knowledge of CVD with dietary skills for behavior change. However, before changes can be made, adolescents must identify personal food choice behaviors and health conditions that place them at risk for CVD. In fall 1989, a study was initiated with a group of adolescents in central Maine to help them lower risk for CVD. Prior to intervention, adolescents assessed their risk for CVD. Assessments included food intake, fasting blood lipids, heights, weights, percent body fat, and cardiovascular nutrition knowledge. Assessments were made prior to and following intervention, as well as during periodic follow-ups. The intervention focused on dietary behavior change skills to improve heart health. This article presents data, assessed prior to intervention, from self-reported food intake records and written assessments of self-perceived food practices and cardiovascular nutrition knowledge. Adrienne A . White, PhD, RD, Assistant Professor. Human Nutrition and Foods; Dorothy J. Klimis-Tavantzis, PhD, Assistant Professor of Clinical Nutrition, Merrill Hall, School of Human Development, University of Maine, Orono, ME 04469. This study was supported by the Maine Agricultural Experiment Station Project #ME08703. This article was submitted January 21, 1992, and revised and accepted for publication June 29, 1992.
428
Journal of School Health
METHOD Participants. Male and female adolescents enrolled in high school health classes in a rural county in central Maine were the target population. Major employment sources for county residents are in retail sales, manufacturing of nondurable goods, and health and educational services. Within the school system, health is a required course offered at the ninth-grade level. Area schools within a 30-mile radius of the University of Maine, Orono, were contacted. Letters were sent to the principals who indicated interest in the study. Investigators met with nurses and health teachers from the schools. Superintendents of two schools gave approval for school participation in the study. Each school had one health teacher and all their classes were included in the study for a total of seven classrooms. Of the 150 adolescents enrolled, 97 (65%) participated. All but one student, an Asian-American, were White. Some 35% declined to join the project since participation was voluntary and required time spent outside of class. Specifically, some assessments occurred during the early morning hours before school started and food intake was recorded outside the classroom. The fact that blood samples were required as part of the project kept some adolescents from participating. Three instruments - a three-day food record, selfperceived food practices, and cardiovascular knowledge instruments - and a demographic/family history information form were used in the study. Two class periods on consecutive days were used to complete written assessments and receive instructions for recording food intake. Trained nutritionists conducted assessments. Consent forms were signed by both adolescents and their parents/guardians. All procedures and samples of test instruments were approved by the University of Maine Review Board for the Protection of Human Subjects. INSTRUMENTATION Adolescents kept three-day food record forms on two weekdays and one weekend day. Forms included written instructions, and a nutrition graduate student instructed the adolescents in portion sizes and food
November 1992, Vol. 62, No. 9
descriptions using food models, actual food containers, and household measuring and eating utensils. Particular attention was given to specifying between fats, for instance, margarine versus butter and various levels of percent fat in dairy products. Adolescents practiced record-keeping through class exercises, which included a typical one-day diet displayed in the form of food models, actual foods, and food containers. After the food record-keeping period, the nutrition graduate student reviewed each record and obtained additional information when needed. A food practices instrument composed of 12 items, designed and tested by White’ was administered (testretest reliability = 0.84). Statements assessed adolescents’ perceptions of their daily meal patterns and adherence to the Dietary Guidelines.‘ A Likert-type scale with five continuum points ranging from “always true” to “never true” was used. A 30-item cardiovascular knowledge instrument, taking 15-20minutes to complete, also was administered. The test was designed as multiple-choice questions compiled from existing tests5s6with the addition of 10 new questions constructed specifically for the instrument. A table of specifications was used in developing the instrument. Sixty percent of the items related to knowledge of heart-healthy food practices, and 40% related to knowledge of cardiovascular disease. Demographic and family history information was elicited from both adolescents and parentdguardians. Items included education of parentdguardians, family structure such as size and gender composition, and family history of cardiovascular risk factors such as obesity, diabetes, and heart disease.
DATA ANALYSIS Food records were coded and analyzed using the Nutritionist I11 microcomputer program. Additional foods were added to the database or consistent substitutions were made with items of similar nutrient content. Values for saturated fat and cholesterol contents of food were added to the database using food composition data from the US Dept. of Agriculture, Handbook 8 series, University of Massachusetts Database, other published sources, and food manufacturers. Nutrient analyses and written questionnaires were coded using the Data Entry I1 microcomputer software program created by SPSS, Inc. Analyses were conducted with the SPSS” mainframe computer program. Descriptive statistics - distributions and means with standard deviations - and t-tests for testing significant differences between means were used to study bivariate relationships. Selected dietary components related to heart health were analyzed: energy, percent kilocalories (kcal) from fat, total fat, saturated fat, cholesterol, dietary fiber, and sodium. For each adolescent, mean daily intakes were calculated as nutrient totals and as nutrients per 1,OOO kcal, as measures of diet quality and as a means of comparing subgroups whose energy intakes differ. Mean dietary component intakes were compared to American Heart Association standards’ and the dietary fiber intake recommendation stated by Kritchevsky,’ which are consistent with the recommendations of the
Population Panel’ and the Expert Panel on Children and Adolescents.2 Individual foods and food groups which were primary sources of total fat, accounting for approximately 80% of total fat intake, were determined from calculations of the three-day average daily gram intake of each food consumed by the adolescents. Food categories defined by Buzzard and colleagues9 and Witschi and colleagues1o were used in selecting food categories.
RESULTS Demographic Characteristics. Table 1 contains the
adolescents’ mean age. Slightly more females than males participated. Approximately 40% of both parents were educated above high school level. Though slightly more than one-third of adolescents’ natural parents were divorced, 86% of the sample lived in two-parent homes, mainly as a result of remarriage. Energy and Nutrient Intake. Mean energy and nutrient levels with standard deviations of the means and nutrient densities are in Table 2. The Recommended Dietary Allowances (RDA) for energy are 2,500kcal per day for males 11-14years old, 3,000 kcal per day for males 15-18years, and 2,200 kcal per day for females in the age ranges of 11-14and 15-18.”Of the seven dietary components studied, based on mean intake, six were significantly lower for females than males: energy (p 5 .OOOl), total fat (p 5 .O001), saturated fat (p 5 .OOOl), cholesterol (p s .003), fiber (p 5 .OOOl), and sodium (p 5 .0001). Slightly more than 14% of total kcal was supplied by saturated fat, which is over the recommended 10% of kcal. When nutrient density was calculated, dietary fiber was the only component significantly lower (p 5 .03) for females. Comparisons of mean daily intake to guidelines for heart health are shown in Table 3. Slightly more than 80% males and 73% females had over 30% kcal from fat. Nearly 59% of the sample derived 3 I Yo to 39% kcal from fat; a higher percent of males (73.2%) than females (48.2%) fell in this range. While almost 27% of females derived 5 30% kcal from fat, a similar percent (25%) derived L 40% kcal from fat. Almost 37% of males and 16% of females had cholesterol intakes above recommended levels. More than 98% of females and 85% of males had fiber intakes below guidelines. FiftyTable 1 Demoflraphic Characteristics of Participating Adolescents
Sample Size (no.) Age (years+SD)
41 15.220.9
EductUon of hnt, 12 years or below 13-15 years
mher 58.2
16+
Adoleicot, Un Wlth Parents Parent and stepparent Single parent Foster parent/relative
Journal of School Health
56 14.8k0.7
-n
-
27.8 14.0
mother 55.1 28.1 16.9
W total srmpb
60.8. 21.6 12.4 5.2
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429
four percent of males and 21% of females had sodium intakes above recommended levels. Table 4 presents the mean daily gram contribution to fat intake for selected food groups that accounted for 80% of the fat intake. In the diets of males, in descending order, mixed dishes such as pizza, pasta dishes, tacos; meats, such as beef and pork; crackers and chips; and sweet bakery goods such as cakes, cookies, and doughnuts were the major contributors to total fat intake. In the diets of females, in descending order, meats, mixed dishes, fats, and milk were the top contributors to total fat intake. Grams of fat contributing to total fat intake were higher for males than females for most food categories. This result was evident especially for mixed dishes, crackers and chips, and meat. For both males and females, the amount of fat contributing to total fat intake was similar for the folTable 2 Mean Dally Intake of Selected Dletary Components
D h W Comporntr Energy (kcal) Fat (% kcal) Total fat (gm) Saturated fat (gm) Cholesterol (mg) Fiber (gm) Sodium (mg)
M u n DN I Inbke nuw hmbr
NutrMon lhnrlty rmwnt prr 1000 kml hnukr Mkl
2406i1101 36i4 98i47
1531 i 4 7 a b 3627 62i24b
41 i 5
40i8
38219 308i208 11i8 3485i1668
24i10b 198*114c 6i4b 2193?908b
16i3 128i53 5i2 1494i379
16k4 128i62 4i24 1436i428
aN = 41 males; 56 females bps 0.0001
50003 4 5 0.03
Table 3 Percent of Adolescents’ Whose Mean Dally Intake is Compared to American Heart Assoclation Guidelines D k t l Componontr ~
Mlbl
hMbS
w
Tom1
(Dally mun Intake) Fat (% kcal) I30%
31-39% 2 40% Cholesterol 5 300 mg z
300 mg
Fiber 5 19gm
t 20 gm Sodium 5 3000 mg z
3000 mg
9.7 (28iO) 73.2 (36i2) 17.1 (42i3)
26.8 (27i3) 48.2 (36i2) 25.0 (44i3)
19.6 (27i3) 58.8 (36i2) 21.6 (44*3)
63.4 (193i81) 36.6 508i 210)
83.9 (162i70) 16.1 (387 i 119)
75.2 (173i75) 24.7 (462 i 188)
85.4 (9*4) 14.6 (27i8)
98.2 (6+4) 1.8 (25iO)
92.8 (7*4) 7.2 (26i8)
78.6
64.9 (1919 651 ) 35.0 (4258i 1219)
46.3 (21 13 i681 ) 53.7 (4670*1315)
aN = 4 1 males; 56 lemales
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Journal of School Health
( 1836i 627)
21.4 (3504i448)
*
lowing food categories: fats, cheese, potatoes, eggs, and candy. Food Practices Instrument. Self-perceived food practices of adolescents are shown in Table 5 . Just more than 64% of the sample reported they always or almost always ate breakfast. Slightly more males than females reported eating breakfast regularly. While more teens (70.6%) said they ate lunch, the increase was due to a greater percent of males (8O%), not females (63.6%). A greater percentage of females (43.6%) than males (22.5%) perceived themselves as limiting fat intake. However, more males (50%) than females (35%) said they used low-fat milk. More males (50%) than females (32.7%) reported eating six to eight foods containing fiber each day. Slightly more males (45%) than females (4OVo) perceived themselves as limiting salt. Approximately 22% of both males and females reported “eating more fish and/or chicken than red meat on a weekly basis. ” Knowledge Instrument. Table 6 contains cardiovascular nutrition knowledge scores. Total scores were low for both males (47% correct) and females (53% correct). Females scored significantly higher (p I .02) than males. Cronbach’s Alpha (internal consistency) coefficient for the knowledge items was 0.68.
DISCUSSl O N Both male and female adolescents consumed a diet with 36% of total kcal supplied by fat. While typical of the American diet, reports for adolescents vary from 34% to 38%.1° Since males had a higher total kcal intake, their intake of the selected dietary components was higher than that of females, supporting previous studies.12-15 Overall, cholesterol intake was not excessive and was lower than that previously reported.1°-16 However, almost 37% of males have intakes over recommended levels. More males than females had higher daily sodium intakes. In terms of meeting nutrient recommendations, females, due to their lower total kcal intake per day than males, must make better choices than males, such as choosing a more nutrientdense diet .I4 However, these results suggest in relationship to cholesterol and sodium, males must make wiser food choices than females since in taking in more kcal per day, their amount of cholesterol and sodium increased. When observing the variation in mean daily intakes of adolescents (Table 3), it is clear that nutrition messages must be individualized. Not all teens need to lower percent of kcal from fat or increase intake of high fiber foods. Kuczmarski and colleagues,l2 using 24-hour recalls from more than 1,OOO adolescents, found three food groups contributed to 74.3% of the total fat intake for both males and females. For males, in descending order, the groups were meat, fish, and poultry; fats; and milk, cheese, and yogurt. For females, the groups were the same but the order differed - fats; meats, fish, and poultry; and milk, cheese, and yogurt. Witschi and colleagues,Io using 24-hour food records, found the primary sources of total fat in the diets of males were
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dairy foods such as milk, cheese, and ice cream; meat, fish, poultry, and eggs; and bakery products such as bread, pastries, pancakes, cookies, and doughnuts. Primary sources for females were dairy foods, bakery products, and snack-type foods such as nuts, peanut butter, potato chips, crackers, and candy. By combining food categories represented in Table 4 for a similar comparison, the primary sources of total fat in the diets of
Table 4 Mean Daily Contribution to Fat Intake for Food Groups Accounting for 80% of Fat Intake Mean Ddty CoRblbution to Fat Intake onms of ht Males hnub
Fwd Orwp
15.7 10.7 9.1
Mixed DisheP Meat (beef. pork) Crackers, chips Sweet bakery goods Nuts, peanut butter Milk Ice Cream Fats Processed meats Cheese Breads, cereals, grains Potatoes Poultry. fish Eggs Candy
6.5 7.1 3.4 3.5 2.2 4.1 3.9 4.4 2.2 3.4 0.9 2.3 3.6 0.6 1.2
6.7 5.7 5.0 4.8 4.5 4.2 3.7 2.4 2.3 1.4 1.1 0.8
%fixed Dishes=pizza. pasta dishes. tacos
Table 5 Self-Perceived Food Practices of Adolescents, Food Pnctlws
Mab
A h v r y t / ~ ~AhwysTrueb ~t Female TobI
n Dally Eat Breakfast Eat Lunch Limit Fat intake Use Low Fat Milk Eat 6-8 Fiber Foods Limit Salt intake
67.5b 80.0 22.5 50.0 50.0 45.0
63.0 63.6 43.6 35.2 32.7 40.0
64.2 70.6 34.7 41.5 40.0 42.1
Wwkly Eat More Flsh and/or Chicken Than Red Meat
22.5
21.8
22.1
apercent oi gender groups; males = 41. females = 56 bR0SponS8S from Likert scale categories "always" and "almos~always" were combined
Table 6 Mean Score on Cardiovascular Nutrition Knowledge TesP Semph
N
Mwn s c o n i S D b
Male Female
40 55
1424 (47%)d 16+4c (53%)
a30 item test (a = 0.68) bSD=standard deviation
males were snacks, dairy products, and meat, poultry, fish, and eggs. The primary sources of total fat for females were the same food categories, but in a different order - meat, poultry, fish, and eggs; dairy products; and snacks. More females than males perceived themselves as limiting fat, yet both consumed the same percent of kcal from fat and more males than females reported choosing low-fat milk. These perceptions of choice of low-fat milk seem consistent with food records, since of those who drank milk during the three-day period, 29% of males versus 25% of females drank low-fat milk. Many female adolescents may believe they are choosing lowfat foods, but lack the knowledge of food composition and dietary skills necessary for such choices. While more males than females had sodium intake over recommended levels, more males than females perceived themselves as limiting salt intake. Adolescents probably think of table salt use when considering whether they limit salt intake and are unaware of the sodium, especially in processed foods. Assessment of table salt use was not quantified in this study. In contrast to this study, Read and colleague~~~ found that males perceived avoiding salt less frequently than females. However, a similar percent of males, 45% versus 43%, in both studies were avoiding or limiting salt. Read and colleague^^^ also found somewhat higher percents of males and females reported complying to the Dietary Guidelines to avoid too much fat, 35% versus 22.5% for males and 50% versus 43.6% for females. Assessment of cardiovascular nutrition knowledge indicated these adolescents knew little about the process of cardiovascular disease and heart-healthy food choices. Though the general public is more aware of issues involving fat intake and heart disease, I * adolescents in this study appeared to have no greater cardiovascular nutrition knowledge than the teens reported by Podell and colleagues6in the mid-seventies. In addition, findings are consistent with results from the National Adolescent Student Health Survey" that adolescents are not able to identify foods high in fat, salt, and fiber. These findings support the general lack of nutrition knowledge among adolescents previously reported.m23 The fact that females scored higher than males also is consistent with findings of other researchers."
CONCLUSION These findings emphasize the importance of the recommendation of the Population Panel for appropriate educational curricula offered within the school system from kindergarten through 12th grade. This concept is embodied in the philosophy of a comprehensive school health program which would provide for integration of services and programs to improve the health of America's school children.w25 Many adolescents in this study did not have food behaviors that promote heart health. Since nutrition can affect future health in terms of CVD, greater emphasis must be placed on prevention, which means providing opportunities for adolescents to identify risk factors for CVD and to modify food-choice behaviors that may otherwise continue into adulthood. This task may not be easy, because it requires an uncharacteristic futuristic
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focus for adolescents. However, school health programs offer opportunities for adolescents to develop behaviors, skills, knowledge, and attitudes necessary to make informed food choices for better health.26 Offering nutrition education curricula that allow for individualization to meet the needs presented by differences in gender and the variation seen among adolescents is imperative to maximize the effect of school health programs on the health and well-being of adolescents. m References 1. Expert Panel on Population Strategies f o r Blood Cholesterol
Reduction. Bethesda, Md: National Cholesterol Education Program, Office of Prevention, Education and Control, National Institutes of Health publication no 90-3047;1990. 2. Expert Panel on Blood Cholesterol Levels in Children and Adolescents. Bethesda, Md: Office of Prevention, Education and Control, National Institutes of Health; publication no 91-2732;1991. 3. White AA. Changing adolescents’ food-related behavior via nutrition education. Knoxville, Tenn: University of Tennessee; 1988. Dissertation. 4. US Dept of Agriculture and US Dept of Health and Human Services. Nutrition and Your Health: Dietary Guidelines f o r Americans. Washington, DC: US Government Printing Office; USDA Home and Garden bulletin no 232; 1985. 5 . National Examination of Cardiovascular Knowledge. Dallas, Texas: American Heart Association Office of Communication; 1982. 6. Podell RN, Keller K, Berger G. Cardiovascular nutrition knowledge and lipid levels among New Jersey high school students. J Med Soc NJ. 1975;72(12):1027-1031. 7 . American Heart Association. Dietary guidelines for healthy American adults. Circulation. 1988;77(3):721a-724a. 8. Kritchevsky D. Dietary fiber. Ann Rev Nutr. 1988;8:301-328. 9. Buzzard IM, Asp EH, Chlebowski RT, Boyar AP, Jeffery RW, et al. Diet intervention methods to reduce fat intake: Nutrient and food group composition of self-selected low-fat diets. J A m Diet ASSOC.1990;90(1):42-53. 10. Witschi JC, Capper AL, Ellison RC. Sources of fat, fatty acids, and cholesterol in the diets of adolescents. J A m Diet Assoc. 1W;W (10): 1429-1431. 11. National Research Council. Subcommittee on the Tenth
Edition of the RDAs: Recommended Dietary Allowances, 10th ed. Washington, DC: National Academy Press; 1989;33. 12. Kuczmarski RJ, Brewer ER, Cronin FJ. Dennis B. Graves K, Hayes S. Food choices among white adolescents: The Lipid Research Clinics Prevalence Study. Pediatr Res. 1986;20(4):309-315. 13. Truswell AS, Darnton-Hill I. Food habits of adolescents. Nutr Rev. 1981;39(2):73-88. 14. Skinner JD, Salvetti NN, Ezell JM, Penfield MP, Costello CA. Appalachian adolescents’ eating patterns and nutrient intakes. J A m Diet Assoc. 1985;85(9):1093-1099. 15. Woodward DR. What influences adolescent food intakes? Hum Nutr Appl Nutr. 1986;40A:185-194. 16. Previtt TE, Haynes SG, Graves K, Haines PS, Tyroler HA. Nutrient intake, lipids and lipoprotein cholesterols in black and white children: The Lipid Research Clinics Prevalence Study. Prev Med. 1988;17947-262. 17. Read MH, Harveywebster M, Usinger-Lesquereux J. Adolescent compliance with dietary guidelines: Health and education implications. Adolescence. 1988;23(91):567-575. 18. The 1990 Health Objectives f o r the Nation: A Midcourse Review. Washington, DC: US Public Health Service; 1986. 19. American School Health Association, Association for the Advancement of Health Education, Society for Public Health Education, lnc. The National Adolescent Student Health Survey: A Report on the Health of America’s Youth. Oakland, Calif Third Party Publishing; 1989. 20. White AA, Skinner JD. Can goal setting as a component of nutrition education effect behavior change among adolescents? J Nutr EdUC. 1988;20(6):327-335. 21. Salvetti NN, Skinner JD. Nutrition attitudes and knowledge of east Tennessee adolescents. Tenn Farm Home Sci. 1985;1391 1-14. 22. Skinner JD, Woodburn MJ. Nutrition knowledge of teenagers. J Sch Health. 1984;54(2):71-74. 23. Portnoy B, Christenson GM. Cancer knowledge and related practices: Results from the National Adolescent Student Health Survey. J Sch Health. 1989;59(5):218-224. 24. Nader PR. The concept of “comprehensiveness” in the design and implementation of school health programs. J Sch Health. 1990;60(4):133-137. 25. Allensworth DD, Kolbe LJ. The comprehensive school health program: Exploring an expanded concept. J Sch Health. 1987;57(10): 409-412. 26. McGinnis JM, DeGraw C. Healthy schools 2000: Creating partnerships for the decade. J Sch Health. 1991;61(7):292-297.
Statement of Purpose The Journal of School Health. an official publication of the American School Health Association, publishes material related to health promotion in school settings. Journal readership includes administrators, educators, nurses, physicians, dentists, dental hygienists, psychologists, counselors, social workers, nutritionists, dietitians, and other health professionals. These individuals work cooperatively with parents and the community to achieve the common goal of providing children and adolescents with the programs, services, and environment necessary to promote health and to improve learning. Contributed manuscripts are considered for publication in the following categories: general articles, research papers, commentaries, teaching techniques, and health service applications. Primary consideration is given to manuscripts related to the health of children and adolescents, and to the health of employees, in public and private pre-schools and child day care centers, kindergartens, elementary schools, middle level schools, and senior high schools. Manuscripts related to college-age young adults will be considered if the topic has implications for health programs in preschools through grade 12.Relevant international manuscripts also will be considered. Prior to submitting a manuscript, prospective authors should review the most recent “Guidelines for Authors.” The guidelines are printed periodically in the Journal; copies also may be obtained from the Iournnl office, P.O. Box 708. Kent, OH 44240.
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ABSTRACT: Dietary risk for cardiovascular disease was assessed in 97 adolescents enrolled in health classes in two high schools in rural, central Maine, using three-day food records and written questionnaires of selfperceived food practices and cardiovascular nutrition knowledge. Mean percent of kilocalories from fat was 36% f o r both males and females. Compared to American Heart Association guidelines. 80% males and 73% females had more than 30% kilocalories from fat; 37% males and 16% females had dietary cholesterol intakes above 300 milligrams. More than 50% of males but less than 25% of females had sodium intakes greater than 3,wO milligrams. Mean dietary fiber intake of females (6 f 4 grams) was significantly lower than the fiber intake of males (I1 f 8 grams). During adolescence, greater emphasis should be placed on modifying food behaviors that may be detrimental to heart health if continued into adulthood. Individualization provided within nutrition education curricula is necessary to meet the needs presented by differences in gender and variation among adolescents. ( J Sch Health. 1992;62(9):428-432)
H
igh blood cholesterol is a major risk factor in developing cardiovascular disease (CVD), a leading cause of mortality and morbidity in the American population. The Population Panel of the National Cholesterol Education Program' and the Expert Panel on Blood Cholesterol Levels in Children and Adolescents* reported that cholesterol lowering strategies are needed for all healthy Americans over age two.' More healthful food choices, such as reducing total fat, saturated fat, and cholesterol, and increasing complex carbohydrates, are seen as the primary means of achieving reduced blood cholesterol among the general population. The need exists for early dietary intervention since habits begun in childhood are likely to continue into adulthood. Targeting adolescents is especially critical because it is developmentally appropriate for them to make independent food choices. Schools offer the environment for adolescents to link knowledge of CVD with dietary skills for behavior change. However, before changes can be made, adolescents must identify personal food choice behaviors and health conditions that place them at risk for CVD. In fall 1989, a study was initiated with a group of adolescents in central Maine to help them lower risk for CVD. Prior to intervention, adolescents assessed their risk for CVD. Assessments included food intake, fasting blood lipids, heights, weights, percent body fat, and cardiovascular nutrition knowledge. Assessments were made prior to and following intervention, as well as during periodic follow-ups. The intervention focused on dietary behavior change skills to improve heart health. This article presents data, assessed prior to intervention, from self-reported food intake records and written assessments of self-perceived food practices and cardiovascular nutrition knowledge. Adrienne A . White, PhD, RD, Assistant Professor. Human Nutrition and Foods; Dorothy J. Klimis-Tavantzis, PhD, Assistant Professor of Clinical Nutrition, Merrill Hall, School of Human Development, University of Maine, Orono, ME 04469. This study was supported by the Maine Agricultural Experiment Station Project #ME08703. This article was submitted January 21, 1992, and revised and accepted for publication June 29, 1992.
428
Journal of School Health
METHOD Participants. Male and female adolescents enrolled in high school health classes in a rural county in central Maine were the target population. Major employment sources for county residents are in retail sales, manufacturing of nondurable goods, and health and educational services. Within the school system, health is a required course offered at the ninth-grade level. Area schools within a 30-mile radius of the University of Maine, Orono, were contacted. Letters were sent to the principals who indicated interest in the study. Investigators met with nurses and health teachers from the schools. Superintendents of two schools gave approval for school participation in the study. Each school had one health teacher and all their classes were included in the study for a total of seven classrooms. Of the 150 adolescents enrolled, 97 (65%) participated. All but one student, an Asian-American, were White. Some 35% declined to join the project since participation was voluntary and required time spent outside of class. Specifically, some assessments occurred during the early morning hours before school started and food intake was recorded outside the classroom. The fact that blood samples were required as part of the project kept some adolescents from participating. Three instruments - a three-day food record, selfperceived food practices, and cardiovascular knowledge instruments - and a demographic/family history information form were used in the study. Two class periods on consecutive days were used to complete written assessments and receive instructions for recording food intake. Trained nutritionists conducted assessments. Consent forms were signed by both adolescents and their parents/guardians. All procedures and samples of test instruments were approved by the University of Maine Review Board for the Protection of Human Subjects. INSTRUMENTATION Adolescents kept three-day food record forms on two weekdays and one weekend day. Forms included written instructions, and a nutrition graduate student instructed the adolescents in portion sizes and food
November 1992, Vol. 62, No. 9
descriptions using food models, actual food containers, and household measuring and eating utensils. Particular attention was given to specifying between fats, for instance, margarine versus butter and various levels of percent fat in dairy products. Adolescents practiced record-keeping through class exercises, which included a typical one-day diet displayed in the form of food models, actual foods, and food containers. After the food record-keeping period, the nutrition graduate student reviewed each record and obtained additional information when needed. A food practices instrument composed of 12 items, designed and tested by White’ was administered (testretest reliability = 0.84). Statements assessed adolescents’ perceptions of their daily meal patterns and adherence to the Dietary Guidelines.‘ A Likert-type scale with five continuum points ranging from “always true” to “never true” was used. A 30-item cardiovascular knowledge instrument, taking 15-20minutes to complete, also was administered. The test was designed as multiple-choice questions compiled from existing tests5s6with the addition of 10 new questions constructed specifically for the instrument. A table of specifications was used in developing the instrument. Sixty percent of the items related to knowledge of heart-healthy food practices, and 40% related to knowledge of cardiovascular disease. Demographic and family history information was elicited from both adolescents and parentdguardians. Items included education of parentdguardians, family structure such as size and gender composition, and family history of cardiovascular risk factors such as obesity, diabetes, and heart disease.
DATA ANALYSIS Food records were coded and analyzed using the Nutritionist I11 microcomputer program. Additional foods were added to the database or consistent substitutions were made with items of similar nutrient content. Values for saturated fat and cholesterol contents of food were added to the database using food composition data from the US Dept. of Agriculture, Handbook 8 series, University of Massachusetts Database, other published sources, and food manufacturers. Nutrient analyses and written questionnaires were coded using the Data Entry I1 microcomputer software program created by SPSS, Inc. Analyses were conducted with the SPSS” mainframe computer program. Descriptive statistics - distributions and means with standard deviations - and t-tests for testing significant differences between means were used to study bivariate relationships. Selected dietary components related to heart health were analyzed: energy, percent kilocalories (kcal) from fat, total fat, saturated fat, cholesterol, dietary fiber, and sodium. For each adolescent, mean daily intakes were calculated as nutrient totals and as nutrients per 1,OOO kcal, as measures of diet quality and as a means of comparing subgroups whose energy intakes differ. Mean dietary component intakes were compared to American Heart Association standards’ and the dietary fiber intake recommendation stated by Kritchevsky,’ which are consistent with the recommendations of the
Population Panel’ and the Expert Panel on Children and Adolescents.2 Individual foods and food groups which were primary sources of total fat, accounting for approximately 80% of total fat intake, were determined from calculations of the three-day average daily gram intake of each food consumed by the adolescents. Food categories defined by Buzzard and colleagues9 and Witschi and colleagues1o were used in selecting food categories.
RESULTS Demographic Characteristics. Table 1 contains the
adolescents’ mean age. Slightly more females than males participated. Approximately 40% of both parents were educated above high school level. Though slightly more than one-third of adolescents’ natural parents were divorced, 86% of the sample lived in two-parent homes, mainly as a result of remarriage. Energy and Nutrient Intake. Mean energy and nutrient levels with standard deviations of the means and nutrient densities are in Table 2. The Recommended Dietary Allowances (RDA) for energy are 2,500kcal per day for males 11-14years old, 3,000 kcal per day for males 15-18years, and 2,200 kcal per day for females in the age ranges of 11-14and 15-18.”Of the seven dietary components studied, based on mean intake, six were significantly lower for females than males: energy (p 5 .OOOl), total fat (p 5 .O001), saturated fat (p 5 .OOOl), cholesterol (p s .003), fiber (p 5 .OOOl), and sodium (p 5 .0001). Slightly more than 14% of total kcal was supplied by saturated fat, which is over the recommended 10% of kcal. When nutrient density was calculated, dietary fiber was the only component significantly lower (p 5 .03) for females. Comparisons of mean daily intake to guidelines for heart health are shown in Table 3. Slightly more than 80% males and 73% females had over 30% kcal from fat. Nearly 59% of the sample derived 3 I Yo to 39% kcal from fat; a higher percent of males (73.2%) than females (48.2%) fell in this range. While almost 27% of females derived 5 30% kcal from fat, a similar percent (25%) derived L 40% kcal from fat. Almost 37% of males and 16% of females had cholesterol intakes above recommended levels. More than 98% of females and 85% of males had fiber intakes below guidelines. FiftyTable 1 Demoflraphic Characteristics of Participating Adolescents
Sample Size (no.) Age (years+SD)
41 15.220.9
EductUon of hnt, 12 years or below 13-15 years
mher 58.2
16+
Adoleicot, Un Wlth Parents Parent and stepparent Single parent Foster parent/relative
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56 14.8k0.7
-n
-
27.8 14.0
mother 55.1 28.1 16.9
W total srmpb
60.8. 21.6 12.4 5.2
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four percent of males and 21% of females had sodium intakes above recommended levels. Table 4 presents the mean daily gram contribution to fat intake for selected food groups that accounted for 80% of the fat intake. In the diets of males, in descending order, mixed dishes such as pizza, pasta dishes, tacos; meats, such as beef and pork; crackers and chips; and sweet bakery goods such as cakes, cookies, and doughnuts were the major contributors to total fat intake. In the diets of females, in descending order, meats, mixed dishes, fats, and milk were the top contributors to total fat intake. Grams of fat contributing to total fat intake were higher for males than females for most food categories. This result was evident especially for mixed dishes, crackers and chips, and meat. For both males and females, the amount of fat contributing to total fat intake was similar for the folTable 2 Mean Dally Intake of Selected Dletary Components
D h W Comporntr Energy (kcal) Fat (% kcal) Total fat (gm) Saturated fat (gm) Cholesterol (mg) Fiber (gm) Sodium (mg)
M u n DN I Inbke nuw hmbr
NutrMon lhnrlty rmwnt prr 1000 kml hnukr Mkl
2406i1101 36i4 98i47
1531 i 4 7 a b 3627 62i24b
41 i 5
40i8
38219 308i208 11i8 3485i1668
24i10b 198*114c 6i4b 2193?908b
16i3 128i53 5i2 1494i379
16k4 128i62 4i24 1436i428
aN = 41 males; 56 females bps 0.0001
50003 4 5 0.03
Table 3 Percent of Adolescents’ Whose Mean Dally Intake is Compared to American Heart Assoclation Guidelines D k t l Componontr ~
Mlbl
hMbS
w
Tom1
(Dally mun Intake) Fat (% kcal) I30%
31-39% 2 40% Cholesterol 5 300 mg z
300 mg
Fiber 5 19gm
t 20 gm Sodium 5 3000 mg z
3000 mg
9.7 (28iO) 73.2 (36i2) 17.1 (42i3)
26.8 (27i3) 48.2 (36i2) 25.0 (44i3)
19.6 (27i3) 58.8 (36i2) 21.6 (44*3)
63.4 (193i81) 36.6 508i 210)
83.9 (162i70) 16.1 (387 i 119)
75.2 (173i75) 24.7 (462 i 188)
85.4 (9*4) 14.6 (27i8)
98.2 (6+4) 1.8 (25iO)
92.8 (7*4) 7.2 (26i8)
78.6
64.9 (1919 651 ) 35.0 (4258i 1219)
46.3 (21 13 i681 ) 53.7 (4670*1315)
aN = 4 1 males; 56 lemales
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( 1836i 627)
21.4 (3504i448)
*
lowing food categories: fats, cheese, potatoes, eggs, and candy. Food Practices Instrument. Self-perceived food practices of adolescents are shown in Table 5 . Just more than 64% of the sample reported they always or almost always ate breakfast. Slightly more males than females reported eating breakfast regularly. While more teens (70.6%) said they ate lunch, the increase was due to a greater percent of males (8O%), not females (63.6%). A greater percentage of females (43.6%) than males (22.5%) perceived themselves as limiting fat intake. However, more males (50%) than females (35%) said they used low-fat milk. More males (50%) than females (32.7%) reported eating six to eight foods containing fiber each day. Slightly more males (45%) than females (4OVo) perceived themselves as limiting salt. Approximately 22% of both males and females reported “eating more fish and/or chicken than red meat on a weekly basis. ” Knowledge Instrument. Table 6 contains cardiovascular nutrition knowledge scores. Total scores were low for both males (47% correct) and females (53% correct). Females scored significantly higher (p I .02) than males. Cronbach’s Alpha (internal consistency) coefficient for the knowledge items was 0.68.
DISCUSSl O N Both male and female adolescents consumed a diet with 36% of total kcal supplied by fat. While typical of the American diet, reports for adolescents vary from 34% to 38%.1° Since males had a higher total kcal intake, their intake of the selected dietary components was higher than that of females, supporting previous studies.12-15 Overall, cholesterol intake was not excessive and was lower than that previously reported.1°-16 However, almost 37% of males have intakes over recommended levels. More males than females had higher daily sodium intakes. In terms of meeting nutrient recommendations, females, due to their lower total kcal intake per day than males, must make better choices than males, such as choosing a more nutrientdense diet .I4 However, these results suggest in relationship to cholesterol and sodium, males must make wiser food choices than females since in taking in more kcal per day, their amount of cholesterol and sodium increased. When observing the variation in mean daily intakes of adolescents (Table 3), it is clear that nutrition messages must be individualized. Not all teens need to lower percent of kcal from fat or increase intake of high fiber foods. Kuczmarski and colleagues,l2 using 24-hour recalls from more than 1,OOO adolescents, found three food groups contributed to 74.3% of the total fat intake for both males and females. For males, in descending order, the groups were meat, fish, and poultry; fats; and milk, cheese, and yogurt. For females, the groups were the same but the order differed - fats; meats, fish, and poultry; and milk, cheese, and yogurt. Witschi and colleagues,Io using 24-hour food records, found the primary sources of total fat in the diets of males were
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dairy foods such as milk, cheese, and ice cream; meat, fish, poultry, and eggs; and bakery products such as bread, pastries, pancakes, cookies, and doughnuts. Primary sources for females were dairy foods, bakery products, and snack-type foods such as nuts, peanut butter, potato chips, crackers, and candy. By combining food categories represented in Table 4 for a similar comparison, the primary sources of total fat in the diets of
Table 4 Mean Daily Contribution to Fat Intake for Food Groups Accounting for 80% of Fat Intake Mean Ddty CoRblbution to Fat Intake onms of ht Males hnub
Fwd Orwp
15.7 10.7 9.1
Mixed DisheP Meat (beef. pork) Crackers, chips Sweet bakery goods Nuts, peanut butter Milk Ice Cream Fats Processed meats Cheese Breads, cereals, grains Potatoes Poultry. fish Eggs Candy
6.5 7.1 3.4 3.5 2.2 4.1 3.9 4.4 2.2 3.4 0.9 2.3 3.6 0.6 1.2
6.7 5.7 5.0 4.8 4.5 4.2 3.7 2.4 2.3 1.4 1.1 0.8
%fixed Dishes=pizza. pasta dishes. tacos
Table 5 Self-Perceived Food Practices of Adolescents, Food Pnctlws
Mab
A h v r y t / ~ ~AhwysTrueb ~t Female TobI
n Dally Eat Breakfast Eat Lunch Limit Fat intake Use Low Fat Milk Eat 6-8 Fiber Foods Limit Salt intake
67.5b 80.0 22.5 50.0 50.0 45.0
63.0 63.6 43.6 35.2 32.7 40.0
64.2 70.6 34.7 41.5 40.0 42.1
Wwkly Eat More Flsh and/or Chicken Than Red Meat
22.5
21.8
22.1
apercent oi gender groups; males = 41. females = 56 bR0SponS8S from Likert scale categories "always" and "almos~always" were combined
Table 6 Mean Score on Cardiovascular Nutrition Knowledge TesP Semph
N
Mwn s c o n i S D b
Male Female
40 55
1424 (47%)d 16+4c (53%)
a30 item test (a = 0.68) bSD=standard deviation
males were snacks, dairy products, and meat, poultry, fish, and eggs. The primary sources of total fat for females were the same food categories, but in a different order - meat, poultry, fish, and eggs; dairy products; and snacks. More females than males perceived themselves as limiting fat, yet both consumed the same percent of kcal from fat and more males than females reported choosing low-fat milk. These perceptions of choice of low-fat milk seem consistent with food records, since of those who drank milk during the three-day period, 29% of males versus 25% of females drank low-fat milk. Many female adolescents may believe they are choosing lowfat foods, but lack the knowledge of food composition and dietary skills necessary for such choices. While more males than females had sodium intake over recommended levels, more males than females perceived themselves as limiting salt intake. Adolescents probably think of table salt use when considering whether they limit salt intake and are unaware of the sodium, especially in processed foods. Assessment of table salt use was not quantified in this study. In contrast to this study, Read and colleague~~~ found that males perceived avoiding salt less frequently than females. However, a similar percent of males, 45% versus 43%, in both studies were avoiding or limiting salt. Read and colleague^^^ also found somewhat higher percents of males and females reported complying to the Dietary Guidelines to avoid too much fat, 35% versus 22.5% for males and 50% versus 43.6% for females. Assessment of cardiovascular nutrition knowledge indicated these adolescents knew little about the process of cardiovascular disease and heart-healthy food choices. Though the general public is more aware of issues involving fat intake and heart disease, I * adolescents in this study appeared to have no greater cardiovascular nutrition knowledge than the teens reported by Podell and colleagues6in the mid-seventies. In addition, findings are consistent with results from the National Adolescent Student Health Survey" that adolescents are not able to identify foods high in fat, salt, and fiber. These findings support the general lack of nutrition knowledge among adolescents previously reported.m23 The fact that females scored higher than males also is consistent with findings of other researchers."
CONCLUSION These findings emphasize the importance of the recommendation of the Population Panel for appropriate educational curricula offered within the school system from kindergarten through 12th grade. This concept is embodied in the philosophy of a comprehensive school health program which would provide for integration of services and programs to improve the health of America's school children.w25 Many adolescents in this study did not have food behaviors that promote heart health. Since nutrition can affect future health in terms of CVD, greater emphasis must be placed on prevention, which means providing opportunities for adolescents to identify risk factors for CVD and to modify food-choice behaviors that may otherwise continue into adulthood. This task may not be easy, because it requires an uncharacteristic futuristic
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focus for adolescents. However, school health programs offer opportunities for adolescents to develop behaviors, skills, knowledge, and attitudes necessary to make informed food choices for better health.26 Offering nutrition education curricula that allow for individualization to meet the needs presented by differences in gender and the variation seen among adolescents is imperative to maximize the effect of school health programs on the health and well-being of adolescents. m References 1. Expert Panel on Population Strategies f o r Blood Cholesterol
Reduction. Bethesda, Md: National Cholesterol Education Program, Office of Prevention, Education and Control, National Institutes of Health publication no 90-3047;1990. 2. Expert Panel on Blood Cholesterol Levels in Children and Adolescents. Bethesda, Md: Office of Prevention, Education and Control, National Institutes of Health; publication no 91-2732;1991. 3. White AA. Changing adolescents’ food-related behavior via nutrition education. Knoxville, Tenn: University of Tennessee; 1988. Dissertation. 4. US Dept of Agriculture and US Dept of Health and Human Services. Nutrition and Your Health: Dietary Guidelines f o r Americans. Washington, DC: US Government Printing Office; USDA Home and Garden bulletin no 232; 1985. 5 . National Examination of Cardiovascular Knowledge. Dallas, Texas: American Heart Association Office of Communication; 1982. 6. Podell RN, Keller K, Berger G. Cardiovascular nutrition knowledge and lipid levels among New Jersey high school students. J Med Soc NJ. 1975;72(12):1027-1031. 7 . American Heart Association. Dietary guidelines for healthy American adults. Circulation. 1988;77(3):721a-724a. 8. Kritchevsky D. Dietary fiber. Ann Rev Nutr. 1988;8:301-328. 9. Buzzard IM, Asp EH, Chlebowski RT, Boyar AP, Jeffery RW, et al. Diet intervention methods to reduce fat intake: Nutrient and food group composition of self-selected low-fat diets. J A m Diet ASSOC.1990;90(1):42-53. 10. Witschi JC, Capper AL, Ellison RC. Sources of fat, fatty acids, and cholesterol in the diets of adolescents. J A m Diet Assoc. 1W;W (10): 1429-1431. 11. National Research Council. Subcommittee on the Tenth
Edition of the RDAs: Recommended Dietary Allowances, 10th ed. Washington, DC: National Academy Press; 1989;33. 12. Kuczmarski RJ, Brewer ER, Cronin FJ. Dennis B. Graves K, Hayes S. Food choices among white adolescents: The Lipid Research Clinics Prevalence Study. Pediatr Res. 1986;20(4):309-315. 13. Truswell AS, Darnton-Hill I. Food habits of adolescents. Nutr Rev. 1981;39(2):73-88. 14. Skinner JD, Salvetti NN, Ezell JM, Penfield MP, Costello CA. Appalachian adolescents’ eating patterns and nutrient intakes. J A m Diet Assoc. 1985;85(9):1093-1099. 15. Woodward DR. What influences adolescent food intakes? Hum Nutr Appl Nutr. 1986;40A:185-194. 16. Previtt TE, Haynes SG, Graves K, Haines PS, Tyroler HA. Nutrient intake, lipids and lipoprotein cholesterols in black and white children: The Lipid Research Clinics Prevalence Study. Prev Med. 1988;17947-262. 17. Read MH, Harveywebster M, Usinger-Lesquereux J. Adolescent compliance with dietary guidelines: Health and education implications. Adolescence. 1988;23(91):567-575. 18. The 1990 Health Objectives f o r the Nation: A Midcourse Review. Washington, DC: US Public Health Service; 1986. 19. American School Health Association, Association for the Advancement of Health Education, Society for Public Health Education, lnc. The National Adolescent Student Health Survey: A Report on the Health of America’s Youth. Oakland, Calif Third Party Publishing; 1989. 20. White AA, Skinner JD. Can goal setting as a component of nutrition education effect behavior change among adolescents? J Nutr EdUC. 1988;20(6):327-335. 21. Salvetti NN, Skinner JD. Nutrition attitudes and knowledge of east Tennessee adolescents. Tenn Farm Home Sci. 1985;1391 1-14. 22. Skinner JD, Woodburn MJ. Nutrition knowledge of teenagers. J Sch Health. 1984;54(2):71-74. 23. Portnoy B, Christenson GM. Cancer knowledge and related practices: Results from the National Adolescent Student Health Survey. J Sch Health. 1989;59(5):218-224. 24. Nader PR. The concept of “comprehensiveness” in the design and implementation of school health programs. J Sch Health. 1990;60(4):133-137. 25. Allensworth DD, Kolbe LJ. The comprehensive school health program: Exploring an expanded concept. J Sch Health. 1987;57(10): 409-412. 26. McGinnis JM, DeGraw C. Healthy schools 2000: Creating partnerships for the decade. J Sch Health. 1991;61(7):292-297.
Statement of Purpose The Journal of School Health. an official publication of the American School Health Association, publishes material related to health promotion in school settings. Journal readership includes administrators, educators, nurses, physicians, dentists, dental hygienists, psychologists, counselors, social workers, nutritionists, dietitians, and other health professionals. These individuals work cooperatively with parents and the community to achieve the common goal of providing children and adolescents with the programs, services, and environment necessary to promote health and to improve learning. Contributed manuscripts are considered for publication in the following categories: general articles, research papers, commentaries, teaching techniques, and health service applications. Primary consideration is given to manuscripts related to the health of children and adolescents, and to the health of employees, in public and private pre-schools and child day care centers, kindergartens, elementary schools, middle level schools, and senior high schools. Manuscripts related to college-age young adults will be considered if the topic has implications for health programs in preschools through grade 12.Relevant international manuscripts also will be considered. Prior to submitting a manuscript, prospective authors should review the most recent “Guidelines for Authors.” The guidelines are printed periodically in the Journal; copies also may be obtained from the Iournnl office, P.O. Box 708. Kent, OH 44240.
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