Nutrition Diet and Weight Issues among Children and Adolescents - Health Risks And Consequences

95th 90th blood pressure

The harmful health consequences of overweight and obesity can begin during childhood and adolescence. According to the CDC, more than half (nearly 60 percent) of overweight children have at least one cardiovascular risk factor compared to 10 percent of those with a BMI-for-age less than the 85th percentile, and 25 percent of overweight children have two or more risk factors. The most frequently occurring medical consequences of overweight among children and adolescents are:

FIGURE 4.9
Percentage of schools that require physical education, by grade, 2000

TABLE 4.5
Percentage of states and districts requiring health education topics to be taught in at least one school level, and percentage of schools at each level requiring each topic to be taught, by topic, 2000

States Districts Elementary schools Middle/junior high schools Senior high schools
Accident* or injury prevention 68.6 85.3 80.3 66.3 71.7
Alcohol or other drug use prevention 78.4 92.2 88.5 87.7 91.2
HIV prevention 72.6 91.7 50.1 75.9 85.6
Nutrition and dietary behavior 70.6 89.9 85.4 81.4 87.1
Physical activity and fitness 64.7 87.8 77.0 74.7 79.0
Pregnancy prevention 49.0 83.3 18.6 54.8 79.6
STD prevention 62.8 89.0 24.7 69.1 84.8
Suicide prevention 48.0 80.2 22.3 49.5 75.1
Tobacco use prevention 78.4 92.1 85.9 86.4 90.1
Violence prevention 60.8 88.7 85.5 72.5 74.1
*Although the School Health Policies and Programs Study 2000 questionnaires used the word "accident" because it is familiar to many people, public health officials prefer the word "injury" because it connotes the medical consequences of events that are both predictable and preventable.
SOURCE: "Percentage of States and Districts Requiring Health Education Topics to Be Taught in at Least One School Level, and Percentage of Schools at Each Level Requiring Each Topic to be Taught, by Topic," in School Health Policies and Programs Study, Centers for Disease Control and Prevention, National Center for Chronic Disease Prevention and Health Promotion, Division of Adolescent and School Health, Atlanta, GA, 2001 [Online] http://www.cdc.gov/shpps [accessed January 12, 2004]

TABLE 4.6
Blood pressure levels for the 90th and 95th percentiles of blood pressure for boys ages 1 to 17 years

Systolic BP (mm Hg), by height percentile from standard growth curves Diastolic BP (mm Hg), by height percentile from standard growth curves
Age BP percentile* 5% 10% 25% 50% 75% 90% 95% 5% 10% 25% 50% 75% 90% 95%
1 90th 94 95 97 98 100 102 102 50 51 52 53 54 54 55
95th 98 99 101 102 104 106 106 55 55 56 57 58 59 59
2 90th 98 99 100 102 104 105 106 55 55 56 57 58 59 59
95th 101 102 104 106 108 109 110 59 59 60 61 62 63 63
3 90th 100 101 103 105 107 108 109 59 59 60 61 62 63 63
95th 104 105 107 109 111 112 113 63 63 64 65 66 67 67
4 90th 102 103 105 107 109 110 111 62 62 63 64 65 66 66
95th 106 107 109 111 113 114 115 66 67 67 68 69 70 71
5 90th 104 105 106 108 110 112 112 65 65 66 67 68 69 69
95th 108 109 110 112 114 115 116 69 70 70 71 72 73 74
6 90th 105 106 108 110 111 113 114 67 68 69 70 70 71 72
95th 109 110 112 114 115 117 117 72 72 73 74 75 76 76
7 90th 106 107 109 111 113 114 115 69 70 71 72 72 73 74
95th 110 111 113 115 116 118 119 74 74 75 76 77 78 78
8 90th 107 108 110 112 114 115 116 71 71 72 73 74 75 75
95th 111 112 114 116 118 119 120 75 76 76 77 78 79 80
9 90th 109 110 112 113 115 117 117 72 73 73 74 75 76 77
95th 113 114 116 117 119 121 121 76 77 78 79 80 80 81
10 90th 110 112 113 115 117 118 119 73 74 74 75 76 77 78
95th 114 115 117 119 121 122 123 77 78 79 80 80 81 82
11 90th 112 113 115 117 119 120 121 74 74 75 76 77 78 78
95th 116 117 119 121 123 124 125 78 79 79 80 81 82 83
12 90th 115 116 117 119 121 123 123 75 75 76 77 78 78 79
95th 119 120 121 123 125 126 127 79 79 80 81 82 83 83
13 90th 117 118 120 122 124 125 126 75 76 76 77 78 79 80
95th 121 122 124 126 128 129 130 79 80 81 82 83 83 84
14 90th 120 121 123 125 126 128 128 76 76 77 78 79 80 80
95th 124 125 127 128 130 132 132 80 81 81 82 83 84 85
15 90th 123 124 125 127 129 131 131 77 77 78 79 80 81 81
95th 127 128 129 131 133 134 135 81 82 83 83 84 85 86
16 90th 125 126 128 130 132 133 134 79 79 80 81 82 82 83
95th 129 130 132 134 136 137 138 83 83 84 85 86 87 87
17 90th 128 129 131 133 134 136 136 81 81 82 83 84 85 85
95th 132 133 135 136 138 140 140 85 85 86 87 88 89 89
*Blood pressure percentile determined by a single measurement.
SOURCE: "Table 16. Blood pressure levels for the 90th and 95th percentiles of blood pressure for boys ages 1 to 17 years," in National High Blood Pressure Education Program Working Group on Hypertension Control in Children and Adolescents, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD [Online] http://www.cdc.gov/nccdphp/dnpa/growthcharts/training/modules/module3/text/hypertension_tables.htm [accessed January 8, 2004]
  • Elevated blood lipids—Overweight children and adolescents display the same elevated levels of cholesterol, triglycerides and/or low density lipoproteins as overweight adults. These hyperlipidemias are linked to increased risk for cardiovascular disease and premature mortality (death) in adulthood.
  • Glucose intolerance and Type 2 Diabetes—Glucose intolerance, a carbohydrate intolerance that varies in severity, is a forerunner of diabetes. The incidence of Type 2 diabetes (also called non-insulin-dependent diabetes mellitus) among adolescents is increasing in response to the national rise in overweight among teens. A skin condition known as acanthosis nigricans—velvety thickening and darkening of skin fold areas at the neck, elbow, and behind the knee—often coexists with glucose intolerance in youth.
  • Fatty liver disease—High concentrations of liver enzymes are associated with fatty degeneration of the liver (also termed hepatic steatosis) and have been found in overweight children and adolescents. Excessively high blood insulin levels (hyperinsulinemia) may contribute to the genesis of this disease.
  • Gallstones—Although gallstones occur less frequently among children and adolescents who are overweight than in obese adults, nearly half of the cases of inflammation of the gallbladder (also called cholecystitis) in adolescents may be associated with overweight. Like adults, the risk for cholecystitis and gallstones in adolescents may decrease with weight reduction.

Another common health consequence of overweight is early maturation, a condition in which measurement of skeletal age is more than three months greater than chronological age. Early maturation is linked to overweight in adulthood and is also associated with the distribution of fat—it predicts the fat predominantly located on the abdomen and trunk that is in turn predictive of increased disease risk.

TABLE 4.7
Blood pressure levels for the 90th and 95th percentiles of blood pressure for girls ages 1 to 17 years

Systolic BP (mm Hg), by height percentile from standard growth curves Diastolic BP (mm Hg), by height percentile from standard growth curves
Age BP percentile* 5% 10% 25% 50% 75% 90% 95% 5% 10% 25% 50% 75% 90% 95%
1 90th 97 98 99 100 102 103 104 53 53 53 54 55 56 56
95th 101 102 103 104 105 107 107 57 57 57 58 59 60 60
2 90th 99 99 100 102 103 104 105 57 57 58 58 59 60 61
95th 102 103 104 105 107 108 109 61 61 62 62 63 64 65
3 90th 100 100 102 103 104 105 106 61 61 61 62 63 63 64
95th 104 104 105 107 108 109 110 65 65 65 66 67 67 68
4 90th 101 102 103 104 106 107 108 63 63 64 65 65 66 67
95th 105 106 107 108 109 111 111 67 67 68 69 69 70 71
5 90th 103 103 104 106 107 108 109 65 66 66 67 68 68 69
95th 107 107 108 110 111 112 113 69 70 70 71 72 72 73
6 90th 104 105 106 107 109 110 111 67 67 68 69 69 70 71
95th 108 109 110 111 112 114 114 71 71 72 73 73 74 75
7 90th 106 107 108 109 110 112 112 69 69 69 70 71 72 72
95th 110 110 112 113 114 115 116 73 73 73 74 75 76 76
8 90th 108 109 110 111 112 113 114 70 70 71 71 72 73 74
95th 112 112 113 115 116 117 118 74 74 75 75 76 77 78
9 90th 110 110 112 113 114 115 116 71 72 72 73 74 74 75
95th 114 114 115 117 118 119 120 75 76 76 77 78 78 79
10 90th 112 112 114 115 116 117 118 73 73 73 74 75 76 76
95th 116 116 117 119 120 121 122 77 77 77 78 79 80 80
11 90th 114 114 116 117 118 119 120 74 74 75 75 76 77 77
95th 118 118 119 121 122 123 124 78 78 79 79 80 81 81
12 90th 116 116 118 119 120 121 122 75 75 76 76 77 78 78
95th 120 120 121 123 124 125 126 79 79 80 80 81 82 82
13 90th 118 118 119 121 122 123 124 76 76 77 78 78 79 80
95th 121 122 123 125 126 127 128 80 80 81 82 82 83 84
14 90th 119 120 121 122 124 125 126 77 77 78 79 79 80 81
95th 123 124 125 126 128 129 130 81 81 82 83 83 84 85
15 90th 121 121 122 124 125 126 127 78 78 79 79 80 81 82
95th 124 125 126 128 129 130 131 82 82 83 83 84 85 86
16 90th 122 122 123 125 126 127 128 79 79 79 80 81 82 82
95th 125 126 127 128 130 131 132 83 83 83 84 85 86 86
17 90th 122 123 124 125 126 128 128 79 79 79 80 81 82 82
95th 126 126 127 129 130 131 132 83 83 83 84 85 86 86
*Blood pressure percentile determined by a single measurement.
SOURCE: "Table 17. Blood pressure levels for the 90th and 95th percentiles of blood pressure for girls ages 1 to 17 years," in National High Blood Pressure Education Program Working Group on Hypertension Control in Children and Adolescents, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD [Online] http://www.cdc.gov/nccdphp/dnpa/growthcharts/training/modules/module3/text/hypertension_tables.htm [accessed January 8, 2004]

Less frequently occurring health consequences include hypertension (high blood pressure), a condition that is nine times more frequent among children who are overweight compared with other children; sleep apnea (breathing becomes very shallow or stops completely because the windpipe becomes obstructed for short periods during sleep), a condition that afflicts an estimated 7 percent of overweight children; and orthopedic problems resulting from excessive stress on the feet, legs, and hips. Hypertension for children and adolescents one to seventeen years old is defined as average blood pressure readings at or above the 95th percentile (based on age, sex, and height) on at least three separate occasions. (See Table 4.6 and Table 4.7 for blood pressures by age and gender that are considered indicative of hypertension or at risk for hypertension. Children and adolescents between the 90th and 95th percentiles for their age, sex, and height are at risk for developing hypertension.) According to the CDC, several studies have confirmed that blood pressure and change in BMI during childhood were the two most powerful predictors of adult blood pressure across all ages and both genders.

The results of a school-based survey of children and adolescents (ages nine, thirteen, and sixteen years) in Canada, presented at the 2003 American Heart Association's Annual Conference on Cardiovascular Disease Epidemiology and Prevention, suggested that increase in blood pressure is related to the obesity epidemic in children and adolescents. The McGill University School of Medicine investigators gathered information on lifestyle and demographic data as well as height, weight, blood pressure, and body fat, and calculated BMI for nearly 3,600 of the participants. They found that average blood pressure rose with increasing BMI categories in all age and sex groups (Joan Stephenson, "Obesity-Hypertension Link in Children?" Journal of the American Medical Association, vol. 289, no. 14, April 2003).

Very rarely, overweight children may suffer from increased skull pressure that causes severe headaches, dizziness, nausea, and vomiting (known as pseudotumor cerebri, because its symptoms mimic the symptoms caused by the pressure of a tumor), or a breathing disorder known as hypoventilation syndrome (also known as Pickwickian syndrome), in which excessive weight impedes movement of the chest wall and diaphragm necessary for breathing. As a result, breathing is shallow, and there may be decreased ability to oxygenate the blood.

Metabolic Syndrome

The metabolic syndrome is a group of risk factors for atherosclerotic cardiovascular disease and Type 2 diabetes mellitus in adults that includes insulin resistance, obesity, hypertension, and hyperlipidemia. (Atherosclerosis is a hardening of the walls of the arteries caused by fatty deposits that build on the inner walls of the arteries and interfere with blood flow.) Atherosclerotic cardiovascular disease is the leading cause of death among adults, but occurs very rarely in young people. Recently, however, the risk factors—high blood pressure, elevated triglycerides (a fatty substance found in the blood), obesity, and low levels of the "good" HDL cholesterol—associated with its development have been appearing during childhood.

At the November 2003 meeting of the American Heart Association, researcher Joanne Harrell from the University of North Carolina at Chapel Hill, Center for Research on Chronic Illness, presented worrisome findings from a study of 3,200 boys and girls ages eight to seventeen years old showing a much higher prevalence of risk factors for metabolic syndrome than previous studies. More than half of the subjects had a least one of six risk factors—obesity, high blood pressure, high triglycerides, low levels of HDL cholesterol, glucose intolerance, and elevated insulin levels—for metabolic syndrome. The most common risk factor, found in more than 43 percent of the subjects, was a low HDL cholesterol level. More than 27 percent had two or more risk factors, and 13.5 percent had at least three risk factors. More girls (16.3 percent) than boys (10.7 percent) had at least three risk factors for metabolic syndrome. More than 8 percent of the children who had three or more factors were between eight and nine years old. The researchers hoped that the results of the study would serve as a warning that without effective intervention, many children and teenagers with these risk factors will develop Type 2 diabetes and heart disease.

In a review of recent research, "Diagnosis of the Metabolic Syndrome in Children" (Current Opinion in Lipidology, vol. 14, no. 6, December 2003), Julia Steinberger found that the process of atherosclerosis starts at an early age and is linked to obesity in childhood. Obesity beginning in childhood often precedes the hyperinsulinemia, and other components of the metabolic syndrome are also present in children and adolescents. Being overweight during childhood and adolescence is significantly associated with insulin resistance, dyslipidemia (high LDL and triglycerides, and low HDL), and high blood pressure in young adulthood. In view of the increasing prevalence of metabolic syndrome in children and adolescents, Steinberger recommended that "The first approach should focus on prevention of obesity in childhood. More attention should be paid to increasing physical activity and decreasing calorie consumption in this age group. Once obesity is established in a child or adolescent, vigorous clinical efforts should be directed at treating it."

Mental Health Consequences

One of the most immediate, distressing, and widespread consequences of being overweight as described by children themselves is social discrimination and low self-esteem. Overweight and obese children and adolescents are at risk for psychological and social adjustment problems such as considering themselves less competent than normal-weight youth in social, athletic, and appearance arenas, as well as suffering from overall diminished self-worth. In "Health-Related Quality of Life of Severely Obese Children and Adolescents" (Journal of the American Medical Association, vol. 289, no. 14, April 2003), Jeffrey Schwimmer and his colleagues at the University of California, San Diego, found that obese children rated their quality of life with scores as low as those of young cancer patients undergoing chemotherapy (medical treatment to combat cancer). The researchers analyzed the responses of 106 children aged five to eighteen to a questionnaire used by pediatricians to evaluate quality-of-life issues. Study participants were asked to rate attributes such as their ability to walk more than one block, play sports, sleep well, get along with others, and keep up in school.

The results indicated that teasing at school, difficulties playing sports, fatigue, sleep apnea, and other obesity-linked problems severely affected obese children's well being. The obese subjects were five times more likely than healthy children and adolescents to have impaired physical functioning and 5.9 times more likely to have impaired psychosocial functioning. They were four times more likely than healthy children and adolescents to report impaired school function and had missed a mean of 4.2 days of school in the month prior to the study compared to less than one day of school missed for children who were not overweight. When the parents of the subjects completed the same questionnaires, their ratings of their children's abilities and well being were even lower than the children's self-reported ratings.

Do Mental Health Problems Cause Overweight?

The mental health consequences of overweight and obesity—stigmatization, discrimination, isolation, and depression—are well known; however, recent research offers evidence that mental health and behavioral problems may be contributing to weight gain among children. In "Association between Clinically Meaningful Behavior Problems and Overweight in Children" (Pediatrics, vol. 112, November 2003), Julie C. Lumeng and her colleagues examined data about 755 children between the ages of eight and eleven derived from a national survey of children whose parents had answered questionnaires about their weight and behavior. After adjusting for a variety of risk factors associated with childhood obesity, the investigators concluded that behavioral problems were associated with a threefold increase in risk for overweight. This increase was comparable to other well-documented risk factors such as having a parent who was obese.

The type of behavior problems the children displayed did not appear to determine whether the children gained weight. Children who were aggressive or defiant were just as likely to become overweight as those who were withdrawn and showed other signs of depression. Although the research did not address the underlying reasons that behavioral problems are linked to weight gain, the investigators hypothesized that behavioral problems are often symptoms of depression and that "Kids who are depressed may be more likely to overeat and to sit around watching TV." They also suggested that future research will identify multiple relationships between obesity and depression, rather than simply cause and effect.

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