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

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.