Increasing obesity in children and adolescents: An alarming epidemic

Obesity in children, as well as in adults, is defined by their BMI. BMI is the preferred measurement for use among children and adolescents to determine their weight status.6 BMI is calculated as body weight in kilograms divided by height in meters squared.7 For children in the United States, overweight status is defined using CDC age- and sex-specific criteria for BMI. A BMI percentile greater than the 5th but less than the 85th is considered normal weight for height; those in the 85th to 95th percentile are considered at risk for becoming overweight; and those in greater than the 95th percentile are defined as overweight.8,9

Weight status can be quickly, simply, and inexpensively estimated using the BMI, as BMI correlates with amount of body fat. BMI can also be used as a predictor of becoming overweight as an adult based on being overweight in childhood. The chance of becoming an overweight adult is greater than 50% among children older than 13 years whose BMI percentile meets or exceeds the 95th percentile for their respective age and gender.6 Individual BMI charts corresponding to age and sex can be found in Figure 1 and Figure 2 and at http://www.cdc.gov/nchs/about/ major/nhanes/growthcharts/clinical_charts.htm.10

CAUSES OF OVERWEIGHT IN CHILDHOOD

Diet Meal portion sizes in restaurants have more than doubled over the past 2 decades. Most fast food restaurants offer up to 20% larger portion sizes (“supersizing”) for minimal additional cost, adding hundreds of extra calories to a meal.4 Children's food preferences are influenced by just 30-second exposures to television commercials.4 One-third of American children aged 4 to 19 years eat fast food daily; this increases their weight by an estimated 6 lb per year.4 Children should triple their birth weight by 1 year of age, quadruple their birth weight by 2 years of age, gain 5 lb per year from age 2 until they begin puberty, and their weight should remain stable after puberty. Significant adverse changes have occurred in older children's food consumption as well. Older children are less likely to eat breakfast regularly. They eat more foods prepared away from home; get more of their total calories from snacks, fried foods, and sweetened beverages; and eat larger portion sizes. Their consumption of dairy products has decreased, as has their intake of high-fiber fruits and vegetables.9,11 Sodium intake is far in excess of recommended levels, whereas calcium and potassium intakes are below recommended levels.9,11

In addition, peer and media pressure heavily influence children's nutritional intake. For example, a substantial proportion of the advertising on children's television promotes food, and there is a direct relationship between the amount of television viewing and body weight.8 Furthermore, reducing television viewing has reduced weight gain and the prevalence of obesity in experimental trials.8 Peer pressure for conformity, also in part driven by media promotion of fast food directly to teens, makes overeating feel like a natural behavior. Currently, adolescents have an increased intake of sweetened beverages, French fries, pizza, and fast food entrees, and a consequent inadequate intake of recommended fruits, vegetables, dairy foods, whole grains, lean meats, and fish.11

School lunch programs are also to blame for the rise in the numbers of overweight children. Research has demonstrated that buying lunch at school significantly increases the risk of becoming overweight.12 The pervasiveness of school a la carte and vending programs that sell foods and beverages that are high in calories and low in nutrients is well-documented.13 However, the food provided is constrained by budgetary and regulatory issues largely external to public health concerns. US Department of Agriculture guidelines require school food programs to provide minimum quantities of specific nutrients over a 3- to 7-day span but do not address maximum food amounts.11

Other practices that may contribute to the development of childhood obesity include providing food choices that are high in calories and low in nutrients at school and classroom fundraising events and as rewards and incentives for students. More than 70% of teachers in surveyed middle schools used candy, cookies, doughnuts, sweetened drinks, and pizza as student incentives or rewards.13

Lack of physical activity Being sedentary is positively associated with becoming overweight, and 25% of American children are classified as completely sedentary.4,9 The amount of time that children spend playing outside has decreased over the past few decades, and physical education programs in schools are being cut. Children are thus spending more time watching television and playing on the computer than engaging in physical activity. Television watching has been directly linked to becoming overweight in childhood, with a rate of obesity that is 8.3 times greater in children who watch more than 5 hours of television per day, as compared with those who watch 2 hours or less of television per day.4,9 The relationship between time spent viewing television and BMI values is well-documented, but even if it were not, it is reasonable to suppose that the time spent in sedentary activities, such as television viewing, is time that could have been spent in physical activity.14

School programs are a major influence in children's lives, as children spend a large part of their time in the school environment. Today, only 25% of students participate in physical education classes, and only 22% meet basic activity level recommendations.4,9 In addition, participation in schoolsponsored after-school teams is frequently limited to elite athletes, so other high school-age students miss out on these opportunities to engage in regular physical activity.11

ADVERSE OUTCOMES OF CHILDHOOD OBESITY

Medical As the number of overweight children increases, the medical complications of excess weight are becoming more common in this age-group and more frequently diagnosed.15 Overweight children often become overweight adults, and being overweight in adulthood is a serious health risk.2,3,8,9,16,17 Adolescence is a critical period for development and expression of obesity-related comorbidities in both sexes. During adolescence, the respiratory and cardiovascular systems are growing slowly in proportion to blood vessels and the rest of the body. Also, the liver grows to adult size, and the kidneys begin to function at an adult level. The bones begin to ossify as the skeleton grows faster than the muscles, and cognitive development expands. Adolescents also progress through the Tanner stages during these years.

Conditions such as type 2 diabetes, hypertension, hypercholesterolemia, cholelithiasis, and cholecystitis, which were previously seen primarily in adults, are becoming more common among children as the prevalence of obesity increases.6,11,12,16,18,19 The metabolic syndrome (elevated triglyceride levels, low HDL cholesterol levels, hypertension, and a high fasting blood glucose level) is now being seen more frequently in overweight children.8,9,15,20-23 Four percent of all adolescents and nearly 30% of overweight adolescents in the United States meet criteria for the metabolic syndrome.15

The lipid profile associated with the metabolic syndrome and obesity increases the risk for cardiovascular disease.4 Atherosclerosis, which commonly occurs in adulthood, has also been found to be linked to childhood obesity.4 The Pathobiological Determinants of Atherosclerosis in Youth research group found that obesity in young men was associated with fatty streaks, raised lesions, and low-grade stenosis of the coronary arteries.6,15,24 Also, cases of pediatric hypertension are on the rise. This is thought to be due, in part, to the increasing prevalence of childhood obesity, not just to growing awareness of this disease.6,24,25 There is evidence that childhood hypertension can lead to adult hypertension, and hypertension is a known risk factor for coronary artery disease.6,24,25 The prevalence of childhood hypertension may contribute to the early development of coronary artery disease.6,24,25

Psychological In addition to the adverse medical outcomes resulting from childhood overweight and obesity, psychological problems can occur as well. Significant short-term morbidities for overweight and obese children are psychological and include social marginalization, decreased self-esteem, decreased quality of life, and negative body image.2,6,12,26 Children's perceptions of obesity emphasize laziness, selfishness, lower intelligence, social isolation, poor social functioning, and decreased academic success as well as low levels of perceived health, healthy eating, and activity; which leads to the assumption that children share the same overall negative picture of those who are overweight.7,9 Children as young as 5 years are aware of being overweight, which impacts their perceptions of appearance, athletic ability, social competence, and self-worth.9 Social network mapping suggests that normalweight children have more relationships with a central network of children, whereas overweight children appear to have more isolated and peripheral relationships.8,9 In addition to having fewer friends, being teased about weight is another important mediator of psychological distress.8,9 Teasing, often experienced by overweight youth, has been shown to be associated with an increase in both suicidal ideation and number of suicide attempts.8,9 Obese girls are more likely to have attempted suicide than are nonobese girls.9 Overweight adolescents reported engaging in significantly more unhealthy behaviors, such as self-mutilation, and experiencing more psychosocial distress than their normal-weight peers.9

Studies have also reported increased incidences of anxiety and depression in overweight and obese children and adolescents. A community-based cohort study from childhood to adulthood using DSM-IV criteria found that in females, anxiety disorders and depression are associated with higher weight.17 The diagnosis of anxiety in males also correlated with high BMI scores.17 In a previous study, adults who had received a diagnosis of depression during their youth had a higher BMI than did adults who did not suffer from depression during their youth.8 Other studies have confirmed the association between depression and subsequent obesity. Another study examined adolescents in grades 7 to 12 and found that elevated BMI was related to depression at 1 year of follow-up.8 The depression scores were highest in children with the greatest increase in BMI.8 Among severely overweight adolescents (BMI greater than the 95th percentile), 48% have moderate to severe depressive symptoms and 35% report high levels of anxiety.9

TREATMENT

Diet modification Decreasing portion sizes and minimizing consumption of high-calorie foods and drinks are the most common dietary recommendations for obese children.4 The American Heart Association (AHA) continues to recommend diets low in saturated fat and trans fat for children as young as 2 years.11 Healthy foods include fruits, vegetables, whole grains, legumes, low-fat dairy products, fish, poultry, and lean meats.8,11 Consuming well-balanced meals is critical to losing weight and learning the principles of healthy eating. Balanced meals have servings from at least three of the four food groups, and balanced snacks have servings from two of the four food groups.27 It is also important to limit intake of salt to less than 6 g per day and reduce dietary sugar.8 Reading nutrition labels on food and not salting foods during meals are helpful ways to achieve these goals.

Emphasizing appropriately-sized food portions is an important step in diet modification for children at all ages and is also critical in the education process. Healthy portion sizes can easily be determined by reading the nutrition information on food packages and consuming only that amount. Portion sizes for fresh foods are available from the US Department of Agriculture's food pyramid, at www. mypyramid.gov. It is also important to reduce the number of meals consumed outside of the home and involve children in meal planning and food preparation.8

Children should follow a low-fat, low-calorie diet, but growing children must also receive the nutrition they need. The general dietary recommendations of the AHA for children aged 2 years and older stress a diet that primarily relies on fruits, vegetables, whole grains, beans, fish, and lean meat.11 Children older than 2 years should consume low-fat or fat-free milk or other dairy products 2 or 3 times daily, and sweetened beverages should be limited to 4 to 6 oz of 100% juice daily. Trans fatty acids and saturated fats should be avoided in favor of polyunsaturated fats.9,11,27 For example, French fries, which contain trans fatty acids, should be exchanged for baked potato chips or crackers, which contain polyunsaturated fats.9,11,27 Studies involving adolescents have found that consumption of sugar-sweetened drinks is an independent variable associated with increased BMI. A modified low-glycemic diet, which includes whole grains, fresh fruits and vegetables, legumes, and lean protein, reduced BMI and fat mass in obese adolescents.9 Elimination of sugary drinks from the diet can significantly reduce caloric intake and obesity.9 Caloric restriction (but not “crash” diets) is safe and can be effective when obese children and their families are motivated to make changes.

Increasing physical activity Along with diet modification, increasing physical activity is essential to weight loss and maintenance of healthy weight. Exercise provides additional health benefits for overweight individuals, including reduction of future health risks, improved insulin sensitivity, BP reduction, and improved socialization through group participation in activities.8 The benefits of exercise are mediated, at least in part, by reductions in total fat stores and increases in lean body mass, which increase resting basal metabolic rate.9 Exercise reduces free fatty acid, LDL cholesterol, and triglyceride concentrations and increases plasma HDL cholesterol levels.5 Other demonstrated benefits of exercise include increased cardiovascular fitness, maintenance of weight loss, improvements in endothelial function, and reductions of inflammatory markers.4 Weight reduction is the primary therapy for obesity-related pediatric hypertension. Regular physical activity and restriction of sedentary activity will improve efforts at weight management and may prevent an increase in BP over time.4

The CDC currently recommends 60 minutes of daily physical activity for children.4,8,9,12 Activities should be enjoyable, rewarding, and appropriate for the child's lifestyle. Riding a bicycle, skating, walking the dog, dancing, swimming, weightlifting (after age 15 years), and training for a sport during the off-season may be more easily integrated into a child's or teen's lifestyle than participating in organized sports teams. Also, sedentary activities should be restricted to less than 2 waking hours per day outside of school. One way to achieve this objective is to encourage children to selfmonitor time spent in sedentary activities, including watching television and playing video or computer games, and set goals to decrease these activities.8,9,14,28 A recent study found that increasing exercise training and education and decreasing sedentary activity resulted in a significant decrease in weight and an improvement in fitness.16

Involvement of school Schools must review their policies and procedures to promote healthy eating. This should include review of vending machine offerings, food available in school cafeterias, and types of food allowed for classroom events. Healthy foods such as baked chips and crackers, lowcalorie snacks (such as 100-calorie packaged snacks), dried fruits, and nuts, for example, could be placed in vending machines as healthy options. A curriculum for nutrition education to promote healthy eating habits, healthy body image, and weight management is essential from preschool through high school. Healthy eating opportunities include affordable, palatable fresh fruits and vegetables and healthier food choices in cafeterias and vending machines.9 Halting the sales of soft drinks in schools has been suggested as a way to reduce the intake of refined sugars and help to prevent children from becoming overweight.12 Soft drinks could be replaced by increasing the sale of bottled water in schools or by simply installing more water fountains in schools so that water is more readily available to students.

The CDC has developed guidelines for healthy eating programs in schools that include recommendations regarding school policies, curricula, integration of school food services and nutrition education, staff training, family and community involvement, and program evaluation.18 Broader implementation of such programs is justified because they have a high potential to reduce childhood obesity and, in the longer term, comorbid conditions and health care spending.18 In addition, schools should institute educational programs that help students learn specific nutrition-related skills, such as how to plan a healthy meal and how to compare food labels, assess health habits, and set goals for improvement.2

Schools should require daily physical education and health education from kindergarten through grade 12. Schools and community programs should provide funding, equipment, and supervision for programs that meet the needs and interests of students and provide access to safe facilities.2 Schools should also be providing time for unstructured physical activity, such as recess, and implement sequential physical education curricula and instruction that emphasize enjoyable participation in lifetime physical activities, not just competitive sports.2 Extracurricular physical activity programs should offer diverse activities, both competitive and noncompetitive.2

Involvement of family Parents are the most influential people in childrens' lives and therefore they should be involved in encouraging a healthy lifestyle. Experts emphasize talking to families about energy balance behaviors that might help prevent obesity and also promote other aspects of health. These behaviors include limiting television viewing, encouraging outdoor play, and limiting the consumption of sugarsweetened drinks.6 Furthermore, families who eat together are less likely to be overweight or obese, in part because children in such families generally eat a healthier diet.12 A second reason is that family meals generally prevent children from eating in front of the television, which may lead to “mindless eating” and a higher energy intake.12

Family involvement is crucial to the treatment of childhood obesity. If treatment is begun when a family is not ready to support the program, then success is unlikely.8 The treatment planned should also take into consideration long-term management, with the continued assessment of the child for proper growth and development.8

Pharmacologic intervention This option should be limited to those with serious comorbidities who cannot lose weight even with the involvement of a health care team.4,9 Several agents are FDA-approved for weight loss in children and adolescents; these drugs are designed to increase energy expenditure (stimulants), suppress caloric intake (anorectic agents), limit nutrient absorption, and/or modulate insulin production and/or action.9 Pharmacologic agents should be coupled with an exercise program and a modified diet. The anorectic agent currently approved for use in obese adolescents older than 16 years is sibutramine (Meridia). It is a nonselective inhibitor of serotonin, norepinephrine, and dopamine.9 In combination with caloric restriction and a comprehensive, family-based behavioral program, sibutramine reduced BMI 8.5% (+/– 6.8%) in 43 obese adolescents during an initial 6-month period, although no additional weight loss occurred during a subsequent 6 months of therapy.9 A randomized, placebo-controlled trial of sibutramine within a comprehensive behavioral treatment program for adolescents showed superior weight loss after 6 months.6,8 In another study, sibutramine resulted in a 5% to 10% initial weight loss, with a concomitant decrease in insulin resistance and other cardiovascular risk factors.4 However, weight was regained upon discontinuation of the medication.4

Another pharmacologic treatment option is the drug orlistat (Alli, Xenical), which inhibits pancreatic lipase and thereby increases fecal losses of triglycerides, decreases body weight, decreases total and LDL cholesterol levels, and reduces the risk of type 2 diabetes mellitus. Orlistat is approved for children older than 12 years.9 Side effects are tolerable as long as subjects reduce fat intake, but fat-soluble vitamin A, D, and E levels may decline despite multivitamin supplementation.9 Dietary noncompliance results in flatulence and diarrhea that ultimately prove unacceptable.9

One other drug that can be used to treat obesity is octreotide (Sandostatin), which binds to the somatostatin-5 receptor and thereby impairs closure of the beta cell calcium channel, reducing glucose-dependent insulin secretion.9 The cost of the medication, the need for parenteral administration, and the side effects—which may include transient GI distress, gallstones, suppression of growth hormone and thyroid-stimulating hormone, and cardiac dysfunction—are limiting factors.9

Surgical intervention Only the most severely obese children should be considered for surgery, and then only when other options have failed. Surgical weight loss procedures are relatively new in adolescents, and long-term outcomes are not yet clear. Surgery should be performed only by experienced teams, and families should be fully informed about the risks.6,9 Indications for surgery include a BMI greater than 40 kg/m2, severe associated comorbidities, and difficulty performing activities of daily living.8 Contraindications to bariatric surgery include substance abuse or psychiatric disabilities, which prevent lifelong compliance with nutritional recommendations or medical surveillance.9

Procedures that can be offered to severely overweight patients include laparoscopic gastric banding procedures and the Roux-en-Y gastric bypass. Gastric banding may cause esophageal dilation and achalasia and may exacerbate gastroesophageal reflux.9 Other potential complications include port site malabsorption or malfunction, balloon rupture, and infection.9 Gastric bypass can result in a high rate of complications, including nutrient malabsorption; iron deficiency anemia; folate, thiamine, or calcium deficiencies; cholecystitis; wound infections and dehiscence; small bowel or stomach obstructions; atelectasis and pneumonia; and incisional hernia.4,9 Other possible complications include leaks at the anastomotic junction, gastric dilation, and dumping syndrome.9 Weight loss goals and reduction of morbidity are often achieved with gastric bypass surgery, and short-term mortality appears to be low. Again, however, current data are insufficient to completely support this treatment in adolescents.8

PREVENTION

Education Although intervention to prevent obesity should ideally begin early in life, the family must be ready for change. If they are not, any intervention is likely to fail. To encourage readiness to change, health care providers can educate families about the medical complications of obesity, involve the family and all caregivers in the treatment program, and encourage patients to succeed. The treatment program should aim to institute permanent lifestyle changes, beginning with small, gradual changes, and teach the patient how to monitor eating and physical activity.2

Prevention begins with the health care provider increasing efforts to identify the problem of overweight and obesity. This can be done by monitoring the patient's BMI at each visit.2 The United States Preventive Services Task Force, along with the CDC, recommend periodic height and weight measure ments for all patients.4,6,9 Comparing height and weight measurements against age- and gender-appropriate standard values to determine the need for additional evaluation, intervention, or referral is recommended for children with a BMI greater than the 85th percentile.4,6,9 Those with a BMI greater than the 95th percentile should be screened for comorbidities and referred to appropriate specialists as needed.4,6,9

Educating parents and teachers is an essential part of preventing childhood overweight and obesity. Training is needed so that parents and teachers can help young children learn and practice healthy behavior. Behavior targets include increasing consumption of fruits, vegetables, and fiber-containing grain products, switching from full-fat to 1% or fat-free dairy products after age 2 years, preparing and eating family meals at home, increasing daily physical activity, and limiting sedentary time.8

Interventions that include changes to classroom and physical education curricula and after-school programs as well as dietary modifications in school meals and vending machine products, can improve dietary patterns and increase physical activity. Some physical education interventions that involve replacing the standard physical education curricula with higher-intensity or more motivating activities, specifically endurance training and popular dance, have successfully promoted weight loss.8

Screening More research needs to be done to enable better screening. Early screening and identification of obesity-related health issues are important; many health consequences of obesity may go unnoticed for years, until irreversible damage has occurred. For screening to be effective, further studies are needed to identify risk factors that are specific to the pediatric population. In addition, having laboratory reference ranges for children would be very helpful and permit better assessment of risk factors such as fasting glucose level, lipid levels, and liver function.29

CONCLUSION

The number of overweight and obese children and adolescents continues to increase in the United States. Associated diseases, such as type 2 diabetes and atherosclerosis, are potential problems in the pediatric population. Reversing obesity through lifestyle changes and increased provider awareness is an important step in caring for these patients. There are increasing signs that this problem is being taken seriously. For example, several states have adopted legislation mandating that school staff report to parents the BMI status of their children.11 The World Health Organization has also formulated a plan to tackle obesity, and the US Department of Health and Human Services recently convened an Obesity Summit to discuss the best means of addressing this critical public health issue.9

More needs to be done, however. Public health programs and policies, as well as clinical and community-based education, are required to increase physical activity and decrease caloric intake in children and adolescents.1 Unless prevention and intervention strategies can be instituted at the local and national level, the health consequences are likely to be severe as the current generation of overweight children and adolescents reach adulthood.25 JAAPA

Kimberly Wilkinson practices with Mark A. Gapinski, MD, FACOG, at Central DuPage Hospital in Winfield, Illinois. She has indicated no relationships to disclose relating to the content of this article.

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