Child and adolescent psychiatrists frequently encounter children who are obese in their practices and may be asked to work alongside primary care physicians and other specialists who treat youngsters with obesity. To offer expert consultation, they must understand all aspects of the pediatric obesity epidemic. By summarizing the relevant endocrinology, cardiology, nutrition, exercise science, and public health literature, this review of pediatric obesity assesses the epidemic’s background, delineates the challenges of clinical care, and appraises the therapeutic recommendations for this population of patients and their families.
Pediatric obesity is an epidemic. Although the problem has been the focus of family physicians, pediatricians, and public health workers, few of them feel comfortable counseling patients and their families about changing behaviors. Child mental health providers may be asked to work alongside primary care physicians and other specialists who treat youngsters with obesity.
Child psychiatrists can assist families and other members of the multidisciplinary team in their attempts to control childhood and adolescent obesity, but expert consultation requires a thorough understanding of the crisis. This review of pediatric obesity assesses the epidemic’s background, delineates the challenges of clinical care, and evaluates the therapeutic recommendations for this population of patients and their families.
Definition and characterization of obesity
Body mass index (BMI, calculated as weight in kilograms divided by the square of height in meters) is the standard measurement for determining an individual’s weight-to-height relationship. This ratio is an indicator of the degree of body fat. Levels of child and adolescent BMI typically are measured as the sex-specific BMI for the age percentile (2–20 years old), which makes allowances for differences in body fat by gender and age. A child and adolescent BMI calculator can be found at http://www.cdc.gov/growthcharts . Pediatric obesity experts define child and adolescent obesity as a BMI greater than or equal to the 95th percentile, and overweight as a BMI greater than or equal to the 85th percentile.
Obesity is a threat to the health of children. The condition is associated with genetic patterns, medical conditions, medications, and environmental factors. Fat cells were once believed to be inert storage depots of energy, but it is now understood that obesity is an inflammatory condition. Adipocytes play a significant role in endocrine signaling, and secreted adipokines have downstream effects on several organs. Biochemical mediators that regulate appetite and food intake include ghrelin, insulin, orexin, PYY-3-36, cholecystokinin, and adiponectin.
Adolescents are at slightly greater risk for obesity than younger children. The mechanisms of increased risk for weight gain seem to be multifactorial, but there seem to be 3 critical periods for the development of obesity that are normally characterized by marked developmental increases in BMI: infancy, the period of adiposity rebound between 5 and 7 years of age, and adolescence.
Scope of the problem
Child and adolescent obesity rates in the United States are a public health issue, and evidence suggests that the current younger generation of Americans may have shorter life expectancies than their parents. Rates of overweight and obesity among adolescents vary by gender, socioeconomic status, and ethnic background, and prevalence is further increased if factors of minority status, rural living, and lower socioeconomic status are considered.
Child and adolescent overweight and obesity rates for girls and boys have greatly increased in the past 30 years. The National Health and Nutrition Examination Survey (NHANES) data suggest that 17.1% of children and adolescents between the ages of 2 and 19 years are at or above the 95th percentile of sex-specific BMI for age on growth charts. Between NHANES I (1971–1974) and NHANES IV (2003–2006), the prevalence of obesity increased 12.4% for the 2- to 5-year-old group of children, 17% for the 6- to 11-year-old group, and 17.6% for the 12- to 19-year-old group. Among adolescents between the ages of 12 and 19 years, Mexican American boys and non-Hispanic black girls had the highest rates of obesity prevalence at 22.1% and 27.7%, respectively. Obesity and socioeconomic status are linked, and lower levels of parent education are associated with multiple metabolic risks in adolescence.
Goals published in the Healthy People 2010 document include objective 19-3: “reduce to 5% the proportion of children and adolescents who are obese.” Youths who are obese preschoolers are likely to be obese as adolescents, and this pattern is linked to adult-onset diabetes, hypertension, hyperlipidemia, asthma, and sleep apnea. The Centers for Disease Control and Prevention (CDC) compile obesity surveillance data for low-income, preschool-aged children participating in federally funded health and nutrition programs. The CDC examined trends between 1998 and 2008 and found that obesity prevalence among low-income, preschool-aged children increased steadily from 12.4% in 1998 to 14.5% in 2003. Since then, the rates have plateaued at a prevalence of 14.6% in 2008. A follow-up study of more than 500 children who were overweight found that, after 40 years, 47% of the children were still overweight as adults. The severity of overweight in puberty was highly associated with weight-related morbidity and mortality in adulthood.
A social network of 12,067 people was assessed repeatedly from 1971 to 2003 as part of the Framingham Heart Study. The BMI was available for all subjects. The investigators reported social factors that seem to determine obesity in adults. They found that a person’s chances of becoming obese increased by 57% (95% confidence interval [CI], 6–123) if he or she had a friend who became obese. This pattern was identified in pairs of adult siblings and in spouses. Neumark-Sztainer and colleagues found that weight-specific socioenvironmental, personal, and behavioral variables were strong and consistent predictors of overweight status, binge eating, and extreme weight-control behaviors in teens. Social support from parents, peers, and teachers was associated with changes in physical activity over time for a population of inactive adolescent girls.
Scope of the problem
Child and adolescent obesity rates in the United States are a public health issue, and evidence suggests that the current younger generation of Americans may have shorter life expectancies than their parents. Rates of overweight and obesity among adolescents vary by gender, socioeconomic status, and ethnic background, and prevalence is further increased if factors of minority status, rural living, and lower socioeconomic status are considered.
Child and adolescent overweight and obesity rates for girls and boys have greatly increased in the past 30 years. The National Health and Nutrition Examination Survey (NHANES) data suggest that 17.1% of children and adolescents between the ages of 2 and 19 years are at or above the 95th percentile of sex-specific BMI for age on growth charts. Between NHANES I (1971–1974) and NHANES IV (2003–2006), the prevalence of obesity increased 12.4% for the 2- to 5-year-old group of children, 17% for the 6- to 11-year-old group, and 17.6% for the 12- to 19-year-old group. Among adolescents between the ages of 12 and 19 years, Mexican American boys and non-Hispanic black girls had the highest rates of obesity prevalence at 22.1% and 27.7%, respectively. Obesity and socioeconomic status are linked, and lower levels of parent education are associated with multiple metabolic risks in adolescence.
Goals published in the Healthy People 2010 document include objective 19-3: “reduce to 5% the proportion of children and adolescents who are obese.” Youths who are obese preschoolers are likely to be obese as adolescents, and this pattern is linked to adult-onset diabetes, hypertension, hyperlipidemia, asthma, and sleep apnea. The Centers for Disease Control and Prevention (CDC) compile obesity surveillance data for low-income, preschool-aged children participating in federally funded health and nutrition programs. The CDC examined trends between 1998 and 2008 and found that obesity prevalence among low-income, preschool-aged children increased steadily from 12.4% in 1998 to 14.5% in 2003. Since then, the rates have plateaued at a prevalence of 14.6% in 2008. A follow-up study of more than 500 children who were overweight found that, after 40 years, 47% of the children were still overweight as adults. The severity of overweight in puberty was highly associated with weight-related morbidity and mortality in adulthood.
A social network of 12,067 people was assessed repeatedly from 1971 to 2003 as part of the Framingham Heart Study. The BMI was available for all subjects. The investigators reported social factors that seem to determine obesity in adults. They found that a person’s chances of becoming obese increased by 57% (95% confidence interval [CI], 6–123) if he or she had a friend who became obese. This pattern was identified in pairs of adult siblings and in spouses. Neumark-Sztainer and colleagues found that weight-specific socioenvironmental, personal, and behavioral variables were strong and consistent predictors of overweight status, binge eating, and extreme weight-control behaviors in teens. Social support from parents, peers, and teachers was associated with changes in physical activity over time for a population of inactive adolescent girls.
Cost of child obesity
An attempt to quantify health care expenditures and health service use associated with childhood overweight and obesity found that this population had significantly higher health expenditures and service use rates than children of normal weight. These figures included hospitalizations for comorbidities of obesity, outpatient and emergency department use, and prescription drug costs. Based on these results, researchers projected that costs of approximately $14.1 billion per annum are associated with increased pediatric BMI. These estimates are much higher if the adult population is included. Overall obesity-related direct heath care costs may be at least $90 billion per year and include coverage for a high number of people who were overweight or obese during youth and experienced the consequences in adulthood. In Maine, adult obesity in an insured population has been estimated to cost $2.56 billion per year in avoidable medical and workers’ compensation costs and lost productivity each year. Although obesity prevention is not a suggested way to reduce overall health care costs, it is a cost-effective way to increase survival rates and quality of life.
Because children and adolescents who are obese and overweight are likely to carry their BMI status into adulthood, the government has an incentive to support obesity prevention and treatment. At least one-half of obesity-related health care expenditures are financed by Medicare and Medicaid. Schools and communities also deplete resources, and these stakeholders have a role in the reversal of this epidemic ( Fig. 1 ).
Medical and psychosocial consequences
Child and adolescent obesity can have medical and psychological consequences. Illnesses previously considered adult diseases are now occurring in youth. Short-term medical consequences include gastroesophageal reflux disease, obstructive sleep apnea (OSA), perioperative and postoperative complications, increased risk for injury, asthma, gallstones, sleep, dental caries, skeletal health, orthopedic injuries, and constipation. Long-term complications include coronary heart disease (CHD), hypertension, metabolic syndrome, diabetes mellitus, dyslipidemia, nonalcoholic fatty liver disease (NAFLD), and increased risk for certain cancers.
Excess adiposity during the developing years is a morbidity and mortality risk factor, but it is not known whether total body fat or its distribution is responsible. One hypothesis is that intra-abdominal adipose tissue in childhood, independent from total body fat, increases the risk for disease in adults.
Mental Health Concerns
The psychological consequences of obesity include low self-esteem, victimization by peers, depression, anxiety, and increased risk for eating disorders. Fatigue is associated with obesity and overweight, but it can masquerade as a neurovegetative sign of a depressive disorder. Obesity is associated with treatments for mental health conditions, such as weight gain resulting from treatment with atypical antipsychotics. Overall mortality is increased for children with weight extremes, and youths with extreme perceptions of body size are at increased risk for suicidal ideation and suicide attempts.
The Pediatric Quality of Life Inventory is an instrument designed to measure health-related quality of life for children and adolescents. It is designed as a child self-report and parent proxy report to measure fatigue in pediatric patients. Pediatric patients with obesity experienced fatigue comparable with pediatric patients receiving cancer treatment. Sedation from medication treatment, trauma symptoms, depression, and other mental illnesses can manifest as low energy levels. Current recommendations ( http://www.mypyramid.gov/kids ) are that youths participate in 1 hour of activity on most days, but it is challenging for the most obese to participate in activity when fatigue is a major symptom.
Early-onset obesity is associated with cognitive impairments. The Journal of Pediatrics reported that toddlers with early-onset morbid obesity had an average IQ of 78, whereas the control group of siblings had an average IQ of 106. Magnetic resonance imaging of infants who were early-onset morbidly obese revealed white matter lesions typically found in the brain of adults with Alzheimer disease or in children with untreated phenylketonuria.
The stigma associated with youth overweight and obesity is pervasive in Western society, and it may come from peers, educators, or parents. Diet and body image are a national preoccupation, and anxiety about body image is a major concern for girls and boys in our culture. Youth obesity is associated with peer bullying, and peer victimization is associated with child-reported depression, anxiety, loneliness, and reduced physical activity.
Some studies show little or no association between child and adolescent obesity and poor emotional health. Others report different results, particularly for minorities and women who may be more likely to have low self-esteem and engage in high-risk behaviors, although this effect may be decreased if body image is controlled for.
Using data from a British birth cohort study, researchers examined the educational, social, socioeconomic, and psychological outcomes for individuals who were obese at age 10 and 30 years. Childhood obesity was associated with negative outcomes in adulthood for men and women, and persistent obesity in women was significantly associated with adverse employment and relationship status. Obesity that begins in childhood or adolescence may be responsible for body image disturbances later in life, particularly in women.
Certain populations accumulate risk along with their weight. For example, obese Hispanic and white women have significantly lower levels of self-esteem by early adolescence and higher rates of sadness, loneliness, and nervousness. They are also more likely to engage in high-risk behaviors, such as smoking or drinking alcohol. Vulnerable children who are exposed to abuse are more likely to be obese as adults.
Comorbid Medical Conditions
Skeletal health
It was once believed that a husky weight status was good for bone, but it has been found that the developing skeleton suffers with rising adiposity. Age-adjusted total body mineral content and bone area relative to body weight are lower in children who are overweight and obese than in children of lower adiposity. During the period of peak bone accrual, the teen years, obesity may have a long-term effect on osteoporosis for this population. Obesity may be a risk factor in pediatric trauma cases and may increase the incidence of extremity fractures that require surgical intervention.
Childhood overweight and obesity are associated with several orthopedic complications, including Blount disease, acute fractures, slipped capital femoral epiphysis, and spinal complications. A chart review of patients enrolled in pediatric clinics who were overweight and obese found that that these patients were more likely to report symptoms of decreased mobility and musculoskeletal discomfort, such as knee pain.
Alimentary disorders
Caries and obesity coexist in children of low socioeconomic status. Public health measures to improve dietary education, availability of appropriate foodstuffs, and access to dental care could decrease the risk of both diseases.
Obesity is a major predictor of gastroesophageal reflux disease among children between the ages of 7 and 16 years. This risk increases with corresponding increases in BMI.
Obesity is responsible for most gallstones in children with no other underlying medical problems. It raises the risk of developing gallstones to 4 times that experienced by individuals of normal weight.
Among children and adolescents with constipation, there is a significantly higher prevalence of obesity than among controls, and this disorder may result from diet, activity level, or other influences. The increased rate is not related to the presence of fecal incontinence or encopresis among children who are constipated. Children who are obese are also more likely to experience recurrent abdominal pain than children of normal weight.
Asthma
A study of 14,654 junior high school students found that increased BMI was one of the risk factors for asthma, and that higher BMI scores were correlated with an increased prevalence of asthma in this population. Obese children with asthma experience more symptoms of asthma and recover more slowly from an acute-onset attack.
Sleep
Cardiovascular and metabolic processes are affected by sleep-wake cycles. Sleep-wake cycles are partly under the direct control of the master circadian pacemaker located in the suprachiasmatic nucleus. Basic functions, such as heart rate and levels of leptin (involved in appetite control), show circadian variation.
Adolescents who are obese have a greater likelihood of experiencing sleep disorders such as OSA. This disorder can cause sleep deprivation and disrupted metabolism, which can further increase BMI and exacerbate other obesity-related conditions. Sleep deprivation is linked to impaired mood and poor school performance. A study of almost 300 children and adolescents found that sleep-disordered breathing, such as OSA, contributed to significantly lower levels of physical health and greater complaints of body pain. Even mild sleep-disordered breathing created measurable decreases in health-related quality of life. OSA is a predictor of nocturnal hypertension in children, and hypertension is a direct complication of obesity and a serious risk factor for cardiovascular disease.
Persistent short sleep duration (<10 hours) during early childhood significantly increases the risk of excess weight. Studies have focused on the importance of sleep duration and sleep hygiene in the creation of obesity and overweight in youth. A prospective cohort study of more than 1100 children who were followed from infancy found that persistent sleep duration of less than 10 hours per night had a significant effect on the risk of developing excess weight. Similar support for the role of shorter sleep duration in developing obesity was found in a study of third- and sixth-graders.
Hypertension
The long-term consequences of childhood obesity include primary hypertension. Children who are obese have 3 times the risk of hypertension compared with peers of normal weight. Charts with norms for children are available at the National Institutes of Health (NIH) Web site ( ). The link between obesity and hypertension may be mediated in part by sympathetic nervous system hyperactivity (ie, increased levels of plasma catecholamines) and by neural manifestations such as increased peripheral sympathetic nerve traffic.
In a study of 546 children and adolescents who were obese and between the ages of 4 and 17 years, television viewing was independently associated with hypertension, even after controlling for BMI. Television viewing was also positively associated with increasing BMI. Converting sedentary screen time to active screen time is an ongoing area of research. Limiting screen time is important for other reasons besides blood pressure. For each additional hour of television viewing, youths consume an additional 167 kcal/d (95% CI 136–198 kcal/d; P <.001), and they consume the foods commonly advertised on television.
CHD
A retrospective study of 276,835 school children found a strong association between increased BMI in childhood (7–13 years old) and future fatal and nonfatal CHD. The risk of CHD increases with BMI and with the age of the child. Other studies have shown no association between early childhood, increased BMI, and later CHD.
One study was designed to measure prescriptions for diabetes, hypertension, and dyslipidemia among children and adolescents. Using a cross-sectional study design, a pharmacy benefits manager database was used to provide descriptive statistics of insured US children and adolescents between the ages of 6 and 18 years. From 2004 to June 30, 2007, these medications increased 15.2% from 3.3 per 1000 youths in 2004 to 3.8 per 1000 youths in 2007. Older teens (16–18 years old) had the highest prevalence overall, but the greatest rate of increase was found among those 6 to 11 years old: 18.7% for girls and 17.3% for boys.
Diabetes
Increased BMI is a major risk factor for developing type 2 diabetes. The endocrine disruption caused by obesity can result in insulin resistance. The prevalence of new diagnoses of diabetes in children 0 to 19 years old increased from 4% before 1992 to 16% in 1994. Adolescents 10 to 19 years old accounted for 33% of the diabetes diagnoses in 1994. Rates for new cases of diabetes in 2002 and 2003 are shown in Fig. 2 . Children with type 2 diabetes may show no or few symptoms and remain undiagnosed for long periods, increasing the risk of developing later cardiovascular diseases.
Fatty liver disease
NAFLD is becoming a more common pediatric diagnosis as the obesity epidemic continues. The exact pathophysiology of NAFLD is unknown, but the result is an accumulation of fat in the liver, causing scarring and potential liver failure. The prevalence of NAFLD among children is difficult to measure because people have no signs, symptoms, or complications. However, reviews of pediatric autopsy results show that approximately 10% of children and adolescents 2 to 19 years old may have this condition. Prevalence may be higher among boys than among girls, and it is significantly associated with visceral fat mass, insulin resistance, and type 2 diabetes. The prevalence of NAFLD among hospitalized children and young adults increased between 1986 and 2006, which correlates with the obesity epidemic.
Cancer
Evidence is mounting in support of a relationship between obesity and many adult cancers, and childhood obesity may provide an additional risk factor for developing cancer. Researchers of a prospective cohort study of more than 900,000 adults estimated that 14% of cancer deaths in men and 20% of cancer deaths in women could be attributed to current rates of overweight and obesity in the United States. The National Cancer Institute strongly supports obesity prevention and treatment research.
Perioperative and Postoperative Complications
Children who are overweight and obese presenting for tonsillectomy and adenoidectomy have a higher incidence of perioperative complications and are more likely to be admitted and to stay longer than children of normal weight. Children who are obese undergoing elective surgical procedures have more preexisting comorbid medical conditions and an increased incidence of perioperative adverse respiratory events.
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