Adolescent Obesity

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Introduction

About 25% of children are overweight or obese, according to newly established national criteria. These teens are at significant risk for becoming obese adults, and adolescent obesity predisposes to a range of medical and psychosocial problems. Despite the enormous medical and economic implications of obesity, effective prevention and treatment strategies are lacking.

First, it is important to distinguish the term obesity, used to describe excess body fat, from other forms of overweight, such as increased muscle mass associated with weight lifting. Recent data support the use of BMI ( body mass index) as an appropriate measure of adiposity, especially in adolescence, since it accounts for linear growth. It is recommended that 95th percentile be used to define obesity, and the 85th to 95th percentile can be used to identify those at risk for obesity, and these individuals are described as overweight.

 

Definition

The following definitions apply to children between 2 and 20 years of age:

Category

BMI

Underweight

<5th percentile for age and sex

Normal weight

Between 5th and 85th percentile for age and sex

Overweight

Between 85th and 95th percentile for age and sex

Obese

³ 95th percentile for age and sex

Severe Obesity

³120 percent of the 95th percentile values, or BMI ³25kg/m2 (whichever is lower)

BMI Calculator

 

Epidemiology

Childhood and adolescent obesity have increased three- to sixfold since the 1970s.  The National Health and Nutrition Examination Survey (NHANES) has monitored changes in body weight among children and adolescents in the US since the 1960's. According to data from the most recent survey, (NHANES III) 16.9% of children and adolescents are obese. These figures represent a twofold increase in prevalence rates since NHANES I.

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Causes

Obesity is caused by caloric intake in excess of energy expenditure. Despite this deceptively simple description, the etiology of obesity is thought be the result of a complex interplay of genetic, metabolic, and environmental influences that is still being clarified

Genetic influences:

  • Studies on identical and fraternal twins raised together versus those raised apart suggest a strong genetic influence on BMI.
  • Gene mutations that contribute to the development of obesity: single-gene mutations in genes that encode proopiomelanocortin, melanocortin receptors, leptin, or leptin receptors.
  • Obesity as part of genetic syndrome: Prader-Willi Syndrome (15q11-q12), Alstrom (2p14-p13), Bardet-Biedl (16q21), or Beckwith-Weidemann (15p15.5)

Environmental factors:

  • Diet and dietary habits: food availability, overeating/restrained eating, portion size, frequency of eating
  • Physical activity: sedentary lifestyle, television viewing time
  • Sleep deprivation
  • Drug-induced weight gain: antipsychotics, anti-depressants, antiepileptic drugs, diabetes drugs

Metabolic factors:

  • Hypothalamic
  • Cushing’s syndrome
  • Hypothyroidism
  • Growth hormone deficiency
  • Polycystic ovary syndrome

 

So the teen is overweight? What's the big deal?

There is an important association between obesity and a variety of immediate and long-term health concerns.  It is also an important early risk factor for much of adult morbidity and mortality related to obesity.

Cardiovascular

Hypertension, dyslipidemias, myocardial infarction, stroke

Dermatologic

Intertrigo, furunculosis, acanthosis nigricans

Endocrine

Insulin resistance, hyperinsulinism, Type 2 Diabetes, metabolic syndrome, early puberty onset/early adrenarche, high androgens high in females and low androgens in males, menstrual irregularities, PCOS

Gastrointestinal

Gallbladder disease, non-alcoholic steatohepatitis, gastroesophageal reflux

Immunologic

Impaired cell-mediated immunity, PMN killing capacity and macrophage maturation

Orthopedic

Slipped Capital Femoral Epiphysis, Blount disease, Legg-Calve-Perthe, degenerative arthritis, Coxa vara

Psychological

Poor self-image, lower self-esteem, social isolation

Respiratory

Sleep apnea, snoring, upper respiratory infections, asthma, Pickwickian syndrome (obesity hypoventilation syndrome)

 

In addition to the medical complications, adolescent obesity has serious psychological consequences. Obese adolescents have lower self-esteem, and follow-up studies of patients who were obese as adolescents show differences in long-term outcomes in adulthood, such as:

  • lower education levels
  • lower incidence of marriage
  • lower household incomes
  • higher rates of poverty

Cultural stereotypes that laziness and sloppiness are associated with fatness also contribute to the negative psychosocial impact.

Conversely, psychosocial problems may predispose to obesity. Those who experienced abuse had a 1.4 to 1.6 fold increase in physical inactivity and severe obesity.

 

Assessment and Prevention

Due to the prevalence of overweight and obesity, and the significant comorbidities that it poses, health care professionals should aim for early identification of children at risk for development of overweight and prevention. Among several recommendations on the prevention of overweight, the AAP and AMA recommends taking the following steps in health supervision:

  • Identify patients at risk by conducting a thorough history including family history, eating and physical activity, socioeconomic, ethnic, cultural or environmental factors
  • Calculate and plot BMI for all patients annually, beginning at age 2
  • Screen for co-morbidities (eg. BP, glucose) in overweight and obese patients, especially those with positive risk factors.
  • Laboratory testing recommendations depend on the degree of obesity and associated illnesses.
  • Routinely promote healthy eating patterns and physical activity:
    • Limit TV and video time to a maximum of 2 hours/day.
    • Encourage at least 60 minutes of moderate to vigorous physical activity.
    • Consume no more than 1 serving of sweetened beverages per day (eg. fruit juice, sports drink, soft drink).
    • Limit fast-food consumption to no more than once per week and encourage families to have meals together as often as possible.
  • Educate families through anticipatory guidance about ways to develop lifelong habits of physical activity and nutritious eating.

The US Preventive Services Task Force (USPSTF) recommends screening children aged 6 years and older for obesity for overweight in children and adolescents using BMI. This is a grade B recommendation. In 2005, The United States USPSTF found adequate evidence that BMI was an acceptable measure for identifying overweight and obesity in children and adolescents. USPSTF did not find sufficient evidence for screening children younger than 6 years of age. No evidence was found regarding appropriate intervals for screening.

 

Treatment

A multidisciplinary approach to treating overweight and obesity is generally the most effective. The physician conducts a medical evaluation to rule out underlying endocrine, metabolic, or genetic conditions. Early diagnosis and collaboration with subspecialists, such as endocrinologists and geneticists, will help optimize growth and development in children with propensity for obesity. Nutritionists can obtain a detailed diet history, identify problem areas and work with the family to set realistic goals for dietary change. Behavioralists can assess the adolescent's level of motivation, relevant family dynamics, and any obstacles to effective lifestyle modification.

Therapy should target three primary areas for both the patient and the family:

  • Dietary modification
  • Increased physical activity
  • Behavioral modification

Dietary modification:

  • Eliminating snacking and reducing high-sugar/high-fat foods or drinks
  • Keeping a food journal
  •  “Traffic light” diets categorize foods into “Green foods” that can be eaten in unlimited quantities, “yellow foods” that are eaten with more caution, and “Red foods” that are eaten rarely.
  • Ketogenic diet (high-protein, low-fat) has been successful in cases of severe obesity
  • Printable materials for patients regarding nutrition and food tracking worksheets can be found here: http://www.choosemyplate.gov/print-materials-ordering/mypyramid-archive.html

Increased physical activity:

  • Instituting an exercise regimen, especially aerobic activity
  • Lifestyle exercise, which builds in more exercise to regular activity (eg. walking up/down stairs, parking further away from destination)

Behavioral Intervention:

  • Controlling the environment (eg. altering home environment by removing high-risk foods)
  • Self-monitoring (eg. patient reduces vending machine snacking)
  • Contracting for reasonable goals
  • Screening for depression and eating disorders

Drugs:

  • Anorexic agents are associated with significant adverse side effects and are not recommended for adolescent patients.

Surgery

  • Most experts do not recommend surgery for a pediatric population due to the numerous complications that can arise from bariatric surgery.

 

For more information:

American Academy of Pediatrics

Centers for Disease Control

World Health Organization

Chicago Department of Public Health: Health Chicago Overweight and Obesity Report among Chicago Public Schools

Consortium to Lower Obesity in Chicago Children

 

References

American Academy of Pediatrics, Committee on Nutrition. Prevention of Pediatric Overweight and Obesity. Pediatrics. 2003;112 :424-430

Bray, GA. Etiology and natural history of obesity. In: UpToDate, Pi-Sunyer FX, Mulder JE (Ed), UpToDate, Waltham, MA, 2013.

Klish, WJ. Definition; epidemiology; and etiology of obesity in children and adolescents. In: UpToDate, Motil KJ, Geffner M, Hoppin AG (Ed), UpToDate, Waltham, MA, 2013.

Ogden C, et al. Prevalence of High Body Mass Index in US Children and Adolescents, 2007-2008. 2010; 303:242-249.

Rao, G. Childhood Obesity: Highlights of AMA Expert Committee Recommendations. American Family Physician. 2008 Jul 1;78(1):56-63.

Schneider, MB and Brill, SR. Obesity in Children and Adolescents. Pediatrics in Review. 2005; 26;155-162.

US Preventive Services Task Force, Barton M. Screening for Obesity in Children and Adolescents: US Preventive Services Task Force Recommendation Statement. Pediatrics. 2010; 125-361.

Wang, Y. Disparities in Pediatric Obesity in the United States. Advance in Nutrition. 2011; 2:23-31.

 

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