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Obesity in Adolescents

  • Committee Opinion CO
  • Number 714
  • September 2017

Number 714 (Reaffirmed 2020)

Committee on Adolescent Health Care

This Committee Opinion was developed by the American College of Obstetricians and Gynecologists’ Committee on Adolescent Health Care in collaboration with committee members Bliss Kaneshiro, MD, MPH and Samantha Erin Vilano, MD, MSc.


ABSTRACT: Rates of obesity among adolescents in the United States have increased at a dramatic rate along with the prevalence of weight-related diseases. Between the 1980s and 2014, the prevalence of obesity among adolescent females in the United States increased from approximately 10% to 21%. Although the steep increase in the prevalence of obesity in children (2–11 years) has slowed, the prevalence of obesity in adolescents (12–19 years) continues to increase. Because the obese female adolescent faces medical, psychologic, and reproductive health challenges, early intervention is imperative in preventing short-term and long-term morbidity. The obstetrician–gynecologist who is knowledgeable about the behavioral and environmental factors that influence obesity may be better able to educate parents, guardians, and adolescents and advocate for programs that increase physical activity and improve nutrition. The obstetrician–gynecologist should be able to identify obese adolescents, particularly those at risk of comorbid conditions. They may have the opportunity to initiate behavioral counseling, participate in multidisciplinary teams that care for overweight and obese adolescents, and advocate for community programs to prevent obesity.


Recommendations

The American College of Obstetricians and Gynecologists (ACOG) offers the following conclusions and recommendations:

  • The obstetrician–gynecologist should be knowledgeable about the behavioral and environmental factors that influence obesity and should educate adolescents and their parents about an active lifestyle and healthy caloric intake.

  • The obstetrician–gynecologist should be able to identify obese adolescents, particularly those at risk of comorbid conditions. They may have the opportunity to initiate behavioral counseling, participate in multidisciplinary teams that care for overweight and obese adolescents, and advocate for community programs to prevent obesity.

  • Oral emergency contraception should not be withheld from adolescents or women who are overweight or obese because no research to date has been powered adequately to evaluate a threshold weight at which it would be ineffective.

  • The risks of all contraceptive methods are lower than the risks of pregnancy and the postpartum period for overweight and obese adolescents.

  • The obstetrician–gynecologist should screen overweight and obese adolescents for depression, bullying, and peer victimization and appropriately refer to school-based and community-based resources as well as psychiatric services.

  • There are currently no evidence-based guidelines for the use of pharmaceutical agents in the management of obesity in adolescents.

  • The obstetrician–gynecologist should caution against the use of weight loss supplements.

  • A multidisciplinary team, including an experienced bariatric surgeon, dietitian, and psychologist or psychiatrist, should be used to select appropriate candidates for surgical intervention and provide postoperative support.


Introduction

Rates of obesity among adolescents in the United States have increased at a dramatic rate along with the prevalence of weight-related diseases. Because the obese female adolescent faces medical, psychologic, and reproductive health challenges, early intervention is imperative in preventing short-term and long-term morbidity. The obstetrician–gynecologist should be knowledgeable about the behavioral and environmental factors that influence obesity and should educate adolescents and their parents about an active lifestyle and healthy caloric intake. The obstetrician–gynecologist should be able to identify obese adolescents, particularly those at risk of comorbid conditions. Obstetrician–gynecologists may have the opportunity to initiate behavioral counseling, participate in multidisciplinary teams that care for overweight and obese adolescents, and advocate for community programs to prevent obesity.


Definition

Body mass index (BMI) is defined as weight in kilograms divided by height in meters squared. Measuring BMI is inexpensive and identifies adolescents at risk of weight-related diseases 1 2. The standard BMI weight-status categories used for adults are not dependent on age or sex and, therefore, cannot be used in the interpretation of BMI in adolescents. To account for normal sex-specific changes in weight, height, and adiposity up to the age of 19 years, BMI should be interpreted after it is plotted on growth charts to determine BMI-for-age and BMI-for-sex percentile https://nccd.cdc.gov/dnpabmi/calculator.aspx. Because BMI does not directly measure adiposity, it is not accurate in predicting health risk in athletic adolescents with increased muscle mass or sedentary adolescents with reduced muscle mass. Overweight is defined as a BMI at or above the 85th percentile, obesity is a BMI at or above the 95th percentile, and severe obesity is a BMI greater than or equal to the 99th percentile for age Table 1. Extreme obesity has been used to describe adolescents who are at or above 120% of the sex-specific 95th percentile for age 3.

Obesity in Adolescents

Prevalence and Trends

Between the 1980s and 2014, the prevalence of obesity among adolescent females in the United States increased from approximately 10% to 21% 4. Although the steep increase in the prevalence of obesity in children (2–11 years) has slowed, the prevalence of obesity in adolescents (12–19 years) continues to increase 4. Obesity is highly complex in terms of etiology and prevalence 5. Genetic predisposition, race, socioeconomic status, built environment (eg, the presence of sidewalks or community design), accessibility of healthy and affordable foods, sleep habits, and geographic region all play a role. Changes in the “American lifestyle,” which includes consuming foods and beverages with a high glycemic index, increased food portion sizes, decreased structured physical activity, and increased screen-based sedentary behavior, have influenced the prevalence of obesity 6 7. Intrauterine environment also plays a role; large-for-gestational-age infants have a higher risk of obesity in adolescence compared with normal-weight infants 8. The prevalence of obesity varies by race, with black adolescents having the highest prevalence (24.4%), followed by Hispanic (22.8%), white (20.4%), and Asian (5.7%) adolescents 4. Eight percent of female adolescents have extreme obesity (BMI at or above 120% of the sex-specific 95th percentile for age) 4.

Health Risks

Adolescents affected by obesity are at an increased risk of developing comorbidities. As weight increases, the risk of impaired glucose tolerance increases. The prevalence of impaired glucose tolerance (HgbA1c greater than 5.7 or fasting glucose greater than or equal to 100 mg/dL) is 1.87% in overweight adolescents (12–18 years) and increases progressively to a prevalence of 13.19% in adolescents with class III obesity Table 1. Because type 2 diabetes is associated with progressive neuropathy, retinopathy, nephropathy, and cardiovascular disease, prevention, early diagnosis, and treatment are imperative.

Even in the absence of type 2 diabetes, obese adolescents are at increased risk of cardiovascular disease in adulthood because they have an increased risk of hypertension and dyslipidemia 9. As BMI increases so does the risk of hypertension. Class III obese adolescents (12–18 years) have 2.5–7.6 times the risk of high blood pressure (greater than 95th percentile for age, sex, and height) compared with class I obese adolescents 9. Obese adolescents begin to develop cardiovascular damage once seen only in adults, including atherosclerotic changes, increased left ventricular mass, and systolic and diastolic dysfunction 10 11 12.

Attaining a healthy weight can dramatically improve the cardiovascular health of adolescents as they transition into adulthood. Data from four large longitudinal studies noted obese and overweight children who are not obese as adults have similar cardiovascular risks as individuals who were never obese 13.

Metabolic syndrome has been used to describe the coexistence of risk factors for type 2 diabetes and cardiovascular disease, including abdominal obesity, hyperglycemia, dyslipidemia, and hypertension. The prevalence of metabolic syndrome among adolescents is estimated to be approximately 9% 14, although pubertal growth results in instability in the diagnosis of metabolic syndrome in adolescents. One half of all adolescents initially classified with metabolic syndrome will no longer meet the criteria after 3 years, whereas others will acquire the diagnosis 15. In adolescents, the long-term cardiovascular and type 2 diabetes risk for individuals with metabolic syndrome is not well defined.

Obesity is associated with nonalcoholic fatty liver disease in adolescents. The prevalence of fatty liver is estimated to be 38% in obese children and adolescents (2–19 years), with the highest risk noted in Hispanic youths followed by Asian, white, and black youth 16. Because nonalcoholic fatty liver disease is associated with insulin resistance, dyslipidemia, and hypertension, adolescents with nonalcoholic fatty liver disease should be evaluated for each of these conditions. The natural history of nonalcoholic fatty liver disease in adolescents is not well-described, although it may lead to fibrosis, cirrhosis, and liver failure in some cases 17.

The prevalence of disordered breathing is increased in obese adolescents. Obesity hypoventilation syndrome is characterized by poor alveolar air exchange during wakefulness secondary to excess weight and typically occurs in cases of extreme obesity 18. Obstructive sleep apnea is a more common condition in obese adolescents. In a study of obese children and adolescents, 11% had mild obstructive sleep apnea and 8% had moderate to severe obstructive sleep apnea 18. The association between sleep and obesity is complex. Obese adolescents are at increased risk of obstructive sleep apnea, and shortened sleep duration or fragmented sleep promotes obesity. A study in children demonstrated they consumed more food and gained weight when deficient of sleep for 1 week 19.

Obese children and adolescents are at an increased risk of orthopedic conditions, including slipped capital femoral epiphysis, tibia vara, genu valgum, and musculoskeletal pain 20 21. Obese adolescents also are more susceptible to fractures because they have reduced bone mass when adjusted for body size 21.

Adolescence and early adulthood is a period of concern for the development of eating disorders; these disorders should be screened for regardless of BMI. Greater-than-expected weight dissatisfaction, large weight fluctuations, and depressive symptoms in adolescents can be signs of a binge eating disorder 22.

Gynecologic Health Risks

Abnormal uterine bleeding is common in obese adolescents who report amenorrhea, heavy menstrual bleeding, or other menstrual abnormalities. In addition to anovulation because of immaturity of the hypothalamic–pituitary–ovarian axis, abnormal uterine bleeding in obese adolescents can result from elevated levels of free estrogens due to increased peripheral aromatization of androgens to estrogens, decreased sex hormone binding globulin, and increased insulin levels that can stimulate ovarian stromal tissue production of androgens 23 24. Elevated peripheral estrogen disrupts normal ovulation, which results in abnormal uterine bleeding. In the rare case reports of adolescents with endometrial cancer, the clinical history typically includes 2–3 years of abnormal bleeding and obesity 25 26. Endometrial evaluation should be performed if medical treatment of abnormal bleeding has failed after a thorough investigation of all potential other causes and comorbid disorders 27.

Polycystic ovary syndrome (PCOS), characterized by ovulatory dysfunction and hyperandrogenism, frequently presents during adolescence. Because PCOS has lifelong implications, including an increased risk of type 2 diabetes, metabolic syndrome, cardiovascular disease, and endometrial carcinoma, a diagnosis of PCOS should be considered in any adolescent female with obesity accompanied by hirsutism or menstrual irregularity 28.

Different organizations have endorsed different diagnostic criteria for PCOS in adult women 29 30 31. Caution should be taken when diagnosing PCOS in adolescents because the features of PCOS overlap with normal pubertal development. Anovulatory cycles can be typical for several years after menarche. Signs of hyperandrogenism, such as hair growth and acne vulgaris, are common in this age group. Table 2 outlines the Pediatric Endocrine Society’s recommendations to assist in the diagnosis of PCOS in adolescents.

Obesity in Adolescents

Even if a definitive diagnosis of PCOS cannot be made during adolescence, treatment may be indicated 32. Treatment of PCOS in adolescents should address the symptoms that the adolescent finds bothersome. Weight reduction can improve menstrual cycle regularity, but does not have a significant effect upon hirsutism. Metformin can be used for abnormal glucose tolerance, although it provides no advantage over lifestyle modification with regard to weight reduction or menstrual regulation in adolescents 33 34. Combined hormonal contraceptives can regulate menstrual cycles and normalize serum androgens, thereby improving acne; they also provide protection against unintended pregnancy and decrease the risk of developing endometrial cancer. The progestin intrauterine device (IUD), implant, and depot medroxyprogesterone acetate (DMPA) decrease heavy bleeding and provide highly effective contraception; however, they are associated with irregular bleeding and will not improve the cutaneous manifestations of hyperandrogenism 35.

Obstetric Health Risks

Obese adolescents who become pregnant are at increased risk of cesarean delivery, labor induction, preeclampsia, and gestational diabetes compared with their normal-weight peers 36 37. However, obesity also has a protective effect on preterm birth in adolescents. This has been noted in white adolescents and black adolescents who have a higher baseline rate of preterm birth 36 37.

Epidemiologic data suggest exercise may be beneficial in preventing gestational diabetes in pregnant women with a BMI greater than 33. The American Diabetes Association has endorsed physical activity as a safe and effective therapy for glucose management in women with gestational diabetes 38.


Contraception

Although no evidence suggests that any contraceptive method is ineffective in obese adolescents or women, concerns have been raised about the diminished effectiveness of certain methods because of physiologic differences in those who are obese versus normal weight. This is a particular concern for methods whose mechanism of action relies on the systemic distribution of steroid hormones (eg, pills, the patch, the vaginal ring, DMPA, and implants) 39 40 41 42.

Although several studies have explored the effect of obesity on the pharmacokinetics and pharmacodynamics of the oral contraceptive pill, studies specific to adolescents are nonexistent 43. In adult women, studies have demonstrated altered contraceptive steroid half-life 44 45, although follicular development did not differ significantly in obese versus normal-weight women who were taking oral contraceptives 44 45 46. A large prospective postmarketing study of more than 52,000 women who contributed 73,000 woman-years of oral contraceptive exposure did demonstrate a slight increased risk of failure (hazard ratio, 1.5; CI 1.3–1.8) in obese women compared with normal-weight women 47. Although women younger than 20 years of age were included in this study, they were not analyzed separately.

No data specific to adolescents have been published to analyze the effect of BMI on the efficacy of the contraceptive patch or ring. The contraceptive patch package label states that the patch may be less effective in women weighing more than 90 kg 48. Two small studies of the vaginal ring reported follicular development was minimal in obese women 49, and hormone levels remained in the therapeutic range up to 35 days after ring insertion in obese women 50.

The efficacy of the intramuscular formulation of DMPA (150 mg) is not decreased in obese women, and the efficacy of the lower-dose subcutaneous DMPA formulation (104 mg) has been confirmed in obese adult women 51. Throughout a period of 26 weeks, median DMPA levels remained above a level needed to prevent ovulation (200 pg/mL) even in women with class III obesity (BMI greater than or equal to 40), and there was no evidence of ovulation 51.

Although not directly studied, BMI should not have an effect on the effectiveness of the copper or hormonal IUD for either adults or adolescents as the contraceptive effect is local 43. A prospective cohort study that included IUD users 14 years of age and older found no difference in contraceptive failure rate by BMI for the first 2–3 years among copper and hormonal IUD users 52.

The efficacy of the etonogestrel implant does not appear to be affected by weight. A 6-month pharmacokinetic study of the etonogestrel implant in obese adult women reported circulating levels of hormone lower than that of normal-weight historical controls. However, the 2-year and 3-year projected serum levels remained above the minimum needed to suppress ovulation 53.

Levonorgestrel and ulipristal acetate-based oral emergency contraception may be less effective as weight increases 54 55. Data specific to adolescents are lacking, although one study did include females who were younger than 18 years 55. Oral emergency contraception should not be withheld from adolescents or women who are overweight or obese because no research to date has been powered adequately to evaluate a threshold weight at which it would be ineffective 56. Not only does the copper IUD have superior efficacy compared with oral forms of emergency contraception, but its efficacy is not affected by body weight and it is a highly effective method of ongoing contraception. Consideration should be given to use of a copper IUD as an alternative to oral emergency contraception in obese adolescents.

Safety of Hormonal Contraceptives in Overweight or Obese Adolescents

The risks of all contraceptive methods are lower than the risks of pregnancy and the postpartum period for overweight and obese adolescents. The main concern with the use of estrogen-containing contraceptives in obese adolescents is the risk of venous thromboembolism (VTE) given that obesity is an independent risk factor for VTE 57. However, VTE is an exceedingly rare event in children and adolescents, even among those with significant risk factors for clotting. For example, patients with hypercoagulable conditions do not typically present with a clot until after the age of 20 years 58. The U.S. Medical Eligibility Criteria for Contraceptive Use gives all contraceptives a classification of either “safe for use with no restrictions” (category 1) or “advantages generally outweigh theoretical or proven risks” (category 2) for obese adolescents from menarche to 18 years without other medical conditions 59.

Weight Gain With Hormonal Contraceptives

Depot medroxyprogesterone acetate injection is classified as category 2 for obese adolescent females because some studies show certain adolescents may be more susceptible to weight gain with DMPA 59, although studies in this area are challenged by poor methodology, specifically, the lack of an appropriate control group. An observational study compared change in body fat and lean body mass in adolescents (12–8 years old) who were using DMPA with those who were using a nonhormonal method 60. Over 6 months, adolescents using DMPA had a 10.3% increase in total body fat compared with a decrease of 0.7% in adolescents who were using a nonhormonal method (mean difference, 11.00%; 95% CI, 2.64–19.36). Another observational study noted racial differences in weight gain, with black adolescents who were using DMPA experiencing a higher increase in weight (4.2% versus 1.2%) and body fat (12.5% versus 1.2%) compared with white adolescents using DMPA 61. Adolescents who gain weight during the first few doses of DMPA may have a propensity for weight gain with DMPA; adolescents who have a 5% increase in body weight in the first 6 months of DMPA use will gain more weight than those who do not 62.

Adolescents who use contraceptive pills, the patch, the vaginal ring, implant, or IUD do not experience an increase in body weight or a change in body composition 63 64. A 12-month study in females 14 years of age and older found no difference in weight gain with the etonogestrel implant, levonorgestrel IUD, or DMPA compared with copper IUD users 65.


Psychosocial Risks

Adolescents who are overweight or obese are at higher risk of low self-esteem, distorted body image, depression, anxiety, discrimination, and strained peer relationships. Psychosocial morbidity is higher in girls than boys and tends to increase as children transition into adolescence and adulthood 66 67 68. Data from the National Longitudinal Survey of Youth reported that women who were obese in late adolescence and early adulthood complete fewer years of advanced education, have a lower family income, lower rates of marriage, and higher rates of poverty compared with their nonobese counterparts 69. This association was not noted in men who were obese during adolescence 69.

Bullying (aggressive behavior, characterized by repetition and power imbalance) and peer victimization (the experience of being the target of aggressive behavior) occurs commonly in overweight and obese adolescents, particularly in those with severe obesity 70. For girls in particular, peer victimization occurs through social exclusion 71. Bullying and peer victimization can lead to a range of adjustment difficulties, anxiety, and depression 72. The obstetrician–gynecologist should screen overweight and obese adolescents for depression, bullying, and peer victimization and appropriately refer to school-based and community-based resources as well as psychiatric services.


Preventing Obesity

The obstetrician–gynecologist who is knowledgeable about the behavioral and environmental factors that influence obesity may be better able to educate parents, guardians, and adolescents and advocate for programs that increase physical activity and improve nutrition. Behavioral modification strategies include self-monitoring, stimulus control, goal setting, and positive reinforcement. Parents are the main role models for adolescent eating and physical activity and have a direct effect on the adolescent’s food and activity environment 73. Parents are encouraged to focus on healthy eating behavior and exercising to be fit rather than talking about dieting or exercising for weight loss 74. Parents who encourage their adolescent to diet or speak about their own dieting are more likely to have adolescents who engage in unhealthy weight-control behaviors or binge eating 75.

As children transition into adolescence, sports and favorite childhood activities may be replaced by sedentary activities like social networking. Girls, specifically, have a significant drop in physical activity during adolescence 76. As adolescents transition into adulthood, they experience additional changes that affect weight 77. Girls who were active in high school sports may stop these activities as they enter college or the workforce. Food availability, cooking skills, and alcohol intake can affect the nutrition of young adults as they enter college or leave the home. During this time, the obstetrician–gynecologist can encourage a healthy lifestyle, including healthy body image, physical activity, and balanced nutrition. The American Academy of Pediatrics has developed a multifaceted program to prevent obesity and engage families and communities in promoting healthy behavior 78.


Management of Adolescent Obesity

Lifestyle Interventions

The American Academy of Pediatrics recommends a four-stage approach to obesity in adolescents with a weight loss goal of no more than 2 pounds per week, depending on BMI percentile 79 Table 3. Interventions include encouraging healthy eating and physical activity and behavioral counseling by health care providers trained in weight management. Familial involvement has been critical in most studies 80 81. However, the optimal behavioral interventions that will result in long-term weight alterations in adolescents have yet to be identified.

Obesity in Adolescents

Medical Therapies

There are currently no evidence-based guidelines for the use of pharmaceutical agents in the management of obesity in adolescents. Medical therapies are most often employed for adolescents who have not responded to lifestyle changes or for those with medical comorbidities. Only tetrahydrolipstatin is approved by the U.S. Food and Drug Administration for use in adolescents and it is considered the first-line adjunct to behavioral interventions 82. Sibutramine was voluntarily withdrawn from the market in 2010 because of cardiovascular concerns 82.

Tetrahydrolipstatin is available over-the-counter and is indicated for adolescents 12 years and older with a BMI greater than or equal to two units above the 95th percentile. Tetrahydrolipstatin inhibits digestive lipases to block approximately 25–30% of dietary fat absorption 82 83. Adverse effects include fatty or oily stools, abdominal pain, fecal urgency, and diarrhea. Dietary fat reduction can decrease gastrointestinal disturbance and increase tetrahydrolipstatin acceptance in adolescents 82 84. Studies of tetrahydrolipstatin report modest reductions in weight. A 2009 meta-analysis of randomized clinical trials in adolescents reported a mean BMI reduction of 0.83 with tetrahydrolipstatin 83.

Metformin is not recommended for adolescents for weight loss alone. Adolescents with PCOS diagnosed with insulin resistance may be considered as candidates for this medication. Metformin can result in modest reductions in weight when used with a behavioral weight reduction program 33 85. Gastrointestinal adverse effects (eg, abdominal pain, diarrhea, vomiting) are dose related and improve with continued use. A meta-analysis of nine randomized clinical trials compared metformin with placebo or other lifestyle interventions in obese adolescents without comorbidities 86. Study duration averaged 6 months, with a range of 2–12 months. The metformin group had a mean BMI reduction of 1.21–1.42 with no effect on fasting glucose levels. There was no difference in adverse effects between the metformin group and the placebo group and the withdrawal rate because adverse effects in those receiving metformin was low (2.7%) 86.

Dietary supplements are widely marketed as weight loss agents, but evidence to support their safety and efficacy is lacking. In addition to having no proven effect on weight, dietary supplements can have stimulant-like cardiovascular effects. The obstetrician–gynecologist should caution against the use of weight loss supplements.

Surgical Interventions

Based on expert opinion, the American Society for Metabolic and Bariatric Surgery has recommended surgery be considered for adolescents who meet the following criteria: BMI greater than or equal to 35 and a severe comorbidity (eg, type 2 diabetes) or BMI greater than or equal to 40 with minor comorbidities; Tanner stage IV or attainment of 95% of predicted adult stature based on bone age; and a history of sustained efforts to lose weight through changes in diet and physical activity 87. Long-term outcome data after gastric bypass surgery in adolescents are lacking, but cohort studies are ongoing. Depressive symptoms and quality of life have been shown to improve in adolescents after surgery 88 89. Designated Centers of Excellence for weight loss surgery for adolescents can be accessed at www.facs.org/search/bariatric-surgery-centers. See Table 4 for a list of surgical procedures for weight loss.

Obesity in Adolescents

A multidisciplinary team, including an experienced bariatric surgeon, dietitian, and psychologist or psychiatrist, should be used to select appropriate candidates for surgical intervention and provide postoperative support. Good candidates are those with mature decision-making abilities, appropriate understanding of the risks and benefits of surgery, and support but not coercion from family members. Patients and their families need to have the ability and motivation to adhere to postoperative treatments, including consistent use of micronutrient supplements.

Surgically induced weight loss will lead to resumption of ovulation in some anovulatory women. Although the effects of bariatric surgery on menstrual irregularities and ovulation in adolescents have not been described, in a series of 47 adolescents who had bariatric surgery, seven pregnancies occurred in the first 2 years after surgery 90. Although women with a history of gastric bypass can have healthy pregnancies, pregnancy should be avoided for at least 12–18 months after gastric bypass because of rapid weight loss and micronutrient deficiencies 91. The U.S. Medical Eligibility Criteria for Contraceptive Use categories are presented in Table 4. Limited data have been published on the placement of an IUD at the time of bariatric surgery; however, it may be considered in adolescents who wish to use it as a long-term contraceptive method 92.


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Obesity in adolescents. Committee Opinion No. 714. American College of Obstetricians and Gynecologists. Obstet Gynecol 2017;130:e127–40.

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