Obesity in adolescence
Definition And Diagnosis
- Body mass index is the most appropriate variable to determine nutritional status in children and adolescents.
- It is calculated as weight in kilograms divided by height in meters squared.
- For adolescents aged 5 to 19 years, the World Health Organization provides specific growth references.
- Overweight is diagnosed when the body mass index for age is greater than 1 standard deviation above the median.
- Obesity is diagnosed when the body mass index for age is greater than 2 standard deviations above the median.
- Severe obesity corresponds to a body mass index for age greater than the 99.9th percentile.
Etiology And Risk Factors
- Obesity is a complex condition resulting from a long-term positive energy balance.
- It arises from an interaction of genetic, biological, behavioral, and cultural factors.
- Environmental and cultural influences generally have a greater impact than genetic factors.
- An obesogenic environment limits access to healthy foods and spaces for physical activity.
Family And Genetic Factors
- A child has a 50 percent chance of developing obesity if one parent has obesity.
- The risk increases to 80 percent if both parents have obesity.
- Family eating and physical activity behaviors are inherited across generations.
Early Life Factors
- The first 1000 days of life are critical for determining future obesity risk.
- Pregnancy risk factors include high maternal body mass index, smoking, and gestational diabetes.
- Early introduction of solids and formula feeding increase risk.
- Breastfeeding acts as a protective factor against obesity.
Behavioral And Psychosocial Factors
- Lack of physical activity and excessive screen time contribute significantly.
- High intake of sugar-sweetened beverages and energy-dense foods promotes weight gain.
- Insufficient sleep and stressful life events increase obesity risk.
Clinical Assessment
History Taking
- A complete history should focus on risk factors for obesity development.
- Assess family history of obesity and premature coronary artery disease.
- Evaluate nutritional intake, focusing on sugared drinks and disordered eating.
- Determine physical activity patterns and screen time duration.
- Assess patient motivation and readiness to make dietary changes.
Exclusion Of Secondary Causes
- Endocrine and genetic causes are uncommon.
- Most children with idiopathic obesity are tall for their age.
- Testing for endocrine disorders is useful only if the child shows reduced growth velocity or central nervous system injury.
| Cause Category | Specific Conditions | Clinical Features And Notes |
|---|---|---|
| Endocrine | Hypothyroidism, Cushing disease, Growth hormone deficiency | Associated with attenuated linear growth. |
| Genetic Syndromes | Prader-Willi syndrome, Laurence-Moon syndrome | Early onset obesity, neuro-developmental delay, dysmorphic features. |
| Monogenic Disorders | Melanocortin-4-receptor mutation, Leptin deficiency | Hyperphagia, food craving, waking at night to eat. |
| Medication-Induced | Glucocorticoids, Risperidone, Olanzapine | Weight gain linked to specific pharmacological treatments. |
Comorbidities And Health Impacts
- Obesity directly causes physical and psychological ill health during adolescence.
- Health problems often track into adulthood, accelerating the onset of chronic diseases.
| System | Complications | Assessment And Clinical Notes |
|---|---|---|
| Cardiovascular | Hypertension, dyslipidemia, left ventricular hypertrophy | Serial blood pressure measurements. Fasting lipid profile recommended for those over 10 years. |
| Metabolic | Insulin resistance, type 2 diabetes, impaired glucose tolerance | Fasting plasma glucose indicated if older than 10 years with risk factors. |
| Respiratory | Obstructive sleep apnea, asthma | Assess for snoring and daytime fatigue. Associated with poor school concentration. |
| Gastrointestinal | Non-alcoholic fatty liver disease, gallstones, reflux | High prevalence. Consider measuring liver transaminases. |
| Orthopedic | Slipped capital femoral epiphysis, Blount disease, back pain | Affects mobility. Requires physical examination. |
| Reproductive | Polycystic ovary syndrome | Assess for irregular menses, hirsutism, and acne. |
| Psychosocial | Depression, low self-esteem, body image disorders | Highly prevalent. Assess for binge-eating disorders. |
Management And Treatment
General Principles
- Treatment involves adjusting eating habits and increasing physical activity.
- Family involvement is crucial for successful weight control.
- The primary goal is weight maintenance while height increases, leading to a downward deflection in body mass index.
Staged Treatment Approach
Stage 1: Prevention Plus
- Suitable for adolescents with overweight or as an initial step for obesity.
- Emphasizes basic healthy lifestyle recommendations.
- Consume at least 5 servings of fruits and vegetables per day.
- Minimize or eliminate sugar-sweetened beverages.
- Limit screen time to 2 hours or less per day.
- Engage in at least 1 hour of physical activity daily.
- Encourage eating breakfast daily and having frequent family meals.
Stage 2: Structured Weight Management
- Provides additional support and structure to achieve behaviors from Stage 1.
- Develop a plan for a balanced-macronutrient diet.
- Provide structured daily meals and snacks.
- Ensure at least 60 minutes of supervised active play per day.
- Implement behavioral monitoring using diet and activity logs.
- Reinforce achievement of targeted behavior goals rather than weight goals.
Stage 3: Comprehensive Multidisciplinary Intervention
- Involves increased intensity of behavioral change strategies.
- Requires referral to a multidisciplinary obesity care team.
- Team includes a behavioral counselor, dietitian, and exercise specialist.
- Implement a structured behavioral modification program with short-term goals.
- Involves weekly office visits for a minimum of 8 to 12 weeks.
Stage 4: Tertiary Care Intervention
- Designed for severely obese adolescents who have not improved with lifestyle changes.
- Requires a pediatric tertiary weight management center.
- Treatment protocols may include meal replacement or very-low-energy diets.
- Pharmacotherapy may be considered.
- Orlistat is approved by the Food and Drug Administration for adolescents 12 years and older.
- Sibutramine is approved for adolescents 16 years and older.
- Gastric bypass surgery is reserved for severe cases.
- Surgical candidates generally require a body mass index of 40 with comorbidities or 50 without.
- Physical maturity is required, typically 13 years for girls and 15 years for boys.
Weight Goals For Adolescents (12 To 18 Years)
| Body Mass Index Category | Recommended Weight Target | Monitoring Notes |
|---|---|---|
| Overweight (>85th percentile) | Weight maintenance until body mass index is below 85th percentile. | Indicated by downward deflection in growth curve. |
| Obesity (>97th percentile) | Weight loss until body mass index is below 85th percentile. | Weight loss must not exceed an average of 0.9 kg per week. |
| Severe Obesity (>99.9th percentile) | Gradual weight loss. | Monitor closely for causes of excessive weight loss if it exceeds 0.9 kg per week. |
Physical Activity Guidelines
- Adolescents should accumulate at least 60 minutes of moderate to vigorous physical activity daily.
- Most daily activity should be aerobic in nature.
- Vigorous-intensity activities should be incorporated at least 3 times per week.
- Activities that strengthen muscle and bone must be included.
- Amounts of activity greater than 60 minutes provide additional health benefits.