Understanding the child's risk for overweight and obesity
In simple terms, the equation of energy in/energy out determines the child's weight. However, the real causes of overweight and obesity – the reasons behind the factors of energy in (food consumption) and energy out (physical activity) are both social and biological in nature.4
Risk factors for obesity in children up to the age of two years may be genetic, environmental, lifestyle-related or combinations thereof.
Genetic – Obesity can originate before birth and take hold during infancy or in early childhood. Children who have parents that are obese are more likely to also be obese; while it may be argued that environment (i.e., family eating and exercise habits) is the more likely culprit, there are a number of hypotheses relating to genetic predisposition to obesity. The "fetal origins" hypothesis links birth weight to higher risk of obesity, traced to factors in utero including the mother's diet and health, especially chronic diseases including hypertension and diabetes, including gestational diabetes. The "thrifty gene" hypothesis explains the tendency of certain ethnic groups (African American, Native American, Hispanic and Pacific Islander) to utilize food more efficiently as a survival mechanism; where more-than-ample calories are available, however, the result is higher risk for obesity. A genetic predisposition combined with environmental triggers certainly poses a risk for obesity.4
Environmental and lifestyle – Environmental factors are key, and represent the best opportunity for intervention. In infancy and early childhood, nutrition and physical activity are determined by the parents. Parental habits are likely to become the child's habits both in early childhood and in the long term. The tendency of certain ethnic groups to equate greater weight with greater health (e.g., Korean, African-American) discourages healthy practices in nutrition and physical activity.4
The American Academy of Pediatrics (AAP) in their 2003 policy statement, "Prevention of Pediatric Overweight and Obesity" observes that the dramatic increase in prevalence and the accompanying comorbidities are associated with significant health burdens. Every obese child should be evaluated for comorbid conditions.7
Excess weight can impact all major organ systems, including skeletal, muscular, endocrine, gastrointestinal, reproductive, cardiovascular, and pulmonary systems. Chronic diseases associated with obesity previously observed only in adulthood are also being seen in early childhood, including:
- type 2 diabetes
- metabolic syndrome
- liver disease (non-alcoholic fatty liver disease)
- sleep apnea/sleep disordered breathing and associated effects including decreased concentration, learning and memory, and attention deficit).4,5,6
Any of these diseases present a danger to the child, potentially life-threatening if left undiagnosed and untreated; for example, diabetic ketoacidosis.4
Social and psychosocial consequences
The younger child may not be aware of the social and psychosocial consequences of overweight and obesity, including bullying and social rejection. However, the child's ability to build and maintain a positive self-image is certainly at risk as they approach school age, with potential to evolve in adolescence into depression and eventually apathy about their physical condition and appearance.4
Early Recognition and Diagnosis
Early recognition and diagnosis of overweight leading to obesity is key to successful intervention and management, leading ideally to the arrest of what can be a lifelong situation of obesity and poor health. Treatment intervention before a diagnosis of obesity is reached is thought to have greater success at reversing a child's progression toward health issues associated with weight.7
Recognition of early excessive weight gain relative to linear growth should be a routine part of pediatric practice. The AAP recommends that physicians regularly assess a child's weight, diet and level of physical activity. This information is especially accessible in the first two years of the child's life, as they tend to visit a physician on a more scheduled basis for "well baby" checkups, vaccinations, etc.7
Body Mass Index Percentile for Age
The primary diagnostic tool recommended by the AAP to identify children who are overweight or at risk of becoming overweight is the body mass index (BMI) percentile for age, the ratio of weight to height (kg/m2 or lb/ft2). In children, BMI values vary with the age and sex of the child. The BMI in children is called BMI-for-age. BMI should be calculated and plotted annually for all patients so that significant changes in a child's BMI can be recognized and addressed before the child becomes severely overweight.7,8
Cutoff criteria are based on the 2000 Centers for Disease Control BMI-for-age-growth charts for the U.S. Based on current recommendations, children with a BMI value at or above the 85th percentile of the sex-specific BMI growth charts are categorized as overweight, and at or above the 95th percentile are categorized as obese.
Length & Weight-for-age percentiles, Boys to 36 months
Length & Weight-for-age percentiles, Girls to 36 months
BMI for Age % Boys 2-20 years
BMI for Age % Girls 2-20 years
Source: Centers for Disease Control and Prevention, National Center for Health Statistics, 2000.8
Early BMIs predictive of future weight status
A study published in 2006 tracked the BMIs of participating children at seven time points between the ages of 24 months and 12 years to explore the question of whether BMI at earlier ages was predictive of weight status at 12. The study showed that children with BMIs >85th percentile are likely to become obese by adolescence; even children with BMIs >50% showed trends for obesity into adolescence. Overall, children who were ever assessed to be overweight (>85%) were more than five times as likely to be overweight at age 12 than children whose BMI is <50%.9
Gaining the family's understanding: A key factor in success
An important challenge in recognition and diagnosis of overweight or obesity is communication with the child's parents to gain their understanding, trust and commitment to change, as they are the decision-makers in their child's health and habits. Being overweight is potentially a family issue involving both nutritional and physical activity factors; cultural or other perceptual issues may also have to be overcome – e.g., a fat baby = a healthy baby; food as reward, etc. These factors can turn a discussion of the child's weight into a discussion of the parent(s)' weight.
Early identification of the child at risk for overweight or obesity provides the pediatrician with an opportunity to begin intervention with parents at an early age rather than waiting for the child to "grow out of it." Parent recognition and understanding of potential comorbidities to the degree that they become motivated to institute change requires education about the symptoms, impact and eventual consequences of overweight and comorbid diseases. This is information that parents can be encouraged to consider as a healthy change for the entire family.7
Intervention and Management: It's All About Balance
It is never too soon to address issues of nutrition and physical activity. Good habits started young will have the same magnitude of impact as poor habits engrained early in life – but for the positive health of the child and eventual adult.
Ideally, intervention and management plans for the overweight child will involve the entire family. Educating the parents about the consequences of excess weight and the lifelong trend toward poor health that may be in store even for a child under the age of two will optimally fuel motivation to change. Family habits and dynamics must be discussed with the parents so that an achievable management approach can be developed and put into action. The AAP suggests that efforts to raise parental awareness should be conducted with a focus on positive new directions rather than negative current habits so that impact on both the parents' and child's self-esteem is spared.7
Intervention and management strategies to help the child return to a normal weight for their age must be based on achieving balance between energy in (food consumption) and energy out (physical activity).
Nutrition – Making changes for the better
Establishing a proper diet for the child, especially during these critical years of growth, may require more than educating the parents; a perceptual and then actual shift of parents' habits may be in order. For example, a 2002 Gerber Products research study involving 3,000 infants and toddlers showed that 40% received sweets daily at less than one year of age, and by the age of two years, 43% of children were given soft drinks on a daily basis.4
Socioeconomic circumstances may be influencing food choices away from fruits and vegetables and toward less expensive carbohydrate-, fat- and sugar-heavy foods. Encouraging change toward a healthy diet for the child and family that focuses on nutrients while reducing fats and sugar can be supported with literature and tools that provide easy-to-follow guidance for home use that fits within budgets.10
Tools from the USDA website, ChooseMyPlate.gov, provide guidance on following a balanced diet representing all food groups as well as calorie guides and serving sizes.11
Physical activity – Getting started with new healthy habits
Dietary changes combined with increased physical activity will have a greater and more rapid impact on the child's weight than dietary changes alone.
The family is the pediatrician's primary partner in encouraging regular physical activity for the child – again, changing children's habits will likely require that family members join in with the treatment plan to make physical activity a daily habit for the whole family, balanced with placing limitations on television and video game time for children to two hours per day, as recommended by the AAP.12
A second chance: Losing weight to regain health
The prospect of changing the young child's nutrition and activity habits may seem daunting; however, the fact that comorbid conditions can be improved by weight loss means that future history can be changed.
A system of regular follow-up appointments with the child to monitor progress will help to ensure successful weight loss through adoption of new eating habits and exercise practices. Referrals to dieticians and local accessible sports and exercise programs will help the family to work toward achieving their goals.4,13
Overweight and obesity are difficult to treat and appear to present a lifelong risk. Prevention therefore is critical.9
It is important to educate and empower families through guidance to recognize the impact they have on their children's development of lifelong habits of physical activity and nutritious eating.
Nutrition for the young child
An interesting characteristic of toddlers identified through research is that they can learn to self-regulate eating, choosing if and how much of a food to eat at a particular time. The parent's role is to provide appropriate food choices; the benefits of fruit and vegetables over high fat or sugar foods, for example, are well known but not necessarily pursued. Deficiencies can quickly develop in the young child's diet, including iron, zinc and vitamin D deficiency, if good nutrition is not maintained.10,14,15
Parents should be given the opportunity to be educated about the benefits of providing a well-balanced and nutritious range of foods and age-appropriate portion sizes. The meal environment – e.g., a meal eaten by the family together, at regularly scheduled times and without television or other distractions – is an additional consideration in establishing healthy eating habits.
The impact of the young child's diet on long-term health, including prevention of obesity and chronic diseases such as cardiovascular disease and diabetes, is recently becoming better understood. Continued research will continue to provide insights into the long-term importance of healthy nutrition that can be shared with families.10,14,15
Regular physical activity achieved through free play or organized activities is not only an intervention, it should be embraced as an important preventive element to be incorporated into the family's daily schedule. Parents should be encouraged to act as role models for their children through their sport and exercise participation. The AAP recommends a maximum of two hours of sedentary activity involving television and video games, with these activities ideally being replaced by physical activity. The AAP Policy statement on prevention of childhood obesity through increased physical activity (2003) recommends that physicians and healthcare professionals advocate for school and community recreation programs and safe and accessible recreational facilities and playgrounds to support these goals.12
Summary of Prevention Strategies
- Genetic, environmental or combinations of risk factors that may predispose children to overweight and obesity should be identified early by the pediatrician and considered in prevention plans.
- Recording and tracking regular BMI measurements (at annual checkup, for example) for the child whose weight appears excessive relative to height will provide immediate and ongoing feedback on the child's weight status.
- Support a family approach to prevention of overweight and obesity through direction on healthy nutrition and physical activity.
To review the full Summary and Conclusions from the AAP's paper on Prevention of Pediatric Overweight and Obesity,click here.
- Kimm SYS, Obarzanck E. Childhood obesity: a new pandemic of the new millennium. Pediatrics 2002;110:1003-1006.
A commentary exploring the increasing prevalence of childhood overweight and obesity, including environmental and biological factors, issues in clinical management, and future directions for management and prevention.
- 2003/2004 National Health and Nutrition Examination Survey (NHANES). Centers for Disease Control and Prevention, U.S. Department of Health and Human Services.
Statistical information on pediatric obesity drawn from the 2003/2004 NHANES survey.
- Strauss RS, Pollack HA. Epidemic Increase in childhood Overweight, 1986-1998. JAMA 2001;286(22):2845-8.
Child overweight continues to increase rapidly in the United States, particularly among African Americans and Hispanics. This study investigated changes in the prevalence of overweight in children aged 4 to 12 years between 1986 and 1998.
- Stender SRS, Burghen GA, Mallare JT. The Role of Health Care Providers in the Prevention of Overweight and Type 2 Diabetes in Children and Adolescents. Diabetes Spectrum 2005;18(4):240-8.
This article focuses on prevention strategies to improve the health of overweight and obese children and adolescents, especially relating to avoidance of type 2 diabetes. Risk factors for obesity and the many comorbid conditions associated with obesity are discussed. Recommendations are made for encouraging improved nutrition and physical exercise in partnership with the family.
- Kahn A et al. Sleep pattern, alteration and brief airway obstruction in overweight infants. Sleep 1989;12(5)430-8.
This study examined sleep patterns in overweight infants and found evidence of obstructive sleep apnea and other sleep disturbances related to overweight in infants as young as five months of age.
- Riley MR et al. Underdiagnosis of Pediatric Obesity and underscreening for fatty liver disease and metabolic syndrome by pediatricians and pediatric subspecialists. J Pediatr 2005;147:839-42.
This retrospective study evaluated the frequency with which children are diagnosed as overweight and how often interventions are recommended including nutritional counseling and screening for fatty liver disease and metabolic syndrome. Results indicated underdiagnosis and resulting underscreening for these chronic diseases, with recommendations made for specific attention to be made to children under the age of five years with a BMI% of 85-94%.
- American Academy of Pediatrics. Policy Statement: Prevention of Pediatric Overweight and Obesity. Pediatrics 2003;112(2):424-30.
An AAP policy statement examining preventive strategies to deal with overweight and obesity in children, including discussion of early identification using the BMI-for-age tool and recommendations for initiating and following dietary and physical activity interventions.
- Centers for Disease Control and Prevention, National Center for Health Statistics, 2000.
PDFs – BMI-by-age charts for boys and girls, ages 2 to 20, and growth charts for boys and girls, birth to 36 months and ages 2 to 20.
- Nader PR, O'Brien M, Houts R, Bradley R, Belsky J, Crosnoe R, Friedman S, Mei Z, Susman EJ for the National Institute of Child Health and Human Development Early Child Care Research Network. Identifying Risk for Obesity in Early Childhood Pediatrics 2006;118:594-601.
The objective of this study was to understand the predictive value of childhood BMI status on the risk of overweight and obesity in later childhood and adolescence. BMI was measured for a longitudinal sample of 1042 healthy children born in 1991 who were followed from age 24 months to 12 years. Results showed that persistence of obesity is apparent for both the preschool and elementary school period.
- Horodynski MA, Stommel M. Nutrition Education Aimed at Toddlers: An Intervention Study. Pediatric Nursing 2005;31(5)364-72.
Discussion and results of the intervention study, "Nutrition Education Aimed at Toddlers" (NEAT) which aimed to enhance parent-toddler feeding practices in recognition of the prevalence of weight problems in children, and the fact that dietary behaviors are established early in life by the family.
- MyPyramid Food Guidance System. United States Department of Agriculture, Center for Nutrition Policy and Promotion website: MyPyramid.gov http://www.ChooseMyPlate.gov/
The Center for Nutrition Policy and Promotion, an organization of the U.S. Department of Agriculture, was established in 1994 to improve the nutrition and well-being of Americans. The Center's core products to support its objectives include: Dietary Guidelines for Americans; MyPyramid Food Guidance System; Healthy Eating Index; U.S. Food Plans; Nutrient Content of the U.S. Food Supply; Expenditures on Children by Families.
- American Academy of Pediatrics. Policy Statement: Active Healthy Living: Prevention of Childhood Obesity Through Increased Physical Activity. Pediatrics 2006;117(5):1834-42.
An AAP policy statement focusing on prevention of childhood obesity and improvement of children's physical health through expanded age-appropriate physical activity for pre-schoolers, school-age children and adolescents. Recommendations are made for assessing physical activity, promoting active lifestyles and discouraging sedentary activities for both the child and family.
- Nemet D, Barkan S, Epstein Y, Friedland O, Kowen G, Eliakim A. Short- and Long-Term Beneficial Effects of a Combined Dietary–Behavioral–Physical Activity Intervention for the Treatment of Childhood Obesity. Pediatrics 2005;115(4):443-9.
The importance of early intervention to treat pediatric overweight and obesity with improved nutrition and physical exercise approaches are well recognized; however, these strategies are not seeing widespread use. This prospective study examined the short- and long-term effects of a three-month dietary-behavioral-physical activity intervention on obese children.
- Morgan J. Nutrition for toddlers: the foundation of good health. 1. Toddlers' nutritional needs: what are they and are they being met? Journal of Family Health Care 2005;15(2):56-9.
This article, the first in a series of two, considers current nutritional recommendations for toddlers in the UK and how well they are being met in today's climate of poor dietary behaviors coupled with insufficient physical activity resulting in nutrition-related chronic diseases including obesity and iron deficiency anemia.
- Morgan J. Nutrition for toddlers: the foundation for good health. 2. Current problems and ways to overcome them. Journal of Family Health Care 2005;15(3):85-8.
This article, the second in a series of two, examines concerns with toddler nutrition in the UK, including lack of a balanced diet with inadequate nutrition resulting in obesity and iron deficiency anemia. Practical approaches are discussed to prevent these chronic diseases with dietary recommendations that consider socioeconomic factors.