Childhood Obesity: The Scope of the Problem

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Symposium on Adult Diseases in Children - February 2009

 

Tex Med. 2009;105(2):23-24.

By Soumya Adhikari, MD

In 2005, recognizing the growing epidemic of childhood obesity, the Texas Legislature considered a bill that would have required school districts to calculate the body mass index (BMI) of each of their students and report it to parents on the student's report card, with appropriate reference ranges to guide their interpretation. Ultimately, in part due to concerns of the increasing stigmatization of childhood obesity, Senate Bill 205 failed. Whether or not the simple act of reporting a child's BMI would have stemmed the inexorable tide of childhood obesity in this state is debatable. That such legislation would even be considered serves only to highlight the need for greater attention to what may be the state's largest looming health crisis.

For years now, the Centers for Disease Control and Prevention (CDC) 1 and the Institute of Medicine (IOM) 2 have defined obesity on the basis of BMI stratifications. Although the use of BMI has limitations, it has remained the main parameter for defining obesity because of its reproducibility, practicality, and ease of determination. Because the normal range for BMI varies depending on the child's age and sex, a single standard cutoff for BMI for all children does not suffice as it does for adults, for whom obesity is defined as a BMI >30 kg/m 2 . Traditionally, children with a BMI ≥85th percentile (for age and sex) but <95th percentile were defined as being "at risk for overweight," whereas children with a BMI ≥95th percentile were defined as "overweight."

In 2007, in an effort to bring greater consistency to reporting mechanisms and to eliminate the clumsy term "at risk for overweight," an expert committee of the American Academy of Pediatrics proposed reclassifying children according to the following stratifications: overweight (BMI for age and sex ≥85th percentile but <95th percentile) and obese (BMI ≥95th percentile). 3

Citing concerns that "the term obesity denotes excess body fat more accurately and reflects the associated serious health risks more clearly than does the term overweight, which is not recognized as a clinical term for high adiposity," the committee suggested that the new strata distinguish children with high BMI due to greater lean body mass (more likely to have a BMI ≥85th percentile but <95th percentile and thus classified as overweight) from those more likely to have excess body fat (BMI ≥95th percentile), newly classified as obese.

 

Prevalence Rates

Using these criteria, the Dallas Independent School District (DISD) reports that 36 percent of high school students are either overweight or obese. 4 Statewide, 32 percent of Texas high school students were either overweight or obese in 2007. These figures exceed national averages reported in the last National Health and Nutrition Examination Survey (NHANES) by almost twofold. 5

Perhaps even more alarming, this increase in obesity is not restricted to adolescents. Recent studies have suggested that 42 percent of fourth graders, 39 percent of eighth graders, and 36 percent of eleventh graders in Texas are overweight or obese. 6 Moreover, 21 percent of low-income children aged 2 to 5 years enrolled in the Texas Women, Infants and Children (WIC) supplemental nutrition program are overweight or obese. 7 These data paint a grim picture of the increasing prevalence of childhood obesity that is starting at younger and younger ages and highlight the need for immediate, sustainable intervention measures.

 

Ramifications

The comorbidities associated with obesity, even in childhood, are numerous and potentially life-threatening. The rising incidence of type 2 diabetes in children has paralleled the steep slope of the obesity epidemic. 8  (See " Type 2 Diabetes in Children and Adolescents .")

Obese children also are at greater risk for developing hypertension, dyslipidemia, polycystic ovary syndrome, nonalcoholic fatty liver disease, obstructive sleep apnea, depression, gastroesophageal reflux, pseudotumor cerebri, and, ultimately, for cardiovascular mortality.

From a purely financial perspective, the rising prevalence of childhood obesity threatens to place unprecedented burdens on our public health care systems. CDC estimates the health care costs attributable to overweight or obesity between 1998 and 2000 in Texas alone to be approximately $5.3 billion. 9 Other data suggest that figure could swell to near $40 billion by 2040. 10 With evidence suggesting that an overweight 12-year-old has a 75 percent chance of being overweight as an adult, 11 the impetus to target interventions toward the pediatric age group has never been more evident.

 

Causative Factors

Several factors are responsible for the increase in childhood obesity, including increased consumption of high-calorie foods and an increasingly sedentary lifestyle. Sugar-sweetened drinks, readily available to children and adolescents even in many schools, play a role in the increased caloric consumption of children across the country. 12

Despite its merits, technology also shares some of the blame in this epidemic. Children spend a far greater number of hours in "screen time" (including use of televisions, video game systems, and computers) than did children of past generations. 13 In the 2007 Youth Risk Behavior Surveillance Study, 50.8 percent of Dallas high school students reported that they watched three or more hours of television per day. 4 There is a strong association between these behaviors and the increasing prevalence of obesity in the pediatric population.

In DISD, only 11 percent of high school students attend daily physical education (PE) classes. Fifty-two percent are not enrolled in PE classes at all. 4 Regular participation in physical activity not only helps to limit weight gain, but also has independently beneficial effects on blood pressure and bone health. 14

Other environmental factors may contribute to the rise in obesity. Many children with working mothers spend a large amount of time in day care facilities, beginning at the age at which the prevalence of obesity and overweight begins to increase. Most children aged 5 to 17 years are enrolled in school and spend most of their day outside the home. These factors suggest that the burden of changing the habits of children falls not only on parents, but also on public institutions.

 

Future Directions

Fortunately, recent IOM data suggest that many schools are implementing innovative intervention programs. 2 Whether these programs focus on increasing the recognition of the problem or target specific behavioral changes, the potential impact is significant.

Is there a light at the end of this otherwise dark tunnel? Texas has implemented several programs to address these problems. Statewide screening programs for acanthosis nigricans attempt to identify children at risk for developing type 2 diabetes before they decompensate and require urgent medical intervention. School lunch programs and the availability of vending machines have been targeted to limit the consumption of sugar-containing drinks and high-calorie snacks.

With the increased attention to the problem of obesity in the last few years, are we beginning to see any sort of a change in epidemiologic trends? The latest data from NHANES offer a glimmer of hope. The most recent survey suggested that the prevalence of obesity in children and adolescents may have plateaued, showing no significant change between 2003-2004 and 2005-2006. Nationwide, 16.3 percent of children and adolescents aged 2 to 19 years were obese (BMI ≥95th percentile) based on combined data from 2003 to 2006. 5 Continued attention to this problem is necessary to improve the public health outlook.

 

References

  1. Kuczmarski RJ, Ogden CL, Guo SS, et al. 2000 CDC growth charts for the United States: methods and development. Vital Health Stat 11. 2002;(246):1-190.
  2. Koplan JP, Liverman CT, Kraak VI, eds. Preventing Childhood Obesity: Health in the Balance . Washington, DC: National Academies Press; 2005.
  3. Barlow SE; Expert Committee. Expert Committee recommendations regarding the prevention, assessment, and treatment of child and adolescent overweight and obesity: summary report. Pediatrics . 2007;120 suppl 4;S164-S192.Eaton DK, Kann L, Kinchen S, et al; Centers for Disease Control and Prevention (CDC).  Youth risk behavior surveillance - United States, 2007. MMWR Surveill Summ . 2008; 57 ( 4 ): 1-131 .
  4. Ogden CL, Carroll MD, Flegal KM. High body mass index for age among US children and adolescents, 2003-2006. JAMA . 2008;299(20):2401-2405.
  5. Hoelscher DM, Perez A, Lee ES, Sanders J, Kelder SH, Day RS, Ward J. School Physical Activity and Nutrition (SPAN) III Survey, 2004-2005. Houston; TX: University of Texas School of Public Health.
  6. Texas Women, Infants and Children program, February 2007.  http://www.dshs.state.tx.us/wichd/default.shtm .
  7. Fagot-Campagna A, Pettitt DJ, Engelgau MM, et al. Type 2 diabetes among North American children and adolescents: an epidemiologic review and a public health perspective. J Pediatr . 2000;136(5):664-672.
  8. Finkelstein, EA, Fiebelkorn, IC, Wang, G. State-level estimates of annual medical expenditures attributable to obesity. Obes Res . 2004;12(1):18-24.
  9. Texas Department of State Health Services. The Burden of Overweight and Obesity in Texas, 2000-2040 . Austin, TX: Texas Department of State Health Services; 2004. http://www.publichealthgrandrounds.unc.edu/catch/handout_txCost_Obesity_Report.pdf .
  10. Wright CM, Parker L, Lamont D, Craft AW. Implications of childhood obesity for adult health: findings from thousand families cohort study. BMJ . 2001;323(7324):1280-1284.
  11. Ludwig DS, Peterson KE, Gortmaker SL. Relation between consumption of sugar-sweetened drinks and childhood obesity: a prospective, observational analysis. Lancet . 2001;357(9255):505-508.
  12. Rideout V, Roberts DF, Foehr UG. Generation M: Media in the Lives of 8-18 Year-Olds. Menlo Park, CA: The Henry J. Kaiser Family Foundation; 2005.  http://www.kff.org/entmedia/entmedia030905pkg.cfm
  13. Strong WB, Malina RM, Blimkie CJ, et al. Evidence based physical activity for school-age youth. J Pediatr . 2005;146(6):732-737.

 

Dr. Adhikari is assistant professor in the Division of Pediatric Endocrinology and director of the pediatric clerkship at The University of Texas Southwestern Medical Center in Dallas.

 

 

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