Question

Examine the obesity epidemic in the United States related to the adolescent age-group. Discuss causes, complications, goals, and ways nurses can help decrease the growing epidemic.

Answer 1

Obesity among children, adolescents and adults has emerged as one of the most serious public health concerns in the 21st century. The worldwide prevalence of childhood obesity has increased remarkably over the past 3 decades. The growing prevalence of childhood obesity has also led to appearance of obesity-related comorbid disease entities at an early age. Childhood obesity can adversely affect nearly every organ system and often causes serious consequences, including hypertension, dyslipidemia, insulin resistance, dysglycemia, fatty liver disease and psychosocial complications. It is also a major contributor to increasing healthcare expenditures. For all these reasons, it is important to prevent childhood obesity as well as to identify overweight and obese children at an early stage so they can begin treatment and attain and maintain a healthy weight. At present, pharmacotherapy options for treatment of pediatric obesity are very limited. Therefore, establishing a comprehensive management program that emphasizes appropriate nutrition, exercise and behavioral modification is crucial. The physician’s role should expand beyond the clinical setting to the community to serve as a role model and to advocate for prevention and early treatment of obesity.

Obesity is characterized by an excess of body fat or adiposity. Obesity is most often defined by the body mass index (BMI), a mathematical formula of weight-for-height index. BMI is measured by dividing the body weight in kilograms to height in meters squared (kg/m2). BMI has a high correlation with adiposity and it also correlates well with excess weight at the population level. It is important to note that the calculated BMI figure can sometimes be inaccurate because it does not quantify total body adiposity, does not distinguish between fat and muscle, nor does it predict body fat distribution. Therefore, it may overestimate adiposity in a child with increased muscle mass, as may be the case in an athletic child and underestimate adiposity in a child with reduced muscle mass, such as a sedentary child. On a population level, however, BMI does seem to track trends in adiposity as opposed to muscularity and those individuals with large muscle mass with resulting high BMI values are easily distinguishable from those with large amounts of adipose tissue. The World Health Organization (WHO) categorizes adults with a BMI of 25 to 30 as overweight, whereas obesity is classified according to stages or grades - Grade 1: BMI 30.0-34.9, Grade 2: BMI 35.0-39.9 and Grade 3: BMI ≥40.0. Grade 3 obesity was formerly known as morbid obesity, but the term was appropriately changed for several reasons: morbidity may not occur at BMI levels higher than 40 but certainly can be found at BMI levels lower than 40. In the pediatric age group, gender-specific BMI-for-age percentile curves are used to define overweight and obesity. Children and adolescents with a BMI over the 85th but less than the 95th percentile for age and gender are considered overweight and those with a BMI greater than the 95th percentile are considered obese. Children and adolescents with a BMI greater than the 99th percentile are considered severely obese. The International Obesity Task Force has developed an international standard growth chart which enables comparison of prevalence globally. However, many countries have continued to use country-specific growth charts. In the United States, the gender-specific CDC Growth Charts, released in May 2000, are used to evaluate BMI for children 2 to 20 years of age.

Obesity is a complex, multifactorial condition affected by genetic and non-genetic factors. In children and adolescents, the overweight state is generally caused by a lack of physical activity, unhealthy eating patterns resulting in excess energy intake, or a combination of the two resulting in energy excess. Pediatric obesity is also a multifactorial condition which is a resultant of genetic and non-genetic factors and the complex interactions among these. Genetics and social factors (socio-economic status, race/ethnicity, media and marketing and the physical environment) also influence energy consumption and expenditure. Obesity seems to be the result of a complex interplay between the environment and the body’s predisposition to obesity based on genetics and epigenetic programming.

Specific causes for the increase in prevalence of childhood obesity are not clear and establishing causality is difficult since longitudinal research in this area is limited. The heritability of body weight is high and genetic variation plays a major role in determining the inter individual differences in susceptibility or resistance to the obesogenic environment. Appetite regulation and energy homeostasis depend on a large number of hormones many of which are secreted by the gastrointestinal tract. Ghrelin is currently the only known appetite-stimulating (orexigenic) gut hormone, secreted by the oxyntic glands of the stomach. Ghrelin levels rise shortly before mealtimes. The other gut hormones identified to date are anorexigenic (decrease appetite and food intake). These include: peptide tyrosine tyrosine (PYY), pancreatic polypeptide, oxyntomodulin, amylin, glucagon, glucagon-like peptide-1 (GLP-1) and GLP-2. For example, PYY acts as a satiety signal. The levels of PYY rise within 15 minutes after food intake, resulting in reduced food intake. The gastrointestinal tract is the body’s largest endocrine organ producing hormones that have important sensing and signaling roles in the regulation of energy homeostasis. There are several determinants or risk factors for development of pediatric overweight or obesity.