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RUNNING HEAD: CHILDHOOD OBESITY: A LOOK AT THE EPIDEMIC, WHO IT AFFECTS,
IT’S CAUSES AND POSSIBLE PREVENTION

Childhood Obesity: A Look at the Epidemic, Who It Affects, and It’s Causes

Stacy Kramer

Concordia University

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RUNNING HEAD: CHILDHOOD OBESITY: A LOOK AT THE EPIDEMIC, WHO IT AFFECTS,
IT’S CAUSES AND POSSIBLE PREVENTION

More than 23 million children and teenagers in the U.S. are obese or overweight, a statistic that health and medical experts consider an epidemic. According to Dr. John Mersch, an epidemic is defined as occurring when "new cases of a certain disease, in a given human population during a given time period, substantially exceed what is expected based upon recent experience (2012)." While obesity rates have soared among all age groups in this country, obesity is a particularly vital concern for children.

Today, overweight and obese children are significant public health problems in the United States. The number of adolescents who are overweight has tripled since 1980 and the prevalence among younger children has more than doubled (DHHS, n.d.). Our children are at risk of falling prey to this epidemic if our society doesn’t determine better tools for preventing obesity.

In order to systematically describe obesity, the concept of body mass index (BMI) was developed. BMI is the ratio between an individual's weight to height relative to their gender and age. BMI addresses the following question: Is the weight of the subject in excess of what is healthy for a given height? Generally (but not always), BMI correlates with the amount of body fat, but it is not a measurement of fat. An individual who has more than the average muscle mass for a given height (for example, weight lifters) will have an elevated BMI but clearly will not be obese. But, for the most part, an individual is overweight when their BMI is between 25.0-29.9. Obesity is defined as a BMI greater than 30.0.

In determining the prevalence of childhood obesity, both qualitative and quantitative data are collected. The National Center for Health Statistics (NCHS), which is part of the Centers for Disease Control and Prevention (CDC), has the responsibility for producing the vital and health statistics for the Nation (CDC, 2012, September 19). A major program of the NCHS is the National Health and Nutrition Examination Survey (NHANES), which is a program of studies designed to assess the health and nutritional status of adults and children in the United States (CDC, 2012, September 19). The survey is unique because it collects data from both interviews and physical examinations.

In 1999, the survey became a continuous program that has a changing focus on a variety of health and nutrition measurements to meet emerging needs. The survey examines a nationally representative sample of about 5,000 persons each year and includes questions pertaining to demographics, socioeconomic status, dietary practices and personal health. The examination component consists of medical, dental, and physiological measurements, as well as laboratory tests administered by highly trained medical personnel. The sample for the survey is selected to represent the U.S. population of all ages. In order to produce reliable statistics, NHANES over-samples persons 60 and older, African Americans, and Hispanics (CDC, 2012, September 19).

The National Institutes of Health, the Food and Drug Administration, and CDC are among the agencies that rely upon NHANES to provide data essential for the implementation and evaluation of program activities. Two important accomplishments of the NHANES are (NHANES, 2012):
1. Past surveys have provided data to create the growth charts used nationally
by pediatricians to evaluate children’s growth.
- The charts have been adapted and adopted worldwide as a reference
standard
2. Overweight prevalence figures have led to the proliferation of programs
emphasizing diet and exercise, stimulated additional research, and provided
a means to track trends in obesity

According to the recent NHANES, obesity is increasing in all age groups, both sexes, and in various ethnic and racial groups (Schwarz, 2012). Furthermore, according to Schwarz, obesity is a complex disorder and is the most prevalent nutritional disorder among children in the United States. Research has proven that children and adolescents who are defined as overweight or obese are highly likely to remain overweight or obese as adults (2012).

There are many factors that affect the occurrence of obesity such as: genetics, environment, metabolism, inadequate sleep, life style choices, physical activity, socio-economic status, and eating habits (Schwarz, 2012). These factors are nondiscriminatory meaning they can affect all people regardless of age, gender, culture or socio-economic status. With that said, the distribution of childhood and adolescent obesity is not equal. There are certain populations who are affected more severely. For instance, according to DHHS, NHANES found that African American and Mexican American adolescents ages 12-19 were more likely to be overweight, at 21 percent and 23 percent respectively, than non-Hispanic White adolescents (14 percent). In children 6-11 years old, 22 percent of Mexican American children were overweight, whereas 20 percent of African American children and 14 percent of non-Hispanic White children were overweight. In addition, at the time of the survey, another 15 percent were at risk of becoming overweight.

In separate studies (also using BMI), it was found that obesity is more prevalent in boys (19%) than it is in girls (15%) and in looking at data, it seems to be apparent that the number of boys who are overweight or obese has increased at a faster rate than girls (Harvard, 2012). In a national survey of American Indian children 5-18 years old, 39 percent were found to be overweight or at risk for overweight (DHHS, n.d.).

Qualitative data gathered from the NHANES compares the prevalence of obesity in different races/ethnic groups as well as the differences between males and females. For instance, according to the American Heart Association, black, non-Hispanic females have the highest prevalence of obesity among adolescents in grades 9-12 while white, non-Hispanic females have the lowest prevalence of obesity among adolescents in grades 9-12. However, overall, fewer females are obese than males. In addition, the prevalence of obesity was higher among adolescents (age 6-19) than in preschool children (age 3-5).

Quantitative data gathered from the NHAMES is based on directly measured weight and heights (Healthy People, 2010). Goals for the obesity epidemic in the United States were not met by the Healthy People 2010 initiative. In fact, goals for obesity prevalence moved away from the targets instead of closer to the targets. Data compared between 1988-94 and 2005-2008 showed a 54.5% increase in obesity for kids aged 6-11 and a 63.6% increase in obesity for kids aged 12-19 (Healthy People, 2010). The target for 2010 (which was set in 2000) was five percent.

Other data collected by the NHAMES and reported by the American Heart Association as of 2009-2010 showed that:

·  Among 2-19 year olds, 1 out of 3 are overweight or obese

o  32.1% are boys and 31.3 are girls

·  Among 2-19 year olds, 1 out of 6 are obese

o  This is approximately 12.5 million children and adolescents

·  20% of children aged 6-11 are obese compared to only 4% of 6-11 year olds from 1971-74

·  18% of adolescents aged 12-19 are obese compared to only 6% of the same age in 1971-74

o  the number of obese children ages 5-19 is 5 times greater than it was in 1971-74

·  Over the past decade, there has been a significant increase in the prevalence of obesity among men and boys but not among women and girls (Carroll, Flegal, Kit & Ogden, 2012)

·  Globally, an estimated 43 million preschool-aged children (3-5 years old) were overweight or obese in 2010 which was a 60% increase since 1990 (Harvard School of Public Health, 2012).

The worldwide prevalence of childhood overweight and obesity have increased from 4.2% in 1990 to 6.7% in 2010 and this trend is expected to reach 9.1% in 2020 (Choquet & Meyre, 2011). Children are consuming more energy (in the form of food) than they require to function. This over-consumption of food energy without any increase in expenditure of the energy results in weight gain. Therefore, it’s not a surprise that epidemiologic studies have found a correlation between the increased number of children who are obese and the decline in nutrition and physical activity habits of U.S. children over the past 40 years (DHHS, n.d.).

Overall, the statistics for childhood obesity are depressing. Overweight adolescents have a 70% chance of becoming overweight as an adult and if they have just one parent who is overweight, that likelihood of being overweight as an adult jumps to 80% (American Heart Association, 2012). As the number of children who are overweight and/or obese increases, so does the number of children with hypertension, type 2 diabetes, high cholesterol and/or blood pressure, and multiple other heart and lung-related diseases. This leads to other potential medical problems as well as higher medical costs; and they will most likely continue into adulthood. Currently, according to the American Heart Association, the total cost related to adolescent overweight and obesity is estimated to be $254 billion. If this trend continues, roughly 18% of U.S. health expenditures will be attributable to obesity by 2030.

According to Han, Kimm & Lawlor (2010), both biological and technological forces are responsible for the childhood obesity epidemic we are facing today. Thousands of years ago, survival meant eating as much as one could when one had the chance because one never knew when food would be available again. Today, agricultural practices have made it nearly impossible to be without food as we have a stable food supply. However, because of the same technology that gives us better agricultural practices, we do not use or expend as much energy on daily living as previous generations. Fewer people are performing physical tasks during the day and are therefore, not utilizing the energy they consume (Han, Kimm & Lawlor, 2010).

Societal changes, such as a more sedentary lifestyle and over-nutrition, are major risk factors for childhood obesity. Other environmental risk factors include: an increase in both dual-income and single working parent homes (especially single mother homes), fewer breast-fed babies and parental diets (HHS, 2012). According to the AACAP (American Academy of Child and Adolescent Psychiatry), having a family history of obesity, medical illnesses (endocrine, neurological problems), taking some medications (steroids, some psychiatric medications), stressful life events or changes (separations, divorce, moves, deaths, abuse), family and peer problems, and having a low self-esteem, depression or other emotional problems also increases the risk of becoming overweight and obese (2011).

According to Schwarz, these risk factors account for approximately 90% of the obesity cases in the United States. The other 10% of children who are overweight and/or obese have either a hormonal disorder or a genetic disorder (2012). Genetic susceptibility to obesity, in most cases, is due to multiple genes that interact with environmental and behavioral factors. Simply having a genetic predisposition to obesity does not guarantee that an individual will develop the disease (HHS, 2011).

As stated above, obesity is a strongly heritable disorder (Choquet & Meyre, 2011). Choquet and Meyre’s research concluded that family history of obesity is a well-established risk predictor for obesity in childhood. Their research showed that the risk of a child becoming obese is 2.5-4-fold higher if one of their parents is obese and 10-fold higher if both parents are obese, compared to having both parents of normal weight. The familial risk for obesity (the risk ratio to be obese for an individual if a first degree relative is obese compared with individuals in the population who have only normal-weight first degree relatives) is comprised between 1.5 and 5 depending on the severity of obesity (Choquet & Meyre, 2011).

For over a decade, obesity genetics has been predominantly driven by research into monogenic or syndromic obesity. According to Blakemore, Froguel & Walley (2006), the cloning of the mouse ob gene and its human homologue, leptin, proved to be a paradigm for the field that resulted in the identification of many genes involved in the regulation of appetite via the leptin–melanocortin pathway. Alongside these ‘pure’ forms of obesity, where the gene defect is in appetite regulation and the disease is characterized by severe early onset obesity because of hyperphagia, syndromic forms have provided additional insights into the mechanisms underlying obesity. There are around 30 different Mendelian disorders that have obesity as a significant clinical feature (Blakemore, Froguel & Walley, 2006).

There is also a polygenetic predisposition to obesity. Polygenetic, in my high school biology terms, means having multiple genes involved. A polygenetic predisposition is found by identifying that an appropriate gene variant (allele) occurs more frequently in an obese person than in a non-obese person. Currently, according to Choquet and Meyre (2011), there are 58 known loci that contribute to polygenetic obesity.

Another area of genetics that is now being studied is epigenetics. According to De Berg, Flanagan, Mroch and Stein (2011), epigenetics refers to genetic patterning not directly evident by looking at the DNA sequence. One example is a genetic phenomenon known as imprinting, that is, certain genes are turned “on” or “off” depending on if they are inherited from the father or the mother. Epigenetic studies are much harder to conduct than studies focused on sequence variations, though mouse models are now providing measurable evidence about how the in utero environment is functionally reprogramming the genome (De Berg, Flanagan, Mroch, and Stein (2011).