When someone is obese, it means that he or she has accumulated so much fat in the body that it negatively affects their health. A Body Mass Index of between 25 and 29.9 is considered over weight. If the BMI is 30 and above, then the person is obese. Childhood obesity occurs when the weight of a child is above normal for his or her age and height. This exposes them to health problems such as diabetes, high levels of cholesterol and high blood pressure. Childhood obesity is a serious public health problem in Australia and globally. It has increased at an alarming rate and particularly affects those in urban settings.
Global Trends in Childhood Obesity
Studies show that childhood obesity in Australia has risen over the past years. The rate of obesity in children in 1995 was 5%. In 2007-08, the rate increased to 8%. About 600,000 children under the age bracket of 5-17 years were either overweight or obese in 2007-08. This shows an increase in the BMI of children over time. 61% of adults in Australia were either overweight or obese in 2007-08. Childhood obesity is a global problem and has been increasing at an alarming rate. The number of overweight children around the world, in 2010, was estimated to be about 42 million, a 60% increase since 1990. Around 25 million of these children live in developing countries. In the US, the number of obese children between 2-19 years is 12.5 million. The rate has almost tripled since 1980. In Europe, research results indicate that 24% of children between 6-9 years are either overweight or obese. In Asia, the rate of prevalence in childhood obesity, in 2010, was 4.9%. The number of obese children was 18 million, a 53% increase since 1990. These results confirm the dramatic increase in childhood obesity over time. Effective interventions may reverse this trend .
Causes of Childhood Obesity
Foremost, obesity is caused by the imbalance between energy input and energy output, which results in a positive energy balance. This occurs when the calories consumed are in excess of what the body needs to maintain normal weight. A positive energy balance of 10 calories per day will produce a weight gain of 1kg over a period of 1 year. This is normally very small and it is easy to notice consuming it.
Secondly, genetic factors in a population contribute to the development of obesity. Researchers have found a relationship between parent and child obesity. Furthermore, genetics determines the likelihood of developing obesity. This may occur through two processes: one is the likelihood to overeat despite the normal energy requirements, and the second one is having a normal drive to eat regardless of low energy requirements. Genetically programmed metabolic pathways influence appetite and the drive to eat. Syndromatic obesity occurs as a result of genetic defects and is seen in patients with Bardet-Biedl syndrome, Trisomy 21 and PraderWilli syndrome.
Thirdly, several environmental factors have contributed to the development of obesity. Children who spend most of their time, on the couch, either watching television or playing video games have a high body fat, and a higher BMI. These children spend a little time on physical activities, and a lot of time on watching TV or sleeping. Television watching has been associated with an increase in food intake during the viewing period. Marketers target consumers by advertisements through television. Many of the ads target children for fast foods, candy and sugared cereals. The increased consumption of fast foods, plus decreased energy use leads to weight gain.
Consumption of fast foods is another contributing factor. Fast food diets have high macronutrient content, high energy density and are of large portions. For instance, a fast food meal may contain 2200 calories. If the rate of burning the calories is 85-100 calories per hour, it may require close to a full marathon to use the energy. Sugar sweetened beverages contain empty calories, and contribute to the total intake of calories.
The increased use of motor transport also contributes to obesity in children. Parents prefer driving their children to school to letting them walk. Kids own and ride motorized cars instead of pedaling bikes. Parents who work outside their homes may serve their children with high calorie fast foods due to lack of time.Parents influence the eating habits of their children. Children are more likely to eat what their parents consume. Children whose parents consume a lot of fast foods are more likely to do the same. Increased calorie intake and less physical activities creates a positive energy balance leading to obesity.
A cohort study revealed that maternal smoking during pregnancy may contribute to childhood obesity. The results of the study showed a higher rate of obesity and overweight in children whose mothers smoked during pregnancy. Maternal smoking is associated with low birth weight. The study linked catch up growth during the first year of life to childhood obesity. Children with catch up growth had a higher BMI and waist circumference at 5 years of age.
Lastly, children who did not breastfeed are likely to be obese. The risk of developing obesity is reduced through breastfeeding. A study conducted in Southern Germany, involving 134,577 children showed a 35% decrease in children breastfed for 3-5 months. Another study showed an increased rate of obesity in children never breastfed. Children fed bottled milk had a higher concentration of insulin in plasma compared to those who were breastfed. This stimulates deposition of fat and an early adipocyte development. Breast milk contains bioactive factors that modulate tumor necrosis factor and epidermal growth factor. These two inhibit the differentiation of adipocytes.
Health Consequences of Childhood Obesity
Obese children are exposed to the risk of developing health problems previously seen only in adults. They may develop insulin resistance leading to type 2 Diabetes. High Blood Pressure and cholesterol levels are other conditions obese children are exposed to. The chances of carrying these health problems into adulthood are high. It increases the risks of acquiring adult obesity, heart disease, and diabetes. Many obese children are teased or ridiculed by their friends, and develop low self-esteem, which can cause anxiety and depression. Their school performance drop and they develop behavioral problems such as withdrawal. Low self-esteem can follow a child into adulthood.
The medical consequences of obesity can cause metabolic effects and mechanical effects. Metabolic effects involve the cardiovascular, endocrine, gastrointestinal and renal systems. The mechanical effects involve the pulmonary, skeletal and the central nervous system. Obesity has a negative effect on the glucose-insulin balance and lipid metabolism. Obese adults have reduced a glucose uptake, especially in skeletal muscle and impaired action of insulin on the oxidation of non-esterified fatty acids. This leads to insulin resistance and abnormal lipolysis. Obese patients have a higher insulin secretion rate compared to the normal weight group. The rate of insulin metabolism in the liver is also low. The defect in glucose metabolism is as a result of impaired insulin response to a meal stimulus. The maximum amount of glucose uptake in obese children decreases with age, and the duration of obesity. Therefore, insulin resistance forms one of the early negative effects of obesity. Insulin resistance and truncal fat are the primary problems in metabolic syndrome. The syndrome complex consists of hyperglycemia, hypertension, dyslipidemia, and obesity. The gravity of the complexes of this syndrome has been shown to increase with increasing obesity.
The rate of type 2 diabetes mellitus in children has increased significantly over the last decade. Obesity and diabetes mellitus are tightly linked in humans. Recent study results on diabetes mellitus in obese children show that insulin resistance and increase in body fat are factors in the development of diabetes mellitus. Increased TNF-α is observed in obese patients. This causes increased free fatty acids release in adipocytes, adiponectin synthesis blockade, and insulin receptor activation. Furthermore, IL-6, which is mainly released by adipocytes and macrophages, affects glucose tolerance by preventing adiponectin secretion and promoting gluconeogenesis, glycogenolysis and inhibiting glycogenesis. Children with obesity are more likely to develop type 2 diabetes.
Studies have shown that childhood obesity is a determining factor of cardiovascular risk in adulthood. Increased amounts of adipocytes and truncal obesity are associated with an increase in atherothrombotic cases. Increased amount of adipocytes is associated with systolic hypertension in children. An increase in the thickness of intima media was observed in obese children when compared to non-obese children. Left ventricular hypertrophy (LVH) is a CVD risk factor faced by obese children. Increased cardiac workload, as a result of atherosclerotic changes, and visceral adipocyte tissue may contribute to the development of LVH in obese children. The relationship between LVH and childhood obesity indicates the need of treatment and prevention of obesity to avoid end-stage heart damage.
Obesity increases the risks of developing certain types of cancer. These include colonic cancer, breast cancer, and cancer of the endometrium, kidney and esophagus. Obese women have a higher risk of developing breast cancer after menopause, especially those women with no hormone replacement therapy. Research studies have associated obesity to colorectal cancer. It may facilitate the development of colorectal cancer at an early stage in tumor growth. Studies show that the risk of obese children to endometrial cancer is increased by 2-5 times the risks faced by normal weight children. Obesity increases the risk to developing adenocarcinoma of the esophagus by 2-3 times. The association between obesity and increased incidences of gastro-esophageal reflux is thought to be the cause.
Obesity plays a role in chronic kidney disease (CKD) development. An obese patient is at risk of developing diabetic nephropathy, hypertensive nephrosclerosis, glomerular sclerosis and urolithiasis. Obesity is linked to structural changes in the kidney such as glomerulomegaly, and increase in the thickness of glomerular basement membrane. These changes cause obesity related nephropathy. An increase in glomerular filtration rate (GFR) has been noted in obese patients as compared to lean patients. High GFR, associated with hyper perfusion, may cause renal injury.
Obese children are at risk of developing non-alcoholic steatohepatitis (NASH) and gallstones. 38% of obese children suffer hepatic steatosis. It is associated with conditions characterized by impaired fat metabolism. These include diabetes mellitus, hyperlipidemia, and fast weight loss. The major complication of the liver as a result of obesity is non-alcoholic fatty liver disease (NAFLD). In children, demonstrations showed that increased lipolytic activity in the adipose tissue caused an increase in the rate of release of fatty acids into plasma. The fats accumulate in muscle and liver. The ectopic accumulation of triglycerides causes insulin resistance to develop as shown in the sequence, “overflow hypothesis”.Dyslipidemia, a characteristic of obese patients causes increased biliary excretion of cholesterol. This increases the chances of gallstone formation. 8-33% of gallstone cases in children are related to obesity.
Obesity has several effects on the pulmonary system. It is estimated that 7% of obese children suffer from obstructive sleep apnea (OBS). They are 6 times more likely to acquire the condition. The condition is characterized by increased levels of CRP and IL-6, decrease in leptin, an increase in ghrelin, an increase in levels of insulin, and a decrease in insulin sensitivity. The occurrence of these changes remains unclear but may be related to the intermittent hypoxemia. Recent studies have associated obesity to current asthma in children. The association is stronger in non-atopic children compared to children with atopy. Adiposity induces systemic inflammation that causes asthma. Obese asthmatic children showed a decrease in response to inhaled steroids.
Childhood obesity has been identified as one of the causes of increased cases of orthopedic problems in children. These problems occur when bones and cartilage undergo increased stress and strain as a result of carrying excess body weight. Overgrowth of the medial aspect of the proximal tibial metaphysis results to bowed tibia. Increased weight on the growth plate of the hip results to slipped capital femoral epiphysis. This causes bowed femur. The frequencies of bone fractures during falls are increased with childhood obesity. This is because the development of bones does not cope well with excess weight. The imbalance between weight and bone mass also increases the stress on growing bones on joints and may result to joint damage. This exposes the child to osteoarthritis in adulthood.
The prevalence of idiopathic intracranial hypertension was reported to be high in patients who had childhood obesity. Furthermore, 30-50% of children with pseudotumorcerebri suffer from obesity. It is suggested that obesity can result to increased intra-abdominal pressure. This causes a rise in intra-thoracic pressure. The increased intra-thoracic pressure is transmitted to the head as increased resistance to venous return from the brain.
Cost of Childhood Obesity
The cost of childhood obesity varies according to several factors like the prevalence of obesity, the cost associated with treatment, and the severity of health consequences related to obesity. Economic cost of obesity is viewed in several ways such as direct costs, indirect costs, and intangible costs. It can also be viewed as to whether the costs are incurred by the obese individual or by the society. Direct costs are incurred by the community and include all costs from diagnosis to treatment. They may include costs of medical services, costs of hospital visits, and personal health care costs like medication. Intangible costs are effects of obesity on the health and the quality of life of the obese child and other members of the society. Obese children are exposed to health problems such as type 2 diabetes, cardiovascular diseases, or cancer and have a lower life expectancy than normal weighing children. They are also exposed to psychological and social problems due to the ridicule they experience from their peers. This affects their overall well-being and quality of life. Indirect costs of obesity include the loss of well-being as well as the economic benefits to society members through reduced amounts of goods and services produced. Personal costs, in the cases of obese children, are incurred by their parents. They pay for the medical services bills, hospital bills and medication of their children. Other costs are incurred by the society as a whole. These include financed programs like medical costs, insurance and pensions. The costs may also include anincrease in taxation to fund health care services. In general, obese children consume more health care costs when compared to normal weight children.
Prevention of Childhood Obesity
Prevention of childhood obesity will involve the role the parents, the society, and the government. The only way of raising healthy children is by promoting a healthy lifestyle such as adopting healthy eating habits and dietary pattern. The consumption of nutrient-dense foods plays a role in obesity prevention. These foods have low energy densities and are an excellent source of nutrients. Research results show that the consumption of nutrient rich foods like fruits, vegetables, and low fat dairy is linked to lower energy intakes and diets of higher quality. Energy-dense foods tend to be convenient and cheap but are poor in nutrients. Obesity is linked to energy-dense foods. Therefore, the prevention of obesity involves improving the density of nutrients in a diet. Affordable nutrient-dense foods exist within different food categories. Regular physical activities increase energy expenditure and facilitate weight loss and prevent weight gain. Increased energy expenditure reverses the positive energy imbalance making energy used higher than energy consumed. It also improves the cardiovascular fitness and increases bone and muscle strength.
Parenting methods are linked to the prevalence of childhood obesity. Children are likely to adopt the lifestyles of their parents. Parents need practice healthy living to show perfect example to their children. Researchers show several parental interventions that may help. These include strategies such as monitoring, and controlling the child’s diet and physical activities, supporting the child’s physical activities; promotion of positive family behavior such as meals together; setting limits on the time spent viewing the television and increased parental knowledge on healthy foods and lifestyle. Parents should also be encouraged to breastfeed their children as it reduces the likelihood of children becoming obese. Parents have the responsibility of giving nutrient rich food to their children to promote healthy living. By educating their children to make healthy choices regarding food types, parents help their children acquire and practice healthy living habits. Parents need to know and monitor the weight and BMI of their children. This helps them know if their children are overweight or obese.
The government has a responsibility to enhance the prevention of obesity. This can be achieved through implementing policies such as tax and subsidies to influence the prices of foods, providing information regarding the benefits of healthy lifestyles, and regulation to affect production of consumption. Increasing the tax on junk food may help to reduce obesity. It helps by shifting preference away from the consumption of energy-dense foods. Subsidies on nutrient-dense foods can increase their consumption. Governments need to develop policies that make food producers provide quality information on the foods they produce. The information should include the nutritive content of the food and other health benefits. This helps parents make informed decisions on the foods that their children consume. The government also needs to make this information accessible to everyone. This can be done by providing information pamphlets. Other strategies include guidelines to control the environment where children eat. For example, encouraging school children to eat together, and reducing the size of eating groups to regulate the quantity children consume. The prevalence of childhood obesity is high among low income families. Programs should be developed to educate these families on healthy lifestyle practices. Information on nutrition and choice of healthy foods need to be provided to them.
Marketers of fast foods target young children. To reduce the consumption of fast foods, several policies need to be implemented to combat the marketers. The government should ban any product that poses health threats to children. A community may regulate the place, time and quantity of sale of a product to control consumption by children. Junk foods sold as complete meals must not exceed an earlier determined unhealthy content such as calories. Advertisers must provide the nutrition contents of their products.
References
Crowle, J., & Turner, E. (2012). Childhood Obesity: An Economic Perspective. Melbourne: Productivity Commission.
Factsheet. (2012, MAY 15). Obesity and Overweight. Retrieved from World Health Organization: http://www.who.int/mediacentre/factsheets/fs311/en/index.html
Schuster, D. P., & Banarjee, A. (2012). Comorbidities of Childhood Obesity. InfoTech: Rijeka.
Trends, A. S. (2009, September 24). CHILDREN WHO ARE OVERWEIGHT OR OBESE. Retrieved from Australian Bureau of Statisitcs: http://www.abs.gov.au/AUSSTATS/abs@.nsf/Lookup/4102.0Main+Features20Sep+2009
Yuca, S. A. (2012). Childhood Obesity. Rijeka: InfoTech.
