Name of the Student
27th November, 2015
Childhood obesity is defined as a clinical condition, where excess deposition of body fat, leads to negative health outcomes in a child. Percentage of body fat or presence of total body fat within the body may be predicted from regression equations, estimated from various skin-fold measurements. However, the popular and most common way of assessing excess body fat is done by estimating Body Mass Index (BMI). BMI can be estimated from the weight and height of a child. A BMI which is less than the specified limits as pertinent to the specific population indicates the child to be undernourished. On the other hand, a BMI which is more than the specified limits as pertinent to the specific population indicates the child to be overweight or obese. In technical terms, obesity may be described as a BMI, which is beyond the normal limits of BMI (on weight and height), in a given population. The other measures of measuring obesity include measurement of waist-hip circumference ratio and assessment of body weight on age / on height (Strauss & Pollack 2845-2848).
Our common perception, throughout the history, denoted that a fat child has a better health and is not undernourished. However, the menace of childhood obesity clearly demonstrates that a fat child may be malnourished, and may suffer from various clinical ailments, which jeopardizes the perception of “healthy child”. The prevalence of childhood obesity is rapidly increasing, all across the globe and is recognized as a global concern. The major causes of childhood obesity have been attributed to poor dietary patterns and decreased physical activity in a child. Other factors, like genetic causes and comorbid clinical conditions, also account for childhood obesity. Childhood obesity has been associated with various negative outcomes. Research indicated that childhood obesity may lead to cardiovascular disorders, either in childhood or during adulthood (Strauss & Pollack 2845-2848).
Epidemiology of Childhood Obesity
From time to time, various studies have been conducted all across the globe, to document the prevalence of childhood obesity. In the United States, there has been a 2.3 to 3.3 fold increase, in the incidences of childhood obesity, within a span of 25 years. In England, there has been an increase of 2.0 to 2.8 fold in the incidences of childhood obesity, within a span of 10 years. While, in Egypt the rise has been 3.9 fold over a span of 18 years. From, the above data it is clearly reflected that prevalence of childhood obesity is increasing very fast, irrespective of economic profile of a country (Flegan & Troian 807-818).
Childhood obesity is a concern in both developed and developing countries. Interestingly, with all the awareness and with all the availability of pharmacological and non-pharmacological interventions, the body weight of already obese children has increased further (considering the mean weight). Truly, childhood obesity is recognized as a global epidemic and has affected various countries and different ethnic groups (Filozof et al 99-106). However, the prevalence of obesity amongst different countries and different ethnic groups vary widely. In the United States, prevalence of obesity increased more in the minority groups compared to the “whites”. Childhood obesity is also more prevalent in the upper socio-economic group of the society (James et al 1545-1549). Poor diet and limited physical activity have been recognized the universal factors for causing childhood obesity (Flegan & Troian 807-818).
Health Impact of Childhood Obesity
Childhood obesity is associated with similar health issues lie obesity in adults. Childhood obesity is a causative factor for various cardiovascular risk factors. These factors include hypertension, atherosclerosis, dyslipidemia, and left ventricular failure. Obesity in childhood leads to poor glycemic control, due to development of diabetes mellitus. Childhood obesity also causes increased tendency of thrombus (blood clot) formations and increased inflammatory disorders. Childhood obesity is also associated with hyper-insulin. The aggravation and collection of cardiovascular risk factors in an obese child leads to a condition called “Insulin Resistance Syndrome”. Insulin Resistance Syndrome is prevalent in obese children, below the age of five years. A British study indicated, that presence of obesity in a child increases the risk of death from ischemic heart disease (Young-Hyman et al 1359-1364).
Moreover, Type 2 diabetes mellitus that was only restricted to adults and adolescents is on the rise amongst children. As discussed insulin resistance is commonly prevalent in obese children. In this condition, the insulin hormone secreted from the pancreas cannot bind to the insulin receptor. Therefore, impairment in receptor signaling, does not lead to up regulation of GLUT-4 receptors (these are glucose channels, through which glucose enters into the cells) on the cell membrane. As a result glucose entry into the cell is prevented, and the blood glucose level increases. This is the cause of diabetes in obese children. Diabetes mellitus is considered the co-morbid risk factor for cardiovascular disorders. Hence, the triad of obesity, diabetes and cardiovascular disorders increases morbidity and mortality, in an individual, either in their childhood, or when they grow up as adults (Young-Hyman et al 1359-1364).
However, the obesity elated co-morbid factors are not uniform across all ethnic groups or different socio-economic status. For example, studies in the United States have revealed that Hispanics are more prone to diabetes mellitus than their white counterparts. Apart from physical and physiological health, obesity also affects the mental health of an individual child. Obese children are often designated as unhealthy, lazy and lack intellect capacity. These individuals often develop a negative self-image, which erodes their personal and academic confidence. Obese children have lower self-esteem and are often associated with sad feelings, loneliness and nervous (Strauss e15).
Obesity is also associated with other physiological debilities. These include increased chances of sleep apnea (sudden rolling back of tongue into the glottis, due to improper maintenance of muscle tone of the genioglossus muscles), asthma ( the obstructive disease marked by increased difficulty in exhaling air, out of the lungs) and muscle tremors. Exercise intolerance is also associated with childhood obesity. Certain hormonal imbalances can also occur during obesity, which leads to polycystic ovary syndrome in females and precocious puberty in both girls and boys (Strauss e15).
Childhood obesity may be caused due to a variety of factors. Bodyweight is stringently regulated by various physiological mechanisms. These mechanisms work to maintain homeostasis of calorie intake with its expenditure. However, if the calorie intake exceeds its daily expenditure, it may lead to the development of obesity. Hence, any factor that causes an increase in calorie intake and any factor that prevents calorie expenditure may lead to obesity (Strauss e15).
Genetic factors have been implicated, as one of the causative factors for childhood obesity. The defect lies in the gene for the leptin receptor. Leptin is a hormone that is released from the assimilated stores of fat in the body. This hormone produces satiety; therefore it prevents hunger and prevents overeating. However, a hereditary defect in the leptin receptor prevents leptin signaling. This causes inhibition of the satiety center in the hypothalamus and stimulation of the hunger center in the hypothalamus leading to overeating. An episode of overeating leads to overweight and obesity. Variable nucleotide tandem repeats have been discovered in the insulin gene which has attributed to the early-onset obesity. Moreover, there are other genes which are associated with congenital diseases are implicated in the development of obesity too (Montague, Farooqi & Whitehead 903-908).
Prenatal over nutrition have been linked with the onset of childhood obesity. It has been debated that maternal obesity or increased nutrition during the pregnant period, causes increased transfer of nutrients to the fetus, through the placenta. This leads to the permanent change in the appetite of an individual child along with altered neuro-endocrine functioning and inefficient energy metabolism.
Children, who are fed through bottles in their childhood, are found to be overweight compared to children who were breast-fed. The reason for such finding has been attributed to the physiological changes and biochemical factors present in the breast-milk. Further, psychosocial factors of forceful suckling is also one of the factors determining a healthy individual or an overweight individual. The rate of feeding and the locus of control (child-parent nurturing) related to feeding is also important, in determining the future obesity profile of a child ( vonKries, Koletzko, & Sauerwald 147-150)
Another contributory factor that is widely recognized is the concept of “adiposity rebound”. In early childhood, the BMI is usually decreased till the age of 5 to 6 years. This is due to the additional demand placed by the body to ensure the growth of bones, muscles and skin. However, during adolescence the BMI starts to increase. An alteration of this physiological phenomenon is associated with the development of obesity. Individuals who are prone to obesity during their adult ages have a prevalence of early adiposity rebound.
Reduction in physical activity is one of the commonest causes of development and persistence of obesity in children. With the technological revolution in information technology, there has been a paradigm shift in the involvement of young children, in daily physical activities. All across the globe decrease in physical activity is a concern in care givers, as well as parents. Television viewing and computer games, has taken over the attraction of outdoor games and physical activity. A cross-sectional study involving obese children in South Carolina, United States demonstrated that obese children were associated with increased physical inactivity compared to their healthy and non-obese counterparts. Another study in the United States indicated that children who were involved in the less physical activity and watched more television were more obese than individuals who were physically active and were restricted from television watching.
A study from Mexico indicated that physical activity (of moderate to vigorous intensity) of at least one hour per day reduced the risk of obesity, by 10% per hour of exercise. On the other hand, television watching increased the risk of obesity by 12% per hour of watching. Physical activity was inversely related to BMI in girls, while media time was shown to be positively correlated to BMI in both the sexes. This meant increased physical activity, decreased the BMI of an individual. On the other hand sedentary life style like watching movies or physical inactivity increased the BMI of an individual. Although physical activity, has been recognized as an important phenomenon in reducing the risk of obesity, the intensity of exercise or duration of exercise per day remains debatable (Berkey, Rockett & Field e56).
Dietary habits are another area, which has received deep focus in the development of obesity. Fat rich diet has been speculated to increase the risk of obesity. However, such speculations have remained controversial. However, it has been undoubtedly proven that type of fat is responsible for the genesis of various health problems including cardiovascular disorders. Saturated fats have been associated with development of atherosclerosis while unsaturated fats are associated with decreased incidences of atherosclerosis. Decreased reduction in the consumption of fats lead to increased craving for carbohydrates. Excess carbohydrates may cause increased formation of acetyl co-A through increased rate of glycolysis. Acetyl-CoA is the building blocks of fatty acids, and hence increased intake of carbohydrates may lead to increased deposition of fats and fatty acids within the body (Hu, vanDam & Liu 805-817).
Lastly, fast food consumption is another area of concern. It has been observed that increased consumption of fast foods are positively correlated with the development of obesity. Fast foods contain increased portion sizes, which leads to unpredicted calorie intake, which is often higher than the calorie required by the individual. Moreover, fast foods are less in dietary fibers, and have increased portions of saturated fat, which lead to the menace of obesity and increase the risk of cardiovascular morbidity and mortality (Hu et al 805-817).
Discussion and Conclusion
Obesity is a global epidemic and hence caregivers, parents, physicians and policy makers must come close together to fight out the menace of obesity. Policy makers and teachers should ensure increased physical activity in a child, while parents and physicians must encourage healthy eating habits. To manage the issue of obesity, various research dimensions must be introspected. First of all the issue of physical inactivity must be addressed. For such issues policies and initiatives have to be taken in school and also in the community. Schools should inculcate mandatory physical activity sessions, and there should be grading system. Moreover, physical activity programs must be designed in accordance to the capability and physical condition of each child. Children with special challenges like heart problems, chest problems and various congenital defects must have individualistic physical activity in the school in strict accordance of the school physician. The school canteen and at home, awareness should be made on healthy dietary habits and reduced and permitted use of saturated fats should only be provided in the foods. Programs like “Walk to School”, should be encouraged wherever feasible and possible. The path to school should be safe and school timings must accommodate such programs. Such programs must be extended to both sexes, and there should not be any gender bias. Parents must be made aware regarding the effects of watching television or the computer, and the overall sedentary life style in children. They should mandatory inhibit, such habits.
Future Research Directions
Apart from the pharmacological management of obesity, various non-pharmacological interventions need to be implemented and researched in specific target population, to frame unanimous guidelines. The foremost issue would be to identify the schedule of physical activity and duration of such activities during the day, which could be considered optimal for reducing obesity. Research on natural foods and nutraceuticals, must be done to assess the quality and context of “ideal food” in obese children. Such studies must be backed up by economical profile of such foods, as because obesity is prevalent in children from affluent and poor socio-economic status.
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