How is a Child Classified as Obese?

Obesity is biologically defined as a disease in which an abnormally excess accumulation of fat influences an individual’s health negatively. Obesity is often correlated and defined according to different ways of body measurements. A common technique in observing body measurements is BMI, which is calculated by dividing an individual’s weight (in kg) by their squared height (in meters). The body mass index then proceeds to categorize the individual based on the number calculated, into a group of underweight if below the BMI of 18.

4, normal if in between the range of 18.5 and 24.9, overweight if between 25.0 and 29.9, obese if 30 BMI and above. However, when the BMI of children are calculated to classify obesity, it is essential that the child’s weight status is compared to children of that age with the same sex for the most precise classification. Obesity is identified to be the BMI at or above the 95th percentile for children of the same sex and age.

Figure 1: An image of a ‘Body Mass Index Chart’ identifying the ranges of obesity in BMI for children based on their age groups.

A clear disadvantage however in using BMI as a source of body measurement to distinguish cases with obesity is that the BMI doesn’t differentiate between fat body mass from lean body mass. Therefore, the BMI itself often isn’t the only type of body measurement used to identify obesity. The waist circumference or skinfold thickness measurements are used to help identify the body deposition and distribution of fat along the body.

The waist circumference helps measure the upper body fat distribution by providing a measurement for the waist and hip area as well as the upper rib to hip sector. The waist circumference measurement if large in comparison to the measurement of the hips, can help be a significant indication that the individual is at a higher risk of cardiovascular diseases or type 2 diabetes and is in fact obese. The waist/hip circumference can also help infer as accurately as possible the intra-abdominal fat. The skinfold thickness measurement is a body measurement on the area of subcutaneous fat and skin thickness using calipers. The most common sites for the skinfold thickness measurement test is the triceps or biceps. The total skinfold thickness is then compared to the norms of the age group of the individual.

Therefore, in order for a child to be identified as “obese”, multiple body measurement tests such as BMI, waist circumference and skinfold thickness can be used to caterogorize that child.

Health Influence of Obesity

Obesity is a leading factor and a major aggravator to an indefinite amount of health concerns. It is known to be predominantly a cause for type 2 diabetes mellitus, respiratory problems such as obstructive sleep apnoea, cardiovascular conditions and diseases, bone problems such as osteoarthritis of joints, high blood pressure, and cancer. In boys, Obesity can be correlated to types of cancer such as prostate cancer or colorectal cancer for men and breast,cervix, uterus cancer for girls. Although the direct link of obesity to health problems isn’t always immediately in children or adults, the effects of increasingly high abnormal amounts of fat and excess weight have been correlated to be delayed in cases for 10 years according to “The Build and Blood Pressure” study.

Type 2 diabetes mellitus:

The deleterious effect of childhood obesity is often linked with an increase in the content of adipose fat in the body which influences the overall response of the child’s body to insulin tolerance and glucose uptake. A lofty amount of carbohydrate intake like in an obese child’s diet leads to a rapidly unstable rate of lipolysis, which is the breakdown of fat that is accompanied by the release of free fatty acids. The release of such free fatty acids increases the amounts of insulin in the liver which impacts the production of glucose from substrates such as amino acids in the process of gluconeogenesis. A release of free fatty acids can also lead to systemic dyslipidemia which is an elevation of lipids including cholesterol and triglycerides in the blood. System dyslipidemia, gluconeogenesis and lipolysis can lead to systemic or compensatory hyperinsulinemia which impacts the ability for skeletal muscles to use insulin. This is because the cells in such tissues and muscles decrease in sensitivity to insulin and therefore become insulin resistant. The body attempts to repair such processes through the continuous increased production of insulin in the pancreas, however overtime, the cells required for the production of such amounts of insulin fail and hyperglycaemia forms. Hyperglycaemia is an increased amount of glucose circulating in the blood and when persistently at an extremely high level, the individual with Hyperglycemia has type 2 diabetes.

Type 2 diabetes is an influential cause of blindness, strokes, heart disease, and even early death. Type 2 diabetes was something commonly found only in obese adults, however with the increase of childhood obesity, children are started to get diagnosed with it as well.

Cardiovascular

A child with obesity is at risk of having multiple conditions that could potentially lead to an eventual heart failure as the vesicles and ventricles tend to collapse. They are also at a high risk of multiple cardiovascular conditions that can lead to both strokes and heart attacks. Although the effect of obesity on the cardiovascular system takes time, it is a very big risk.

As obesity includes an increase in mass (both lean mass and fat mass) and a corresponding increase of blood volume, an evident increase in the chances of cardiac arrest and stroke is expected as the amount of blood discharged during ventricular contracts increases . With children that are obese, as they have a larger surface area, the body’s oxygen consumption increases, therefore the cardiovascular system is required to work more. An overworking of the cardiovascular system can lead to conditions such as left ventricular dilation. Left ventricular dilation is a condition in which the left ventricle in the heart pumping chamber increases in size and weakens in strength which leads to a decrease in the rate of the heart pumping blood around the body. Obesity also tends to be a leading factor in the constriction of arterial blood vessels as overweight people tend to have artery- clogging LDL cholesterol. Atherosclerosis, a cardiovascular condition that a child with obesity is at risk of having, is caused by cholesterol attaching to the arteries, increasing the chances of stroke and heart attacks. Systemic Vascular resistance also is a condition that individuals with obesity tend to have and can lead to arterial hypertension. Arterial Hypertension is a condition in which the blood pressure of arteries tend to be elevated and once again increases the chances for an individual to have strokes and heart attacks.

Respiratory

As obese children gradually increase in size and weight, shifts in the respiratory system while the child sleeps occurs. A large amount of fat in areas such as the chest, abdomen or stomach can minimize the size of the lung capacity and affect the inhaling expansion and exhalation contraction of the lungs in the process of ventilation. Through lying flat, any respiratory problems are shown to be more prominent. Obese children are often diagnosed with sleep anea which is the constant interruption of an individual’s sleep because of the irregular breathing. Obese kids tend to have alveolar hypoventilation during their sleep which is poor ventialation in the respiratory system that often leads to hypercapnia or hypoxia. Hypercapnia is a condition in which carbon dioxide partial pressure increases to be at an unusually high amount. Hypoxia, however, is the condition in which certain parts of the body are deficient in oxygen. Hypoxia and Hypercapnia can eventually lead to hypersomnolence which is sleepiness throughout the day even when having an appropriate amount of hours of sleep. They can also contribute to the body not breathing properly despite the decrease in oxygen arterial concentration in the body. Respiratory failure is a risk as well because an obese child is at risk of having pulmonary hypertension which is a type of high blood pressure that can harm the right side of the heart and arteries in the lung.

Musculoskeletal Disorders

Slipped Capital femoral epiphysis is a hip condition that often affects children from ten to sixteen of age. It happens when the femoral head slides off the femoral neck on the thigh bone. Slipped Capital femoral epiphysis is less likely to occur in girls than boys, however is very common in obese children. This is because obese children have more weight placed on the growth plate, eventually leading it to weaken. In the cases that Slipped Capital femoral epiphysis is unstable, which is when it occurs suddenly, it can lead to children not being able to put weight on the side in which it occurred. An unstable slipped capital femoral epiphysis can even lead to the death of tissue in the femur head as it can prevent the flowing of blood to the hip joint.

Another musculoskeletal disorder that is often caused by obesity is Blount disease. Blount disorder is a growth disorder on the tibia that leads to the lower leg to turn inwards. This can happen because of the pressure an obese child puts on the tibial growth plate, leading to the suppression of growth in the right way. Blount disease therefore affects the inside of the shin bone and prevents it from growing in the right way.

Bone Problems

Obesity can be a leading factor in joint problems such as Osteoarthritis or Gout. Osteoarthritis is a joint condition that influences the performance of joints such as the knees and hips. Obese children tend to put more pressure on these joints due to excess weight, therefore the cartilage that protects the joints begans to delapidate. The cartilage is a soft, flexible tissue that protects the ends of joints. Through the loss of the cartilage around the joints, the joints are more vulnerable to breaking or becoming damaged. Gout is a joint disease that is caused by abnormal amounts of uric acid in the blood. Great amounts of uric acid in the blood form crystal like structures that accumulate in the joints. Obese children tend to have higher levels of insulin in their blood that prevents the kidneys from attempting to eliminate such high levels of uric acid. This can lead to gout attacks in children or can even develop into cardiovascular diseases.

Metabolic Syndrome:

Metabolic Syndrome is a health complication that consists of 5 major conditions or risks that are a direct result of obesity. These 5 conditions include an increase in blood pressure to be greater than 130/85 mmHG, insulin resistance shown by high sugar blood levels, abnormally sunken levels of cholesterol, excessive triglycerides levels, and finally excessive fat around the middle section of the body. In order for an individual to be diagnosed with metabolic syndrome, the individual must have at least 3 out of 5 of these conditions. These conditions can lead to not only metabolic syndrome but other conditions such as stroke, diabetes, cardiovascular diseases, kidney problems, and atherosclerosis.

Gastroenterology

An important body part that plays an essential role in obesity is the gastrointestinal tract as its a major contributor that influences the appetite. The gastrointestinal tract plays a major role in the production of the hormones in the gut that contributes to the individual’s appetite and consumption. These hormones include cholecystokinin and peptide YY. The gastrointestinal tract also impacts hormones such as incretins that are metabolic hormones that lead to a decrease in glucose levels in the blood as they cause the release of insulin and prevent the release of glucagon. The gastrointestinal tract can influence the absorption of nutrients in the body and change the microbial digestion of nutrients which influences the overall metabolic factors in the body that are associated with obesity. With obesity, many disorders can impact the gastrointestinal tract including the non alcoholic fatty liver disease. Although it was profoundly not common in children, as the rates of obesity are increasing and along with it the insulin resistance in these children’s bodies, nonalcoholic fatty liver disease is more common in children nowadays. Nonalcoholic fatty liver disease is caused by the collection of high levels of fat in the liver. Children with Nonalcoholic fatty liver disease are at risk of getting Nonalcoholic steatohepatitis which is a type of fatty liver disease that leads to the inflaming of the liver and can eventually lead to either liver scarring or liver failure.