Childhood obesity is a condition where excess body fat negatively affects a child's health or well-being. As methods to determine body fat directly are difficult, the diagnosis of obesity is often based on BMI. Due to the rising prevalence of obesity in children and its many adverse health effects it is being recognized as a serious public health concern. The term overweight rather than obese is often used when discussing childhood obesity, as it is less stigmatizing, although the term overweight can also refer to a different BMI category. The prevalence of childhood obesity is known to differ by sex and gender.

Classification

Body mass index (BMI) is acceptable for determining obesity for children two years of age and older. It is determined by the ratio of weight to height.

The normal range for BMI in children vary with age and sex. While a BMI above the 85th percentile is defined as overweight, a BMI greater than or equal to the 95th percentile is defined as obesity by the Centers for Disease Control and Prevention (CDC). Obesity is further categorized as class 1 obesity with BMI at or above the 95th percentile to 119% of the 95th percentile, class 2 obesity with a BMI 120 to 139% of the 95% percentile and class 3 obesity which is 140% or greater of the 95th percentile. The CDC has published tables for determining this in children.

The US Preventive Service Task Force reported that not all children with a high BMI need to lose weight, however. High BMI can identify a possible weight problem, but does not differentiate between fat or lean tissue. Additionally, BMI may mistakenly rule out some children who do have excess adipose tissue. It is therefore beneficial to supplement the reliability of a BMI diagnosis with additional screening tools such as adipose tissue or skin fold measurements.

Effects on health

Psychological

The first problems to occur in obese children are usually emotional or psychological. Obese children often experience bullying by their peers.Obesity.Org Some are harassed or discriminated against by their own family. Stereotypes abound and may lead to low self-esteem and depression.

Physical Childhood obesity, however, can also lead to life-threatening conditions including diabetes, high blood pressure, heart disease, sleep problems, cancer, and other disorders.Childhood obesity - CNN Some of the other disorders would include liver disease, early puberty or menarche, eating disorders such as anorexia and bulimia, skin infections, and asthma and other respiratory problems.Childhood obesity: Complications - MayoClinic.com

The early physical effects of obesity in adolescence include almost all of the child's organs being affected, gallstones, hepatitis, sleep apnoea and increased intracranial pressure. Overweight children are also more likely to grow up to be overweight adults. Obesity during adolescence has been found to increase mortality rates during adulthood.

A 2008 study has found that children who are obese have carotid arteries which have prematurely aged by as much as thirty years as well as abnormal levels of cholesterol.

SystemConditionSystemCondition Endocrine Impaired glucose tolerance Diabetes mellitus Metabolic syndrome Hyperandrogenism Effects on growth and puberty Nulliparity and nulligravidity Cardiovascular Hypertension Hyperlipidemia Increased risk of coronary heart disease as an adult Gastroentestinal Nonalcoholic fatty liver disease Cholelithiasis Respiratory Obstructive sleep apnea Obesity hypoventilation syndrome Musculoskeletal Slipped capital femoral epiphysis (SCFE) Tibia vara (Blount disease) Neurological Idiopathic intracranial hypertension Psychosocial Distorted peer relationships Poor self-esteem Anxiety Depression Skin Furunculosis Intertrigo Uptodate.com|http://www.uptodate.com/online/content/topic.do?topicKey=pedigast/13911#25

Long-term effects Children who are obese are likely to be obese as adults. Thus, they are more at risk for adult health problems such as heart disease, type 2 diabetes, stroke, several types of cancer, and osteoarthritis. A large population based study showed that adolescents who were overweight or obese had a 2.2 times increased risk of sudden death and a 3.5 times increased risk for death from coronary heart disease or stroke in adulthood as compared to normal BMI peers. Another study showed that those with an elevated BMI in childhood and adulthood were at an elevated risk of certain chronic medical conditions including a 5.4 times increased risk of diabetes, 2.7 times increased risk of hypertension, and 1.8 times increased risk of elevated LDL cholesterol (a cholesterol-based measure of risk of atherosclerosis) in adulthood. However, in children or adolescents with elevated BMI who reduce their BMI to normal levels, these risks are decreased to a similar level as those with normal BMI in childhood and adulthood. One study showed that children who became obese as early as age two were more likely to be obese as adults.https://www.cdc.gov/healthyyouth/obesity/facts.htm , Adolescent and school health, CDC According to an article in The New York Times, the health effects of childhood obesity may lead to a reduction in lifespan of two to five years. It is the first time in two centuries that the current generation of children in America may have a shorter lifespan than their parents.

Causes Childhood obesity can be brought on by a range of factors which often act in combination. "Obesogenic environment" refers to a mixture of environmental factors that are permissive of obesity, especially for those who are genetically predisposed.McBride, D. (2010). Childhood obesity. Practice Nurse, 39(11), 40-45 The greatest risk factor for child obesity is the obesity of both parents. This may be reflected by the family's environment and genetics.Cole T.J. (2006). Early Causes of Childhood Obesity and Implications for Prevention. Retrieved December 1, 2011, from http://discovery.ucl.ac.uk/14548/1/14548.pdf Other reasons may also be due to psychological factors and the child's body type.

A 2010 review stated that childhood obesity likely is the result of the interaction of natural selection favouring those with more parsimonious energy metabolism and today's consumerist society with easy access to cheap, energy-dense foods and less energy requirements in daily life.

Factors include the increase in use of technology, increase in snacks and portion size of meals, and the decrease in the physical activity of children. A study found that children who use electronic devices three or more hours a day had between a 17–44% increased risk of being overweight, or a 10–61% increased risk of obesity (Cespedes 2011).

Childhood obesity is common among children from low-income, African American and Hispanic communities. This is mainly because minority children spend less time playing outside the house and staying active. Parents may prefer their children stay inside the home because they fear gang and drug violence and other dangers.

Genetics Childhood obesity is often the result of an interplay between many genetic and environmental factors. Polymorphisms in various genes controlling appetite and metabolism predispose individuals to obesity when sufficient calories are present. Over 200 genes affect weight by determining activity level, food preferences, body type, and metabolism. Having two copies of the allele called FTO increases the likelihood of both obesity and diabetes.

As such, obesity is a major feature of a number of rare genetic conditions that often present in childhood:

Prader–Willi syndrome, with an incidence between 1 in 12,000 and 1 in 15,000 live births, is characterized by hyperphagia and food preoccupations which leads to rapid weight gain in those affected. Bardet–Biedl syndrome MOMO syndrome Leptin receptor mutations Congenital leptin deficiency Melanocortin receptor mutations

In children with early-onset severe obesity (defined by an onset before ten years of age and body mass index over three standard deviations above normal), 7% harbor a single locus mutation.

One study found that 80% of the offspring of two obese parents were obese, in contrast to less than 10% of the offspring of two parents who were of normal weight. The percentage of obesity that can be attributed to genetics varies from 6% to 85% depending on the population examined.

Family practices In the recent decades, family practices have significantly changed, and several of these practices greatly contribute to childhood obesity: With a decreasing number of mothers who breast-feed, more infants become obese children as they grow up and are reared on infant formula instead. Fewer children go outside and engage in active play as technology, such as television and video games, keeps children indoors. Rather than walking or biking to a bus-stop or directly to school, more school-age children are driven to school by their parents, reducing physical activity. As family sizes decrease, the children's pester power, their ability to force adults to do what they want, increases. This ability enables them to have easier access to calorie-packed foods, such as candy and soda drinks. The social context around family meal-time plays a role in rates of childhood obesity.

Social policies

Different communities and nations have adopted varying social practices and policies that are either beneficial or detrimental to children's physical health. These social factors include: the quality of school lunches the emphasis of schools on physical activity access to vending machines and fast-food restaurants prevalence of and access to parks, bike paths, and sidewalks government subsidies for corn oil and sugar advertising of fast-food restaurants and candy prices of healthy and unhealthy foods access to fresh, healthy, and affordable food

Advertising Advertising of unhealthy foods to children increases their consumption of the product and positive attitudes (liking or wanting to buy) about the advertised product. Children's critical reasoning (the ability to understand what an advertisement is and the aim of advertising to buy the product) is not protective against the impact of advertising, and does not appear to be fully developed during adolescence. In some nations, advertising of candy, cereal, and fast-food restaurants is illegal or limited on children's television channels. The media defends itself by blaming the parents for yielding to their children's demands for unhealthy foods.

Socioeconomic status It is much more common for young people who come from a racial or ethnic minority, or for those who have a lower socioeconomic status, to be overweight and to engage in less healthy behaviors and sedentary activities.

Prevention

Schools play a large role in preventing childhood obesity by providing a safe and supporting environment with policies and practices that support healthy behaviors. At home, parents can help prevent their children from becoming overweight by changing the way the family eats and exercises together. The best way children learn is by example, so parents should lead by example by living a healthy lifestyle. Screening for obesity is recommended in those over the age of six. Both physical activity and diet can help to reduce the risk of obesity in children from 0 to 5 years old; meanwhile, exclusive physical activity can reduce the risk of obesity for children aged from 6 to 12 years old, and adolescents aged from 13 to 18 years old. The implementation of strategies to improve childcare services such as preschools, nurseries, daycare, and kindergarten on healthy eating, physical activity, and obesity prevention shows little effect on a child's diet, physical activity, and weight status.

Maternal body mass index