Childhood obesity is a serious medical condition that affects children and adolescents. It occurs when a child is well above the normal weight for his or her age and height. Childhood obesity has important consequences for health and wellbeing both during childhood and also in later adult life. The rising prevalence of childhood obesity poses a major public health challenge in both developed and developing countries by increasing the burden of chronic noncommunicable diseases.
Despite the urgent need for effective preventative strategies, there remains disagreement over its definition due to a lack of evidence on the optimal cut-offs linking childhood BMI to disease risks, and limited evidence on the most effective components of interventions to prevent childhood obesity. (Lakshman, Rajalakshmi MD, PhD; Elks, Cathy E. PhD, MPhil; Ong, Ken K. MB, BChir, PhD; Circulation Issue: Volume 126(14), 2 October 2012, p 1770–1779) Obesity is defined as a condition of excess body fat that creates increased risk for morbidity and/or premature mortality “In many countries, including in the United States since 2010,23 childhood obesity is defined as a BMI above the 95th percentile for age and sex (and above the 85th percentile for overweight); however, a wide range of reference BMI charts are available. (Lakshman, 2012) In basic terms, obesity occurs because the calories con- sumed are greater than the energy expended.
For example, consuming just an extra 10 calories per day could amount to a weight gain of 1 pound per year (1 pound of fat = 3,500 kcal), so it really does not take much to gain weight. Losing this extra pound of weight requires engaging in activities resulting in the expenditure of 3,500 kcal. To put this into context, an individual burns approximately 100 kcal running 1 mile. So how does one know if he or she is overweight or obese? To determine the presences of obesity, several measurements can be used. The most frequently used determinant of body fat is to calculate body mass index (BMI), which is weight in kilograms divided by height in eters squared (BMI = kg/height in m2) or weight in pounds times the constant 703 divided by height in inches squared (BMI = pounds ? 703/height in in. 2). A BMI >25 but <29. 9 indicates overweight; someone with a BMI >30 is considered obese, and someone with a BMI >40 is considered morbidly obese. Children are classified according to a BMI chart, which compares weight to height and age. Children who fall between >85th and <95th percentile are considered to be at risk for overweight, and children who are >95th percentile are considered overweight.
Another measure of body fat is the waist circumfer- ence, a measurement frequently touted as a better indica- tor of obesity and a more accurate predictor of health risk. Women with waist circumferences of >35 inches and men with >40 inches are considered to be at higher risk for obesity-related diseases than those with smaller waist circumferences. (Patricia T. Alpert, Obesity: A Worldwide Epidemic, Magazine – Home health Care Management Practice, 2009) ntroduction and aim Obesity has recently become very common in children and adolescents and its prevalence is still increasing rapidly.
Strategies to combat childhood obesity have been overtaken by the scale and speed of the childhood obesity epidemic. Most parents, professionals in health and social care and education and children/adolescents are uncertain about basic issues such as what we mean by obesity in children, why it matters and what we might do to prevent it. The aim of the present review was to summarise recent systematic reviews on these topics in order to provide an informed basis for future interventions intended to tackle the childhood obesity epidemic.
Definitions: what do we mean by overweight and obesity in children and adolescents? Obesity is a disorder in which the body fat content has become so high that it creates health problems or and increased risk of health problems. As body fat content cannot be measured accurately, we need, for most practical purposes, a simple proxy or surrogate measure of fatness to act as the basis of an obesity definition. Recent systematic reviews have shown that the body mass index (BMI), i. e. eight (in kg) divided by height2 (m2) provides the best simple means of defining overweight and obesity in children and adolescents. In adults the BMI can be interpreted fairly simply by applying rules: BMI ‡ 25 1?4 overweight; BMI ‡ 30 1?4 obesity. In children and adolescents this is more problematic because the BMI should be much lower than in adults and it changes with age O 2007 The Author(s) Journal compilation O 2007 National Children’s Bureauand differs between the sexes. The solution to this problem is to interpret BMI relative to a reference population of healthy children and adolescents.
In the UK, the reference population is taken from children and adolescents in 1990 and is conveniently interpreted using charts (analogous to growth charts) by measuring weight and height, calculating BMI and then plotting on the appropriate chart. The BMI charts in the UK are available for purchase from Harlow Printing via the Child Growth Foundation (n. d. ). Charts for BMI interpretation are increasingly widely available for other countries, and in the USA are available free from the Internet National Center for Health Statistics (n. d).
A high BMI for age in a boy or girl is what we mean by ‘obesity’; a slightly lower BMI for age is defined as ‘overweight’ (Reilly and others, 2002). For clinical purposes, when using the UK 1990 BMI charts, a child with BMI at above the 98th percentile line should be defined as obese, and one who is in or above the 91st percentile as overweight. For public health pur- poses, such as monitoring the obesity epidemic, lower BMI percentile cut-offs are preferred. Usually BMI ‡ 95th percentile for obesity and ‡ 85th percentile for overweight is used. (Reilly and others, 2002).
By definition, only 2 per cent of the UK reference population in 1990 would have had a BMI above the 98th percentile at any given age and 5 per cent would have BMI at or above the 95th percentile. Interpreting a BMI in this way may seem fairly arbitrary, but in fact children and adolescents with BMIs above these points are consis- tently the fattest children in the population and are at highest risk of the medical and other problems associated with obesity (Reilly, 2006a). (John J Reilly, 2007, childhood obesity: an overview, Children and Society Volume 21 p. 390-396)
Why does childhood obesity matter? Adverse consequences of obesity A systematic review (Reilly and others, 2003) concluded that obesity in childhood and adoles- cence does matter in the short-term (for the obese child) and the long-term (for the adult who was obese as a child). In childhood and adolescence the most common complications of obesity are increased risk of: orthopaedic problems (particularly in the foot and hip); asthma symptoms and psychosocial morbidity (largely the result of teasing and stigmatisation, particularly in adolescents and in girls).
Obesity in children and adolescents has adverse effects on the cardio- vascular system: an abnormal blood lipid profile; chronic low-grade inflammation and higher blood pressure. In addition, overweight and obesity in childhood and adolescence have adverse effects on the metabolism of glucose and obese adolescents in particular are at higher risk of type 2 (non-insulin-dependent) diabetes. Type 2 diabetes was once thought of as ‘adult onset diabetes’ but adolescents now account for a high proportion of newly diagnosed type 2 diabetes in the USA.
Childhood obesity also seems to be associated with an increased risk of developing type 1 diabetes (non-insulin-dependent or ‘childhood onset’ diabetes). In the longer term, for the adult who was obese as a child or adolescent, the best established complications of childhood obesity include the persistence of obesity, an increased risk of premature mortality and, for women, impaired social, educational and economic prospects (Reilly and others, 2003).
Modern children are much less likely to ‘grow out of their obesity’ than in the past: at least 70 per cent of contemporary obese adolescents will remain obese and so become obese adults. In recent years, since the publication of our systematic review on the health effects of child- hood obesity, evidence has been emerging of a range of other adverse consequences of childhood obesity. Of particular note here is liver disease (‘fatty liver’) and cancer. The con- tinuing childhood obesity epidemic therefore predicts future increases in liver disease and the incidence of certain cancers. 2007 The Author(s)CHILDREN & SOCIETY Vol. 21, 390–396 (2007) Journal compilation O 2007 National Children’s BureauIn summary, there is now a substantial body of evidence which suggests that obesity should be taken seriously by parents and by health and other professionals. There is also a large body of evidence that parents and (health and education) professionals underestimate the importance of obesity in children and adolescents, and are often ignorant of the effects of obesity.
Childhood obesity has been described as ‘practically invisible’ (Baur, 2005). There is also evidence that when parents seek medical help for childhood obesity they may often face a lack of support from health professionals (Edmunds, 2005). There is a striking contrast between the scale of the problem of obesity and its adverse consequences and the scale of ignorance about it. It seems likely that this degree of ignorance about obesity is acting as a major barrier to efforts to prevent it and treat it effectively. (Reilly)