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Thursday, December 12, 2013
We hear it on the news all the time: overweight and obesity are on the rise in the United States and around the word. It is easier to get fast food and hard to find places and time to exercise. At the same time, overweight and obesity have serious consequences. This includes diabetes, heart disease, stroke and some cancers. Facts from the Centers for Disease Control, known as the "CDC," tell us that:
Children and teens are also becoming overweight and obese at an alarming rate. In 2010, the CDC found that more than a third of children were overweight or obese. See Childhood Obesity Facts. This raises new concern. Diseases that were previously ‘adult diseases’ are now affecting children and teens. For example, type 2 diabetes has increased parallel to the rise in childhood obesity. The hidden damage to the body starts much earlier in life. This can result in serious harm like heart disease and vision loss at a younger age.
Definitions of overweight and obesity are important to understand. They can also be confusing in children.
Body Mass Index, also called BMI, uses a person’s weight and height to calculate a new number. That BMI number is a way to tell how much body fat a person has. It shows whether a person is overweight and at risk for future health problems.
Children and teens need a special tool to show if their BMI is in an overweight or obese group. This tool is a "BMI-for-age percentile." It is used because:
The same BMI number may be obese for a younger child and normal for an older child. Or, a boy might be obese and a girl not obese even though their BMIs are exactly the same BMI scores used for adults have little meaning for children and teens. You can get information on BMI and what it means the CDC’s page about BMI for Children and Teens.
Special BMI percentile charts take this all into account. There is one chart for girls and another chart for boys. Knowing your child's BMI is the starting point.
When the BMI number is entered for the age of the child, the chart shows if they are underweight, normal weight, overweight or obese.
Normal Weight: BMI between 5th and 85th percentile
This means that a child has a normal weight if their BMI is between 5 percent and 85 percent of all children who are the same sex and age.
Overweight: BMI between 85th and 95th percentile
This means that a child is overweight if their BMI is between 85 percent and 95 percent of all children who are the same sex and age.
Obese: BMI equal to or above the 95th percentile
This means that a child is obese if their BMI is the same or higher than 95 percent of all children who are the same sex and age.
You can see 2 BMI Percentile Charts with examples below. There is one for girls and one for boys. The first chart shows BMI numbers for 2 seven year old girls who have different BMI numbers. The girl with a BMI number of 17 falls in the normal weight group and the girl with a BMI number of 22 is in the obese group. The second chart shows a 5 year old boy and a 17 year old boy with the same BMI number: 24. That puts the 17 year old boy in the normal weight group and the 5 year old boy in the obese group.
These charts have been modified from the National Center for Health Statistics charts
"2 to 20 years: Boys Body mass index-for-age percentiles" and "2 to 20 years: Girls Body mass index-for-age percentiles".
The CDC has a special Do-it-Yourself BMI Calculator that does it all for you. Once you enter information the calculator:
Eating more calories than you use in activity causes overweight and obesity. Many people believe that obesity is inherited. That is actually very rare. A few medical conditions can cause weight gain in children. These include low thyroid hormone, called “hypothyroidism,” and too much cortisol, called “Cushing syndrome.” Medical causes are not common and are detected by laboratory tests.
Most of the time, overweight and obesity are caused by:
The diet and activity of children and teens is strongly influenced by:
When children and teens are overweight or obese, it affects confidence and self esteem. It is important for parents, teachers and providers to be aware of these needs. It is also important not to ignore childhood obesity.
There are efforts to limit marketing of unhealthy foods to children. Many schools ban soda machines. Some schools have healthier menu options for school lunches. More school programs increase exercise and activity. Cities have increased availability of fresh fruits and vegetables. Communities have made safe places for exercise. Much work remains to be done, especially in our inner cities.
Education about healthy weight is extremely important. Current efforts include communities, schools churches and social media. Healthy eating and activity are promoted. Education outreach to school nurses and doctors supports tracking BMI. This improves detection and care of children at risk
Points to Remember:
Many research studies are underway to help us learn about overweight and obesity in children. Would you like to learn more about being part of this exciting research? Please visit the following links:
This children's health content is brought to you with support from University Hospitals Rainbow Babies & Children's Hospital.
This article is a NetWellness exclusive.
Last Reviewed: Jun 27, 2013
Sumana Narasimhan, MD
School of Medicine
Case Western Reserve University