Defining Overweight and Obesity in Preschoolers: Interview with Dr. Wendy M. Miller

by Carla on December 18, 2009

Nearly 25 percent of children ages 2 through 5 are classified as obese or overweight. Is your childcare center taking measures to prevent overweight and obesity or is it adding to the problem?  The Commission to Prevent Childhood Obesity recent released a list of 14 recommendations to prevent childhood obesity.

As a childcare provider, one of your duties is to be aware of the issues that affect young children, including obesity. An interview with Wendy M. Miller, MD, Medical Director, Beaumont Weight Control Center, provides some guidelines to help child care professionals understand the difference between overweight and obese:

OwnADaycare: What is the difference between overweight and obese?

Dr. Miller: Overweight in children is often associated with a body mass index (BMI) that is above the 85th percentile and less than the 95th percentile on the Centers for Disease Control and Prevention (CDC) BMI-for-age chart (for ages 2 to 20 years old).  However, BMI is a screening tool and not a diagnostic tool (see question #2).  The term “at risk for overweight” has also been used for those falling within the 85th to 95th percentiles.

Obesity in children is often associated with a BMI that is at or above the 95th percentile on the CDC BMI-for-age chart (for ages 2 to 20 years old).  The term “overweight” has also been used to describe those above the 95th percentile.

OwnADaycare: How can a daycare provider determine if a child is overweight or obese?

Dr. Miller: There are different ways to assess whether a child is at a healthy weight.  Calculating and plotting your child’s BMI on the CDC BMI-for-age chart will let you know whether your child is above the cut-points of the 85th or 95th percentiles.  The CDC web site has a “Child and Teen BMI Calculator” that will calculate BMI, give you the corresponding BMI percentile, and let you know whether this is a healthy weight.  The calculator is available at http://www.cdc.gov/nccdphp/dnpa/bmi/.

However, keep in mind that the BMI-for-age percentile is a screening tool.  Your pediatrician or family physician is able to do a more thorough assessment of your child’s weight, including examining your child’s previous trends in growth (both height and weight), bone frame, and dietary/physical activity habits, in addition to their BMI percentile.

OwnADaycare: What is BMI?

BMI stands for body mass index.  BMI is a number that describes weight in relation to height.  The calculation is:  weight (kg)/height (m)2 or weight (lb)/[height (in)2] x 703.  For children, BMI is age and gender specific.  So BMI-for-age is the measure used.  As stated above, BMI is a good screening tool, but not a diagnostic tool.  A pediatrician or family physician can provide a more thorough assessment of whether a child is overweight or obese.

OwnADaycare: What is BMI percentile?

Dr. Miller: Per the CDC website:  Percentiles are the most commonly used indicator to assess the size and growth patterns of individual children in the United States. The percentile indicates the relative position of the child’s BMI number among children of the same sex and age. The growth charts show the weight status categories used with children and teens (underweight, healthy weight, at risk of overweight, and overweight).

Weight Status Category

Percentile Range

Underweight Less than the 5th percentile
Healthy weight 5th percentile to less than the 85th percentile
At risk of overweight 85th to less than the 95th percentile
Overweight Equal to or greater than the 95th percentile

OwnADaycare: Are adult and children’s BMI calculators the same?

Calculating the BMI for both children and adults is done with the exact same formula, but interpretation of the BMI is different.  Adults have absolute cut points for weight status based on BMI, whereas the cut points for children and teens are based on BMI-for-age percentile.  Therefore, the BMI calculator for children and teens must also include BMI-for-age percentile.  This type of calculator can be found at http://www.cdc.gov/nccdphp/dnpa/bmi/

OwnADaycare: Are BMI results calculated differently for males and females? Are they calculated differently depending on the age range of the child? In other words if I have two children with the same BMI can one be considered healthy and one considered overweight or obese?

Dr. Miller: The same formula is used to calculate BMI for males and females, as well as for children that are 2 years old or greater.  However, in order to interpret the BMI for children, you need to know the corresponding BMI percentile for that child’s age.

Two children with the same BMI, but who are different ages, can have a different weight status.  For example, a BMI of 21 kg/m2 for a 6-year-old girl places her above the 95th percentile (in the obesity range).  However, a BMI of 21 kg/m2 is normal for a 13-year-old girl.

OwnADaycare: Is calculating BMI the only way to measure overweight and obesity?

Dr. Miller: BMI for adults and BMI-for-age percentile for children are currently the recommended screening tools for overweight and obesity.  Other ways to assess overweight and obesity include bioelectrical impedance analysis, dual energy x-ray absorptiometry (DXA), and skin fold testing.  However, standardized cut points for percent body fat in children, as measured via bioelectrical impedance and DXA, do not exist.  Measurements of skin fold thickness require calipers and training on the technique.

About Carla

Carla Snuggs has written 88 post in this blog.

Carla is a freelance writer from Southern California. She has a B.A. in early childhood education and a Master of Library and Information Science degree specializing in public librarianship and youth services.

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