BMI Presentation

Definition of Obesity

� Obesity is commonly defined with reference to:

�body mass index: wt(kg)/ ht2 (m)

What is BMI?

•Body mass index (BMI) is a practical measure used to determine overweight and obesity.

•BMI is the most widely accepted method used to screen for overweight and obesity in children and adolescents because

•It is relatively easy to obtain the height and weight measurements needed to calculate BMI

•Measurements are non-invasive•BMI correlates with body fatness

•BMI it is not a diagnostic measure because BMI is not a direct measure of body fatness.

Body Mass Index (BMI)

� A common measure expressing the relationship (or ratio) of weight-to-height

� A mathematical formula◦ weight (kg) / [height (m)]2

◦ weight (lb) / [height (in)]2 x 703

BMI-for-age weight status categories and the

corresponding percentiles for children are shown

in the following table.

Weight status category Percentile range

Underweight Less than the 5th percentile

Healthy weight 5th percentile to less than the 85th percentile

Overweight 85th to less than the 95th percentile

Obese Equal to or greater than the 95th percentile

Causes of Childhood Obesity

Modifiable causes:� Sedentary behavior� Socioeconomic status� Eating habits� Environment

Non-changeable causes:� Genetics

Environmental Influences on Overweight Children

1. The Family Eating Environment2. Household Food Insecurity 3. Changes in the Food Environment4. Physical Inactivity5. School Physical Education6. School Food Environment

7. Television Viewing

Why is childhood obesity a concern?� Leading cause of pediatric hypertension

� Associated with type II diabetes� Increases the risk of CHD� Increases stress on the weight-bearing joints

� Lowers self esteem� The economic cost of obesity in the United States was about $117 billion in 2000.

1999

Obesity Trends* Among U.S. AdultsBRFSS, 1990, 1999, 2009, 2010

(*BMI ≥≥≥≥30, or about 30 lbs. overweight for 5’4” person)

1990

No Data <10% 10%–14% 15%–19% 20%–24% 25%–29% ≥30%

2009

2010

2008 Estimates of the Percentage of Adults† Who Are Obese in Oregon

Centers for Disease Control and Prevention: National Diabetes Surveillance System. Available online at: http://apps.nccd.cdc.gov/DDTSTRS/default.aspx. Retrieved 9/7/2011.

Prevalence of Obesity* Among U.S. Children and Adolescents

(Aged 2–19 Years)

Survey Periods

NHANES I

1971–1974

NHANES II

1976–1980

NHANES III

1988–

1994

NHANES

2003–2004

Ages

2 through 5

5% 5% 7.2% 13.9%

Ages

6 through 11

4% 6.5% 11.3% 18.8%

Ages

12 through 19

6.1% 5% 10.5% 17.4%

*Sex-and age-specific BMI ≥ 95th percentile based on the CDC growth charts

From CDC: http://www.cdc.gov/nccdphp/dnpa/obesity/childhood/prevalence.htm

Trends in Childhood Overweight

Age (in

years)1

NHANES

1963-1965

1966-19702

NHANES

1971-1974

NHANES

1976-1980

NHANES

1988-1994

NHANES

1999-2000

NHANES

2001-2002

NHANES

2003-2004

NHANES

2005-2006

NHANES

2007-2008

Total (3) 5.0 5.5 10.0 13.9 15.4 17.1 15.5 16.9

2-5 (3) 5.0 5.0 7.2 10.3 10.6 13.9 11.0 10.4

6-11 4.2 4.0 6.5 11.3 15.1 16.3 18.8 15.1 19.6

12-19 4.6 6.1 5.0 10.5 14.8 16.7 17.4 17.8 18.1

Prevalence of obesity among U.S. children and adolescents aged 2-19,

for selected years 1963-1965 through 2007-2008

2011 State Prevalence Among Low-Income Children

Aged 2 to 4 Years

2009—2011 County Obesity Prevalence Among

Low-Income Children

History of BMI Screening at Bethel

� 2005: All K-5 students (community-researchers-schools)

� 2006-7: Grades K, 3, and 5 (school staff)

� 2008- 12: All K-5 students (CAST-school collaboration)

Questions and Comments?

Review of Protocol

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