Health >> Obesity / Overweight >> Obesity/Overweight: Notes & Sources

Obesity & Overweight: Notes & Sources


Confidence Interval (also known as error bar) is the range of values that includes the true value 95% of the time. If the confidence intervals of two groups do not overlap, the difference between groups is considered statistically significant (meaning that chance or random variation is unlikely to explain the difference).   

Obesity and Overweight:

  • Body Mass Index (BMI) is a ratio of weight to height used in defining obesity and overweight.
  • Among adults, overweight is defined as having a Body Mass Index greater than or equal to 25 and less than 30, and obesity is defined as a BMI of 30 or more.
  • Youth are considered obese if their BMI is at or above the 95th percentile for children of the same age and gender. Youth are considered overweight if the BMI at or above the 85th percentile and below the 95th percentile for children of the same age and gender.

Race/Ethnicity: Federal standards mandate that race and ethnicity (Hispanic origin) are distinct concepts requiring 2 separate questions when collecting data from an individual. "Hispanic origin" is meant to capture the heritage, nationality group, lineage, or country of birth of an individual (or his/her parents) before arriving in the United States. Persons of Hispanic ethnicity can be of any race. Communities Count's terms for racial/ethnic groups are derived from those used by the U.S Census Bureau in 2010.

  • Communities Count terms:  Hispanic, Non-Hispanic, White Non-Hispanic, Black, American Indian/Alaska Native (AIAN), Asian, Native Hawaiian/Pacific Islander (NHPI), White, and Multiple Race (Multiple). Persons of Hispanic ethnicity can be of any race and are included in other racial categories. Racial/ethnic groups are sometimes combined when sample sizes are too small for valid statistical comparisons of more discrete groups. 
  • 2010 Census terms: Hispanic or Latino, Not Hispanic or Latino, White alone (Not Hispanic or Latino),  Black or African American, American Indian or Alaska Native, Asian, Native Hawaiian or Other Pacific Islander, White, Some Other Race, and Two or More Races.


New! Interact with Communities Count data using Weave, our new data visualization tool. Zoom into maps for more detail -- from Washington State to King County all the way down to census tracts or zip codes. Mouse over entries to see labels and values (plus upper and lower bounds of confidence intervals). Right click to export or print images. Weave (Web-based Analysis and Visualization Environment) is an open-source, web-based platform developed at the Institute for Visualization and Perception Research at the University of Massachusetts Lowell in partnership with the Open Indicators Consortium.

Gender Differences:  National data based on physical measurements of height and weight show that adult men are more likely to be overweight or obese than women. Survey data for King County are based on self-report, however, and may result in underestimates of weight in female respondents. For this reason, adult obesity data by gender are not reported here.

Statistical Significance: Unless otherwise noted, any difference mentioned in the text is statistically significant (unlikely to have occurred by chance).

Data Sources

Data on adult overweight and obesity are from the Washington State and national Behavioral Risk Factor Surveillance System (BRFSS). The BRFSS is a random telephone interview survey of non-institutionalized adults ages 18 and older that has been conducted in King County every year since 1987. Starting in 2003, the BRFSS was administered in English and Spanish. The limitations of an English-and-Spanish-only telephone survey include the following: a) people who do not have a land line telephone or who do not speak English or Spanish are excluded, and b) people who have less education and lower incomes are underrepresented.

Local data on youth overweight and obesity are from the 2010 Washington State Healthy Youth Survey. This is a survey of public school students in grades 6, 8, 10, and 12.  Students in grades 8, 10, and 12 self-report their body weight. National data are from the 2009 National Youth Risk Behavior Surveillance System (

For additional information on the Healthy Youth Survey, see:

Other Sources

City Health Profiles provide demographic and health information for 25 geographic areas in King County – mostly large cities (e.g., Seattle, Bellevue), groups of small cities (Bothell/Woodinville), or combinations of cities with nearby unincorporated areas (e.g., Renton/Fairwood). Each report has seven sections:

  • Demographics
  • General health status
  • Leading causes of death
  • Health risk factors and chronic diseases
  • Injury and violence-related mortality
  • Maternal and infant health
  • Access to care and preventive services

School District Health Profiles provide demographic and health information for several school districts in King County.  The profiles were developed by Public Health-Seattle and King County in collaboration with school districts for the purpose of informing school policy-makers and administrators, health and wellness planners, and the public about student health indicators at the district level. The data come from the Healthy Youth Survey, which is administered every 2 years to students in grades 6, 8, 10, and 12.  Each profile report has 6 sections: 

  • Demographics of survey respondents
  • Obesity, physical activity, and dietary behaviors
  • Mental health
  • Personal safety and violence
  • Alcohol, tobacco, and other drug use and second-hand smoke exposure
  • 3 additional indicators, selected by each district (examples: adults to turn to for help when feeling sad or hopeless; family skipped meals in past 12 months due to finances; bullied in the past 30 days because of face, ethnicity, or national origin)

Definitions of youth obesity and overweight can be found at Barlow SE and the Expert Committee.  Expert committee recommendations regarding the prevention, assessment, and treatment of child and adolescent overweight and obesity: summary report. Pediatrics 2007; 120 Supplement December 2007:S164-S192.

Maps of King County covering a wide range of topics can be accessed at  Maps most immediately relevant to Communities Count are under the headings of Community data & demographics, Public health, and Environment & natural resources, but other maps should be useful as well (farmers markets, transit routes, walking and biking routes, parks, traffic counts, etc.).

Report on national data from 2009-2010 can be found at Ogden CL, Carroll MD, Kit BK, Flegal KM. Prevalence of obesity in the United States, 2009–2010. NCHS data brief, no 82. Hyattsville, MD: National Center for Health Statistics. 2012., retrieved on 8/1/2012. In contrast to the self-report data on obesity from the BRFSS, these national obesity estimates are based on measured weight and height.

Women in King County show association between obesity and residential property values:  Reported in April 2012 by Colin Rehm, Anne Vernez Moudon, Phil Hurvitz, Adam Drewnowski.,  This recent finding supports a consistent relationship between obesity and a variety of socioeconomic indicators.