At A Glance

Noteworthy Characteristics

  • Measured height (or length) and weight available to calculate body mass index.
  • Physical activity assessed with accelerometers.
  • Numerous other nutrition and health indicators obtained through physical examination, questionnaire, and assays.
  • Established linkages with National Death Index, and linkages planned with Centers for Medicare and Medicaid Services, and Social Security Administration data sets.
  • Dietary intake assessed through USDA’s What We Eat in America (WWEIA), the dietary component of NHANES from 2002 to the present. Beginning with the 2003-2004 data release, WWEIA, NHANES contains two 24-hour recalls (2002-present).
  • Includes data on sleep from actigraphy and questionnaires.



To collect data about the health, nutritional status, and health behaviors of individuals in the United States (U.S.).

Target Population

Civilian, noninstitutionalized individuals in the U.S.; all ages.


Began in 1999. Conducted continuously in 2-year cycles. The most recent cycle completed is 2017-2018 (data will be released Q1 2020).


National Center for Health Statistics, Centers for Disease Control and Prevention, U.S. Department of Health and Human Services

Special Note(s)

NHANES dietary intake data are collected using the U.S. Department of Agriculture’s (USDA) dietary data collection instrument, the Automated Multiple-Pass Method (AMPM). The AMPM is a fully computerized method for collecting 24-hour dietary recalls. Learn more. The dietary intake data are processed at USDA using USDA’s Food and Nutrient Database for Dietary Studies (FNDDS). The NHANES dietary recall component is simultaneously released by NCHS and USDA. At USDA, the NHANES dietary intake component is referred to as What We Eat in America. Previously conducted nationally representative dietary surveys conducted by the USDA are:

1998 Continuing Survey of Food Intakes by Individuals (CSFII) Special Supplemental Children’s Survey
1994-1996 CSFII and Diet and Health Knowledge Survey (DHKS)
1989-1991 CSFII and DHKS

See Also:
NHANES III 1988-1994
Hispanic Health and Nutrition Examination Survey (HHANES), 1982-1984
NHANES II 1976-1980
NHANES I 1971-1975

HUD Programs and Associated Administrative Data:

In collaboration between the National Center for Health Statistics and HUD, data for participants from the National Health and Nutrition Examination Survey and National Health Interview Survey were linked to data from HUD administrative records. The HUD administrative files contain housing, income, and program participation data for recipients of Multifamily programs (MF), Housing Choice Vouchers (HCV), and Public Housing (PH) programs in all states, the District of Columbia, and some territories. The NCHS-HUD Linked Data enables researchers to examine the health and well-being of individuals who live in HUD-assisted housing.

A Primer on HUD Programs and Associated Administrative Data:
NCHS-HUD Linked Data: Methodology and Analytic Considerations:


Sample Design

Cross-sectional survey.

Complex, stratified, multistage, probability sample representative of the civilian, non-institutionalized U.S. population. Oversampling of specific age groups, racial/ethnic groups, and low-socioeconomic status populations. Learn more.

Sample Size

Target sample size is 10,000 individuals examined in each 2-year cycle.

Special Note(s)

NHANES has constructed various sample weights for single 2-year survey cycles to take into account survey non-response, oversampling, post-stratification, and sampling error. Learn more.

Key Variables


NameMethods of Assessment
Birth country (head of household)Interview/questionnaire
Disability (hearing; movement/physical; vision)Interview/questionnaire
Education levelInterview/questionnaire
Family sizeInterview/questionnaire
Household income level and sourcesInterview/questionnaire
Language spoken at homeInterview/questionnaire
Occupation (head of household)Interview/questionnaire
Participation in welfare/food assistance programs (including reduced meals)Interview/questionnaire


NameMethods of Assessment
Attitudes toward health/dietInterview/questionnaire
Availability of fruit, dark-green vegetables, salty snacks, low-fat milk, and soda/flavored drinks in homeInterview/questionnaire
Breast/formula/milk feedingInterview/questionnaire
Factors influencing grocery shoppingInterview/questionnaire
Fat content of milk consumedInterview/questionnaire
Food securityInterview/questionnaire
Frequency and types of meals away from homeInterview/questionnaire
Frequency of consumption of ready-made mealsInterview/questionnaire
Frequency of family meals at homeInterview/questionnaire
Frequency of home-cooked mealsInterview/questionnaire
Intakes of fruits and vegetables, fiber/whole grains, added sugars, dairy, calcium, red meat/processed meatDietary screener
Monthly grocery spendingInterview/questionnaire
Monthly spending on eating outside home, takeout/delivery, and food purchases at convenience storesInterview/questionnaire
MyPyramid knowledgeInterview/questionnaire
Perceived health of dietInterview/questionnaire
Salt useTwo 24-hour recalls
Special diet for health or weight lossInterview/questionnaire
Supplement usageInterview/questionnaire, 24-hour dietary recall
Total food and nutrient intakeTwo 24-hour recalls
Use of food labelingInterview/questionnaire

Physical Activity-Related

NameMethods of Assessment
Cardiorespiratory fitnessPhysical examination (ages 12-49 years)
Frequency and amount of time spent on vigorous and moderate physical activityInterview/questionnaire
Frequency of physical activity (60 minutes+/day)Interview/questionnaire
Sedentary activities (e.g., television, computer outside school, sitting)Interview/questionnaire
Walking/bicycling for travelInterview/questionnaire


NameMethods of Assessment
Daytime fatigue/sleepiness and/or alertnessActigraphy/Questionnaire
Sleep continuity: Sleep latencyQuestionnaire
Sleep continuity: Total time asleep while in bed (sleep efficiency)Actigraphy
Sleep disordered breathing: Observed breathing pauses while sleepingQuestionnaire
Sleep disordered breathing: SnoringQuestionnaire
Sleep disorders: InsomniaQuestionnaire
Sleep disorders: OtherQuestionnaire
Sleep disturbances and quality: Trouble falling back asleep at nightQuestionnaire
Sleep disturbances and quality: Waking up too earlyQuestionnaire
Sleep disturbances and quality: Trouble going to sleepQuestionnaire
Sleep duration and quantity: Total sleep time during weekends/holidaysQuestionnaire
Sleep duration and quantity: Total sleep time during workdays/schooldaysQuestionnaire
Sleep duration and quantity: Total sleep timeActigraphy
Sleep timing and regularity: Midpoint of sleepCan be calculated from actigraphy
Sleep timing and regularity: Sleep timing on weekends/holidaysQuestionnaire
Sleep timing and regularity: Sleep timing on workdays/schooldaysQuestionnaire
Sleep timing and regularity: Time to bedQuestionnaire
Sleep timing and regularity: Time woke upQuestionnaire
Sleep-related behaviors: Leg jerks during sleepQuestionnaire
Sleep-related behaviors: Leg crampsQuestionnaire
Sleep-related substance use: Medication useQuestionnaire
Sleep-related substance use: MelatoninQuestionnaire
Sleep-related substance use: Use of sleep aidsQuestionnaire


NameMethods of Assessment
HeightPhysical examination, interview/questionnaire (ages 8+ years)
Relative weight perceptionInterview/questionnaire (ages 8+ years)
Skinfold thicknessPhysical examination
Waist circumferencePhysical examination
Waist/hip ratioPhysical examination
WeightPhysical examination, interview/questionnaire (ages 8+ years)
Weight historyInterview/questionnaire (ages 8+ years)
Weight loss attempts/strategiesInterview/questionnaire (ages 8+ years)

Nutritional Status

NameMethods of Assessment
Nutritional biochemistry and hematology, blood lipidsLaboratory analyses on blood and urine samples

Special Note(s)

All variables are not assessed in every 2-year cycle. Learn more about which variables are included in various cycles.

Additional physical activity-related variables are available through the 2012 NHANES National Youth Fitness Survey. These data include: body measurement (anthropometry), physical activity monitor (accelerometry), treadmill (cardiovascular fitness and endurance test), lower body muscle strength, grip strength, modified pull-up, plank, and gross motor development.

Data Access and Cost

Data Availability

Download public-use data from the NHANES website.
To protect the confidentiality of respondents, some data are restricted use. These data are available only through the NCHS Research Data Center. Learn more.


All public-use data are available free of charge.
Restricted-use data have charges associated with them, depending on the access mode, the number of survey cycles included, and other factors. Learn more.

Special Note(s)

Investigators must contact the NCHS Research Data Center to obtain restricted-use data. For a fee (which varies based on number of survey cycles analyzed and how data will be accessed), NCHS will create a data file and offer basic analytic support to researchers. Investigators must submit proposals to obtain these data (processing usually takes 6 to 8 weeks). Learn more about the proposal process and how the data can be accessed.


Geocode Variable(s)

County and state Federal Information Processing Standards (FIPS) codes, census block, census tract, latitude, and longitude. Geographic data are restricted use data and available only through the National Center for Health Statistics (NCHS) Research Data Center.

Existing Linkages

NCHS has established linkages between the 1999-2008 NHANES data and the National Death Index.

NCHS has also established linkages between 1999-2012 National Health Interview Survey (NHIS) and 1999-2012 NHANES to administrative data for the Department of Housing and Urban Development's (HUD) three largest rental assistance programs through 2014. Learn more.

In addition, it is planning linkages with:
• National food assistance program data
• Medicaid data
• Birth record data for the offspring of pregnant women in the 1999-2006 NHANES, and for children ages 6 to 10 years in the 2005-2010 NHANES.

Special Note(s)

See the Data Access and Cost page for information about accessing restricted-use data through the NCHS Research Data Center.

Selected Publications

Click here for a full list of publications.


Bachman JL, Reedy J, Subar AF, Krebs-Smith SM. Sources of food group intakes among the U.S. population, 2001-02. Journal of the American Dietetic Association. 2008;108(5):804-814.

Food Surveys Research Group, U.S. Department of Agriculture. What We Eat in America, NHANES.

Kaur J, Lamb MM, Ogden CL. The Association between Food Insecurity and Obesity in Children-The National Health and Nutrition Examination Survey. J Acad Nutr Diet. 2015 May;115(5):751-8.

Risk Factor Monitoring and Methods Branch, Applied Research Program, National Cancer Institute. Selected Intakes as Ratios of Energy Intake, U.S. Population, 2001-04.

Physical Activity-Related

Ervin RB, Fryar CD, Wang CY, Miller IM, Ogden CL. Strength and body weight in U.S. children and adolescents. Pediatrics. 2014 Sep;134(3):e782-9.

Mark AE, Janssen I. Dose-response relation between physical activity and blood pressure in youth. Medicine and Science in Sports and Exercise 2008;40(6):1007-1012.

Mark AE, Janssen I. Influence of bouts of physical activity on overweight in youth. American Journal of Preventive Medicine 2009;36(5):416-421.

Matthews CE, Chen KY, Freedson PS, Buchowski MS, Beech BM, Pate RR, Troiano RP. Amount of time spent in sedentary behaviors in the United States, 2003-2004. American Journal of Epidemiology 2008;167(7):875-881.

Troiano RP, Berrigan D, Dodd KW, Mâsse LC, Tilert T, McDowell M. Physical activity in the United States measured by accelerometer. Medicine and Science in Sports and Exercise 2008;40(1):181-188.


Flegal KM, Carroll MD, Ogden CL, Curtin LR. Prevalence and trends in obesity among U.S. adults, 1999-2008. JAMA 2010;303(3):235-241.

Lamb MM, Ogden CL, Carroll MD, Lacher DA, Flegal KM. Association of body fat percentage with lipid concentrations in children and adolescents: United States, 1999-2004. Am J Clin Nutr. 2011 Sep;94(3):877-83.

Ogden CL, Carroll MD, Kit BK, Flegal KM. Prevalence of childhood and adult obesity in the United States, 2011-2012. JAMA. 2014 Feb 26;311(8):806-14.

Ogden CO, Carroll MD, Flegal KM. High body mass index for age among U.S. children and adolescents, 2003-2006. JAMA 2008;299(20):2401-2405.









The Continuous NHANES Tutorial is designed to help users learn how to perform general analyses using the Continuous NHANES. Users can browse through different modules to gain insight into NHANES data.

The NHANES Dietary Web Tutorial explains the steps of conducting an analytical project from beginning to end, with examples of many common analytic procedures. Relevant dietary data information and nuances, tips, and explanations for SAS or SUDAAN programs; downloadable sample program code; and analytical guidance are organized and integrated into different modules and tasks to facilitate this learning process.

Analytic Guidelines

Survey Methods and Analytic Guidelines


The NHANES listserv provides a mechanism for disseminating information about NHANES activities, products, and release dates.