At A Glance
Noteworthy Characteristics
- Measured height (or length) and weight available to calculate body mass index.
- 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.
- Physical activity assessed with accelerometers.
- 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.
Website
http://www.cdc.gov/nchs/nhanes.htm
Purpose
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.
Conducted
Began in 1999. Conducted continuously in 2-year cycles. The most recent cycle completed is 2017-2018 (data will be released Q1 2020).
Sponsor
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: https://www.cdc.gov/nchs/data-linkage/hud.htm
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: https://www.cdc.gov/nchs/data/datalinkage/primer-on-hud-programs.pdf
NCHS-HUD Linked Data: Methodology and Analytic Considerations: https://www.cdc.gov/nchs/data/datalinkage/NCHS-HUD-Linked-Data-Methodology-and-Analytic-Considerations.pdf
Sampling
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
Demographic
| Name | Methods of Assessment |
|---|---|
| Age | Interview/questionnaire |
| Birth country (head of household) | Interview/questionnaire |
| Disability (hearing; movement/physical; vision) | Interview/questionnaire |
| Education level | Interview/questionnaire |
| Family size | Interview/questionnaire |
| Household income level and sources | Interview/questionnaire |
| Language spoken at home | Interview/questionnaire |
| Occupation (head of household) | Interview/questionnaire |
| Participation in welfare/food assistance programs (including reduced meals) | Interview/questionnaire |
| Race/ethnicity | Interview/questionnaire |
| Sex | Interview/questionnaire |
Diet-Related
| Name | Methods of Assessment |
|---|---|
| Attitudes toward health/diet | Interview/questionnaire |
| Availability of fruit, dark-green vegetables, salty snacks, low-fat milk, and soda/flavored drinks in home | Interview/questionnaire |
| Breast/formula/milk feeding | Interview/questionnaire |
| Factors influencing grocery shopping | Interview/questionnaire |
| Fat content of milk consumed | Interview/questionnaire |
| Food security | Interview/questionnaire |
| Frequency and types of meals away from home | Interview/questionnaire |
| Frequency of consumption of ready-made meals | Interview/questionnaire |
| Frequency of family meals at home | Interview/questionnaire |
| Frequency of home-cooked meals | Interview/questionnaire |
| Intakes of fruits and vegetables, fiber/whole grains, added sugars, dairy, calcium, red meat/processed meat | Dietary screener |
| Monthly grocery spending | Interview/questionnaire |
| Monthly spending on eating outside home, takeout/delivery, and food purchases at convenience stores | Interview/questionnaire |
| MyPyramid knowledge | Interview/questionnaire |
| Perceived health of diet | Interview/questionnaire |
| Salt use | Two 24-hour recalls |
| Special diet for health or weight loss | Interview/questionnaire |
| Supplement usage | Interview/questionnaire, 24-hour dietary recall |
| Total food and nutrient intake | Two 24-hour recalls |
| Use of food labeling | Interview/questionnaire |
| Vegetarianism | Interview/questionnaire |
Physical Activity-Related
| Name | Methods of Assessment |
|---|---|
| Cardiorespiratory fitness | Physical examination (ages 12-49 years) |
| Frequency and amount of time spent on vigorous and moderate physical activity | Interview/questionnaire |
| Frequency of physical activity (60 minutes+/day) | Interview/questionnaire |
| Sedentary activities (e.g., television, computer outside school, sitting) | Interview/questionnaire |
| Walking/bicycling for travel | Interview/questionnaire |
Sleep-Related
| Name | Methods of Assessment |
|---|---|
| Daytime fatigue/sleepiness and/or alertness | Actigraphy/Questionnaire |
| Sleep continuity: Sleep latency | Questionnaire |
| Sleep continuity: Total time asleep while in bed (sleep efficiency) | Actigraphy |
| Sleep disordered breathing: Observed breathing pauses while sleeping | Questionnaire |
| Sleep disordered breathing: Snoring | Questionnaire |
| Sleep disorders: Insomnia | Questionnaire |
| Sleep disorders: Other | Questionnaire |
| Sleep disturbances and quality: Trouble falling back asleep at night | Questionnaire |
| Sleep disturbances and quality: Waking up too early | Questionnaire |
| Sleep disturbances and quality: Trouble going to sleep | Questionnaire |
| Sleep duration and quantity: Total sleep time during weekends/holidays | Questionnaire |
| Sleep duration and quantity: Total sleep time during workdays/schooldays | Questionnaire |
| Sleep duration and quantity: Total sleep time | Actigraphy |
| Sleep timing and regularity: Midpoint of sleep | Can be calculated from actigraphy |
| Sleep timing and regularity: Sleep timing on weekends/holidays | Questionnaire |
| Sleep timing and regularity: Sleep timing on workdays/schooldays | Questionnaire |
| Sleep timing and regularity: Time to bed | Questionnaire |
| Sleep timing and regularity: Time woke up | Questionnaire |
| Sleep-related behaviors: Leg jerks during sleep | Questionnaire |
| Sleep-related behaviors: Leg cramps | Questionnaire |
| Sleep-related substance use: Medication use | Questionnaire |
| Sleep-related substance use: Melatonin | Questionnaire |
| Sleep-related substance use: Use of sleep aids | Questionnaire |
Weight-Related
| Name | Methods of Assessment |
|---|---|
| Height | Physical examination, interview/questionnaire (ages 8+ years) |
| Relative weight perception | Interview/questionnaire (ages 8+ years) |
| Skinfold thickness | Physical examination |
| Waist circumference | Physical examination |
| Waist/hip ratio | Physical examination |
| Weight | Physical examination, interview/questionnaire (ages 8+ years) |
| Weight history | Interview/questionnaire (ages 8+ years) |
| Weight loss attempts/strategies | Interview/questionnaire (ages 8+ years) |
Nutritional Status
| Name | Methods of Assessment |
|---|---|
| Nutritional biochemistry and hematology, blood lipids | Laboratory 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.
Cost
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/Linkage
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.
Diet-Related
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.
Weight-Related
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.
Resources
Documentation/Codebook(s)
Tutorial(s)
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
Listserv
The NHANES listserv provides a mechanism for disseminating information about NHANES activities, products, and release dates.
