National Health and Nutrition Examination Survey

NCHS Fact Sheet, January 2016

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About NCHS

The National Center for Health Statistics (NCHS) is the nation’s principal health statistics agency, providing data to identify and address health issues. NCHS compiles statistical information to help guide public health and health policy decisions.

Collaborating with other public and private health partners, NCHS uses a variety of data collection mechanisms to obtain accurate information from multiple sources. This process provides a broad perspective to help understand the population’s health, influences on health, and health outcomes.

 

National Health and Nutrition Examination Survey (NHANES)

The National Health and Nutrition Examination Survey (NHANES) is NCHS’ most in-depth and logistically complex survey, designed to assess the health and nutritional status of adults and children in the United States. Annually, NHANES examines a nationally representative sample of 5,000 persons of all ages. To produce reliable statistics, the survey oversamples African American, Asian American, and Hispanic persons, and persons over age 60.

NHANES is the only national source of objectively measured health data capable of providing accurate estimates of both diagnosed and undiagnosed conditions. It is unique in that it combines personal interviews with standardized physical examinations, diagnostic procedures, and laboratory tests to determine the prevalence of major diseases and risk factors for diseases. Physical examinations are conducted in mobile examination centers that travel to 15 U.S. counties annually.

 

Examples of NHANES Data

• Obesity
• Diabetes
• Nutrition
• Kidney disease
• Infectious diseases
• Oral health
• Physical fitness and physical functioning
• Sexual behavior and sexually transmitted diseases
• Environmental exposures
• Supplements and medications

NHANES data produce national references for such measurements as height and weight (pediatric growth charts) and blood pressure.

 

Recent NHANES Findings

Prevalence of hypertension among adults

Hypertension is a public health challenge in the United States because it directly increases the risk for cardiovascular disease.

• Overall, the prevalence of hypertension among adults was 29.0% for 2011–2014 and was similar among men (30.0%) and women (28.1%).
• From 1999 through 2014, no significant change was seen in the percentage of adults with hypertension. 
• From 1999 through 2014, a significant increase was noted in the percentage of adults with controlled hypertension, that is, individuals with physician-diagnosed hypertension whose blood pressure was in normal range at the time of the examination. But no significant change was noted from 2009 through 2014.

 

 

Prevalence of obesity among adults

Adult obesity is associated with increased risk of a number of health conditions, including diabetes, hypertension, high cholesterol, cardiovascular disease, stroke, arthritis, and certain cancers. The prevalence of obesity was 36.5% among U.S. adults during 2011–2014.

NHANES data for 2011–2014 show differences by:

Age

• The prevalence of obesity among middle-aged adults aged 40–59 (40.2%) and older adults aged 60 and over (37.0%) was higher than among younger adults aged 20–39 (32.3%). No significant difference in prevalence was observed between middle-aged and older adults.

 

Race and ethnicity

• The prevalence of obesity was lowest among non-Hispanic Asian adults (11.7%), followed by non-Hispanic white (34.5%), Hispanic (42.5%), and non-Hispanic black (48.1%) adults.

Sex

• The prevalence of obesity was lower in non-Hispanic Asian men (11.2%) compared with non-Hispanic white (33.6%), non-Hispanic black (37.5%), and Hispanic (39.0%) men.   
• The prevalence of obesity was 11.9% in non-Hispanic Asian, 35.5% in non-Hispanic white, 45.7% in Hispanic, and 56.9% in non-Hispanic black women.

 

 

Additional NHANES findings

Prevalence of obesity among youth

• The prevalence of obesity among U.S. youth aged 2–19 years was 17.0% in 2011–2014.
• Overall, the prevalence of obesity among preschool-aged children (2–5) (8.9%) was lower than among school-aged children (6–11) (17.5%) and adolescents (12–19) (20.5%).

 

Trends in adult and childhood obesity

• From 1999–2000 through 2013–2014, a significant increase in obesity was observed in both adults and youth.
• Between 2003–2004 and 2013–2014, however, no change in prevalence was seen among youth.  No change in the obesity prevalence among youth was noted between 2011–2012 and 2013–2014, and the observed change in adults between 2011– 2012 and 2014–2013 was not significant.

 

NHANES cholesterol data on children and adolescents  

• The prevalence of high total cholesterol among U.S. children and adolescents was 7.4%. The prevalence of high total cholesterol was greater among adolescents aged 16–19 (8.9%) than among children aged 6–8 (6.0%). 
• The prevalence of high total cholesterol was lower in boys (5.9%) than in girls (8.9%).
• The prevalence of high total cholesterol was greater among non-Hispanic black and non-Hispanic Asian children and adolescents, and lower among non-Hispanic white and Hispanic children and adolescents. 
• The prevalence of high total cholesterol was greater in children and adolescents with obesity (11.6%) than in those of normal weight (6.3%) and in those who were overweight (6.9%). 

 

Challenges and Future Opportunities

• Due to the comprehensive nature of the interviews and examinations, as well as increasing challenges in reaching participants in the household, it is increasingly difficult to maintain survey response rates. In addition, the oversampling of some special populations increases the likelihood that interviewers will encounter linguistic and cultural barriers to participation.
• As health issues and biomedical science advance, a continuing need exists to develop new components in NHANES and related surveys to ensure that needed information can be collected using state-of-the art methods.

For further information about NCHS and its programs, visit http://www.cdc.gov/nchs.

For further information on NHANES, visit http://www.cdc.gov/nchs/nhanes.htm.