Informing Health Policy
National Health and Nutrition
Examination Survey (NHANES)
Susan Schober, Ph.D.
U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES
Centers for Disease Control and Prevention
National Center for Health Statistics
Presentation Topics
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NHANES overview
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Examples of analyses relevant to health
policy
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Access to public data files
Health condition components and
healthcare access measures collected
Goals of NHANES
U.S. population-based estimates of:
• Health conditions
• Awareness, treatment and control
of selected diseases
• Environmental exposures
• Nutrition status and diet behaviors
Measured versus self-reported
information
Prevalence of Obesity Among Adults ≥ 18
years, United States
35
30
Measured
NHANES 99-02
Self-reported
NHANES 99-02
Self-reported
NHIS 2000
Self-reported
BRFSS 2000
Percent
25
20
15
10
5
0
Total
SOURCE: Hedley, unpublished analyses
Male
Female
Measures of undiagnosed and
subclinical disease
Diabetes and impaired fasting glucose,
1999-2000
Percent
16
12
8
6.2
Impaired
fasting
glucose
2.5
Undiagnosed
6.1
Diagnosed
4
0
SOURCE: CDC/NCHS, National Nutrition and Health Examination Survey, 1999-2000
NHANES
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NHES I: 1960-62, ages 18-79
NHES II: 1963-65, ages 6-11
NHES III: 1966-70, ages 12-17
NHANES I: 1971-75, ages 1-74
NHANES II: 1976-80, ages 6 mos.-74
HHANES: 1982-84, ages 6 mos.-74
NHANES III: 1988-94, ages 2 mos. and older
NHANES: 1999 and beyond, all ages
Continuous (current) NHANES
Sample Design
• Continuous data collection beginning in 1999
• Annual national sample of 5,000 persons
• 15 survey locations each year
Eligible population
• Civilian, non-institutionalized population
• Residents of all states and D.C.
• All ages
NHANES – Oversampling
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African Americans
Hispanics (beginning in 2007)
Mexican Americans
Adolescents aged 12-19
(1999-2006)
• Persons aged 60+
• Pregnant women (1999-2006)
• Low-income families
NHANES Household Interview
• Broad range of health conditions
• Environmental and occupational
exposures
• Health behaviors
• Nutrition and dietary supplements
• Prescribed medications
• Health care access and utilization
NHANES Mobile Exam Center
NHANES Examination
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Standardized physical exam
Conducted at mobile exam center
• Medical & dental exams
• Physiological measurements
• Laboratory test
Administered by trained medical
personnel
NHANES Laboratory
• CBC and WBC differential
• Pregnancy test
• Blood, urine and vaginal swab
processing
76 different vials of samples
26 laboratories
300 laboratory assays
NHANES topics 1999-2006
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Nutrition, Oral health
Bone status, osteoporosis
Cardiovascular disease
Diabetes, Kidney disease
Obesity, body composition
Fitness and strength
Environmental exposures
Infectious disease, STDs
Vision, hearing, balance
Prescription medications
Mental health
Respiratory health
Landmark findings and
public health results
• High blood lead levels
Lead out of gasoline
• Low folate levels
Mandatory food fortification
• Rising levels of obesity
Public health action plan
• Racial and ethnic disparities in Hepatitis B
Universal vaccination of all infants & children
Examples of health care-related
information from NHANES
• Insurance coverage
• Undiagnosed disease
• Untreated disease
• Prescription medication use
• Disease control
• Health care utilization
Percentage of overweight* children and adolescents who have
ever been told by a doctor that they are overweight by sex and
age group, NHANES 1999-2002
2-5 years
6-11 years
12-15 years
16-19 years
60
52.8
50.7
50
percentage
43.2
40
33.8
36
31.1
30
20
17.8
17
10
0
Boys
Girls
* Defined as body mass index >95th percentile of the BMI-for-age sex-specific 2000 CDC Growth Charts
Source: CDC. Children and teens told by doctors that they are overweight – United States, 1999-2002.
MMWR 2005;54:848-849
Percent of Persons with Untreated Dental Caries by
Poverty Status
80
Ages 6-17 years
70
Ages 18-64 years
60
50
<100
40
100-<200
<100%
30
100-<200%
200+%
20
200+
10
0
1971-74
Year
1988-94
1999-02
1971-74
Data Source: National Health and Nutrition Examination Survey
1988-94
1999-02
Age-adjusted percent of adults age 40 and over with diagnosed
diabetes who have HbA1c, total cholesterol, and blood pressure
under control by race/ethnicity, NHANES 2003-2006
Percentage
80
non-Hispanic
white
non-Hispanic
black
MexicanAmerican
Confidence
70
60
50
40
30
20
10
0
HbA1c<7.0%
Total cholesterol
<200 mg/dL
Blood pressure
< 130/80 mm Hg
Non-Hispanic white diabetics were more likely than non-Hispanic black and Mexican American diabetics to have
HbA1c controlled to less than 7%. There were no differences by race/ethnicity for diabetics whose blood
cholesterol and whose blood pressure were controlled to recommended levels.
SOURCE: National Health and Nutrition Examination Survey (NHANES) 2003-2006.
Available at http://www.cdc.gov/nchs/nhanes.htm.
Percent of persons 12 years and older contacting a
mental health professional in past 12 months by
depression severity, United States, 2005-2006
None
Mild
Moderate
Severe
0
10
20
30
40
Percent
SOURCE: Pratt LA, Brody DJ. Depression in the United States household population, 2005-2006. NCHS Data Brief #7.
Hyattsville, Maryland: National Center for Health Stististics, 2008
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NHANES Data
• Directly download from our website
http://www.cdc.gov/nchs/nhanes.htm
• 2007-2008 data will begin to be released
in September 2009
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