Eve Powell-Griner, PhD
National Center for Health Statistics
Centers for Disease Control and PreventionNational Center for Health Statistics
Overview of the National Health Interview
Survey (NHIS)
NHIS purpose
• To collect data on the health status and health services utilization of the US population
• To address specific issues of current public health concern
• To provide national health data to the public
Uses of NHIS data
• “Snapshot” of health of the US population
• Track national health objectives
• Plan and evaluate health policies
• Public health research
NHIS sample design
• Household based
• Representative of U.S. and of four Census regions (non-institutionalized civilian population)
• Provides sampling frame for Medical Expenditures Panel Survey (MEPS)
NHIS sample design
• 2006 design
40,000 households • 100,000 persons• 37,000 Sample Adults• 15,000 Sample Children
Over-samples blacks, Hispanics, Asians, elderly minorities
NHIS questionnaire modules
• Basic Module or Core
Fielded each year
• Supplemental Modules
New topics or more detail on Core topics
Different each year
Health conditions
• Chronic Disease
• Hearing and vision impairment
• Health status compared to year ago
• Injuries/poisonings
• Functional limitation and associated conditions
• Mental health questions (vary by age)
Utilization and access to care• Hospitalizations
• Medical care contacts by provider
• Surgical procedures
• Dental
• Immunizations
• Usual place of care
• Delayed care and why
• Unmet need by type
Health behaviors and risk factors
• Smoking
• Physical activity
• Alcohol
• Height/Weight (BMI)
Socio-demographic variables
• Hispanic ethnicity, race, sex, age
• Family type/structure
• Generational relationships
• Birthplace and citizenship
• Country of birth (only on in-house file) US/not US (on public use file)
• Citizen or non-citizen of US
Economic variables
• Characteristics of family housing unit
• Number of working adults in family
• Education/family income
• Health Insurance Type of coverage Cost/policy holder/source Reason for no coverage
• Work loss/sick days
NHIS Supplements 1998-2006
• 2000: Cancer Control
• 2001: Healthy People 2010, Children’s mental health
• 2002: Healthy People 2010, Complementary and Alternative Med., Children’s mental health
• 2003: Healthy People 2010, Children’s mental health
• 2004: Healthy People 2010 Children’s mental health, adult immunization
• 2005: Healthy People 2010, Cancer control
• 2006: Adult chronic conditions (Stroke, diabetes, arthritis)
NHIS Products
• Microdata files
• Annual reports of estimates
Population; Children; Adults
• Reports on specific topics
• FastStats
• Early Release
Background
• As timeliness of annual MICRODATA release improved, a need for timely release of ESTIMATES
• Expert meeting: Identified key measures
• Determined how to expedite editing and weighting
• Chose to release on Internet only
• First release: April 2001
NHIS Early Release (ER) Program
• 2 reports: main and detailed health insurance
• Releases updated ESTIMATES every 3 months
• Releases occur 6 months after the end of each quarter of data collection (March, June, September, December)
• Internet only release
NHIS ER Program
NHIS ER Program
Objectives
Provide ready and timely access to the most recent NHIS key estimates
Monitor health and health care
Measure progress toward national public health objectives
ER Indicator Selection
• Public health objectives which benefit from timely data
• Healthy People 2010 Leading Health Indicators
• Key areas for the elimination of racial disparities in health
• Stable definitions over past several data years
• Sufficient sample sizes
Main report
1. Health insurance coverage
2. Usual place to go for medical care
3. Obtaining needed medical care
4. Influenza vaccination
5. Pneumococcal vaccination
6. Obesity
7. Leisure-time physical activity
8. Current smoking9. Alcohol consumption10. HIV testing 11. General health status12. Personal care needs 13. Serious psychological distress14. Diabetes15. Asthma
Indicators
Main ER report
Format• Graph of trend since 1997• Graph of current estimates by age group and gender• Graph of current estimates by race/ethnicity • Data tables for all graphs• Extra graph and/or tables as needed• Text highlights
Detailed health insurance ER report Lack of health insurance coverage
• at time of interview• for at least part of the past year• for more than a year
Type of health insurance coverage• public health plan coverage• private health insurance coverage
Noncoverage for selected sociodemographic measures
Annual state-level estimates for large states
Uses of ER data• Cited in other government publications and
Web sites
• Data requests for universities and other government agencies
• Collection of indicators used in methodological research
• Other health measures can be added to ER production to do expedited research
Percentage of persons who had received an influenza
vaccination during the past 12 months, by age group and sex:
United States, 2005
0
20
40
60
0–17 18–49 50–64 65 and over
PercentTotal Male Female
95% confidence interval
Age group (years)
Percentage of adults aged 65 years and over who had
received an influenza vaccination during the past 12 months, by
race/ethnicity: United States, 2005
20
30
40
50
60
70
Hispanic White Black
Percent
Non-Hispanic
95% confidence interval
Percentage of persons without health insurance, by three measurements and age group; and percentage of persons with health insurance, by coverage type and age group: United States, 2005
Percentage of persons under 65 years of age without health insurance coverage at the time of interview, by age group and sex: United States, 2005
Prevalence of current smoking among adults aged 18 years and over: United States, 1997– March 2005
10
15
20
25
30
1997 1998 1999 2000 2001 2002 2003 2004 2005
Percent 95% confidence interval
(Jan.–March)
Prevalence of obesity among adults aged 20 years and over: United States, 1997–2005
10
15
20
25
30
1997 1998 1999 2000 2001 2002 2003 2004 2005
Percent95% confidence interval
0
10
20
30
40
Excellent Very good Good Fair Poor
PercentTotal Male Female
95% confidence interval
Health status
Percent distribution of respondent-assessed health status, by sex for all ages: United States, 2005
Prevalence of current asthma among persons of all ages, by age group and sex: United States, 2005
2
4
6
8
10
12
14
0–14 15–34 35 and over
PercentTotal Male Female
Age group (years)
0
95% confidence interval
Sex-adjusted prevalence of current asthma among persons of all ages, by age group and race/ethnicity: United States, 2005
0
5
10
15
20
Hispanic White Black
Percent
0–14 years 15 years and over
Non-Hispanic
95% confidence interval
Other examples of NHIS Estimates
Percentage of adults aged 18 years and over who engaged in any leisure-time strengthening activity, by sex and age group — United States, 2005
0
5
10
15
20
25
30
35
40
Sex
Pe
rce
nt
Men
Women
0
5
10
15
20
25
30
35
40
Age group (years)
Pe
rce
nt
18–2425–4445–6465–7475 and over
National Health Interview Survey
Percentage of adults aged 18 years and over who had received an Percentage of adults aged 18 years and over who had received an influenza vaccination during the past 12 months, by age group influenza vaccination during the past 12 months, by age group and quarter and quarter — — United States, 1997–2005 United States, 1997–2005
0
20
40
60
80Percent
65 years and over
50–64 years
18–49 years
Year (quarter)
1998 20001999 2001 200420031997 2002 2005
National Health Interview Survey
Annual rate of nonfatal, medically attended fall injury episodes Annual rate of nonfatal, medically attended fall injury episodes among noninstitutionalized adults aged 65 years and over among noninstitutionalized adults aged 65 years and over —— United States, 2001United States, 2001––20032003
0
20
40
60
80
100
120
140
65–74 75–84 85 and over
Ra
te p
er
1,0
00
po
pu
lati
on
Men Women
Age group (years)National Health Interview Survey
Percentage of foreign-born Hispanic adults aged 18 years and over with selected health conditions, by length of time living in the United States, 1998–2003
16.113.4
3.5
22.019.8
5.4
0
5
10
15
20
25
Obesity Hypertension Cardiovasculardisease
Condition
Perc
en
t
Less than 5 years 5 years or more
National Health Interview Survey
Cigarette smoking prevalence among adults aged 18 years and over who have ever spent >24 hours on the streets, in a shelter, or in a jail or prison, by sex — United States, 2004
20.9 23.518.6
56.2 56.9 54.4
0
20
40
60
Both sexes Men Women
Pe
rce
nt
All adults
Adults who had ever spent >24 hours on the streets, in a shelter, or in a jail orprison
National Health Interview Survey
0
2
4
6
8
10
12
14
16
18
2001 2002 2003 2004Year
Pe
rce
nt
Black non-Hispanic boys Black non-Hispanic girls
White non-Hispanic boys White non-Hispanic girls
Percentage of children under 18 years of age with current asthma, by race/ethnicity and sex — United States, 2001–2004
National Health Interview Survey
65.3 64.5 64.8 65.8 64.7 68.6 69.4
010203040506070
1998 1999 2000 2001 2002 2003 2004Year
Pe
rce
nt
Percentage of young adults aged 18–24 years who never Percentage of young adults aged 18–24 years who never smoked cigarettes smoked cigarettes —— United States, 1998 United States, 1998––2004 2004
National Health Interview Survey
Percentage of teens aged 14Percentage of teens aged 14––17 years who used 17 years who used indoor tanning devices during the preceding 12 indoor tanning devices during the preceding 12 months, by sex and age months, by sex and age —— United States, 2005 United States, 2005
0
2
4
6
8
10
12
14
16
18
20
Sex
Pe
rce
nt
Male Female
0
2
4
6
8
10
12
14
16
18
20
Age
Pe
rce
nt
14 years 15 years
16 years 17 years
National Health Interview Survey
Distribution of type of health insurance for working age Distribution of type of health insurance for working age adults (18 – 64 years), United States 2005adults (18 – 64 years), United States 2005
Uninsured 19.1% Private HMO
29.9%
Private non-HMO 40.7%
Medicaid HMO 5.3%
Medicaid non-HMO 1.6%
Other 3.0%
Source: estimates for health insurance type are calculated using the person file
NHIS Strengths• Large, representative sample
• In-person survey
• Broad range of information
• Demographic detail
• Ongoing annual survey
• Topical supplementary information
• Relatively high response rates
• Links to NDI, MEPS
NCHS Web site:
http://www.cdc.gov/nchs
Information Showcase
NHIS Web site:
http://www.cdc.gov/nchs/nhis.htm
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