Surveillance Methodologies Utilized within NHANES with Emphasis on Identification of Non-communicable Chronic

DiseaseVan S. Hubbard, M.D., Ph.D.National Institutes of Health

and

Clifford L. Johnson, M.S.P.H.Centers for Disease Control and PreventionDepartment of Health and Human Services

National Health and Nutrition Examination Survey

To assess the health and

nutritional status of adults and

children in the United States

Objective

NHANES

Unique in combining a home interview with health examinations conducted in a mobile examination center

Almost 50 years experience conducting survey using direct physical measures

To produce U.S. population-based estimates of: Health conditions and environmental exposures

Awareness, treatment and control of selected diseases

Prescription drug and supplement use

Nutrition status and diet behaviors

What are the goals of NHANES?

Measuring is better than asking

Prevalence of adult obesityMeasured vs Self-reported data

3027

21 20

0

5

10

15

20

25

30

35

Total

Per

cen

t

MeasuredNHANES 99-00

Self-reportedNHANES 99-00

NHIS 2000 (self-reported)

BRFSS 2000 (self-reported)

SOURCE: CDC/NCHS

0

5

10

15

20

25

30

35

Self-report Direct Measure

% m

eeti

ng

gu

idelin

es

Direct Measure vs. Self-report Physical Activity

BRFSS

NHANES

Who is eligible to participate?

Civilian, non-institutionalized household population in the US

All ages5,000 individuals each yearOversample:

African AmericansHispanicsOlder persons aged 60+Low income whitesAsians – new for 2011-14

Stage 4Participants

Stage 1Counties Stage 2

Segments

Stage 3Households

Multiple stages in NHANES

Screener interview Participant interview (in-person)

Participant examinationAdditional interview or exam components

• Doorstep screening

• Traditional CAPI interviewing with portable keyboard.

What is the home interview?

Broad range of health conditions

Health-related behaviors and exposures

Health care utilization

Health insurance

Prescription medications

Dietary supplements

What do we ask about in the interview?

NHANES Mobile Exam Center (MEC)

Mobile Examination CenterProvides Standardized Data

Collection Systematic operation with travelling staff and

standardized environment MEC design provides standardized specimen

collection and exam protocols with regularly calibrated equipment

Facilitates automated data collection Minimizes site-specific error

How long is the exam?

Adults and teens: 3.5 hoursChildren: 1-2 hours

Two sessions per day; up to 12 participants per sessionMorning, afternoonAfternoon, eveningMorning, evening

NHANES response rates1999-2008

60

80

100

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008

%

Interviewed Examined

How do we decide what gets in?

Public health significance

Scientific meritAppropriateness Feasibility and ethical issues

Financial considerations

NHANES 2011-12 examination

Hearing, Taste and Smell Blood pressureMuscles strength/Physical

activity monitorDietary recallPrivate and AudioCASI interviewSpirometry w/bronchodilator,

ENOOral healthAnthropometry/Body

CompositionCognitive functionBlood, urine collection, PPD Specimen bank

NHANES Provides Data for Many Essential Public Health Functions

Reference data Growth ChartsNutrition monitoring Obesity,

CholesterolDisease control DiabetesPrevention initiatives Infectious

Diseases, FolateMonitor chemical/ Lead

pollutant exposureTrack health behaviors Second-hand

Smoke

7.7%

5.1%

29.5%

0

5

10

15

20

25

30

35

40

45

Undiagnosed

Diabetes and Pre-diabetes (%) 2005-2006

Diagnosed

ImpairedFastingGlucoseor ImpairedGlucoseTolerance

Monitoring Increase in Diabetes, Measuring Disease Management &

Undiagnosed Disease

Diagnosed diabetes doubled from 3.4% to 7.7 % between 1976-80 and 2005-2006 12.9% of adults age > 20

years have diagnosed or undiagnosed diabetes; no gender-specific differences (2005-2006)42% of adults age > 20 years have diabetes or pre-diabetes (2005-2006)

Monitor Improvements in Diabetes Management

Hemoglobin A1C declined from 7.8% to 7.2% between 1999-2004 (good control = 7.0%)

Monitor Diagnosed and Undiagnosed Disease

Cornerstone of the CDC’s National Biomonitoring Program and the US

Environmental Exposure Report Card Monitoring environmental exposures through direct measures of over 200 chemicals in blood, urine, or hair

Passive exposure monitors for volatile chemicals, household dust, allergen and water samples

Data reported in CDC’s National Report on Human Exposure to Environmental Chemicals

1976 1978 1980 1982 1984 1986 1988 1990 1992

2

4

6

8

10

12

14

16

Blo

od

lead

lev

els

(mg

/dL

)

0

1994 1996 1998 2000

Blood lead levels in the U.S. ChildrenAges 1-5 yrs, 1976 - 2002

Year2002

Directly download from our websitehttp://www.cdc.gov/nchs/nhanes.htm

NHANES Data

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Adapting to Complex Data Needs

Each new generation of surveys -• Added unique specimens, post-exam components, and

follow-back surveys • Required innovative survey design, operations, and methods• Provided ability to integrate a breadth of interdisciplinary

health data• Enhanced utility of baseline survey data

Hair sample formercury measurement

2nd Dietary recall and FCBS follow-up interview by phone

Food frequency questionnaire by mail

Hepatitis C and PSA follow-up interview by phone 6 months laterPhysical activity

monitor worn for 7 days

Dust samplecollected by vacuum

Tap water sample from home

Oral HPV rinse

Additional urine sample collected at home

Self-administeredvaginal swab

NHANES Core Characteristics

Sound scienceProduce high quality dataResponsive to emerging

public health issuesTimelyInnovativeProven model

A Pot of Gold

and

a Gold Standard

Our ultimate goal is to prevent disease and disability

Surveillance and Research Are Keys to Success

Thank you