NHANES III Linked Mortality File Overview

1. U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES Centers for Disease Control and Prevention National Center for Health Statistics NHANES IIILinked Mortality File Overview Christine S. Cox Special Assistant for Record Linkage Donna Miller, Jim Brittain, Bryan Sayer

2. NHANES III • Nationally representative survey of the civilian non-institutionalized U.S. population. • Conducted from 1988 to 1994. • Sample size of 33,994 • 20,050 respondents who age 17+ at interview eligible for mortality follow-up. • Collects information on variety of health factors including: health status, risk factors and health behaviors, nutritional status, and physical examination data • Survey design materials, questionnaires, and analytic reports available from the NCHS web site. http://www.cdc.gov/nchs/nhanes.htm

3. National Death Index • A centralized electronic data base containing death information from U.S. death certificates   • Available by application for statistical research only • Users submit records containing study participant data to attempt to match to correct death records • Each death record contains: demographic characteristics of the decedent, state of death, and underlying/multiple causes of death • Current Coverage: 1979-2002 • NDI webpage: http://www.cdc.gov/nchs/r&d/ndi/ndi.htm

4. NHANES III-NDI Linkage • Conducting NDI data linkage is both a scientifically valuable and cost effective data collection activity. • Provides the opportunity to conduct a wide variety of mortality outcome studies analyzing health conditions and behaviors, along with extensive nutritional intake, examination, and laboratory data. • Example: serum cholesterol levels and risk of stroke mortality

5. NHANES III – NDI Linkage Methodology • Based on a probabilistic match to the NDI • Death information collected through 12/31/2000 • A sample of death certificates was collected for verification purposes • Final match status assigned by NCHS • Based on probabilistic match results and death certificate review

6. NHANES III Mortality Linkage Results 20,050 NHANES III adults 26Ineligible (due to missing data) 3,384Deceased (17% of eligible) 16,640 Presumed alive as of Dec 31, 2000

7. NHANES III Linked Mortality File Access NCHS Research Data Center (RDC) Purpose – • To provide access to restricted data files which data users would not be able to otherwise access Accessibility – • On-site access – NCHS, Hyattsville, MD • Off-site access - User’s remote location

8. User Procedures To gain access to NCHS restricted data users must: • Submit a research proposal and receive approval • Sign an affidavit of confidentiality and promise not to use any method to attempt to identify respondents • Submit data files to be linked with RDC data ahead of time – all linking is conducted by RDC staff • Subject all output and/or materials removed from the RDC to a disclosure limitation review • Pay a user’s fee that will be estimated prior to proposal approval

9. RDC Contact Information For general Questions/Comments Email: rdca@cdc.govPhone: (301)458-4732 For On-site Info: Negasi Beyene Email: NBeyene@cdc.govPhone: (301)458-4097 For Remote Access Info: Vijay Gambhir Email: vgambhir@cdc.govPhone: (301)458-4226

10. Linked Mortality File Documentation • File documentation will be available soon for download on the NCHS Data Linkage web page (www.cdc.gov/nchs/rd.htm) • Send email queries to datalinkage@cdc.gov • Include NHANES III Linked Mortality File in subject line if possible for quicker routing

11. NHANES III Linked Mortality File Variables • NHANES III public use ID number • Eligibility status indicator • NDI match results/certificate match results • Dates of birth, death, interview, examination • Underlying and multiple causes of death

12. Future NHANES Mortality Linkages NHANES I Linked Mortality File • Mortality period 1971-2000 NHANES II Linked Mortality File • Mortality period 1976-2000