NIOSH Data Documentation

Surveillance of Mortality and Morbidity in U.S. Workers

University of Miami Study Database Documentation

For the purposes of this Study, the Investigators have made a series of policy decisions with regards to definitions, statistical analyses and other issues. In addition, in the process of their explorations of the NHIS database, the Investigators have encountered particular issues (e.g. “SOC” coding) which are detailed below in hopes that this will aid other investigators. Several of these explorations have resulted in detailed tabular data which have also been made available to other investigators where indicated in the documentation below. Of note, this is an ongoing study and exploration, as such this Study Documentation will continue to be updated as necessary.

The following issues have been addressed:

• Time Period
• NHIS Working Population
• Use of Supplement Survey Data
• Occupation
• "SOC" Codes
• Longest held job
• Industry
• Smoking/Tobacco Use
• Ethanol Use
• Response to NHIS
• Proxy
• Vital Status
• Comparison Population
• Education
• Age
• Race Ethnicity
• Sample Size Considerations
• Statistical Analyses
• Obesity / Height & Weight Measurement
• Acute & Chronic Disability Study Definitions
• NHIS Survey Questionnaire Anaylsis - Occupational, Employment, Work Questions
• Proposed Transformations Into NORA SECTORS

Time Period
• 1986-1994 since these were the years with mortality follow up available through 1997 (as of    2003).

NHIS Working Population
• “Currently employed” (paid and unpaid) within last 2 weeks prior to annual NHIS interview    (Kaminski and Spirtas 1980)
• 18 yrs of age or older at time of annual NHIS interview

Use of Supplement Survey Data
• Use only from the same year as their NHIS Survey
• Do not use any supplements involving < 18 year olds
• Weights for supplemental data
     o a) use supplemental survey weight if doing prevalence/incidence
     o b) use NHIS annual survey weight for all other uses (for example if used as a         covariate)
• If there is a year with > 2 or more supplements and overlap of participants, then
     o a) for Prevalence estimates, use only the larger Supplement and its weights
     o b) for smoking enrichment, use both supplements but IF discordance, use the data         from the larger Supplement
     o ex: 1991, use Health Promotions Supplement for Prevalence with appropriate         supplement weight; for smoking enrichment, use both Health Promotions and         Smoking Supplements with annual NHIS survey weight, if discordance of smoking         information, use Health Promotions smoking information
• For years with > 2 or more supplements and no overlap and equal selection criteria, then   use both supplements with appropriate supplement weight divided by the number of   supplements
     o ex: 1987 Cancer Control and Cancer Epidemiology Supplements were mutually         exclusive and used similar selection criteria
• Eliminate 1989 Diabetes and 1988 TAPS supplements due to very little data and/or too   selective

Occupation
• Defined as current work in past 2 weeks prior to NHIS interview
• “SOC” and “SIC” codes available
    o “SOC” and “SIC” codes mis-identified/labeled by NHIS documentation; really US        Census Occupational and Injury codes
    o “SOC” codes used for specific occupational evaluations
• 13 and 42 category recodes
    o used for initial evaluations
• For major analyses, selected occupations with a 9 year average of >100,000    workers/occupation based on US Population of 1990
    o Label/indicate if >30% SE (as per Brackbill R 1988)

"SOC" Codes
• In 1992, the NHIS began using the 1990 version of the census occupational codes.    Prior   to 1992, the 1980 census codes were used. There were differences in some of the   occupational categories between the 1980 version and the 1990 version. The changed   occupational codes were programmatically recoded in the 1986-1991 data sets to   categories compatible with the 1990 version. All of our reports are expressed in terms of the   1990 census occupational categories.
• Instruction Manual Part 19, Industry and Occupation Coding for Death Certificates,    Appendix D, 1993. Hyattsville, MD: 1992         http://www.cdc.gov/nchs/about/major/dvs/im.htm
• Vital Statistics reference: Technical Appendix         http://www.cdc.gov/nchs/data/natality/96linked/94mortad.pdf

Longest held job
• Only use as supplemental check
• 1986 Supplement on Longest Held Job (37,917)
• 1988 Supplement on Occupational Health (44,233)
    o information on: current job, last 12 months job, longest held job
• 41-75% concordance longest held job vs current job
• Burnett (1989), Cooper (1993) important references
• Longest Held Job in US Occupational Groups: The National Health Interview Survey   Journal Of Occupational and Environmental Medicine

Industry
• Defined as current work in past 2 weeks prior to NHIS interview
• “SIC” codes available but really US Census industry codes and are mislabeled as “SIC”    by NHIS documentation

Smoking/Tobacco Use
• Create additional variable for all NHIS employed participants
• NHIS Questions: Have you smoked 100 > cigarettes in your life?. What is your current   smoking status?
    o These two questions were asked of a subset of adults in the following years: 1987,        1989, 1990, 1991, 1992,1993, 1994.
• Variable created for all NHIS participants:
    o Keep Historic Smokers (ie known smoked > 100 cigs but not if current or former) as        “Unknown or Missing”; These people can be used if using: Ever vs Smokers but not if        any detail on the smokers (then must set to “missing”)
    o Therefore Smoking Categories: Never, Ever (Former, Current), Unknown
• No smoking questions from the 1994 second supplement on aging and the 1994    followback survey
• See section on use of Supplement Survey Data for additional information
• Brackbill (1988), Nelson (1994) important references
• Trends in US Smoking Rates in Occupational Groups: The National Health Interview   Survey 1987-1994   Journal Of Occupational and Environmental Medicine

Ethanol Use
• Only use as supplemental check
• 1988 Alcohol Supplement (43,809 subjects)
    o Variable: Current Drinkers” = people who answered “yes” to “in the past 12 months the        subject has had at least 12 drinks of any kind of alcoholic beverages.” (Question 1b)
• 1991 Alcohol and Drug Supplement (21,174 subjects)
    o Variable Current Drinker =people who drank alcohol in the past 12 months (ie.        Answered yes to tape location 337-338, item number 2, items and codes 01-12 (1-12        months drank).

Response to NHIS
• In the period 1986-1994, a nnual NHIS household survey response rates ranged from 94% to 97% (1-9) ; annual response rates to the 1997-2002 adult core ranged from 70% (in 1999) to 80% (in 1997) (10-15) .

REFERENCES

1. Dawson DA, Adams PF. Current estimates from the National Health Interview Survey, 1986. Vital Health Stat 10 1987:1-177.

2. Schoenborn CA, Marano M. Current estimates from the National Health Interview Survey, 1987. Vital Health Stat 10 1988:1-233.

3. NCHS. Current estimates from the National Health Interview Survey, 1988. Vital Health Stat 10 1989:1-250.

4. Adams PF, Benson V. Current estimates from the National Health interview survey, 1989. Vital Health Stat 10 1990:1-221.

5. Adams PF, Benson V. Current estimates from the National Health Interview Survey, 1990. Vital Health Stat 10 1991:1-212.

6. Adams PF, Benson V. Current estimates from the National Health Interview Survey, 1991. Vital Health Stat 10 1992:1-232.

7. Benson V, Marano MA. Current estimates from the National Health Interview Survey, 1992. Vital Health Stat 10 1994:1-269.

8. NCHS. Current estimates from the National Health Interview Survey, 1993. Vital Health Stat 10 1994:1-221.

9. Adams PF, Marano MA. Current estimates from the National Health Interview Survey, 1994. Vital Health Stat 10 1995:1-520.

10. Blackwell DL, Collins JG, Coles R. Summary health statistics for U.S. adults: National Health Interview Survey, 1997. Vital Health Stat 2002;10(205):1-110.

11. Pleis JR, Coles R. Summary health statistics for U.S. adults: National Health Interview Survey, 1998. Vital Health Stat 2002;10(209):1-121.

12. Pleis JR, Coles R. Summary health statistics for U.S. adults: National Health Interview Survey, 1999. Vital Health Stat 2003;10(212):1-145.

13. Pleis JR, Benson V, Schiller JS. Summary health statistics for U.S. adults: National Health Interview Survey, 2000. Vital Health Stat 2003;10(215):1-141.

14. Lucas JW, Schiller JS, Benson V. Summary health statistics for U.S. adults: National Health Interview Survey, 2001. Vital Health Stat 2004;10(218):1-143.

15. Lethbridge-Cejku M, Schiller JS, Bernadel L. Summary health statistics for U.S. adults: National Health Interview Survey, 2002. Vital Health Stat 2004;10(222):1-160.

Proxy
• Since only one household member used for the NHIS interviews (and often for the    supplements), proxy information is provided for a large component
• Always re-look at analyses using proxy as an interaction term

Vital Status
• Use NHIS algorithm criteria for matching with National Death Index
• Keep proxy deaths
• Make first day of each quarter the arbitrary date of death
•Eliminate any deaths that occurred prior to date of NHIS interview although keep these   individuals in the dataset but will list as “missing” data
• Assume if not dead then alive

Comparison Population
• 2000 US Census
• 2000 US Mortality rates

Education
• Variable categorical defined as <12 grade, 12 grade, > 12 grade
• Approximately 4000 missing data kept in analysis except for education

Age
• Variable continuous
• Variable categorical defined as: 18-44, 45-64, 65+ years

Race Ethnicity
• Variable categorical defined as: White Non-Hispanic, White Hispanic, Black
   Non-Hispanic, All Others

Sample Size Considerations
• NHIS default of >30% of the Relative Standard Error (RSE) gets and asterix to    indicate that the data are unstable
• Do not use data with less than 45 individuals/yr

Statistical Analyses
• Mortality
    o O/E
    o Cox
    o Standardized Mortality Ratios (SMRs)

The Investigators have provided SAS program language to perform the SMR calculations. In addition, Noble, Drever, and Shah give details on computing confidence intervals, with formulas for events > 100 and table values for events between 0 and 100

•Morbidity
    o Logistic Regression
    o Trend

Obesity / Height & Weight Measurement
• In 1996 the National Center for Health Statistics (NCHS) truncated the range of weight from   50-500 pounds to 98-289 pounds and height from 36-98 inches to 59-76 inches in order to   protect possible identification of survey participants.
• For the 1996 NHIS participants outside of the abovementioned ranges, Body Mass Index   (BMI) cannot be calculated.
• Beginning in 1997, the NCHS computed BMI values for all survey participants, including   those outside of the restricted range.

Acute & Chronic Disability Study Definitions

	Study Variable Definition
Acute Disability
	AFD1 = 0 vs ≥ 1 Restricted Activity Days in Prior 2 Wks AFD2 = 0 vs ≥ 1 Bed Days in Prior 2 Wks AFD3 = 0 vs ≥ 1 Lost Work Days in Prior 2 Wks
Chronic Disability
	CFD1 = 0-3 vs ≥ 4 Doctor Visits in Prior 12 months CFD2 = 0 vs ≥ 1 Hospitalizations in Prior 12 months
Health Status
	HS1 = 0 if Health Self-rated Excellent or Good; = 1 if Health Self-rated Fair or Poor HS2 = 0 vs ≥ 1 Health Condition reported

1986 - 1994 NHIS Chronic Condition Prevalence