• Component Description
• Eligible Sample
• Interview Setting and Mode of Administration
• Quality Assurance & Quality Control
• Data Processing and Editing
• Analytic Notes
• References
• Codebook
  • SEQN - Respondent sequence number
  • RIDSTATR - Interview/Examination Status
  • RIAGENDR - Gender - Adjudicated
  • RIDAGEYR - Age at Screening Adjudicated - Recode
  • RIDAGEMN - Age in Months - Recode
  • RIDAGEEX - Exam Age in Months - Recode
  • RIDRETH1 - Race/Ethnicity - Recode
  • DMQMILIT - Veteran/Military Status
  • DMDBORN - Country of Birth - Recode
  • DMDCITZN - Citizenship Status
  • DMDYRSUS - Length of time in US
  • DMDEDUC1 - Education Level - Children/Youth 6-19
  • DMDEDUC2 - Education Level - Adults 20+
  • DMDSCHOL - Now attending school?
  • DMDMARTL - Marital Status
  • INDHHINC - Annual Household Income
  • INDFMINC - Annual Family Income
  • INDFMPIR - Family PIR
  • RIDEXPRG - Pregnancy Status at Exam - Recode
  • WTSF6Q - Final 6 Year LA Interview Weight
  • WTSF6M - Final 6 Year LA MEC Exam Weight
  • WTSF6F - Final 6 Year LA Fasting Weight
  • WTSTVPSU - Taylor Series-Variance PSU Identifier
  • WTSVSTRA - Taylor Series-Variance Strata Identifier
  • WTSF6Q01 - Final 6 Year LA Interview Wt: Rep 01
  • WTSF6Q02 - Final 6 Year LA Interview Wt: Rep 02
  • WTSF6Q03 - Final 6 Year LA Interview Wt: Rep 03
  • WTSF6Q04 - Final 6 Year LA Interview Wt: Rep 04
  • WTSF6Q05 - Final 6 Year LA Interview Wt: Rep 05
  • WTSF6Q06 - Final 6 Year LA Interview Wt: Rep 06
  • WTSF6Q07 - Final 6 Year LA Interview Wt: Rep 07
  • WTSF6Q08 - Final 6 Year LA Interview Wt: Rep 08
  • WTSF6Q09 - Final 6 Year LA Interview Wt: Rep 09
  • WTSF6Q10 - Final 6 Year LA Interview Wt: Rep 10
  • WTSF6Q11 - Final 6 Year LA Interview Wt: Rep 11
  • WTSF6Q12 - Final 6 Year LA Interview Wt: Rep 12
  • WTSF6Q13 - Final 6 Year LA Interview Wt: Rep 13
  • WTSF6Q14 - Final 6 Year LA Interview Wt: Rep 14
  • WTSF6Q15 - Final 6 Year LA Interview Wt: Rep 15
  • WTSF6Q16 - Final 6 Year LA Interview Wt: Rep 16
  • WTSF6Q17 - Final 6 Year LA Interview Wt: Rep 17
  • WTSF6Q18 - Final 6 Year LA Interview Wt: Rep 18
  • WTSF6Q19 - Final 6 Year LA Interview Wt: Rep 19
  • WTSF6Q20 - Final 6 Year LA Interview Wt: Rep 20
  • WTSF6Q21 - Final 6 Year LA Interview Wt: Rep 21
  • WTSF6Q22 - Final 6 Year LA Interview Wt: Rep 22
  • WTSF6Q23 - Final 6 Year LA Interview Wt: Rep 23
  • WTSF6Q24 - Final 6 Year LA Interview Wt: Rep 24
  • WTSF6Q25 - Final 6 Year LA Interview Wt: Rep 25
  • WTSF6Q26 - Final 6 Year LA Interview Wt: Rep 26
  • WTSF6Q27 - Final 6 Year LA Interview Wt: Rep 27
  • WTSF6Q28 - Final 6 Year LA Interview Wt: Rep 28
  • WTSF6Q29 - Final 6 Year LA Interview Wt: Rep 29
  • WTSF6Q30 - Final 6 Year LA Interview Wt: Rep 30
  • WTSF6Q31 - Final 6 Year LA Interview Wt: Rep 31
  • WTSF6Q32 - Final 6 Year LA Interview Wt: Rep 32
  • WTSF6Q33 - Final 6 Year LA Interview Wt: Rep 33
  • WTSF6Q34 - Final 6 Year LA Interview Wt: Rep 34
  • WTSF6Q35 - Final 6 Year LA Interview Wt: Rep 35
  • WTSF6Q36 - Final 6 Year LA Interview Wt: Rep 36
  • WTSF6Q37 - Final 6 Year LA Interview Wt: Rep 37
  • WTSF6Q38 - Final 6 Year LA Interview Wt: Rep 38
  • WTSF6Q39 - Final 6 Year LA Interview Wt: Rep 39
  • WTSF6Q40 - Final 6 Year LA Interview Wt: Rep 40
  • WTSF6Q41 - Final 6 Year LA Interview Wt: Rep 41
  • WTSF6Q42 - Final 6 Year LA Interview Wt: Rep 42
  • WTSF6Q43 - Final 6 Year LA Interview Wt: Rep 43
  • WTSF6Q44 - Final 6 Year LA Interview Wt: Rep 44
  • WTSF6M01 - Final 6 Year LA MEC Exam Wt: Rep 01
  • WTSF6M02 - Final 6 Year LA MEC Exam Wt: Rep 02
  • WTSF6M03 - Final 6 Year LA MEC Exam Wt: Rep 03
  • WTSF6M04 - Final 6 Year LA MEC Exam Wt: Rep 04
  • WTSF6M05 - Final 6 Year LA MEC Exam Wt: Rep 05
  • WTSF6M06 - Final 6 Year LA MEC Exam Wt: Rep 06
  • WTSF6M07 - Final 6 Year LA MEC Exam Wt: Rep 07
  • WTSF6M08 - Final 6 Year LA MEC Exam Wt: Rep 08
  • WTSF6M09 - Final 6 Year LA MEC Exam Wt: Rep 09
  • WTSF6M10 - Final 6 Year LA MEC Exam Wt: Rep 10
  • WTSF6M11 - Final 6 Year LA MEC Exam Wt: Rep 11
  • WTSF6M12 - Final 6 Year LA MEC Exam Wt: Rep 12
  • WTSF6M13 - Final 6 Year LA MEC Exam Wt: Rep 13
  • WTSF6M14 - Final 6 Year LA MEC Exam Wt: Rep 14
  • WTSF6M15 - Final 6 Year LA MEC Exam Wt: Rep 15
  • WTSF6M16 - Final 6 Year LA MEC Exam Wt: Rep 16
  • WTSF6M17 - Final 6 Year LA MEC Exam Wt: Rep 17
  • WTSF6M18 - Final 6 Year LA MEC Exam Wt: Rep 18
  • WTSF6M19 - Final 6 Year LA MEC Exam Wt: Rep 19
  • WTSF6M20 - Final 6 Year LA MEC Exam Wt: Rep 20
  • WTSF6M21 - Final 6 Year LA MEC Exam Wt: Rep 21
  • WTSF6M22 - Final 6 Year LA MEC Exam Wt: Rep 22
  • WTSF6M23 - Final 6 Year LA MEC Exam Wt: Rep 23
  • WTSF6M24 - Final 6 Year LA MEC Exam Wt: Rep 24
  • WTSF6M25 - Final 6 Year LA MEC Exam Wt: Rep 25
  • WTSF6M26 - Final 6 Year LA MEC Exam Wt: Rep 26
  • WTSF6M27 - Final 6 Year LA MEC Exam Wt: Rep 27
  • WTSF6M28 - Final 6 Year LA MEC Exam Wt: Rep 28
  • WTSF6M29 - Final 6 Year LA MEC Exam Wt: Rep 29
  • WTSF6M30 - Final 6 Year LA MEC Exam Wt: Rep 30
  • WTSF6M31 - Final 6 Year LA MEC Exam Wt: Rep 31
  • WTSF6M32 - Final 6 Year LA MEC Exam Wt: Rep 32
  • WTSF6M33 - Final 6 Year LA MEC Exam Wt: Rep 33
  • WTSF6M34 - Final 6 Year LA MEC Exam Wt: Rep 34
  • WTSF6M35 - Final 6 Year LA MEC Exam Wt: Rep 35
  • WTSF6M36 - Final 6 Year LA MEC Exam Wt: Rep 36
  • WTSF6M37 - Final 6 Year LA MEC Exam Wt: Rep 37
  • WTSF6M38 - Final 6 Year LA MEC Exam Wt: Rep 38
  • WTSF6M39 - Final 6 Year LA MEC Exam Wt: Rep 39
  • WTSF6M40 - Final 6 Year LA MEC Exam Wt: Rep 40
  • WTSF6M41 - Final 6 Year LA MEC Exam Wt: Rep 41
  • WTSF6M42 - Final 6 Year LA MEC Exam Wt: Rep 42
  • WTSF6M43 - Final 6 Year LA MEC Exam Wt: Rep 43
  • WTSF6M44 - Final 6 Year LA MEC Exam Wt: Rep 44
  • WTSF6F01 - Final 6 Year LA Fasting Wt: Rep 01
  • WTSF6F02 - Final 6 Year LA Fasting Wt: Rep 02
  • WTSF6F03 - Final 6 Year LA Fasting Wt: Rep 03
  • WTSF6F04 - Final 6 Year LA Fasting Wt: Rep 04
  • WTSF6F05 - Final 6 Year LA Fasting Wt: Rep 05
  • WTSF6F06 - Final 6 Year LA Fasting Wt: Rep 06
  • WTSF6F07 - Final 6 Year LA Fasting Wt: Rep 07
  • WTSF6F08 - Final 6 Year LA Fasting Wt: Rep 08
  • WTSF6F09 - Final 6 Year LA Fasting Wt: Rep 09
  • WTSF6F10 - Final 6 Year LA Fasting Wt: Rep 10
  • WTSF6F11 - Final 6 Year LA Fasting Wt: Rep 11
  • WTSF6F12 - Final 6 Year LA Fasting Wt: Rep 12
  • WTSF6F13 - Final 6 Year LA Fasting Wt: Rep 13
  • WTSF6F14 - Final 6 Year LA Fasting Wt: Rep 14
  • WTSF6F15 - Final 6 Year LA Fasting Wt: Rep 15
  • WTSF6F16 - Final 6 Year LA Fasting Wt: Rep 16
  • WTSF6F17 - Final 6 Year LA Fasting Wt: Rep 17
  • WTSF6F18 - Final 6 Year LA Fasting Wt: Rep 18
  • WTSF6F19 - Final 6 Year LA Fasting Wt: Rep 19
  • WTSF6F20 - Final 6 Year LA Fasting Wt: Rep 20
  • WTSF6F21 - Final 6 Year LA Fasting Wt: Rep 21
  • WTSF6F22 - Final 6 Year LA Fasting Wt: Rep 22
  • WTSF6F23 - Final 6 Year LA Fasting Wt: Rep 23
  • WTSF6F24 - Final 6 Year LA Fasting Wt: Rep 24
  • WTSF6F25 - Final 6 Year LA Fasting Wt: Rep 25
  • WTSF6F26 - Final 6 Year LA Fasting Wt: Rep 26
  • WTSF6F27 - Final 6 Year LA Fasting Wt: Rep 27
  • WTSF6F28 - Final 6 Year LA Fasting Wt: Rep 28
  • WTSF6F29 - Final 6 Year LA Fasting Wt: Rep 29
  • WTSF6F30 - Final 6 Year LA Fasting Wt: Rep 30
  • WTSF6F31 - Final 6 Year LA Fasting Wt: Rep 31
  • WTSF6F32 - Final 6 Year LA Fasting Wt: Rep 32
  • WTSF6F33 - Final 6 Year LA Fasting Wt: Rep 33
  • WTSF6F34 - Final 6 Year LA Fasting Wt: Rep 34
  • WTSF6F35 - Final 6 Year LA Fasting Wt: Rep 35
  • WTSF6F36 - Final 6 Year LA Fasting Wt: Rep 36
  • WTSF6F37 - Final 6 Year LA Fasting Wt: Rep 37
  • WTSF6F38 - Final 6 Year LA Fasting Wt: Rep 38
  • WTSF6F39 - Final 6 Year LA Fasting Wt: Rep 39
  • WTSF6F40 - Final 6 Year LA Fasting Wt: Rep 40
  • WTSF6F41 - Final 6 Year LA Fasting Wt: Rep 41
  • WTSF6F42 - Final 6 Year LA Fasting Wt: Rep 42
  • WTSF6F43 - Final 6 Year LA Fasting Wt: Rep 43
  • WTSF6F44 - Final 6 Year LA Fasting Wt: Rep 44

National Health and Nutrition Examination Survey

1999-2004 Data Documentation, Codebook, and Frequencies

Los Angeles County, California - Demographic Variables & Sample Weights (LA_DEMO)

RDC Only Data File: LA_DEMO.xpt

First Published: August 2008

Last Revised: NA

Due to disclosure issues, this dataset is not available publicly. Access may be obtained through the NCHS Research Data Center (https://www.cdc.gov/rdc).

Component Description

Los Angeles (L.A.) County is a self-representing primary sampling unit in the National Health and Nutrition Examination Survey sample design. This demographic file contains the household interview and examination status variables, sample weights, and selected demographic variables such as gender, age, race/ethnicity, education, country of birth, pregnancy status, total family and household income, and poverty income ratio values for participants selected from Los Angeles County. Selected variables from the Sample Person and Family questionnaires are included in the L.A. Demographics file.

Disclosure risks and issues pertaining to confidentiality protection prevent NCHS from releasing the L.A. County Demographics file publicly. Analysis of these data must be done through the NCHS Research Data Center (RDC). The RDC website has information about special request data files: https://www.cdc.gov/rdc/.

Eligible Sample

All Sample Persons (SP) selected from Los Angeles County who completed the household interview have a Demographics file record. Some questions are asked for all SPs, whereas others are asked for a particular subgroup; please refer to the NHANES website to review the questionnaires used during NHANES 1999-2000, 2001-2002 and 2003–2004.

Interview Setting and Mode of Administration

Persons 16 years of age and older and emancipated minors were interviewed directly. A proxy provided information for SPs less than 16 years of age and for individuals who could not self-report.

The household interview was conducted face-to-face by a trained interviewer in either English or Spanish; information was recorded using a computer-assisted data entry method. Some of the questions in this section required the use of printed hand cards. In most cases, the respondent selected a response choice (or choices) after looking at the hand card(s). When necessary, the household interviewers read the hand card response categories to the respondent.

The NHANES 1999-2000, 2001-2002 and 2003–2004 interview and examination procedures manuals and questionnaires are posted on the NHANES website.

Quality Assurance & Quality Control

The computer-assisted personal interview (CAPI) system used to collect the interview data had built-in consistency checks, online information screens that provided the interviewers with information about the terms used in the questionnaires, and hard and soft edit checks to reduce the number of keying entry errors. All of the interviews were reviewed by the NHANES field office staff for accuracy and completeness. A subset of the household interviews was verified by re-contacting the survey participants. Additional details describing the quality assurance/quality control processes are provided in the survey procedures manuals.

Data Processing and Editing

SEQN is the unique number assigned to each survey participant.

RIDSTATR is a recoded variable representing interview/examination status.

RIDAGEYR: Age in years is top coded at 85 years. This is the age of the SP at the time of the screening interview. The exact date of birth is used to calculate the exact age on the date of screening. Otherwise, an imputed date of birth is created using the information provided by the SP.

The procedure used to impute age at screener when date of birth information is missing or refused but age in years is provided by the SP is as follows: If month of birth is missing or not given, it is imputed as 7; if day of birth is missing or not given, it is imputed as 1; if year of birth is missing or not given, it is imputed as the year of the screening interview less the age in years provided by the SP at screening. Corrections are made to this imputed information for SPs who are less than 1 year of age at the time of screening.

RIDAGEMN is age in months at household screening; RIDAGEMN is provided for SPs under 85 years of age (RIDAGEYR<85). If the exact date of birth is not provided by the SP, the age in months is calculated based on the imputed age at screener to allow the SP to proceed with the questionnaire and examination.

RIDAGEEX is age in months at MEC examination. RIDAGEEX is provided for subjects under 85 years of age at the time of household screening (RIDAGEYR<85); 25 SPs under 85 years of age at the time of the household screening interview have missing data on RIDAGEEX because their exact date of birth was not available. RIDAGEEX was not calculated for these individuals with an imputed age.

RIDRETH1: This race/ethnicity variable is derived by combining responses to questions on race and Hispanic origin. Respondents who self-identified as “Mexican American” were coded as such (i.e., RIDRETH1=1) regardless of their other race-ethnicity identities. Otherwise, self-identified “Hispanic” ethnicity would result in code “2, Other Hispanic” in the RIDRETH1 variable. All other non-Hispanic participants would then be categorized based on their self-reported races: non-Hispanic white (RIDRETH1=3), non-Hispanic black (RIDRETH1=4), and other non-Hispanic race including non-Hispanic multiracial (RIDRETH1=5).

DMQMILIT: This variable provides information on veteran’s/military status. Veterans include persons who served in the armed forces of the United States, specifically, the U.S. Army, Navy, Air Force, Marine Corps, and Coast Guard.

DMDBORN: Country of birth was recoded into three categories: 1) born in one of the 50 U.S. states or Washington, D.C.; 2) born in Mexico; and 3) born in any other location or foreign country.

DMDCITZN: Citizenship status is reported using two codes: 1) citizen by birth or naturalization or 2) Not a citizen of the U.S. Persons who were born in the U.S. or US territories who acquire citizenship at birth were coded as US citizens.

DMDYRSUS: This variable is the number of years the respondent has lived in the United States. Respondents who were born outside the U.S. were asked the month and year when they came to the U.S. to stay (DMQ.160). A small number of records were imputed because the respondent did not report the month of their arrival. A month value of 7 (July) was used to impute DMDYRSUS for these respondents. The responses to the question were recoded into 9 categories ranging from less than one year to 50 years or more.

DMDEDUC1: This variable provides information on the highest grade or level of education completed by respondents 6-19 years of age. The responses were recoded by NCHS as follows: single years of education (grades 1-12), high school graduate/GED, and post-high school. Code ‘66’ (less than 9th grade) was used to categorize older youth who had very low education levels.

DMDEDUC2: This variable is the highest grade or level of education completed by adults 20 years and older. The response categories are: less than 9th grade education, 9-11th grade education (includes 12th grade and no diploma), High school graduate/GED, some college or associates (AA) degree, and college graduate or higher. Please refer to the Analytic Notes for additional information on education level variables.

DMDSCHOL: This variable is school attendance status. It is asked for respondents 6-19 years of age.

DMDMARTL is the derived marital status variable. The marital status question was asked for sample persons 14 years of age and older. If this item was missing for sample persons 14 years of age older, marital status was imputed from other questionnaire items that made reference to their marital status.

INDHHINC: This variable is the estimated total household income. If a household was comprised of a single CPS family, the family income value was used as previously described. When more than one CPS family resided in the household, two methods were used to compute the estimated total household income. The preferred method was to use income data reported by each CPS family that was interviewed (INQ200). A second method was used with multi-family households in which the total household income information (INQ200) was asked of the household reference person.

When income information was obtained from each of the CPS families in a household, the reported CPS family income values were summed to compute total household income (INDHHINC). When information was missing for any of the CPS families in the household, the estimated household income value provided by a family reference person was used to compute estimated total household income. Total household income was not calculated for multi-family households when income range data were reported by any of the families in the household; INDHHINC was coded as missing.

INDFMINC: This variable is the total family income variable and is released as an income range value. NCHS used the U.S. Bureau of the Census Current Population Survey (CPS 2004) definition of “family” to group household members into one or more families (US Census 2003a). The CPS defines a family as “a group of two people or more (one of whom is the householder) related by birth, marriage, or adoption and residing together”; all such people (including related subfamily members) are considered to be members of one family. Approximately 90 percent of the NHANES 2003–2004 households were single-family households; the remaining households were comprised of two or more families.

The income section of the household interview includes several questions about sources of income including wages, retirement income, disability payments, interest income, and assistance programs, but the amounts of income from each source were not obtained. The respondent was asked to report total family income for themselves and the other members of their family in dollars (question INQ200). If the respondent refused to answer INQ200 or did not know the total combined family income, an income screener question was asked (question INQ220) to query if the total family income was < $20,000 or ≥ $20,000. If the respondent answered INQ220, a follow-up question asked the respondent to select an income range (question INQ230) from a list of income ranges listed on a printed hand card; the midpoint of the income range value was used as the total family income value. Family income was used to calculate the ration of income to poverty (INDFMPIR) and estimated total household income (INDHHINC).

INDFMPIR: This variable is an index for the ratio of family income to poverty. The Department of Health and Human Services’ (HHS) poverty guidelines were used as the poverty measure to calculate this index. These guidelines are issued each year, in the Federal Register, for determining financial eligibility for certain federal programs such as Head Start, Supplemental Nutrition Assistance Program (SNAP) (formerly Food Stamp Program), Special Supplemental Nutrition Program for Women, Infants, and Children (WIC), and the National School Lunch Program.

The variable INDFMPIR was calculated by dividing family income by the poverty guidelines, specific to family size, as well as the appropriate year and state. The values were not computed if the income screener information (INQ 220: < $20,000 or ≥ $20,000) was the only family income information reported. If family income was reported as a range value, the midpoint of the range was used to compute the variable. Values at or above 5.00 were coded as 5.00 or more because of disclosure concerns. The values were not computed if the family income data was missing.

RIDEXPRG: Pregnancy status at the time of the health examination was ascertained for females 8–59 years of age. The information used to code RIDEXPRG values included urine pregnancy test results and self-reported pregnancy status. Urine pregnancy tests were performed prior to the dual energy x-ray absorptiometry (DXA) exam. Menstruating girls 8–11 years of age and all females 12 years and over received a urine pregnancy test. Persons who reported they were pregnant at the time of exam were assumed to be pregnant. If the urine test was negative, but the subject reported they were pregnant, the status was coded as ‘pregnant at exam’ (RIDEXPRG = 1). If the urine pregnancy results were negative and the respondent stated that they were not pregnant, the respondent was coded ‘not pregnant at examination’ (RIDEXPRG = 2). Persons who were interviewed, but not examined have an RIDEXPRG value = 3 (could not be determined).

Analytic Notes

Sample Weights:

The following six year weights are based on population estimates for Los Angeles County, California, during 1999-2004. Analysts should use the following weights to appropriately analyze the combined six year dataset.

WTSF6Q is the final 6 year L.A. interview weight
WTSF6M is the final 6 year L.A. examination weight
WTSF6F is the final 6 year fasting weight

Variances:

WTSVPSU is the Taylor series variance PSU identifier
WTSVSTRA is the Taylor series variance Strata identifier

There are 44 replicate interview, examination, and fasting weights provided for the Los Angeles sample. Replication techniques can be used to estimate sampling errors.

Please refer to the Analytic Guidelines for further details on the use of sample weights and other analytic issues. The Analytic Guidelines are available on the NHANES website. https://wwwn.cdc.gov/nchs/nhanes/analyticguidelines.aspx.

For analysis of the national survey, the stratum variable is SDMVSTRA. The comparable variable for the L.A. sample is WTSVSTRA. Similarly, the PSU variable for the national survey is SDMVPSU, and the comparable variable for the L.A. sample is WTSVPSU.

The Los Angeles County Demographic microdata is available only through the NCHS Research Data Center (RDC).

References

• U.S. Census Bureau. Current Population Survey (CPS) Definitions and Explanations. 2003. http://www.census.gov/population/www/cps/cpsdef.html
• U.S. Department of Health & Human Services. Poverty Guidelines, Research, and Measurement. Washington, DC: U.S. Department of Health & Human Services, January 2011. http://aspe.hhs.gov/POVERTY/

Codebook and Frequencies