Created Variables

40+ HEALTH MODULE - These data were collected over a number of years from each respondent interviewed as s/he turned 40. Most of these data items are actual survey data collected directly from the respondent. They have been compiled into the following single set of variables for all respondents who provided data. Created variables are listed below:

H40-SOURCEYR: The survey year in which the respondent reported his/her 40+ health module data
H40-CES-D_SCORE_7_ITEM: Computed standardized 7-item CES-D score
H40-BPAR-5_CODE#: Codes for major health problems of respondent's biological father
H40-BPAR-10_CODE#: Codes for major health problems of respondent's biological mother
H40-SF12_PCS_SCORE: Computed SF-12 physical component summary score
H40-SF12_MCS_SCORE: Computed SF-12 mental component summary score
H40-CHRC-3C_CODE.##: Organ/body part affected by reported cancers

50+ HEALTH MODULE - This module of questions contains baseline information on various aspects of the respondent's health collected for two-year birth cohorts as they have turned or about to turn 50. Data collected includes information on general health status, the SF-12 battery of questions, the CES-D depressions scale, specific diagnosis of a number of health conditions, and a larger inventory of conditions from which the respondent may suffer. Created variables are listed below:

H50-SOURCEYR: The survey year in which the respondent reported his/her 50+ health module data
H50-CES-D_SCORE_7_ITEM: Computed standardized 7-item CES-D score
H50-BPAR-5_CODE#: Codes for major health problems of respondent's biological father
H50-BPAR-10_CODE#: Codes for major health problems of respondent's biological mother
H50-SF12_PCS_SCORE: Computed SF-12 physical component summary score
H50-SF12_MCS_SCORE: Computed SF-12 mental component summary score
H50CHRC-3C_CODE.##: Organ/body part affected by reported cancers

COGNITION_SOURCEYR: The survey year in which the respondent reported his/her 48+ cognition data. Note: the 48+ Cognition module contains data from a cognition battery administered to respondents by cohort during the survey year in which they would turn at least 48. Most of these data items are actual survey data collected directly from the respondent. They have been compiled into a single set of XRND variables.


Important Information About Using Health Data

Use H00002.00 to show the year the 40+ health module questions were given. Beginning in 1998, only those respondents age 40 or over at the date of interview were given the 40+ health module. Then in 2000, these questions were administered to those respondents age 40 or over who had not answered the 40+ health module in 1998. The set of questions have remained the same, although the set of respondents taking them has changed. So, instead of releasing a separate set 40+ health module variables for each round, there is one set of variables showing all respondents who have answered the questions, regardless of the survey round the questions were administered. H00002.00 shows the survey year the questions were asked of each respondent.

  NLSY79 health sections are divided into two periods:

  • From 1979 to 1996, most of the questions focus on health concerns that restrict or inhibit the respondent's ability to work
  • From 1998 on, as respondents reached middle age, the Health section was expanded to provide a baseline profile of the respondent's overall health as they turn 40 and 50 years old

Table 1. Year-by-Year Variations in Ability to Work Data Collection

Year(s) Ability to Work data collected
1979 - 1982 A standard set of health questions was administered during each survey. The focus of these questions was on health problems that restricted or prohibited a respondent's ability to work. For example, in each year the survey asked three questions:
  1. Respondents not currently working were asked "Would your health keep you from working on a job for pay now?"
  2. All respondents were asked, "(Are you/Would you be) limited in the kind of work you (could) do on a job for pay because of your health?"
  3. All respondents were asked "(Are you/Would you be) limited in the amount of work you (could) do because of your health?" If an individual answered 'yes' to being limited in either the kind or amount of work they could do because of health, the NLSY79 then probed for specific details on the health ailment.

While information is collected on up to three health conditions, the respondent is asked to identify which of the conditions is the "main" condition. Follow-up questions regarding the main condition include the month and year the condition began and how long the respondent has been limited in this way. In addition, the name of the condition is gathered and later coded using a modified version of the International Classification of Diseases (ICD-9) codes taken from the World Health Organization, International Classification of Diseases, Ninth Revision, 2 vols., WHO, Geneva, 1977 (vol. 1) and 1978 (vol. 2). See Attachment 8 of the NLSY79 Codebook Supplement for a detailed description of these codes. Additional details collected on respondent health conditions include information on whether the youth ever saw or talked to a medical person regarding the condition, what the cause of the condition was, what part of the body was affected, and when the respondent first noticed the condition. If the condition was caused by an accident or injury, the date of the accident/injury, as well as information on the parts of the body that were hurt, was collected. A description of the coding scheme used for the body part information is also contained in Attachment 8 of the NLSY79 Codebook Supplement.

1983 - 1987 The amount of data collected on health was significantly reduced to basic information on whether the respondent had a work-limiting health problem and the duration of any limitation. While this same short series of questions has been asked in virtually every round of the NLSY79, significant additions were made in the late 1980s. 
Beginning in 1988 An extensive series of questions was initiated on work-related injuries or illnesses. The respondent is asked specifically for the most recent and most severe work injury. The questions are asked to determine the nature and extent of the condition, whether the respondent received Workers Compensation payments, and the impact of the condition on the respondent. A sample of the impact questions include whether there were lost wages or missed days at work or the worker had to quit work or change occupations or was fired from the job as a result of the injury or illness.
Beginning in 1998 All respondents are asked about their participation in regular physical activity on and off the job.

40-and over Health Module

Beginning in 1998, because of the aging of the cohort, an extended health module was administered to respondents at the first interview after turning age 40 and general questions on physical activity and exercise were administered to all respondents. While the pre-1998 health questions provide a picture of the respondent's current health restrictions, they offer little insight into chronic health problems that will affect their labor force activity in the future. For example, a serious ailment that slowly develops over time will not be picked up by the regular health questions until the respondent actually drops out of the labor market. This extended health module was created to provide a baseline health profile of the respondent for examining the interrelationship of health and labor market activity in advance of the retirement years. Variables with CCR (Chronic Conditions Roster) in the title have been labeled with this acronym internally for consistent sorting.

To broaden the usefulness of the NLSY79 health data, this extended module, comprising four major parts, is not restricted to work-related health problems, and all questions are asked irrespective of the respondent's labor force status.

  1. The first part of the 40-and-over module asks respondents to answer the Center for Epidemiological Studies Depression Scale (CES-D). The 1998 and 2000 surveys collected a reduced set of seven items from the original 20 item CES-D scale (the full 20-item scale was last administered in 1992). The number of items was increased to nine beginning in 2002.
  2. The second part of the extended health profile asks respondents when they last saw a health care professional. These questions provide researchers with the date of the respondent's last physical exam and last visit to the doctor for any reason. Information on individuals who never visit a doctor is available as well. This subsection also gathers information about the health and life status of the NLSY79 respondents' biological parents. Questions which ask respondents about their parent's health are designed to improve researchers' understanding of hereditary health problems. Respondents are asked whether their biological parents are alive and if not, their parent's age at death and cause of death. Information is also gathered about any major health problems afflicting either parent.
  3. The third section reproduces the SF-12 scale, a 12-question health survey designed by John Ware of the New England Medical Center Hospital. The SF-12 is designed to provide a measure of the respondents' mental and physical health irrespective of their proclivity to use formal health services. Detailed information on the SF-12 is available from QualityMetric (now part of Optum). QualityMetric also provides researchers with software and algorithms to score the SF-12. For more information see Appendix 19.
  4. The last section of the 40-and-over health module asks respondents if they suffer from an extensive list of health conditions. Respondents with certain major conditions, such as cancer, hypertension, or diabetes, are asked the date at which the condition was first diagnosed and other details relevant to the particular condition.

50-and-over Health Module

This module was included beginning in 2008. The module is administered to progressive two-year birth year cohorts in the survey year during which they would turn at least age 50. NLSY79 respondents were born in 1957-1964. In 2008, the module was administered to respondents born in 1957-1958. In 2010, the module was administered to those born in 1959-1960, and anyone who skipped the 2008 interview, and so on. The 50-and-over Health module contains many of the same questions as the 40-and-over Health module. Some questions provide a second decennial point of reference for general health information. Many others provide updates on previously reported conditions. Questions about diagnosis of skin cancer and other types of cancer, various heart disease-related conditions, and stroke were also asked.

50-and-over respondents are again administered the CES-D items and the SF-12 question series, as well as questions about the life and health status of their parents if they were reported living in the 40-and-over module. In addition, 50-and-over respondents were asked to update information on previously reported conditions such as hypertension/high blood pressure, diabetes/high blood sugar, asthma and non-asthma breathing problems, depression and other emotional/psychiatric problems and arthritis. 

The 50-and-over Health module also contains questions on diagnosis of osteoporosis and the use of special equipment needed to accomplish usual activities, as well as a scale of functionality and the respondent's sleep habits.

General Health

Questions about general health practices and visits to health care professionals were moved out of the more specialized 50-and-over Health module into the universal Health section to be asked of all respondents.

Cognition Module

Beginning in 2006, the survey included a battery of exercises designed to capture cognitive capabilities. Similar to the 50-and-over Health module, the Cognition module was administered to two birth-year cohorts in the survey year during which they would turn at least age 48. In 2006, the module was administered to respondents born in 1957-1958; in 2008, the module was administered to those born in 1959-1960 and age-eligible respondents who skipped the 2006 interview, and so on.

Respondents were first asked for their own assessment of the current quality of their memory. They were then given a word recall exercise using four randomly assigned sets of 10 words. The numbers of correctly and incorrectly recalled words were recorded. Respondents were next asked to count backwards from 20, then from 86. Following this, they were given the starting point of 100 and asked to subtract 7; the process was continued five times (e.g., until the final subtraction answer should have been 65). Finally, respondents were asked to recall the same list of 10 words that they were given at the beginning of the cognition battery.

The vast majority of respondents completed the Cognition module by the 2012 interview. A relatively small but not insignificant number of respondents, who missed the interview at their first eligible year for the Cognition module and missed multiple interviews after that, took the battery in the 2014 or 2016 interview.

The 48+ cognition data from round 22 through round 27 (2006-2016) has been compiled into a single set of variables. Variable names for this set of items begin with "COGNITION" and are contained in the COGNITION area of interest. These items are assigned to the XRND survey year and do not identify non-interviewed cases for specific survey years. The variable COGNITION_SOURCEYR (Reference #X00311.00) contains the survey year in which each respondent's data was collected.

Depression Scale (CES-D)

The Center for Epidemiologic Studies Depression Scale (CES-D) measures symptoms of depression, discriminates between clinically depressed individuals and others, and is highly correlated with other depression rating scales (see Radloff 1977; Ross and Mirowsky 1989). First administered to NLYS79 respondents in 1992 (R38949.- R38968), the CES-D is a 20-item instrument. Sixteen of the items ask about negative symptoms (e.g., feeling sad, depressed, poor appetite, etc.). Four items (R38952., R38956., R38960., & R38964.) ask about positive symptoms (e.g., feeling happy). Symptom severity is measured by asking the frequency of occurrence of each item over the preceding week. Responses range from 0 (rarely or none of the time/1 day) to 3 (most or all of the time/5-7 days). The four positive symptom items are reverse- scored, and responses to all items are then summed, resulting in a maximum score of 60. Most studies have used a cutoff of 16 as an indicator of depression.

Based on research by Ross and Mirowsky (1989) and others, the number of CES-D items included in the 1994 NLSY79 was reduced to seven (R49783. - R49789.). However, only 5 items of the 7-item Mirowsky and Ross scale were used and the item response choices in the NLSY79 were kept consistent with the 1992 NLSY79 (and original Radloff) responses to the full CES-D: 0 (rarely or none of the time/1 day) to 3 (most or all of the time/5-7 days). (Mirowsky and Ross used the following response set in their 7-item administration: # days in the past week, 0-7.)  The CES-D scale was NOT administered in the 1996 NLSY79 survey round. Beginning in 1998 the CES-D was moved to the HEALTH section and is asked only of respondents once when they turn age 40 and again when they turn age 50.

Additional information on NLSY79 CES-D variables can be found in Appendix 25 and Appendix 27.

Respondent Characteristics

Height and Weight. A respondent's height and weight are natural indicators of health. Height questions were asked in 1981, 1982, 1983 (only to females who were ever pregnant), 1985, and 2006-2016. Exercise caution because the height questions have been collected in a variety of formats. The 1981 question combines feet and inches into a single number. Hence, respondents range from 400 (four feet and zero inches) to 611 (six feet and eleven inches). The 1982 and 1985 questions convert all answers into just inches. The 1983 height questions are found under two different reference numbers: female height in feet is provided in R09989., while height in inches is provided in R09990. 

Since weight fluctuates more than height, questions on weight are asked more frequently. Weight questions appear in the 1981, 1982, 1985, 1986, 1988-90, and 1992-2016 surveys. Weight in all years is recorded in pounds. The weight data are normally distributed from 50 to 400 pounds in all years except 1989. In 1989, there are 11 individuals marked as weighing 996 pounds. This number is not a true weight but rather an out-of-range code. Users are advised to examine height and weight distributions prior to analysis in order to make informed decisions as to how to handle outliers.

Hair and Eye Color. Respondent hair and eye colors were collected during the 1985 interview and information on whether they were left or right handed was collected in the 1993 interview. 

Asthma. In 2004 a series of questions about asthma were added to the survey. These included the onset and diagnosis of asthma, whether the respondent missed work, when they had an attack and methods of prescribed treatment. Also included were questions regarding onset in the children of female respondents. A reduced set of asthma questions were included beginning with the 2006 survey.

Heart Medication. Beginning in 2008 respondents were asked if they were taking any statin drugs or heart medications. 

Childhood Health. In 2012, all respondents were asked a series of new questions on childhood health including overall health, major hospitalizations, or long periods of home recovery. Adversity questions included family mental health, alchohol abuse, physical abuse, and amount of parental affection. Researchers believe that questions such as these are predictive of adult obesity and other health-related outcomes. This question series was asked in 2014 or 2016 for those who were not interviewed in 2012.

Head Injury. Also introduced in 2012 was a module on traumatic head injury. All respondents were asked if they have experienced a serious head injury or loss of smell. Because traumatic head injury and loss of smell have been found in numerous studies to be linked to subsequent dementia, these questions were added to augment ongoing efforts to track respondents' cognitive function as they advance into middle age and beyond. This module was repeated in 2014 or 2016 for those not interviewed in 2012.

Health Insurance

The NLSY79 provides researchers with a variety of insurance information. Almost every survey asked working respondents if their current or most recent job provided health insurance benefits. Table 2 is taken from the employee benefits series and shows that, over time, an increasing number of NLSY79 respondents work in jobs that are covered by health insurance benefits. While only 39.3 percent were working in covered jobs in 1979, by 2016 81.0 percent had employee health insurance available.

Table 2. Percentage of Respondents Whose Current or Most Recent Job Provided Health Insurance Benefits

Year Percentage   Year Percentage
1979 39.3 1993 76.8
1980 56.8 1994 72.6
1981 na 1996 75.6
1982 55.6 1998 78.4
1983 66.4 2000 80.3
1984 68.9 2002 82.1
1985 69.8 2004 82.9
1986 71.8 2006 83.6
1987 74.4 2008 83.4
1988 72.6 2010 83.0
1989 75.2 2012 81.6
1990 75.9 2014 82.1
1991 76.6 2016 81.0
1992 76.4    

There are a number of problems with using the employee benefits question series in the CPS and ES section to understand and track health insurance coverage. First, respondents who are not working are excluded from these questions. Second, not all health insurance is employer provided. Some individuals pay directly for health insurance, while others are covered by their spouse's or partner's plans. Lastly, while an employer may offer this benefit, workers might not participate in the plan and therefore may not be aware of its availability. To overcome these limitations, the "Health" section of the NLSY79 was expanded beginning in 1989 to directly ask about sources of health insurance coverage.

The "Health" section of the questionnaire in 1989, 1990, and 1992-2016 asks respondents if they are covered by a health plan. If the respondent answers "yes," the interviewer asks who pays for the plan. Responses include current employer, previous employer, spouse's employer, purchased directly, and Medicaid or welfare source. If the respondent is married, the same set of questions on medical coverage are asked about the wife or husband (and beginning in 1994, about the nonmarital, opposite-sex partner, (the term opposite-sex was excluded in 2002) if any). Additionally, if the respondent has any children, the same questions are asked about the children's health insurance coverage.

Related Variables: Additional information on the relationship between health and labor force status can be found in the CPS section. The CPS section contains questions allowing respondents to state that they are not in the labor force because of health problems. Unfortunately, these questions do not describe the specific problem, when the problem started, or how long the problem has lasted. Information on substance use (smoking, drugs, alcohol) is collected as part of a largely self-administered report in selected survey years. See the Alcohol Use, Cigarette Use, and Drug Use sections of this guide for further information on these topics. Information on health practices related to sexual activity and pregnancy can be found in the fertility section of selected surveys. For further information see the Fertility and Sexual Activity and Contraception sections. Information on self-perceptions and self-esteem measures can be found in the Attitudes and Expectations section.

Comparison to Other NLS Cohorts: Maternal prenatal care information and health-related characteristics are provided on the NLSY79 Child and Young Adult data set. As part of the child data collection, the Mother Supplement (MS) survey instrument includes a selection of scales measuring the child's temperament, motor and social development, and behavior problems. Information on the child's health is also collected from the mother in the Child Supplement (CS) survey instrument. 

Respondents in the other cohorts have answered questions about their health; however, the specific questions have varied widely as the health sections were modified to reflect the respondents' varying life cycle stages. Health insurance information has been collected from respondents in these cohorts except the Young Men. The round 1 NLSY97 interview included a series of questions, addressed to youths born in 1983, on respondents' health practices and knowledge. For more precise details about the content of each survey, consult the appropriate cohort's User's Guide using the tabs above for more information.

Survey Instruments and Documentation Health and health insurance questions are located within the "Health" section of each questionnaire. Documentation augmenting the questionnaire and codebook include Attachment 8 in the NLSY79 Codebook Supplement.
Areas of Interest Data related to health can be found in the following NLSY79 main file areas of interest: "Health," "Alcohol," "Drugs," "CPS," "Birth Record," "Birth Record xxxx," and "Misc. xxxx."