Health

Data collected:  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

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. 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 Incorporated (www.sf36.com/ or 640 George Washington Highway, Lincoln, RI 02865).  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.

The 50-and-over health module was included beginning in 2008. The module is being 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 is being 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.

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, respondents age 48 and 49 were given a battery of exercises designed to capture cognitive capabilities.  Similarly to the 50-and-over Health module, the Cognition module is being administered to progressive two-year 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 anyone who skipped the 2006 interview, and so on.  This module solicits the respondent’s own assessment of his/her general health, and word recall exercise using randomly assigned sets of 10 words, as well as exercises requiring the respondent to count backwards from a starting point by a specified number.

Respondent Characteristics: 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, 2006, and 2008.  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 1992-2008 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.

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

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 respondent's children. A reduced set of asthma questions were included in the 2006 and 2008 surveys.

In 2008 respondents were asked if they were taking any statin drugs or heart medications.  A set of questions on cognition were added as well.  Respondents were asked to rate memory now versus two years ago and were given a series of recall tasks to perform.

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 2008 more than 83.4 percent had health insurance available.

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

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 1992-2008 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, 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 of this guide.  Information on self-perceptions and self-esteem measures can be found in the "Attitudes and Expectations" section of this guide.

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.  Users should refer to the BLS website at www.bls.gov/nls or the appropriate cohort's User's Guide for more precise information.