Wave IV
The planned Wave IV component of Add Health has been funded from
December 2005 through November 2010. Below is a description of
the project.
In a second continuation of the Add Health program project, a fourth
in-home interview is planned with original Wave I respondents who will
be aged 24 to 32 at the time of data collection. The goal is to trace,
locate, and reinterview respondents who participated in Wave I of the
National Longitudinal Study of Adolescent Health (Add Health) with a
two hour personal interview in 2007-08 representing a Wave IV follow-up
of a nationally representative sample of over 20,000 adolescents in
1994-95. In Wave IV we will expand the scientific frontiers of
research and knowledge by taking Add Health in new directions to
increase our understanding of biology in relation to social,
behavioral, psychological, and environmental processes of human
development. We plan to collect longitudinal survey data on the
social, economic, psychological, and health circumstances of our
respondents, longitudinal geographic data, and new biological data to
capture the prevailing health concerns of our Add Health cohort as well
as biological markers of future chronic health conditions and disease.
When Wave IV data are combined with existing longitudinal Add Health
data over 10 years of our respondents’ lives beginning in adolescence
and extending through their transition to adulthood, Add Health will
provide unique opportunities to study linkages in social, behavioral,
environmental, and biological processes that lead to health and
achievement outcomes in young adulthood.
The research purpose of Wave IV is to study developmental and health
trajectories across the life course of adolescence into young adulthood
using an integrative approach that combines social, behavioral, and
biomedical sciences in its research objectives, design, data
collection, and analysis. Add Health participants will be 24 to 32
years old and settling into young adulthood. At the same time that the Add
Health cohort assumes adult roles and responsibilities, they develop
crucial health habits and lifestyle choices that set pathways for their
future adult health and well-being. We have designed Add Health
Wave IV in the vision of the NIH Roadmap by integrating biological
information into our models of health and human development and by
stimulating interdisciplinary research teams that aim to reshape
biomedical research to improve people's health (Zerhouni 2003).
Several features of the proposed data collection represent new
directions in Add Health, including methods to obtain more objective
measures of health status and strategies to explore alternative modes
of reinterviewing our sample in the future. Wave IV will employ
innovations in the collection of biological measures in a field setting
on a large national sample that are both practical and
groundbreaking. For example, we plan to collect DNA on everyone
in our national sample and obtain indicators of metabolic syndrome and
immune functioning using noninvasive procedures. The combination
of longitudinal social, behavioral, and environmental data with new
biological data will expand the breadth of research questions that can
be addressed in Add Health regarding predisease pathways,
gene-environment interactions, the relationship between personal ties
and health, factors that contribute to resilience and wellness, and
environmental sources of health disparities.
Data Collection
Data collection for the National Longitudinal Study of Adolescent
Health: Wave IV will be carried out by the Research Triangle Institute
(RTI) under sub-contract to the University of North Carolina at Chapel
Hill. The basic plan for data collection is to locate Wave I
respondents and complete a two-hour interview. We will collect
survey data using a 90-minute CAPI/CASI instrument, followed by
biospecimen data collection. We will collect saliva samples for
buccal cell DNA and blood spots for a lipids profile and to dry for
assays of C-reactive protein (hsCRP), glycosolated hemoglobin (HbA1c),
and Epstein-Barr virus (EBV) antibodies. Interviewers will
instruct respondents on self-collection of three saliva samples for
assays of cortisol on the day following the interview, which they will
mail in prepared packages to Salimetrics Laboratories in State College,
PA. DNA samples will be mailed by the interviewers to the
Institute for Behavioral Genetics in Boulder, CO, the DNA
subcontracter, where DNA will be extracted, quantified, genotyped, and
stored. Dried blood spots will be mailed to Craft Technologies in
Wilson, NC, the contractor who will conduct the assays on blood spots.
Locating Respondents
The challenging part of the data-collection project is tracing
respondents. RTI has a special operational unit that is organized
for respondent tracing. Our tracing and locating activities start
from a solid foundation. We have accurate addresses for all
respondents interviewed in Waves II and III of Add Health, and parent
addresses for all respondents interviewed in Wave I. In addition,
at Wave III we gained consent from 67 percent of Add Health respondents to use
their social security numbers for purposes of following them up for
subsequent interviews. RTI expects to be successful in tracing
and interviewing 85 percent of the Wave I respondents (about 17,000
cases). Because all of the respondents have been interviewed at
least once before, and most have been interviewed at least three times,
we expect refusals to be minimal once respondents are contacted.
(In Wave III, only 6 percent of respondents refused to be
interviewed.) The Add Health sample is dispersed across the
nation; at Wave III respondents lived in all 50 states.
Recruitment for Wave IV
Using respondent and parent locating information, current addresses for
respondents will be solicited. More intensive techniques will be
sequentially employed to maximize the number of original respondents
who can be located. Every effort will be made to locate women and
minorities, including computerized searches of electronic databases and
vital statistics (e.g., marriage records, DMV records). In 2006,
original Wave I respondents will be sent advance letters notifying them
of the upcoming survey. Interviewers will then schedule with
respondents, either by telephone or in person, a mutually acceptable
time to meet. Interviewers will explain Add Health Wave IV and
obtain written, informed consent from respondents.
Interview Setting
Most interviews will be conducted at the respondent’s home, but this is
not a requirement. Add Health interviewers have always been
flexible to accommodate respondents’ schedule, lifestyle, or living
arrangements by conducting a handful of interviews in restaurants,
college lounges, or places of work. The Wave IV interview will be
administered on a laptop computer with a CAPI/CASI survey
instrument. The Wave IV questionnaire administration will be
approximately 90 minutes long. Less-sensitive questionnaire
sections and questions will be administered with the assistance of an
interviewer (computer-assisted personal interview). We discovered
at Wave III that when the interviewer and the respondent sit side by
side during the CAPI sections so that the respondent can read along
while the interviewer reads out loud the questions on the computer
screen, this setting improves respondents understanding and reduces
need for clarification of questions, and considerably shortens the
length of the interview. More sensitive questionnaire sections
will be self-administered using CASI technology (computer-assisted
self interview). Interviewers will obtain residential latitude
and longitude readings using a Global Positioning System (GPS) device
which will be directly transferred into the survey instrument on the
laptop. Immediately following the 90-minute interview,
interviewers will take physical measurements and collect biological
specimens, which should take no more than 30 minutes.
Survey Content
In determining questionnaire content, Add Health consulted widely with
experts on each specific health outcome and with representatives of NIH
institutes who had contributed financial support to the project.
For example, in conjunction with the National Institute of Alcohol
Abuse and Alcoholism (NIAAA), we developed a short inventory of alcohol
use and abuse items. Likewise, in conjunction with the National
Cancer Institute (NCI), we introduced new questions on sun exposure and
diet in the Wave II questionnaire. In Wave IV we are following a
similar strategy, drawing on the expert advice of NIH representatives
to ensure that our questions capture the necessary elements of each
health domain.
The Wave IV survey will maintain longitudinal elements from earlier
waves of data collection, but will add new questions and sections to
the survey that are more pertinent to the lives of young adults.
In Wave IV we plan to continue to collect longitudinal data on
household composition and residence history; contact with and
emotional/financial support from parents, siblings, and friends;
educational achievement; occupational and military service history;
romantic relationship/cohabitation/marriage history; pregnancy history;
childbearing and health conditions of children; general sexual
experiences and STDs; access to health services and insurance; self
esteem, depression, and suicidality; religiosity; violence and
involvement with the criminal justice system; substance use; and civic
participation and citizenship. Questions in these domains update
sociodemographic transitions that are central to the movement into
adulthood, and provide information about continuity and change in
multiple indicators of physical and mental health status and health
care; in social, emotional, and physical contexts; and in risk taking,
prosocial, and antisocial behavior.
New Survey Data
New data will be collected in a number of domains, reflecting funded
research needs and salient aspects of the young adult years of the
20s. For example, we plan to expand survey questions on
educational transitions, economic status and financial resources and
strains, sleep patterns and quality, eating habits and nutrition,
illnesses and medications, physical activities, emotional content and
quality of current and recent romantic/cohabiting/marriage
relationships, and maltreatment during childhood by caregivers and
other adults. We plan to add new questions to tap the “Big 5"
personality dimensions (NEO-FFI, McCrae and Costa 1989);
interpersonal and occupational stressors; loneliness; substance
addiction and treatment (Composite International Diagnostic Interview -
Substance Abuse Module, Cottler and Keating 1990; Robins, Cottler, and
Babor 1993; Young et al. 2002); obstacles to educational goals; and
intersections and balance between work and family
responsibilities. We plan to collect the name of the college from
which any degrees were obtained and the names of all colleges attended
to facilitate a project that will collect the college transcripts and
college contexts of our sample. Moreover, particular survey data
will be added to the instrument for purposes of interpreting biological
data, such as currently breast-feeding, medication use, recent
infections, and recent participation in intense forms of exercise.
Event History
The survey will continue to use a CAPI/CASI event history calendar to
collect the dates and circumstances of key life events that occur to
young adults, including a complete relationship history since Wave III,
pregnancy and fertility histories from both men and women, an
educational history of dates of degrees and school attendance, and an
employment history of jobs, with respective information on occupation,
industry, wages, hours, and benefits. We will also collect a
residential history of state locations since Wave III, and recent
mobility (e.g., previous address, length of time at previous
residence). We can repeat our questions on relationship and
childbearing events and activities because Wave III had rather in-depth
sections on these domains. However, we plan to expand our data
collection of education and work events since these activities are
particularly intense and quite consequential in this stage of
life. Our event history survey data will also include major
health events (e.g., hospitalizations, occurrences of severe or
chronic illnesses, accidents causing disability), involvement with the
criminal justice system (e.g., arrests, imprisonment), and other forms
of institutionalization.
Geographic Data
At Wave IV we will collect geographic data in two forms: home and work
addresses and latitude/longitude coordinates from GPS devices. Geocodes
will be obtained from all reported addresses using state of the art
methods as well as from the latitude and longitude coordinates of the
home residence. Residential geocodes from multiple sources (e.g.,
from reported home addresses as well as from GPS readings at the time
of the interview) enable us to cross-check the validity and clean the
geographic data to produce a valid residential geocode. In
addition, if the interview does not take place at the respondent’s
home, residential geocodes can still be obtained from the home address
reported in the survey.
A set of core community variables will then be assembled and made
available to Add Health users. Working under strict
confidentiality protocols defined by Add Health, community-level
environmental data will be collected, compiled, or derived from public
domain and commercially available spatial/environmental data for each
of the Add Health respondents for Wave IV. Contextual geographic
data available to Add Health investigators will include a large array
of socioeconomic and demographic census block, tract, and county-level
characteristics based on matching earlier census data created for Add
Health in previous waves. For example, we will add community data
on race and ethnic composition, linguistic isolation, household income,
poverty status, educational attainment, unemployment, household tenure
and migration, household value, and a wealth of other contextual data.
We will also add quarterly time-varying price data for each area in the
US for food (at home, fast food), housing, cigarette, and other
cost-of-living elements from ACCRA (American Chamber of Commerce
Researchers
Association).
Biological Data
Given the size and geographic spread of our sample, and the
non-clinical setting of our interviews, we have chosen methods to
collect biological data that are noninvasive, innovative,
cost-efficient, and practical for population-level research. For
example, trained and certified interviewers will use finger prick to
obtain whole blood for automated analyses in the field and subsequent
assays of dried blood spots at a centrally located facility.
Anthropometric Measures. As in earlier waves, interviewers will
measure the weight and height of Wave IV participants who are dressed,
have removed their shoes and are standing on an uncarpeted floor (if
possible).
Cardiovascular Measures. Interviewers will measure the SBP, DBP
and pulse of Wave IV participants according to a standardized protocol.
Metabolic Measures. A Professional CardioChek PA will be used to obtain
the lipid panel from a blood spot placed on a PTS PANELS test
strip.
HPA Axis Measures. In Wave IV, Add Health participants will be
asked to self-collect three saliva samples (on awakening, thirty
minutes later, before bed) and complete a collection checklist the day
after their interview. Saliva samples will be assayed for
cortisol.
Genetic Measures. In collaboration with the Institute for
Behavioral Genetics (IBG) in Boulder, CO, Add Health will
collect, extract, quantify, and store DNA samples from all 17,000
respondents in Wave IV.
