Trial Information

Gulf Long-Term Follow-Up Study

The Gulf Long-term Follow-up Study (GuLF STUDY) will investigate potential short- and
long-term health effects associated with the clean-up activities following the Deepwater
Horizon disaster in the Gulf of Mexico on April 20, 2010. Crude oil, burning oil, and the
dispersants used during clean-up efforts contain a range of known and suspected toxins.
Over 100,000 persons have completed safety training in preparation for participation in
clean-up activities related to the spill. While many of these individuals participated in
active clean-up efforts, others did not. Exposures among persons involved in clean-up range
from negligible to potentially significant, especially for workers involved in tasks
associated with direct exposure to crude or burning oil, or to chemical dispersants.
However, prediction of adverse health effects is not possible because the long-term human
health consequences of oil spills are largely unknown due to the dearth of research in this
area. The potential health effects associated with the levels of exposure experienced by
clean-up workers are largely unstudied. Heat and stress experienced by these workers may
also have adverse long-term health effects. In addition to the oil itself, the widespread
economic and lifestyle disruption caused by the oil spill may contribute to mental health
problems among this population.

The over-arching hypotheses of this study are:

1. Exposure to constituents of oil, dispersants, and oil-dispersant mixtures, and to
spill-related stress by workers engaged in clean-up of the Deepwater Horizon oil spill
are associated with adverse health effects, particularly respiratory, neurological,
hematologic, and psychological or mental health.

2. There are exposure-response relationships between the above exposures and health
effects.

3. Biomarkers of potentially adverse biologic effects are associated with the above
exposures.

Based on what is known about individuals involved in clean-up efforts, the cohort will
consist primarily of English-, Spanish-, or Vietnamese-speaking adults who performed
oil-spill clean-up-related work ( exposed ) and similar persons who did not engage in
clean-up-related work ( unexposed controls). Accommodations for enrolling participants
speaking other languages will be developed through community collaborations as appropriate.
Workers will be sampled from across job/potential exposure groups. A total of approximately
55,000 persons are expected to be enrolled into the cohort. A random sample of the full
cohort, stratified by category of job/potential exposure (including N~6,000 with no
oil-spill work to serve as controls) and oversampled for workers with higher potential
exposures, will be enrolled into an Active Follow-up Sub-cohort (N~20,000). A random sample
of the Active Follow-up Sub-cohort, also stratified by category of job/potential exposure
and oversampled for workers with higher potential exposures, will be enrolled into a
Biomedical Surveillance Sub-cohort (N~5,000). Participants will be interviewed about their
clean-up-related tasks, demographic and socioeconomic factors, occupational and health
histories, psychosocial factors, and physical and mental health. Members of the Active
Follow-up Sub-cohort will also be asked to provide biological samples (blood, urine, hair,
toenail clippings, and possibly saliva) and environmental samples (house dust) and will have
basic clinical measurements (height, weight, waist and hip circumference, blood pressure,
urinary glucose levels, FEV1 and FVC as a measure of pulmonary function) taken during home
visits at baseline. The Biomedical Surveillance Sub-cohort will participate in a more
comprehensive clinical assessment after the initial home visit, including more comprehensive
pulmonary function testing, neurological testing, and collection of additional biological
and environmental samples. The specific tests to be performed and clinical protocols will
be developed in collaboration with extramural investigators selected through a request for
proposals (RFP). When developed, the protocol for this portion of the study will be
submitted separately to the Institutional Review Board as a study amendment.

Exposures will be estimated using detailed job-exposure matrices developed from data from
monitoring performed by different agencies and organizations during the crisis, as well as
information on recommended or actual use of personal protection, information obtained by
interview, and the available scientific literature. It should be noted that, in the absence
of individual or group monitoring data for most workers, estimates of exposure, whether
based on job activities or on more refined job-exposure matrices, will indicate the degree
of potential exposure (i.e., exposure opportunity) rather than known exposure. We will
investigate acute health effects via self-report from the enrollment interview among all
cohort members and also via clinical measures and biological samples from Active Follow-up
Sub-cohort members. All cohort members will be followed for development of a range of health
outcomes through record linkage (cancer, mortality) and if feasible, through linkage with
electronic medical records that may become available during the course of follow-up. Health
outcomes among the Active Follow-up Sub-cohort will also be identified through self-report
via periodic follow-up interviews. Additional outcome information will be obtained on the
Biomedical Surveillance Sub-cohort from periodic follow-up clinical evaluations (e.g.,
spirometry, neurological testing) and analysis of follow-up biospecimens (e.g., immunologic
parameters, liver function, renal function, DNA damage). Follow-up of the entire cohort is
initially planned for 10 years, with extended follow-up possible depending upon scientific
and public health needs and the availability of funds.

Recruitment of subjects should begin in March 2011, with the telephone interviews expected
to be completed within 12-24 months and the baseline home visits within 18-26 months. For
the home visits, we will initially target workers residing in the four most affected Gulf
States (LA, MS, AL, and FL), although we may expand to other states if further information
about the geographic distribution of workers and their potential exposures warrants
additional follow-up in these states. We will work closely with a Community Advisory Board
to develop community support for this study and appropriate communications and study
materials.