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BARRIERS TO CANCER CLINICAL TRIAL PARTICIPATION AMONG NATIVE ELDERS
Donna L. LaVallie, DO, MPH; Fredric M. Wolf, PhD;
Clemma Jacobsen, MS; Dedra Buchwald, MD
Objectives: American Indians/Alaska Natives
are underrepresented in clinical trials. There-
fore, they must participate in large-scale
cancer clinical trials to ensure the generaliz-
ability of trial results and improve their access
to high-quality treatment. Our goal was to
identify factors that influenced participation in
cancer clinical trials among American Indians/
Alaska Natives.
Methods: An anonymous survey that assessed
willingness to participate in a hypothetical
cancer clinical trial and how 37 factors
influenced their willingness to participate was
administered to 112 older American Indian/
Alaska Native adults at an annual social event
honoring elders. Responses ranged from one
(definitely would not participate) to five
(definitely would participate). Data were ana-
lyzed with ordinal logistic regression.
Results: Factors that most strongly increased
willingness to participate were having a lead
researcher of Native descent, having a study
physician with experience treating American
Indians/Alaska Natives, personal experience
with the cancer being studied, family support
for participation, and belief/hope that the
study would result in new treatments. Factors
that decreased willingness to participate most
strongly were living far from the study site and
a high risk that confidentiality could be
breached.
Conclusions: Our results identify conventional
and culturally unique barriers to research
participation among older American Indians/
Alaska Natives. These data emphasize the
need to establish partnerships with Native
communities and include American Indian/
Alaska Native and culturally competent pro-
fessionals in research efforts. Of equal impor-
tance are disseminating information about
clinical trials and recognizing the role of family
in decisionmaking in this group. (Ethn Dis.
2008;18:210–217)
Key Words: Clinical Trials, Patient Participa-
tion, Decision-Making, North American Indi-
ans
INTRODUCTION
Cancer is the second leading cause
of death in the United States. Persons
from under-served populations are more
likely than the overall US population to
be diagnosed with, and die from,
preventable and curable cancers, present
with late-stage cancers that are detect-
able through screening, and receive
suboptimal treatment and palliative
care.
1–5
The Institute of Medicine
3,4
and the Agency for Healthcare Research
and Quality
6
have underscored the need
to understand barriers and promoters of
research participation as a means to
reduce such health disparities. Large
disparities in mortality rates for all
cancers combined among American
Indians/Alaska Natives compared to
their all races counterparts suggest they
could benefit from participating in
clinical trials to ensure accrual of the
benefits from, and access to, more
advanced cancer treatment.
7
Many studies have substantiated that
minorities and the socially disadvan-
taged are underrepresented in cancer
clinical trials.
8,9
Randomized controlled
clinical trials have historically been
conducted in the majority culture, rarely
including American Indians/Alaska Na-
tives.
10
For example, a recent National
Cancer Institute-funded systematic re-
view on barriers and promoters of
accrual to therapeutic trials in under-
represented populations found that only
10% of studies reported subgroup data;
only 15 of .35,000 participants could
be identified as American Indian/Alaska
Native.
6
In an earlier publication,
potential American Indian study partic-
ipants knew little about cancer clinical
trials and had no opportunity to
participate.
11
Although they believed
participating could be beneficial, they
expressed concerns about ‘‘mistrust of
White people’’ and being treated like
‘‘guinea pigs.’’ This situation is contrary
to the 1993 mandate that requires
federally sponsored clinical trials to
include minorities in all human subjects
research.
12
Enrolling racial, ethnic, and cultural
minorities in clinical trials is crucial
because without adequate representa-
tion, the generalizability of study results
to all segments of the population is
questionable. Participation in trials also
provides access to state-of-the-art cancer
care, which itself may be a major
determinant of racial disparities in
cancer mortality.
2
The purpose of this
investigation was, therefore, to identify
factors that influence willingness to
participate in cancer clinical trials
among older American Indians/Alaska
Natives.
METHODS
Study Sample and Design
Potential participants for this study
were American Indian/Alaska Native
adults attending a dinner and social
event in Seattle, Washington. An anon-
ymous, written survey was offered to
attendees as they arrived and were seated
at tables before the meal was served.
Potential respondents were informed
the survey was about factors that
influence participation in clinical re-
search studies and asked to complete it
independently. Participants were en-
tered into a raffle to win gifts upon
completion of the survey. The study was
Address correspondence and reprint
requests to: Donna LaVallie; Medical Edu-
cation and Biomedical Informatics; Univer-
sity of Washington; Box 357240; Seattle,
WA 98195; 206-543-8475; 206-543-3830
(fax); dl2@u.washington.edu
From the Department of Medical Edu-
cation and Biomedical Informatics (DLL,
FMW), Center for Clinical and Epidemio-
logical Research (CJ, DB), Department of
Medicine (DB), University of Washington,
Seattle, Washington, USA.
210 Ethnicity & Disease, Volume 18, Spring 2008
approved by the University of Washing-
ton’s institutional review board.
Measures
The survey included a brief vignette
describing a hypothetical cancer study,
followed by the following question on
willingness to participate in the trial:
‘‘Given only what you know from the
story above, how likely would you be to
participate in the study?’’ We then
assessed how 37 additional factors, such
as institutional sponsorship, community
involvement, human subjects’ issues,
and convenience, might influence re-
spondents’ willingness to participate in
the hypothetical cancer clinical trial. For
both the vignette and each factor,
respondents rated their willingness to
participate on a Likert scale with these
possible answers: 15I definitely would
not participate, 25I probably would not
participate, 35I’m not sure, 45I prob-
ably would participate, and 55I defi-
nitely would participate. The vignette
and factors were based on materials used
in a previous study;
13,14
the original
vignette and factors were reviewed by
American Indian/Alaska Native faculty
and focus groups for cultural relevance
and comprehensibility.
The outcome for this analysis was
willingness to participate in the cancer
trial, scored from one to five, as described
above. For each survey respondent we
created an indicator variable with 38
categories. The first category correspond-
ed to the original vignette, and categories
2–38 represented the potentially influ-
ential factors. Covariate measures were
age (40–54 years, 55–64 years, $65
years), education (did not graduate from
high school, high school graduate, some
college, college graduate or beyond),
current residence (urban, non-reserva-
tion rural, reservation), marital status
(married, never married, divorced/wid-
owed/separated), and yes/no indicators
of female sex, 50% of life lived on or near
a reservation, previous participation in
research, and having a home telephone.
The latter question was included because
up to a third of American Indian/Alaska
Native homes do not have telephones.
15
Statistical Analysis
Respondents who did not rate
willingness to participate in the vignette
were excluded from the analysis. Be-
cause of sample size limitations, we did
not require complete data for all
covariates. We calculated descriptive
statistics by using percentages for each
categorical variable and included the
total number of valid observations for
each measure. We also calculated the
percentage of respondents that endorsed
each of the five participation categories
for each scenario in the survey. We used
ordinal logistic regression to evaluate
the association of each factor with
willingness to participate. The dataset
was structured so that each respondent
had 38 outcomes, 1 for the vignette and
37 for the additional factors. We used
the robust variance estimator to account
for within-person correlation of the 38
outcomes. This model structure allowed
respondents to have missing data for
some factors, with the missing values
assumed to be missing completely at
random.
16
Results for each factor are
given as odds ratios (ORs) with 95%
confidence intervals (CIs). ORs .1.0
indicate a greater willingness to partic-
ipate in the trial when the factor was
considered compared to the vignette
alone. We ran models adjusting for
covariates, but because of sample size
limitations and the large number of
factors, we included these variables in
the final model only if they confounded
Table 1. Demographic characteristics of 112 Native American/Alaska Native elders
surveyed about clinical trial participation
Variable Number missing % (of valid observations)
Age 4 (108 valid)
40–54 years 16%
55–64 years 33%
65–84 years 51%
Sex 1 (111 valid)
Female 71%
Male 29%
Education 6 (106 valid)
Did not graduate from high school 27%
High school graduate 21%
Some college 35%
College graduate or beyond 17%
% of life lived on or near a reservation 12 (100 valid)
#49% 63%
50%–100% 37%
Current residence 4 (108 valid)
Urban 56%
Rural, non-reservation 16%
Reservation 29%
Marital status 3 (109 valid)
Married 29%
Divorced/widowed/separated 54%
Never married 17%
Previous participation in research 4 (108 valid)
Yes 19%
No 81%
Telephone in home 10 (102 valid)
Yes 85%
No 15%
CLINICAL TRIALS AND AMERICAN INDIANS,ALASKA NATIVES - LaVallie et al
Ethnicity & Disease, Volume 18, Spring 2008 211
Table 2. Frequency distribution of willingness to participate in a hypothetical cancer trial among American Indian/Alaska
Native elders
Factor
Willingness to participate
Definitely
would not %
Probably
would not %
Not
sure %
Probably
would %
Definitely
would %
Vignette alone 8 18 24 30 20
Factors that did not influence participation:
You knew that members of your community were involved
in developing and conducting the study
613223920
Your local healthcare provider referred you to the study 6 10 21 48 15
The study was conducted by an organization like the American
Cancer Society or the Lance Armstrong Foundation
513215011
You were reimbursed for the costs of traveling to the study visits 7 14 24 39 16
Your treatment would be more closely monitored with the
experimental cancer drug than with the approved drug
813253518
Free child care was provided during the study visits 10 17 16 45 12
The study was conducted by your state university 7 15 27 39 12
You felt sure that the experimental cancer drug was at least as
likely as the approved drug to help you
914283415
Factors that decreased participation:
The study was conducted at a healthcare facility located
20 miles away from your home community
91829367
A doctor you did not know referred you to the study 13 20 31 27 9
Your doctors felt the approved cancer drug would not help you
very much
14 23 22 32 8
You think you would be assigned by chance to the experimental
cancer drug
16 19 28 30 7
Nausea or pain were common side effects of the drugs used in
the study
16 20 34 22 8
The study was conducted by the federal government 15 19 38 23 5
You thought that confidentiality might be broken, and your
personal experiences, thoughts, feelings, opinions or health
problems became known to other people
28 20 23 23 6
The study was conducted at a healthcare facility located
50 miles away from your home community
19 32 24 23 2
Factors that increased participation:
You, a family member, or friend had the type of cancer being
studied
3 9 13 38 37
Your doctor in the study had experience treating Americans
Indians and Alaska Natives
4 6 16 39 35
What was being studied was lung cancer and you, a family
member, or friend had this type of cancer
113143934
You thought that the study would lead to new treatments for the
cancer
3 9 13 45 31
The researcher was American Indian or Alaska Native 6 6 19 34 35
What was being studied was cancer of the colon or rectum and
you, a family member, or friend had this type of cancer
212154032
You were paid for your participation 5 5 21 37 32
Your doctor in the study was an expert in the type of cancer you
have
6 5 15 45 29
What was being studied was breast cancer and you, a family
member, or friend had this type of cancer
511153832
The study was conducted in a health care facility with a cancer
unit designed especially for Native people
6 8 16 39 31
You thought that the study would help other people with cancer
in your community
310154725
What was being studied was cervical cancer and you, a family
member, or friend had this type of cancer
411173929
You felt sure that all the study procedures were clearly
explained
7 5 18 42 27
It was easy for you to get information about the study 4 11 16 43 26
CLINICAL TRIALS AND AMERICAN INDIANS,ALASKA NATIVES - LaVallie et al
212 Ethnicity & Disease, Volume 18, Spring 2008
the primary association. We considered
an a level of .05 as the threshold for
statistical significance. All analyses were
conducted with Stata version 9.0 (Sta-
taCorp LP, College Station, Texas).
RESULTS
We handed out 148 surveys, of
which 136 (92%) were returned to us.
Of these 136 completed surveys, 1 was
excluded because of a missing response
for the original vignette, and 23 were
excluded because the respondent did
not self-identify as being of American
Indian or Alaska Native heritage. This
left 112 observations available for
analysis. Age ranged from 40 to 84
years, and half the respondents were
$65 years (Table 1). Most respondents
were female, had graduated from high
school, and a minority reported living at
least half of their lives on or near a
reservation. Nineteen percent reported
previous participation in clinical re-
search. In response to the original
vignette question, 20% responded ‘‘I
definitely would participate,’’ 30% re-
sponded ‘‘I probably would partici-
pate,’’ 24% responded ‘‘I’m not sure,’’
18% responded ‘‘I probably would not
participate,’’ and 8% responded ‘‘I
definitely would not participate’’ (Ta-
ble 2).
Figures 1–3 show results from the
ordinal logistic regression analysis.
None of the covariates confounded the
primary association, and the results
reflect the unadjusted analysis. Confi-
dence intervals that span the vertical line
at 1.0 are not statistically significant.
Figure 1 presents ORs for factors that
did not significantly influence partici-
pation, including community involve-
ment in the trial (OR 1.4, 95% CI .9–
1.9), and the level of monitoring during
treatment (OR 1.1, 95% CI .8–1.6). As
shown in Figure 2, the factors that most
significantly lowered the odds of partic-
ipation were longer travel distance to
the study site (OR .3, 95% CI .3–.5)
and the threat that confidentiality
would be breached (OR .3, 95% CI
.2–.5). Figure 3 illustrates the odds
significantly associated with increasing
participation in the clinical trial. Among
those with the highest odds were
personal experience with cancer (OR
2.9, CI 2.0–4.5), having a study
physician with experience treating
American Indians/Alaska Natives (OR
2.9, 95% CI 2.0–4.1), belief/hope that
the study would lead to better treat-
ments (OR 2.6, 95% CI 1.9–3.7), and
American Indian or Alaska Native
researcher (OR 2.5, 95% CI 1.7–3.7).
Family support for participation also
significantly increased odds of partici-
pation (OR 1.5, 95% CI 1.1–2.0).
DISCUSSION
Recruitment of American Indians/
Alaska Natives for clinical trials is
affected by a complex mixture of
cultural, heathcare system, and societal
barriers including patient-provider
communication patterns, illness beliefs,
and family organization and influence
in decisionmaking.
10
We found the
strongest predictors for increased trial
participation were involving a study
physician experienced in working with
American Indians/Alaska Natives, hav-
ing personal experience with the type of
cancer being studied, and believing the
new treatment would be beneficial.
Factors most strongly predicting de-
creased participation were the distance
to the study site and concern about
confidentiality being compromised.
Comparing our results to other studies
on barriers to participation in cancer
clinical trials is difficult as virtually none
reported data for American Indians/
Alaska Natives. Even so, themes emerg-
ing from the literature on the barriers
most frequently experienced by minor-
ities include the time required to
participate, mistrust of the medical
establishment, unknown effects of med-
ications or placebos, lack of information
about clinical research, and the need for
culturally relevant education on clinical
trials.
17–20
Factor
Willingness to participate
Definitely
would not %
Probably
would not %
Not
sure %
Probably
would %
Definitely
would %
You knew that you would receive feedback about the study
results
410213828
Free transportation was provided to the study visits 6 6 19 45 23
You felt sure that all the risks, benefits, and side effects were
carefully explained
6 7 19 43 24
You felt your chance for cure was higher with the experimental
cancer drug
7 7 23 44 19
The study was conducted at a health care facility in your home
community
611165016
You were given written information about the study to take
home
410254120
Your family was in favor of your participation in the study 6 7 23 49 16
Table 2. Continued
CLINICAL TRIALS AND AMERICAN INDIANS,ALASKA NATIVES - LaVallie et al
Ethnicity & Disease, Volume 18, Spring 2008 213
The importance of building com-
munity trust was demonstrated in our
study by the positive influence of having
Native researchers, study physicians
with experience treating American In-
dians/Alaska Natives, and being referred
to a clinical trial by local providers.
Many studies have cited mistrust of the
healthcare system and research estab-
lishment as barriers to participation in
cancer clinical trials,
10,19–24
but we
found only two that specifically dis-
cussed American Indians/Alaska Natives
as a subgroup of participants.
11,20
In
one study of 19 African American and 7
American Indian focus group members,
mistrust of the medical establishment
and a lack of understanding and
knowledge about clinical research were
noted as barriers to participation in
cancer clinical trials.
20
In another re-
port, potential American Indian study
participants knew little about cancer
clinical trials and were suspicious of the
majority culture and experimental treat-
ments.
11
The negative influence of a
federal government-conducted study
was demonstrated in our results. Mul-
tiple sociocultural barriers underlie the
scant representation of American Indi-
ans and Alaska Natives in clinical
trials;
10
however, mistrust, specifically
of the federal government, may be
Fig 2. Factors that decreased participation in cancer clinical trials. ¤=Odds Ratio with 95% confidence interval
Fig 1. Factors that did not influence participation in cancer clinical trials. ¤=odds ratio with 95% confidence interval
CLINICAL TRIALS AND AMERICAN INDIANS,ALASKA NATIVES - LaVallie et al
214 Ethnicity & Disease, Volume 18, Spring 2008
promulgated by the significant health
disparities that persist, .50 years after
the Indian Health Service was estab-
lished. American Indian and Alaska
Native health status improved after the
establishment of this service; however,
the government has failed to adequately
fund this system
25
—inaction conceptu-
ally analogous to the unfulfilled, signed
treaties that date back to the 1800s.
Similarly, suspicion of medical re-
search and lack of information about
cancer clinical trials were the most
frequent reasons given by community-
based physicians and oncologists for the
underrepresentation of minorities in
cancer clinical trials.
17,19
The compre-
hensive Agency for Healthcare Research
and Quality evidence-based review also
found mistrust of researchers and re-
search institutions were obstacles to
cancer therapeutic and prevention trial
participation among many minority
groups; in contrast, culturally relevant
education promoted participation.
6
The
literature search for this review yielded
virtually no information on American
Indian/Alaska Native populations, pre-
cluding salient conclusions or recom-
mendations.
In addition, we substantiated that
feedback regarding study results was key.
Others have pointed out the vital
importance of sharing study results with
Native communities and the negative
effect of lack of community interaction
concerning study planning and conduct,
especially in regard to value and potential
benefits of the study for the communi-
ty.
10
Our study also examined the
salience of personal experiences with
cancer. In contrast to other studies,
20,26
we observed these survey questions were
among the strongest predictors, at least
doubling the likelihood of trial partici-
pation. In an earlier study of Canadian
cancer patients seen at a regional center,
family and friends did not influence the
Fig 3. Factors that increased participation in cancer clinical trials. ¤=Odds Ratio with 95% confidence interval
CLINICAL TRIALS AND AMERICAN INDIANS,ALASKA NATIVES - LaVallie et al
Ethnicity & Disease, Volume 18, Spring 2008 215
decision to enter into a randomized
clinical trial.
26
Likewise, a qualitative
study on minorities in cancer clinical
trials did not find personal experience
predicted trial participation.
20
Converse-
ly, experience with a problem, either
personally or through a close relative or
friend, was more likely to be cited as a
reason for participating in a pertinent
treatment clinical trial among cancer-free
African American women interested in
joining a clinical trial, as opposed to
those not interested in joining a trial.
26,27
The strength of our findings may speak
to the critical role of family in recruiting
American Indians/Alaska Natives, and
their ultimate decision to be involved in
clinical trials.
10
Surprisingly, items relating to ran-
domization inconsistently influenced
decisions to participate. For example,
the likelihood of participation was
lowered when individuals were in-
formedtheywouldbeassignedby
chance to the experimental cancer drug.
In contrast, information that the exper-
imental cancer drug was as least as likely
to help as the approved drug had no
effect on participation. Many studies
have documented patient concerns
about randomization and entering a
randomized clinical trial.
28–30
Although
previous work has not examined ran-
domization in the context of clinical
trials among under-served or minority
populations, our findings may be ex-
plained by respondents’ incomplete
understanding of the ramifications of
being randomized in a clinical trial.
We documented the importance of
access, since a long distance to the
research study site was a strongly
negative influence on the likelihood of
participation. This theme is consistent
with previous investigations conducted
in minority populations.
6,20
According
to the 2000 census, an estimated 34%
of American Indians/Alaska Natives
resided on Indian reservations, trust
lands, or other tribal areas,
31
and
transportation difficulties are commonly
experienced by American Indians/
Alaska Natives in both rural and urban
settings.
32
Several limitations to our study
should be noted. First, our analyses are
based on 112 respondents who are not
representative of all American Indians/
Alaska Natives. Thus, our findings
cannot be generalized to other settings,
rural populations, or individual tribes
and cannot address intertribal variation
in cancer prevalence. Even so, our sample
consisted largely of older adults, who are
at highest risk for the more prevalent
cancers. Second, although vignette-based
research is an established form of
qualitative research,
33,34
it has not been
widely used in quantitative research. Our
use of vignettes may not have adequately
captured all relevant constructs, especial-
ly because our survey was brief enough to
be completed during a social event. A
related issue is that some participants
may have been unfamiliar with research
studies, and therefore might not have
fully understood the questions. Third,
we conducted hypothesis tests on a large
number of alternative scenarios, increas-
ing the likelihood of a type I error in our
conclusions. Most of the scenarios that
were significantly associated with partic-
ipation, however, were highly significant,
with P values ,.001, and we are
confident that the risk of type I error
for these factors is low. Finally, the
hypothetical vignette and subsequent
questions may not accurately reflect
decisions that individuals make when
presented with opportunities to partici-
pate in actual studies. In this regard, the
actual response rate for this study, which
was .90%, was far higher than that for
the study vignette on which we queried
people regarding research participation,
suggesting American Indians/Alaska Na-
tives are quite willing to engage in
minimally demanding forms of research,
if not clinical trials. Despite these
limitations, our report is the first to
describe and quantify barriers and pro-
moters of involvement with clinical
cancer trials among the most underrep-
resented minority in research.
In conclusion, these data emphasize
the importance of establishing partner-
ships and building trust with American
Indian/Alaska Native communities, in-
creasing efforts to disseminate informa-
tion about cancer clinical trials, main-
taining confidentiality, including family
in decisionmaking, and addressing geo-
graphic concerns. Future research should
explore in more detail American Indian/
Alaska Native peoples’ understanding of
cancer clinical trials, test interventions to
enhance understanding, and assess meth-
ods of disseminating cancer clinical trials
information. Lastly, the strong prefer-
ence our participants voiced for Ameri-
can Indian/Alaska Native researchers and
culturally competent physicians illus-
trates the need to increase diversity and
cultural awareness among professionals
in cancer care and research.
A
CKNOWLEDGMENTS
This study was supported by Native People
for Cancer Control, a Community Networks
Program funded by the National Cancer
Institute (1U01 CA114642-01). We would
like to thank Carolyn Noonan for her
contribution to manuscript revision.
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AUTHOR CONTRIBUTIONS
Design concept of study: LaVallie, Wolf,
Buchwald
Acquisition of data: LaVallie, Jacobsen
Data analysis and interpretation: LaVallie,
Wolf, Jacobsen, Buchwald
Manuscript draft: LaVallie, Wolf, Jacobsen,
Buchwald
Statistical expertise: Wolf, Jacobsen
Acquisition of funding: Buchwald
Administrative, technical, or material assis-
tance: LaVallie, Jacobsen
Supervision: LaVallie, Wolf, Buchwald
CLINICAL TRIALS AND AMERICAN INDIANS,ALASKA NATIVES - LaVallie et al
Ethnicity & Disease, Volume 18, Spring 2008 217
