Advances in Anthropology
2013. Vol.3, No.2, 112-120
Published Online May 2013 in SciRes (
Copyright © 2013 SciRes.
Integrating Biomarkers into Research with Latino Immigrants
in the United States
Heather H. McClure1,2, J. Josh Snodgrass2, Charles R. Martinez Jr.1, J. Mark Eddy3,
Thomas W. McDade4, Melanie J. Hyers5, Anne Johnstone-Díaz6
1Center for Equity Promotion, College of Education, University of Oregon, Eugene, USA
2Department of Anthropology, University of Oregon, Eugene, USA
3School of Social Work, University of Washington, Seattle, USA
4Department of Anthropology and Institute for Policy Research, Northwestern University,
Evanston, USA
5Department of Romance Languages, University of Oregon, Eugene, USA
6Family Resource Center, Bethel School District, Eugene, USA
Received February 5th, 2013; revised March 5th, 2013; accepted March 15th, 2013
Copyright © 2013 Heather H. McClure et al. This is an open access article distributed under the Creative Com-
mons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, pro-
vided the original work is properly cited.
Despite extensive research into the toll of persistent psychosocial stress on individual physiology and
health, little is known about the effects of chronic biosocial stress for immigrant populations. In the pre-
sent paper, the authors review challenges encountered when integrating minimally-invasive stress-related
biomarkers (e.g., blood pressure, Epstein-Barr Virus [EBV] antibodies, C-reactive protein [CRP], and
salivary cortisol), as well as anthropometric (e.g., height, weight, waist circumference) and metabolic
measures (e.g., glucose, cholesterol), into research with Latino immigrant adults and families in Oregon,
USA. Finally, the authors present lessons learned and discuss strategies to support the full engagement of
Latino immigrants as participants in studies that rely on the collection of biological data as a central
component of research into psychosocial stress and its effects.
Keywords: Biomarker; Latino; Immigrant; Psychosocial Stress
Despite the size of the Latino population in the United States
(16.7% of the US population [US Census Bureau, 2011]), the
role of stress as a contributor to poor mental and physical health
outcomes among Latinos is little known. This is especially true
for the approximately 40% of Latinos in the United States who
are foreign born (Lopez & Taylor, 2010), and the over 50% of
Latino families in which children are US born of immigrant
parents (The Urban Institute, 2010).
Many immigrant families, particularly if recently arrived to
the US, experience stressors (i.e., exposure to circumstances)
that can contribute to profound psychosocial stress (i.e., the
extent to which an individual is challenged to maintain function
[McEwen, 2000]). Common stressors for immigrant families
include low socioeconomic status (SES), challenges of adapting
to life in the U.S. (acculturation), employment uncertainty, dis-
crimination, and concerns about legal status, among others
(Rumbaut & Portes, 2001; Vega & Kolody, 1985; Vega et al.,
2004). In states with unprecedented recent population growth of
immigrants, such as Oregon and North Carolina, there may be
few formal buffers (e.g., well-established ethnic enclaves, cul-
turally-competent services) against such stressors (Capps et al.,
2002; Smokowski & Bacallao, 2007). Though extensive re-
search has been conducted on the toll of persistent psychosocial
stress on individual physiology and health (e.g., Kiecolt-Glaser
et al., 1994; McDade et al., 2007), little is known about the
effects of chronic biosocial stress for Latino immigrants.
Research with US born populations suggests that chronic
psychosocial stress is a key link between challenging social
contexts and negative health outcomes (Dressler et al., 2005;
William et al., 2003). The measurement of stress among immi-
grant populations, however, may present unique challenges. As
the notion of “stress” is deeply culturally-bound, dominant no-
tions regarding “stress” in the US may be distinct from and
even unrecognizable to immigrants, especially if they are re-
cently arrived. Attempts to measure self-reported Latino immi-
grant stress and its effects using standardized instruments,
which are often validated through studies with second and third
generation Latinos in the US, may fail to resonate with immi-
grant respondents. More sensitive and objective measures of
stress are needed for a clearer understanding of links between
contexts favoring stress and health outcomes among Latino
immigrants (Martinez, 2006).
To begin to fill these knowledge gaps, in 2007, the Latino
Research Team (LRT) at the Oregon Social Learning Center
(OSLC) initiated two pilot research projects to determine the
feasibility of collecting biological data among Latino immi-
grants, and to better “map” the pathways through which psycho-
social stressors related to acculturation, discrimination, and
SES, among others, influence self-report and biological meas-
ures of immigrant stress. Both projects utilized minimally-
invasive techniques (i.e., saliva collection and pricking a par-
ticipant’s finger with a lancet for the collection of a few drops
of blood on filter paper cards). Our use of multiple, complemen-
tary biological markers of stress is novel, as most investigations
into stress and health have relied upon measures of self-re-
ported stress, rather than upon physiological measures such as
stress biomarkers (McDade et al., 2007); this is particularly true
for studies involving immigrant populations.
In the present paper, we review challenges encountered when
integrating stress-related biomarkers (e.g., blood pressure, Ep-
stein-Barr Virus [EBV] antibodies, C-reactive protein [CRP],
and cortisol), as well as anthropometric (e.g., height, weight,
waist circumference) and metabolic measures (e.g., glucose, cho-
lesterol), into research with Latino immigrant adults and fami-
lies in Oregon. Finally, we present lessons learned and discuss
strategies to support the full engagement of Latino immigrants
in studies that rely on the collection of biological data as a com-
ponent of research into psychosocial stress and its effects.
Overview of Pilot Studies
Despite the apparent value of incorporating stress biomarkers
into research with Latino immigrants in the US, few previous
studies had done so and many questions regarding feasibility
remain (Ryan et al., 2006; Steffen et al., 2006). To examine
questions relating to participants’ comfort with biomarker me-
thods, in 2007, we began a two-phase Latino stress and health
study (a.k.a. “The Farmworker Study” or TFS) in collaboration
with a highly respected farmworker housing and social service
organization, and with biological anthropologists at the Univer-
sity of Oregon and Northwestern University. This cross-sec-
tional study took place in three geographically distant housing
complexes in Oregon’s northern Willamette Valley; analyses
involved 132 Latino immigrant adults (18 years of age; 86
females, 46 males; 96% Mexican origin; 96% were parents).
Approximately 38% of men and 33% of women had a third
grade education or less, with 11% of men and 19% of women
completing high school or receiving post-secondary education.
Ninety-three percent of men and 46% of women were em-
ployed. Heads of household reported an annual median house-
hold income of $15,825 to support an average household of five
people (SD = 1.5).
This project was followed by the 2009-2010 Stress and Ac-
culturation Project (SAP), which focused on links among stress,
health, and parenting in 44 Latina immigrant mothers and their
young children in the 1st to 3rd grades (93% Mexican origin),
and collaboration with the University of Oregon. About a third
of mothers (32%) had a third grade education or less, and 23%
completed high school or received post-secondary education.
Forty-three percent of mothers worked outside the home. Mo-
thers reported an annual median household income of $18,750
to support an average household of five people (SD = 1.5).
Recruitment for Studies
Study samples were drawn from non-probability designs and
recruitment was conducted through trusted social networks, and
by recruiters who share characteristics of the target study popu-
lation (Martinez et al., 2012; Villarruel et al., 2006). TFS took
place during the busiest time of year for agricultural workers.
Despite this, recruitment was completed quickly with staff of
our partner organization recruiting all participants within 10 days.
In the SAP pilot, 24 families in the Eugene/Springfield area
were recruited in one week. Our participation rate for both pilot
studies was 98%.
The Farmworker Study
On a single day, residents participated in a health assessment
and responded to a 20 minute interview. Senior staff from the
LRT and the farmworker organization collaborated on the de-
sign of the interview. Due to its brevity, specific questions were
drawn from a larger assessment battery that had been exten-
sively developed by the LRT for use with the Latino population
in Oregon (see Martinez & Eddy, 2005; Martinez et al., 2009).
A focus group composed of Latino immigrant farmworkers
reviewed the questionnaire, and changes were made per focus
group findings. The SAP interview was modeled after that for
TFS, with items added relating to depression and parenting.
The Institutional Review Boards at OSLC and the University of
Oregon approved all research protocols and all participants
provided written consent prior to the assessment. All respon-
dents were assessed in Spanish.
Assessors for TFS included LRT professional interviewers,
staff from our partner organization, volunteer undergraduate
students, and community members. All assessors received four
hours of intensive training in how to conduct the interview and
collect biological and health data, and between four and eight
hours of on-site supervision. Assessments were scheduled for
Saturday and Sunday mornings (residents were given a choice
of days), and childcare was provided.
Assessments for the first study were conducted in the com-
munity center in each housing complex. The health exam in-
volved measures of blood pressure, height, weight, and waist
circumference (WC). Staff used a lancet to prick the partici-
pant’s finger to collect a drop of blood for the immediate meas-
urement of fasting glucose and total cholesterol (all participants
had fasted [>8 hours]), and two drops of blood to dry onto filter
paper for later laboratory analyses of EBV antibodies and CRP.
Assessors then conducted the interview and provided a one-on-
one saliva collection demonstration (see cortisol measurement
section below for detail). Finally, each participant met with a
health educator to review their health values. Participants with
measures indicating need for follow-up were referred to part-
nering public health agencies. During the following week, staff
made reminder calls to participants the evening before and the
day of each saliva collection. A week after the health assess-
ment, a staff member collected participants’ saliva samples and
transported them to the laboratory for later analysis. Partici-
pants received $30 in compensation. Findings from this study
have been reported elsewhere (McClure et al., 2010a, 2010b,
2010c, 2012; Midttveit et al., 2010; Squires et al., 2012).
The Stress & Acculturation Project
The SAP study incorporated similar indicators and involved
only LRT assessors. This study was conducted in the homes of
participating families and involved two visits approximately
one week apart. At the first home visit, data were collected on
mother and children’s height, weight, WC, and blood pressure.
Staff also conducted a 30 - 40 minute interview with mothers
and provided training in the collection of saliva samples.
Though we measured blood pressure for both mothers and chil-
dren, our focus was on mothers’ blood pressure; we measured
children’s blood pressure as part of the health information
Copyright © 2013 SciRes. 113
provided to families as an incentive for participation. Mothers
received $15 at the completion of the first home visit, and chil-
dren were given a toy of their choice.
The second home visit occurred upon completion of saliva
collection. A few drops of blood generated through finger stick
were analyzed for separate measures for mother and child.
Mothers’ fingers were pricked first and analyzed for fasting
glucose and lipid levels (i.e., total cholesterol, HDL cholesterol,
triglycerides, and calculated LDL cholesterol; equipment in-
formation below). The assessor then pricked the child’s finger
to test for hemoglobin levels (a test for anemia; equipment in-
formation below). Mothers were given a copy of their own and
their child’s health values, health information in Spanish, and a
list of local clinics for follow-up if indicated. An exit interview
(5 minutes) was administered to the mother regarding her and
her child’s experience in the project. Assessors also picked up
saliva samples and delivered them to a lab for later analysis.
For compensation, mothers received $15 and children chose a
Measurement of Psychosocial Stress
Our investigation of physiological measures of psychosocial
stress is informed by a large body of research dating back to
Selye (1956), and integrates complementary biomarkers to bet-
ter understand how stress gets “under the skin” to affect health
(McDade, 2007). The following briefly reviews the specific
biomarkers and health measures used in TFS and SAP and
measurement techniques.
The hypothalamic-pituitary-adrenal (HPA) axis has been
recognized for its important role in the stress response and, in
particular, its role in energy mobilization (Sapolsky et al., 2000).
Cortisol, the primary glucocorticoid hormone in humans and a
marker of HPA activity, has a strong diurnal rhythm with high-
est levels typically occurring in the early morning hours and
lowest levels in the late evening (Kirschbaum & Hellhammer,
2000). Over time, everyday negatively perceived experiences
can contribute to atypical cortisol fluctuation with either high or
blunted cortisol levels in the morning, and flatter diurnal curves
over the day. Although increased cortisol release in response to
acute stressors can be adaptive, the prolonged activation of the
HPA axis can lead to HPA dysregulation with downstream
effects including the progression of various diseases, such as
obesity, type 2 diabetes, and cardiovascular disease (McEwen
& Wingfield, 2003). Studies indicate that Latinos have signifi-
cantly flatter diurnal cortisol slopes than Caucasians due per-
haps to greater stress exposure, including perceived discrimina-
tion (DeSantis et al., 2007).
Measurement. In TFS, cortisol was measured from six saliva
samples: each participant collected three samples each day for
two consecutive days. The SAP study involved nine samples per
participant with mothers collecting their own and their child’s
saliva three times a day for three consecutive days. Adult par-
ticipants collected 1.0 mL of saliva in Eppendorf tubes from
themselves (and from any participating child) upon awakening,
within 30 minutes of awakening, and a half-hour before bed-
time. In addition, adult participants were asked to record the
date and time of the collection of each sample. In SAP, mothers
were asked to maintain a saliva diary for themselves and their
child that recorded the exact time and date of sample collection,
substances used in the prior 24 hours that might interfere with
cortisol assay (e.g., medications, tobacco, and alcohol), and
major events during the day. Participants were instructed not to
eat, smoke, brush their teeth, drink alcoholic or caffeinated
beverages, or engage in intense physical activity in the 30 min-
utes prior to each sample due to possible changes in salivary
cortisol concentrations (Pollard & Ice, 2007). To ensure the
stability of salivary cortisol (Kirschbaum & Hellhammer, 2000),
participants were instructed to refrigerate all saliva samples
until a staff member collected them during a follow-up visit and
transported them in an ice chest to the Snodgrass laboratory.
Once in the lab, all samples were stored frozen at 30˚C in a
secure location until analysis. All cortisol samples were ana-
lyzed using enzyme immunoassay with a commercially avail-
able salivary cortisol assay kit (Salimetrics, State College, PA).
Epstein-Barr Virus Antibodies
Over the past two decades, EBV antibody levels have been
applied as a useful biomarker of chronic psychosocial stress
(McDade, 2007). EBV is a ubiquitous herpes virus for which
80 to 90 percent of adults and adolescents in the US test posi-
tive by the age of 40 (Jones & Straus, 1987), though little is
known about EBV prevalence among children. Once infected,
individuals harbor the virus for life in infected cells. Adequate
cell-mediated immune function maintains the virus in a latent
state and most adults infected with EBV are clinically asymp-
tomatic (Henle & Henle, 1982). Stress-induced immunosuppres-
sion, however, allows EBV to reactivate, which may trigger an
antibody response (Glaser et al., 1991). Thus, EBV antibodies
provide a measure of cell-mediated immune function over the
duration of several days or weeks (McDade, 2007). Researchers
have found elevations in EBV antibody levels among adults in
poor quality marriages (Kiecolt-Glaser et al., 1994), children
experiencing family stress (McDade et al., 2000), and Latino
men who report discrimination stress (McClure et al., 2010a,
2010b). Because of EBV’s utility as a marker of chronic psy-
chosocial stress, it has been incorporated into the National
Longitudinal Study of Adolescent Health (Add Health) and the
World Health Organization’s Study on Global Ageing and
Adult Health (SAGE).
Measurement. EBV was measured through the collection of
dried blood spot samples. Following standard procedures
(McDade et al., 2000), each participant had their finger pricked
with a sterile disposable lancet; 2 - 5 drops (approximately 50
µL) of whole blood were then collected on standardized filter
paper (No. 903; Whatman). Blood spot samples were then dried
overnight, and stored at 80˚C until laboratory analysis. Blood
spot EBV antibodies were measured using DiaSorin (Stillwater,
MN) EBV VCA IgG kits according to a high-sensitivity en-
zyme-linked immunosorbent assay (ELISA) protocol described
elsewhere (McDade et al., 2000). In our studies, all participants
were seropositive for EBV antibodies. Protocols in English and
Spanish are available online
C-Reactive Protein
CRP is a nonspecific acute phase reactant that rapidly in-
creases in plasma concentration in response to inflammation,
infection, and injury (Pepys & Hirschfeld, 2003). Studies have
Copyright © 2013 SciRes.
linked minor CRP elevations, previously considered clinically
normal, with increased cardiovascular risk (Ridker et al., 1998).
Elevated levels of CRP are linked to factors such as obesity
(Rexrode et al., 2003), and with several dimensions of psycho-
social stress, including lack of social integration (Ford et al.,
2006) and low SES (Nazmi & Victora, 2007). Few studies in-
volving CRP have been conducted with Latino populations
(Midttveit et al., 2010).
Measurement. CRP was measured through the collection of
dried blood spot samples following the same procedure descry-
bed above for EBV. CRP samples were used for two purposes.
First, CRP was used to identify acute infection or tissue injury,
which could potentially impact EBV antibody levels. Second,
subclinical CRP concentrations were used as indicators of chro-
nic inflammation, and for the examination of whether low-
level elevations CRP concentrations related to psychosocial
stressors. CRP was analyzed using a high-sensitivity enzyme
immunoassay protocol (McDade et al., 2004) that uses Bio-
Design International (Saco, ME) capture and detection anti-
Blood Pressure
It is well-established that blood pressure is associated with
diet and physical activity, among other lifestyle factors. In ad-
dition, psychosocial stress related to perceived discrimination
and low SES have been shown to correlate with elevated sys-
tolic blood pressure (SBP) and diastolic blood pressure (DBP;
Dressler et al., 2005). The few studies among Latino adults in
the US reveal important gender differences (Steffen et al.,
2006), with higher discrimination stress relating to higher SBP
among men only (McClure et al., 2010a).
Measurement. For the first pilot study, blood pressure (SBP
and DBP) was measured using an Omron HEM-422CRLC
manual inflation oscillometric blood pressure monitor (Vernon
Hills, IL); for each individual, blood pressure was measured
twice, separated by at least 10 minutes. In a few cases involving
obese participants, blood pressure was measured with a manual
sphygmomanometer by a registered nurse. In the second pilot
study, blood pressure was measured using an Omron HEM-
907XL professional oscillometric instrument (Bannockburn, IL).
In both studies, blood pressure was measured by a trained as-
sessor using standard procedures (Chobanian et al., 2003).
Anthropometric and Metabolic Values
Chronic stressors such as job strain, divorce, and perceived
discrimination have been associated with greater levels of fast-
ing glucose, lipids, and insulin (Vitaliano et al., 2002). Findings
from the British Whitehall studies indicate that the degree to
which individuals were treated unfairly independently predicted
larger waist circumference, higher hypertension, triglycerides,
and fasting glucose, and lower serum HDL cholesterol, even
after controlling for SES, behavioral risk factors, and other
psychosocial factors (DeVogli et al., 2007). Extensive evidence
also illustrates links between chronic stress and depression,
which can lead to increased caloric intake, elevated BMI, and
associated metabolic and coronary risks (Dallman et al., 2003).
Chronic stress can trigger a complex cascade of behavioral
and physiological changes that contribute to the development of
the metabolic syndrome (MetS). MetS is characterized by a
constellation of risk factors including abdominal obesity, insu-
lin resistance, and elevated blood pressure and plasma lipid
levels that ultimately can lead to type 2 diabetes (Sattar et al.,
2008) and cardiovascular disease (Byrne & Wild, 2005). Though
there is a burgeoning literature on Latino adult and child obe-
sity, type 2 diabetes, hypertension, and their contributors, few
studies have focused on psychosocial stress and Latino meta-
bolic function (McClure et al., 2010b; Weigensberg et al.,
2008). In the SAP study, 33% of mothers had values indicating
MetS, comparable to high (and rising) national prevalence
Measurement. In both studies, stature, body mass, and WC
were recorded using established procedures (Lohman et al.,
1988). Body mass index (BMI) was calculated as mass divided
by height in meters squared (kg/m2). In the first study, glucose
and total cholesterol concentrations (mg/dL) were obtained
from fasted participants using 30 µL samples of capillary blood
collected from finger prick and using a CardioChek PA ana-
lyzer and PTS Panels (Polymer Technology Systems, Indian-
apolis, IN). This professional testing system meets standard
clinical guidelines for accuracy and precision. In the second
study, Cholestech LDX monitors (Hayward, CA) were used for
the measurement of fasting glucose and lipid levels from 35 µL
samples of capillary blood collected from finger prick. Presence
of the metabolic syndrome was assessed using the updated ATP
III criteria (Grundy et al., 2005).
Chronic childhood anemia can contribute to delays in mental
and physical development, and evidence is increasing that La-
tino toddlers have a high rate of anemia related in part to pov-
erty and acculturation factors (Brotanek et al., 2007). As parents
in our first project considered this health information highly
valuable, we included it in the SAP study to encourage recruit-
ment and retention.
Measurement. Hemoglobin is considered a standard measure
for assessing anemia, and values are interpreted based on age-
and sex-specific cutoffs. Children’s blood hemoglobin in SAP
was measured from a drop of blood obtained from finger stick,
and assessed using the HemoCue Hb201+ (Lake Forest, CA) to
determine if levels were within normal range (typically over 11
g/dL). This system has been extensively validated and its accu-
racy is within ±1.5% of the reference method.
Lessons Learned
Despite the development of new techniques for the meas-
urement of stress outside of clinical settings, there can be barri-
ers to their incorporation in studies with Latino populations in
general and with Latino immigrant groups in particular (Na-
tional Institutes of Health, 2002). We were interested to learn
whether the integration of health measures and biomarkers into
our studies reduced historic barriers or instead served as an
additional challenge to participation in research. Lessons learn-
ed (Table 1) include ways to best support participants’ com-
pliance with complex and time-sensitive protocols, especially
given long days spent in agricultural work and unpredictable
daily routines. Ultimately, our goal is to contribute to knowl-
edge about successful practices for engaging ethnic minorities,
including immigrant populations, in research in order to con-
tribute to effective interventions with these populations (Na-
tional Institutes of Health, 2001).
Copyright © 2013 SciRes. 115
Copyright © 2013 SciRes.
Table 1.
Summary of lessons learned: challenges, solutions, and future strategies for biomarker research with Latino immigrants.
Challenge Solution/Future Strategy
Training staff with no prior experience collecting health and biological
data Ample training time + “hands-on” supervised training
Barriers to care (BtC) Provision of health information & follow-up
referrals as indicated
BtC: Limited knowledge about pre-existing conditions that could
render ineligible for study Testing (e.g., of glucose) as pre-condition of study enrollment
BtC: Potential over-enrollment of sick/health-focused participants Eligibility criteria and encouragement of healthy enrollees
Distrust among prospective participants Recruiter characteristics + recruitment methods that rely on trusted social networks
Lack of familiarity with biological data collection
Creation of strong rapport to ensure open
communication; assessors offer clear explanations; on-line videos of data
collection techniques to increase participant exposure
Measurement of very obese participants’ blood pressure with Omron
Manual blood pressure readings by trained staff person or use of Omron
HEM-907XL for automatic measure
Saliva sample return rate
One-on-one training of participants; reminders; support for participants with low
involvement of children
Busy morning schedules Collection of one morning sample; participants advised to collect on days with less
busy morning schedules
Filling out saliva diaries Reminders; fewer questions; support for
participants with low literacy; participants call automated system
Conducting finger sticks with farmworker participants with calloused
Use of BD Microtainer Contact-Activated lancets (blue) with a high flow blade
(2.0 × 1.5 mm)
Effective follow-up with participants
Partner with community organization with trained staff and resources for
follow-up; hire or have volunteer trained health professional as part of research
team to conduct follow-up
Assessor Training
As previously mentioned, staff members in TFS received
four hours of intensive training followed by 4 to 8 hours of on-
site supervision to hone their newly acquired skills. Following
training, staff from our partner organization that had no prior
experience with biological measures was able to consistently
and accurately collect health data and biomarker samples. The
same training model was implemented with the SAP study with
staff measurement techniques remaining consistent across both
studies. Though assessors had ample time to gain the necessary
skills, assessor confidence was the largest issue in training staff
new to biological data collection. Assessors often reported
feeling comfortable applying their newly acquired skills only
after having completed two or three actual visits with families,
which included an experienced staff person to provide guidance
if necessary.
Recruitment and Health Information
The incorporation of biomarkers into our studies did not
serve as a disincentive or barrier to participation. On the con-
trary, participants were eager for information about their health,
and for referrals and information about bilingual/bicultural, sli-
ding scale, and immigrant-friendly health services. In exit in-
terviews, participants frequently cited our provision of their
health values as a major reason for their study participation.
Although financial compensation was appreciated, many fami-
lies regarded it as an added benefit and some stated it was un-
necessary. The value of health information was further reflected
in some families’ offers to pay to obtain measures for non-
participating family members, and in requests that we include
additional family members in future studies. In addition to pro-
viding participants with immediate information about their
levels of fasting glucose, total cholesterol and other lipids, sev-
eral participants requested their individual cortisol, EBV and
CRP measures after laboratory analyses were completed.
The provision of health information to participants raised two
critical issues: 1) the need for adequately trained health per-
sonnel and a referral system (discussed below), and 2) the po-
tential overrepresentation of sick or health-focused participants
in the study, particularly as we did not utilize a random sam-
pling approach. The second concern was addressed to some
extent by eligibility criteria stating that prospective participants
be healthy, and excluding individuals with colds, the flu, or
chronic conditions such as diabetes or autoimmune disorders
(e.g., Crohn’s disease). Given barriers to access to care that are
particularly acute for recent immigrants, a number of prospec-
tive participants had no knowledge of whether they had chronic
and potentially disqualifying conditions. For instance, some
women had been diagnosed with gestational diabetes but had
never received follow-up testing and were unaware if they cur-
rently had diabetes. In cases involving possible diabetes, asses-
sors conducted a preliminary fasting glucose test as a pre-con-
dition of study enrollment, and individuals with a glucose value
indicating diabetes were excluded from participation (and pro-
vided with referrals for follow-up). As this circumstance affect-
ed approximately 15% of all potential participants, our studies
required additional supplies and assessor time than previously
anticipated. Given pervasive barriers to care in the US among
Latinos in general and immigrant populations in particular, we
anticipate researchers nationwide will encounter this challenge.
Finally, to date, we have conducted cross-sectional studies
and have yet to confront the prospect that could arise in a lon-
gitudinal study of influencing participant behavior and subse-
quent waves of data through the provision of health information
in the first wave of assessment. Because of the risk of influenc-
ing participant behavior, some OSLC longitudinal studies that
incorporate health data and stress biomarkers have opted not to
provide participants with information about their health.
Rapport and Effe cti ve Com m unication
As in most prevention research, strong rapport between par-
ticipants and assessors in our studies was key to participants’
full engagement. This rapport was especially important for re-
cruittment of some Latino immigrants who wished to remain
part of a “hidden” population in response to a hostile social and
political climate (Martinez et al., 2012). In addition, rapport led
to open communication that facilitated participants’ learning
about potentially complex procedures (e.g., saliva collection),
their timely communication with us when there were problems,
and our ability to effectively support participants’ involvement.
Familiarity with Methods
Nearly all participants were familiar with measures of height,
weight, and blood pressure, though most were unfamiliar with
finger sticks and saliva collection. In addition to providing an
overview of methods as part of our informed consent process,
assessors took special care while performing all health assess-
ment procedures, including finger sticks, to explain each step
and invite questions. During one-on-one saliva collection train-
ing, assessors also discussed insights we hoped to gain into
stress among Latino immigrants through analysis of salivary
cortisol, and the importance of participants’ adherence to in-
structions for the accuracy of results. Finally, in the SAP study,
assessors pricked mothers’ fingers first, which often helped to
reduce any anxiety the child felt. Together, these steps may
have contributed to only one SAP mother and three children re-
porting that finger sticks were challenging, and to high return
rates of saliva samples (details below). In the future, our team
has considered creating short Spanish language demonstrations
that could be accessed via DVD or the Internet to provide fami-
lies with even more information about and exposure to biologi-
cal data collection methods.
Blood Pressure: Me asurement Ch al le ng es
In TFS, when using Omron manual blood pressure machines
(HEM-422CRLC), we had trouble getting blood pressure read-
ings for several morbidly obese participants. Though blood pres-
sure cuffs were appropriately sized for each participant, error
messages persisted. This challenge of reading blood pressure
among some obese individuals, which has been noted in clinical
settings, was worrisome given high rates of obesity within the
study population at 30% for men and 33% for women, which
included approximately 7% with morbid obesity.
In the second phase of TFS, our staff included a registered
nurse who took manual blood pressure readings using a sphyg-
momanometer. In order to avoid stigmatizing visibly obese par-
ticipants whose blood pressure we anticipated might be difficult
to measure, the nurse worked at station one (where the first of
two blood pressure measures was taken) and volunteered to take
the participant’s blood pressure. As it was common at station
one for multiple assessors to measure participants’ blood pres-
sure at the same time, this strategy worked well to normalize
the nurse’s intervention. The nurse then tracked participants
throughout the health exam and stepped in to take the second
blood pressure reading at the final station to ensure consistency
of measurement. In the SAP study, we used Omron HEM-
907XL professional oscillometric instruments (Bannockburn,
IL) for the automatic measure of mothers’ and children’s blood
pressure. Though these devices were significantly more expen-
sive than the Omron 422-CRLC, they proved more reliable and
we encountered no measurement difficulties.
Finger Sticks: Lancets
The choice of lancets was important for ensuring that a single
finger prick was sufficient to produce an adequate number of
blood drops for the measurement of glucose and lipids (adults),
hemoglobin (children), and for blood spot cards. In TFS, we
initially used Stat-Let Auto lancets (Stat Medical Devices, Inc.)
with a depth of 2.2 mm. These lancets, however, were too shal-
low to draw sufficient blood as most male and some female
participants had thick calluses from agricultural work. The most
effective lancets we identified for use with this population are
BD Microtainer Contact-Activated lancets (blue) with a high
flow blade (2.0 × 1.5 mm). We also used BD lancets with
mothers and children in the SAP study. However, for very
young children, researchers may wish to consider using smaller
lancets (e.g., Stat-Let Auto lancets of 2.0 mm).
Saliva Collection: Supporting Participant
In TFS, 70% of participants returned all six saliva samples.
In the SAP study, 98% of participants returned all nine saliva
samples, considered an excellent return rate (Adam & Kumari,
2009). We attribute these high return rates to training (dis-
cussed above), collection reminders, support for participants
with limited literacy and the involvement of children (in SAP).
Reminders. Participants reported that the following methods
helped them to remember to collect their saliva according to
instructions: 1) toothbrush cover labels and removable stickers
for bathroom mirrors reading “Pare! Colecte su muestra” (Stop!
Collect your sample); 2) colorful wrist “gel” bands that partici-
pants donned the evening before as a reminder to collect their
saliva when they woke in the morning; and 3) assessors’ re-
minder calls made the evening before. Additional calls the day
of collection served as a further reminder, and provided par-
ticipants with a chance to ask questions, voice concerns, or re-
quest additional supplies.
Literacy. In the first study, we learned that our saliva collec-
tion directions were difficult for participants with limited liter-
acy to understand. Though we considered designing an alterna-
tive set of instructions composed of diagrams and two or three
words in lieu of each step, staff from our partner organization
advised that a customized approach would be more useful to
participants. Ultimately, when working with participants with
low literacy, assessors handwrote instructions on the saliva col-
lection guide tailored for each participant’s comprehension level.
Involvement of children. During the SAP study, we learned
that children as young as six years of age were often eager and
quick to learn saliva collection procedures. As a result, we
Copyright © 2013 SciRes. 117
actively involved both mother and child in the training, with
children often reinforcing their mother’s learning. Though we
did not formally ask about children’s involvement in saliva
collection (e.g., whether they initiated collection, or reminded
mothers of the need to collect), participant comments indicated
that children were an important factor in the family’s full par-
ticipation in the saliva collection portion of the study.
Saliva Collection: Morning Schedules
In the SAP study, early morning visits for the collection of
fasting measures, which could involve arriving at the family’s
home as early as 5 am so that the mother could leave for work
on time, were disruptive for families. In order to collect two
morning samples 30 minutes apart, busy morning schedules led
some mothers to alter their own and their youngster’s wake up
times, potentially influencing morning cortisol levels. For stud-
ies incorporating two or more morning measures, assessors may
wish to relay to participants the possible need to alter their
schedules to allow for extra time (not including an earlier
wake-up time or collection on a day that is not a typical week-
day) or discuss reducing the number of samples on a given
Saliva Collection: Saliva Diaries
In TFS, of participants who returned saliva samples, 86%
also filled out and returned a half-page form where they re-
corded the days and times they collected their saliva. In the
SAP study, 95% of participants recorded the time of day and
date they collected each sample. These data are critical because
they allow staff to track irregularities in collection schedules,
and make possible the calculation of time lapses between sam-
ples for the study of cortisol level changes throughout the day.
Again, reminder calls by staff seemed to facilitate these high
response rates.
Mothers in SAP also were asked to respond to questions in a
saliva diary for both themselves (6 - 16 Questions) and their
participating child (2 - 8 Questions) every time they collected a
saliva sample. Questions ranged from the time and day of saliva
collection to inquiries about sleep patterns and emotional state
during each 24-hour period, factors known to covary with Sali-
vary cortisol levels. Though most participants responded to items
whose range of responses were on a five-point Likert scale,
open-ended questions asking for more detail were rarely filled
out. Participant feedback to assessors indicated that some par-
ticipants lacked time to respond to all questions. In addition,
some participants reported that the saliva diaries were over-
whelming in length. In the future, assessors advised asking
fewer questions and having a binder for the saliva diaries where
all questions would be color coded to the sample collection
tubes for that day and clearly separated by collection time.
Literacy. Saliva diaries in the SAP study presented signifi-
cant challenges to the participation of a few mothers with low
literacy. In these cases, the assessor called the family at each
collection time and administered the saliva diary as a telephone
interview. Though saliva diary data collected by telephone pro-
ved to be more complete than data in saliva diaries that partici-
pants filled out themselves, telephone interviews were burden-
some schedule-wise for mothers and assessors and less cost-
effective. In the future, we will investigate new strategies that
support the inclusion of participants with low literacy, such as
requesting that participants call in and respond to pre-recorded
questions through an automated system.
Referral System and Follow-Up
As mentioned, the receipt of health information was one of
the greatest incentives for participants’ involvement in the
studies. Despite widespread enthusiasm regarding this facet of
our studies, however, several issues were raised. Approximately
one-third of all TFS and SAP participants had high levels of
glucose, total cholesterol or other lipids, and blood pressure
indicating the need for follow-up testing. Additional partici-
pants were referred for follow-up relating to chronic pain, low
blood pressure, impaired vision (needing glasses), smoking, nu-
triation, the self-administration of medication, and desire to lose
Effective follow-up in TFS was facilitated by a number of
factors. All participants were easy to re-contact as they were re-
sidents of housing complexes owned and run by the organiza-
tion, and the organization’s staff (many of whom were study
assessors) already referred residents to a range of services. Also,
a key member of the organization’s staff and of our research
team was an experienced health promoter who had strong rela-
tionships with local public health agencies and community
The SAP study was distinct in that it was not a community-
partnered project and all follow-up was conducted by LRT asse-
ssors. In this study, some participants’ busy schedules contrib-
uted to assessors feeling rushed to explain the results, which
was worrisome to staff when trying to explain values that indi-
cated need for follow-up testing. Further, although assessors
clearly explained that they were not medical personnel and
could not offer advice, participants frequently asked health
related follow-up questions. Finally, a few families requested
assessor support in making appointments with clinics. Though
staff provided support to every participant who requested it,
future studies involving larger sample sizes and more com-
pressed assessment timelines would do well to include funding
for a health professional (or have a committed volunteer) to re-
spond to families’ questions and concerns, and to serve as a
health care navigator by assisting participants to access fol-
low-up care.
Though recent developments in minimally-invasive biologi-
cal measurement allow for more refined understandings of the
effects of psychosocial stress, these methods have been under-
utilized in studies with Latino populations. This is unfortunate
given existing Latino health disparities and the need to better
understand contributors to these disparities. Studies involving
recent immigrants, however, can confront unique challenges.
There is a clear need to fully support Latino immigrants’ invol-
vement in research involving biomarkers—and to identify the
strategies that make this possible—in order to better inform
public health policy and clinical practice. Further, carefully
designed studies can provide potential positive benefits to indi-
viduals who take part and to the larger communities in which
they are members. Finally, though the studies described here
focus on the Latino immigrant community, better models of
stress processes that rely on multiple measures may have im-
plications for a range of preventive interventions that target the
Copyright © 2013 SciRes.
effects of stress on family health within diverse communities.
The authors thank the Oregon Latino families who partici-
pated in the studies and study assessors. We also thank Felicia
Madimenos for biomarker training assistance, Julia Ridgeway-
Díaz and Sasha Johnson-Freyd for cortisol analyses, and Lynn
Stephen and Frances White for discussions of the project. We
appreciate the support of the National Institutes on Drug Abuse,
National Institutes of Health (R01 DA017937 and R01 DA-
01965), as well as the Oregon Social Learning Center Scien-
tists’ Council, Northwestern University, the University of Ore-
gon (UO), and the UO Center for Latino/a and Latin American
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