Hispanic Health Research Center
The Hispanic Health Research Center (HHRC) was established at the Brownsville campus of the UTHealth School of Public Health in 2003 through funding from the National Center on Minority Health and Health Disparities at the National Institutes of Health. The HHRC is directed by Dr. Joseph McCormick.
|Joseph McCormick, MD
The primary objective of the Center is to identify the salient risk factors for obesity and diabetes and their complications in Americans of Mexican descent living in the Lower Rio Grande Valley. The HHRC was responsible for establishing the Cameron County Hispanic Cohort a Clinical Research Unit, on-site laboratory facilities to support epidemiological studies. The HHRC also engages extensively in community outreach to promote physical activity and healthful food choices in the Hispanic population.
The Hispanic Health Research Center at the UTHealth School of Public Health in Brownsville is on one of the six campuses of UTHealth School of Public Health. The campus is located on its own site, adjacent to the UTRGV Brownsville Campus. The faculty has a wide range of expertise in epidemiology, disease control, behavioral health and outreach, data management and biostatistics and genetic epidemiology. They have extensive experience in research and teaching. Research is a major part of the expectations of all faculty as part of The University of Texas Health Science Center at Houston (UTHealth). All faculty are well-published with a range of research programs. Collaborative studies with established scientists at the Houston campus of the School of Public Health, the McGovern Medical School at UTHealth and The University of Texas MD Anderson Cancer Center also include collaborators from other institutions such as UTRGV, The University of Texas Health Science Center at San Antonio, University of California San Diego, Baylor College of Medicine, Vanderbilt University, the University of Washington, and many more.
|Susan Fisher-Hoch, MD
Further, research links with the medical community along the border include most of the clinics and hospitals in the area. The major research initiative of the HHRC is the Cameron County Hispanic Cohort (CCHC). This is a cohort of low-income Mexican Americans randomly recruited from households in Cameron, Hidalgo and Webb counties on the Mexican border. It now numbers more than 4,600 individuals followed up every five years. Data from the CCHC have been published widely and are being used to inform intervention and outreach programs.
Clinical Research Unit
|Rocio Uribe, Project Manager
Sue Fisher-Hoch, MD oversees a NIH-supported Clinical Research Unit established in 2004.It is located in a suite of offices provided to us by the Valley Baptist Medical Center in Brownsville. It has a project manager, Rocio Uribe and project coordinator, Norma Perez-Olazaran several highly trained field workers. Since 2004, the Brownsville CRU has been an integral part of the UTHealth General Clinical Research Center in Houston. The CRU has recently been expanded to 3,423 square feet, with seven examination rooms, office space and a conference room equipped with video equipment for communicating with collaborators and telemedicine. A small laboratory area allows immediate processing and freezing of specimens. WiFi and 5 computers connected to the university network are also behind the firewall and provide video conferencing across the state.
|Norma Perez-Olazaran, Project Coordinator
The Brownsville CRU is home of the Cameron County Hispanic Cohort uses a unique team approach tailored to the local community. CCHC investigators are Spanish-speaking, highly trained and experienced community health workers who conduct subject recruitment in local homes, processing and specimen collection. University vans are used for recruiting and transporting participants. The clinic is extensively equipped including several modalities for ultrasound, Dual-Energy X-ray Absorptiometry and dopper imaging. It also has a a three FibroScans incorporating Controlled Attenuation Parameter (CAP) which allows quantification of steatosis as well as measurement of liver stiffness indicating fibrosis using Vibration Controlled Transient Elastography technology (VCTE), two of which can be taken for home visits.The Brownsville CRU has two outposts, one in Laredo, Webb County, established in 2012, and the other a new center in Pharr, in Hidalgo county established in 2018. These sites provide a wider community sample. The Laredo CRU consists of 2,053 square feet which includes 4 exam rooms and a laboratory area. It is supported by a project manager and 3 recruiters. The Pharr clinic in Hidalgo county. Further research facilities are provided in the Doctor’s Hospital Renaissance in Edinburg, Hidalgo County, where we have dedicated research space within the new Transplant Unit. Here we conduct research with a second cohort consisting of hepatocellular carcinoma patients and their close relatives in collaboration with Drs. Almeda and Patil of DHR Laboratory.
|Marcela Morris, Laboratory Director
The University of Texas School of Public Health at Brownsville laboratory has a 6000 square foot wet-laboratory completed in 2008. The laboratory director. Marcela Morris, oversees laboratory technicians performing a wide range of studies on our CCHC specimens. The laboratory was designed to provide high technology and use of high throughput assays for screening large numbers of specimens from our field sites and clinics. The main laboratory space is divided into a BSL3 laboratory and a larger BSL2 laboratory with restricted access reserved for major equipment and for genetic and cell culture studies. A large open laboratory is available for general purposes. The laboratory possesses a Luminex 200X xMAP Technologies plate reader and 405 TS Magnetic Microplate Washer. It has the MicroLab Nimbus Elisa and the MicroLab Starlet Liquid Handling System from Hamilton. It has a Muse Cell Counter by EMD Millipore, and a QuantStudioDX Real Time PCR by Life Technologies. It has a SpectraMax MS Real Time Spectrophotometer by Molecuar Devices, a BD PACS CANTO 11 Flow Cytometer by BD Biosciences, and an Olympus IX51 fluorescent microscope and a CX31 Microscope. It has a NanoSprint nCounter, a BACTEC MGIT 960, 1575 Immunowash plate washer, PTC 200 Peltier Thermocycler, and a 2100 Agilent Bioanalyzer. Centrifuges includes a Cytospin 4 cell preparation centrifuge, one ultra-speed and 3 microcentrifuges. A specimen archive is also managed by the laboratory.
Blanca Ortiz Community Outreach Annex is located at the University of Texas School of Public Health (UTSPH) Brownsville campus and houses many exciting activities. This annex provides vital work and meeting space dedicated to community outreach to improve public health through research and community projects at UTSPH Brownsville.One part of the annex houses promotoras or lay health workers who are professionals from the community who have been specifically chosen because of their talents in educating, motivating and teaching skills to community members for improving their health. They have been trained in topics such as physical activity, healthful food choices, diabetes and cancer prevention and control through the Tu Salud Si Cuenta! (Your Health Matters!) community wide campaign. The annex also provides a conference room for community meetings, a clinic space used by the Clinical Research Unit for clinical research activities including participant enrollment in the Cameron County Hispanic Cohort. Finally the annex provides an office for local health oriented non-profit organizations including Healthy Communities of Brownsville and The Brownsville Farmers’ Market. These organizations are working to improve the health of the community through environmental change efforts including recycling initiatives and access to locally grown fruits and vegetables. The entire annex is dedicated to community activities and as such is a warm place enriched by the volunteers and staff who work to provide healthy resources for the local community.
The Cameron County Hispanic Cohort (CCHC):
The CCHC is a cohort of Mexican Americans established in 2004 and currently numbering 4,584 individuals living on the Texas-Mexico border. The CCHC has been funded by the National Institute for Minority Health Disparities (MD000170 P20). Dr. Fisher-Hoch along with Dr. McCormick has directed, developed, and expanded the cohort over 14 years. The provides a low income, homogenous ethnic population with high health risk which is largely missing from large national cohorts. The CCHC recruitment and examinations will be in the CTSA supported Clincal Research Unit which is located at Valley Baptist Medical Center Brownsville in donated space. Further recruitment at our other CRU's in Hidalgo and Laredo enlarges the sampling from of this cohort. This cohort is used to address multiple research questions.
Composition of the CCHC:
The CCHC (N=4,584) is recruited from randomly ascertained households. The mean age of the population at baseline is 47.8 years (median 46.9). At baseline, 62% of participants were over 40 years of age. Currently, 72% of participants are over 40 years of age, nearly half (52%) are over 50 years of age, and 98% identify themselves as Mexican American. To better understand the ethnic background of this population and the potential impact of ancestry genetics and culture, we assessed admixture using ancestry informative markers. The median proportion of European ancestry was 45.8% (coefficient of variation (CV) 32.5%), median African ancestry 11.0% (CV 59.5%), and median Amerindian ancestry 42.9% (CV 37.0%).
The majority of the cohort has been recruited in Brownsville which has a large population of Mexican Americans resident for several generations. It is an American city with a strong Mexican flavor and culture with strong family and community ties. Laredo has a similar population and is the oldest city on the south Texas border (established 1755, population 236,091, 95.6% Hispanic) also with a large long-time resident Mexican American population. Most of the Hispanics along the border are Mexican Americans, particularly in the poorer communities and many have relatives in large cities across Texas and the United States (U.S.), Hispanics are the most rapidly growing minority in the U.S. now accounting for ~58 million, and constituting 37.6% of the population of Texas most of whom (31.6%) are Mexican American. This ethnic group generally represents a difficult-to-reach, low-income population with high health risk which is mostly missing from large national cohorts.
The CCHC is a true randomly-selected cohort. This relatively homogenous Mexican American sample is selected randomly by US Census Bureau tracts/blocks, stratified into socioeconomic strata (SES) quartiles, and not recruited through advertisement, as in most other cohorts. Recruitment is ongoing in households and occupied dwelling designated in randomization is visited up to 5 times. Poverty levels in the catchment area is over 30%, twice the national average (15.4%), making these districts among the very poorest in the country. Concentrating sampling in Brownsville and Laredo now give us a predominantly Mexican American cohort. We benefit from years of experience with this community, taking care to provide a safe environment for participants notably fearful of authority. Both recruitment and follow up present particular challenges in this population, which is among the poorest in the nation and often mobile. We have improved our follow up as we continue to build a respected identity in the community.
Individuals from the households who agree to participate visit the Clinical Research Unit .We accommodate participants as much as possible, such as scheduling appointments for their convenience, e.g. Saturdays, and make home visits if requested. Once a participant arrives at the CRU, the protocols are explained in detail and an IRB approved individual written informed consent is obtained from each participant to participate in the examination and to allow the measurements, collection of data and biospecimens outlined below. The informed consent form specifically includes consent to access electronic medical records (EMR), consent for use of archived materials for new studies including genetics, and permission to be contacted for new studies and for follow up studies. Results are returned to participants with explanation, and recommendations for follow up are given if needed with advice to either visit their physician if they have one, or one of the local Federally Qualified Clinics (FQC). Participants may opt out of any part of the study at any time as they wish.
Robust methodology has been in place since 2004 that extensively phenotypes individuals using consistent, comprehensive protocols and procedures. Validated questionnaires are administered by staff in English or Spanish. These cover sociodemographics, medical and medication histories, behavioral/environmental, family medical histories, diet and physical activity, and alcohol and smoking behaviors. A mental health examination to assess anxiety, depression, and cognitive function is routinely administered using the validated instruments including the Center for Epidemiological Studies: Depression Scale and Zung’s Self-Rating Anxiety Scale Complete medical histories are taken, and family histories include records of sociodemographics, medical and family histories, diet, physical activity, smoking and alcohol use, and performing clinical examinations. We measure participants’ weight with their shoes removed using a portable electronic scale and record the weight to the nearest 0.2 kg. Height is measured to the nearest 0.2 cm with a stadiometer. Body mass index (BMI) is calculated and waist circumference (visceral adiposity) is determined at the level of the umbilicus to the nearest 0.2 cm, with participants in a standing position and breathing normally. We measure blood pressure according to the protocol described in the National High Blood Pressure Education Program(National Heart, 2003) and obtain an electrocardiogram (EKG). Participants are asked to fast for 10 hours prior to blood collection, and we reschedule any participants who have not fasted. We obtain routine clinical hematology (white blood cell count, differential, hematocrit, hemoglobin) and chemistries (lipid profile, metabolic profile, urinalysis, liver function tests) and glycated hemoglobin, C-reactive protein, and urinalysis are performed in our local Clinical Reference Laboratory (CRL) and the remainder of the specimens archived at optimal -80oC We perform in house insulin assays and Luminex adipocytokine panels.. In addition, Since 2012 we have sequentially added imaging modalities to all visits; specifically, ultrasound measures of carotid intimal thickness (cIMT), flow mediated dilatation (FMD), echocardiograms, and a range of measures of peripheral artery disease (PAD), using Doppler based techniques, and more recently retinal exam with optical coherence tomography with angiography, eye pressure, and a stool sample is collected for microbiome studies. We measure liver stiffness using the FibroScan VCTE-CAP technology. These new measures represent ancillary study content that builds upon the CCHC infrastructure.
The major areas of research revolve around obesity, diabetes, and their effect on heart disease, liver disease, infectious diseases and mental health. In addition, the CRU and CCHC serve as a means to evaluate the behavioral and biological effects of population based and clinical interventions. Several publications using data from this important minority, health disparity cohort are published and many more are in progress. We are currently performing 5, 10 and 25-year follow-up visits to track our participants and their health. We obtain death certificates from the National Death Index (CDC).
A separate freezer room with restricted access contains 15 ultra-low freezers for with a large archive of specimens, liquid nitrogen, freeze dry equipment, general storage, and space for equipment used occasionally, and is supported by a backup generator (5-day capacity) for possible power failures (e.g., hurricanes). Specimens are frozen at minus 80oC at the collection sites, then transferred on frozen ice packs to the archive. This now includes longitudinal plasma, serum, DNA and peripheral blood RNA. Stored specimens have been assayed for quality control showing high quality. Samples are managed and tracked using FreezerPro®.
Description of Research Questions that have been investigated in the CCHC and major findings:
In the context of the national epidemics of increasing obesity in adults (national prevalence 39.8%, 2015 data), Hispanics context of the national epidemics of increasing obesity in adults (national prevalence 39.8%, 2015 data), Hispanics have the highest prevalence (47.0%). Similarly the national prevalence of diabetes is 9.4%, but among Hispanics it is 12.1%, rising to 13.8% in Mexican Americans. We therefore first sought to establish the prevalence of obesity and diabetes in the CCHC population. Rates of diabetes and obesity are at least three time higher than those reported nationally. The CCHC represents a population with many chronic conditions that are often undiagnosed. Findings in the CCHC are generalizable to the Mexican American population, and novel since this is an understudied minority. For example, we have shown that the Framingham risk score used for predicting cardiovascular events is inaccurate in Mexican Americans. Another study showed that a high proportion of participants (77.8%) were found to be metabolically unhealthy. In addition to studies looking at cardiovascular risk factors, the CCHC data shows that the prevalence of liver disease, including cirrhosis and hepatocellular carcinoma, is much higher than the national rates. Furthermore, we have shown that hepatocellular carcinoma is the third most common cancer in men and seventh in women. We performed elastography to determine levels of hepatic fibrosis in CCHC participants and find that 15% had evidence of significant fibrosis, mostly presumed due to non-alcoholic liver disease. Given the general poor health of this community, the CCHC should allow for clear definition of some of the key biologic aspects of the nature and even veracity of the Hispanic Paradox observation. The availability of this population-based sample with extensive measures of cardiometabolic and cardiovascular disease, coupled with lifestyle and demographic data (such as place of birth and length of time in the US), provides a unique opportunity to examine the distribution of sub-clinical disease in the CCHC and the predictors of cardiovascular outcomes.