Hispanic Health Research Center

Cameron County Hispanic Cohort

Local investigations with national significance

Much of our work focuses on Hispanic communities living in the Rio Grande Valley, where more than 90% of the population is of Mexican origin.  The sheer volume of information and data gathered by these projects makes us one of the most robust and authoritative research groups on Mexican American health in the United States. The bedrock of these data is our population-based cohort, the Cameron County Hispanic Cohort (CCHC), now numbering about 5,000 individuals recruited from randomly selected households. As a result, we have a large and unique population-based database and specimen archive from low-income Mexican Americans. This has led to collaborations with researchers in major institutions throughout Texas and across the nation. The extensive data generated underpin intervention and outreach programs, aimed at factors that impact this population’s health and well-being. There are many opportunities for students to combine their studies with working in these programs. 

Purpose and Aims

Established in 2004, the Cameron County Hispanic Cohort (CCHC) is a randomly-ascertained, community-based cohort of Mexican Americans and currently numbering around 5,000 individuals recruited from border communities on the Texas-Mexico border from Brownsville to Laredo. (map) The CCHC samples a low income, poorly educated, homogeneous ethnic population, notoriously difficult to reach. The Hispanic population accounts for half of the national population growth since 2000, numbering more than 58 million individuals among whom 36 million are Mexican Americans; the largest, least wealthy and fastest-growing subgroup in the nation. They are the most poorly studied, but with severe health disparities and generally missing from national cohorts since they are difficult to access and poorly represented in scientific studies. The CCHC recruits and trains bilingual and bi-cultural researchers from the community itself top access this population. These researchers are now highly trained and experienced in conducting recruitment in local homes, and collecting and processing and specimen according to protocol.

Composition, sampling and population characteristics

The CCHC is recruited from randomly ascertained households in Cameron and Webb counties. The population is young, low income and with limited education, and 95% Mexican American, with 11 years of education on average. About 30% are below the poverty level, and more than 60% have no health insurance. Households are randomly identified by the U.S. census tract/block, and all household members are invited to participate. Data are weighted to allow estimation of prevalence. We are now conducting five, 10 and 15-year visits. Contact with participants for follow up is by cell phone or home visit since most do not use computers. We have more recently added a pediatric cohort (aged 8-17 years) now numbering more than 400 who are seen at two-yearly intervals, and on reaching 18 years join the adult cohort. Participants regularly participate in nested studies and clinical trials.

Clinical examination

Individuals agreeing to participate visit the Clinical Research Unit (CRU), or are seen on request at home. The studies are explained in detail and an IRB approved individual written informed consent is obtained from each participant for the examination. The consent allows all measurements, collection of data and biospecimens including plasma, RNA and DNA at each visit. Informed consent 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. The robust methodology is based on consistent, comprehensive protocols and procedures. Validated questionnaires are administered by staff in English or Spanish, covering sociodemographics, medical and medication histories, behavioral/environmental, family medical histories, diet and physical activity, and alcohol and smoking behaviors. Imaging includes carotid and brachial ultrasound and echocardiography for cardiovascular disease, Doppler studies for peripheral artery disease, elastography for steatosis and liver fibrosis, Spectralis OCT and retinal photographs for eye disease, and dual X-ray absorptiometry (DXA) for bone health and body fat composition.

Major findings and implications

In the 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 first established a prevalence of obesity and diabetes in the CCHC population and found that rates of diabetes (28%) and obesity (51%) are significantly higher than those reported nationally. These findings are generalizable to the Mexican American population, and novel since this is an understudied minority. Consequent to these findings we have published on cardiovascular diseases, liver diseases, mental health and genetic drivers of disease.

Diabetes and metabolic diseases

As stated above. we have published the prevalence of diabetes to be 28% in this population, but also that 30% of these individuals are undiagnosed. Prediabetes prevalence is 37%, such that about two-thirds of the population has diabetes or is at risk. Along with this, we find high rates of other dysmetabolic factors, such as 45% with elevated lipids and a total of 80% of participants with one or more dysmetabolic conditions. Poor metabolic health has been shown to be more significantly associated with diabetes and with cardiovascular disease and other complications, than just obesity. Further studies show that men between the ages of 18 and 25 have high rates of diabetes and have generally poor health. A recent publication using paired specimens validated 31 gene-level associations not previously reported by genome-wide association study in people transitioning to diabetes using a novel two-stage approach to studies of gene expression.

Cardiovascular diseases

We have shown that the Framingham risk score used for predicting cardiovascular events considerably underestimates cardiovascular risk in Mexican Americans. Echocardiography shows that the prevalence of left ventricular diastolic dysfunction, a precursor to heart failure, is very high in the cohort (24%). Interestingly we also see that increased carotid intimal thickness correlates with non-alcoholic fatty liver disease and that cardiometabolic risk factors are more important than obesity in driving heart disease. Similarly, studies of endothelial dysfunction show this is also associated with cardiometabolic risk factors. We are currently studying the association of prolonged Q-T intervals with diabetes and the risk of sudden cardiac death.

Liver cancer

The incidence of hepatocellular carcinoma is near twice the national rate in Cameron county. In the cohort, we have shown that hepatocellular carcinoma is the third most common cancer in men and seventh in women, and in several studies, we have shown that prodromal asymptomatic liver disease (fibrosis and even cirrhosis) are frequent in the cohort. We performed elastography to determine levels of hepatic fibrosis in CCHC participants and find that 14% had evidence of significant fibrosis, mostly presumed due to non-alcoholic liver disease. Nearly half have fatty liver. A second study shows that the stage of fibrosis correlates closely with glycated hemoglobin (HbA1c) levels. Prospective studies are underway to understand what influences the progression of fibrosis to cirrhosis and hepatocellular carcinoma.

Additional resources

Protocols, consents, instruments and data, and specimen archives.

Protocols

• Protocol Study A & B Ver. 3.6  
• Liver Study Protocol Ver. 4 
• Ultrasonography Protocol Ver. 1.5 

Consents

• Household Survey (English)  
• Household Survey (Spanish)  
• Diabetes Impact Study (English) 
• Diabetes Impact Study (Spanish) 
• Advanced Fibrosis and Hepatocellular Carcinoma (Liver Study) 
• Ultrasound Study 

Instruments

• CCHC Limited Instruments 

Collaborations

The Hispanic Health Research Center of UTHealth School of Public Health in Brownsville has an interest in sharing specimens and data with other interested and qualified research groups of individual researchers who may wish to contribute analyses for the benefit of the scientific and health care communities. We encourage and solicit manuscript proposals and ancillary studies.

Principles and Procedures

• Data Sharing Plan

Proposal Submission Memo

• Proposal Submission Memo

Proposal Forms

• Manuscript Proposal Form
• Ancillary Study Proposal Form

Opportunities for students and investigators

The CCHC provides extensive opportunities for collaborations at many levels. Students may have access to data, and if on campus are able to gain experience in real-time data collection and working within the community. Large data resources and specimen archives are available to investigators in many areas of interest including diabetes-related diseases, mental health and social determinants of health.

Potential areas of research for collaborators and students:

• Topic research on the CCHC
  • obesity, diabetes and related conditions
  • lifestyle research (physical activity, nutrition) and impact on disease
  • mental health  (depression, anxiety, cognitive function)
  • cardiovascular disease
  • liver disease including cancer
  • metabolic disease
  • pediatric cohort
• Types of research for the above topics
  • Descriptive (clinical, biological, clinical laboratory, pathogenesis)
  • Analytical (hypothesis-driven, machine learning, population or clinical, cross-sectional or longitudinal)
  • Genomics
  • Gene expression (cross-sectional or longitudinal)
  • Metabolomics (cross-sectional or longitudinal)
  • Epigenomics (cross-sectional or longitudinal)

Current projects and collaborations

Our community outreach programs focus on health problems and solutions specific to the border area. Special areas of interest include intervention research with adults and children to prevent and control obesity and diabetes, as well as other chronic or genetic diseases. Students can gain invaluable experience in international health with numerous bi-national programs with Mexican organizations and studies in adjacent areas of Mexico.

Tu Salud Si Cuenta

Founded in 2004, Tu Salud ¡Si Cuenta! is an evidence-based, collaborative, innovative, and results-driven program focused on improving health outcomes in the Rio Grande Valley. The program’s Your Health Matters! curricula provides scientifically accurate information to community health workers and people outside of the health profession about healthy food choices and physical activity to promote individual behavior change and/or policy, environmental and system changes.

Visit the program page.

Telemedicine

The HHRC’s telemedicine program increases access to primary and specialty care and provides opportunities for training and research.

Primary care

This program is a collaboration between the Department of Medicine of the McGovern School of Medicine at UTHealth Houston and three clinics in the Rio Grande Valley: Projecto Juan Diego, Su Clinica, and Rio Grande State Center.

Specialty Care

We work with Baylor College of Medicine to provide psychiatry and ophthalmology services to Brownsville Community Health Clinic, another Federally Qualified Health Center in Brownsville. We also provide specialty services in endocrinology (particularly type 2 diabetes) to partner clinics from UTHealth.

Medical resident training programs in Telemedicine

We work with Tiffany Champaign-Langabeer, PhD, at UTHealth School of Biomedical Informatics to provide training modules in telemedicine for medical residents at the McGovern Medical School.  These residents will be supervised to conduct continuity clinics to our partner clinics in Brownsville. Dr. Champaign-Langabeer is also creating a novel program with training modules for community health workers, enabling them to facilitate in-home telemedicine consultations. Telemedicine training is also available to providers in the partner clinics. Our goal is to create a sustainable telemedicine program in the Rio Grande Valley.

Unidos Contra Diabetes

Unidos Contra la Diabetes (UCD) is a community partnership dedicated to preventing diabetes.

Our guiding principles:

• Serve the whole community through a systems-oriented approach: We support not only the individuals at risk for diabetes but also their families and the communities they live within.  We strive to change the overall system, including policies, practices and cultural norms to create a healthier community.
• Take an asset-based approach: We will recognize and elevate community, family and individual assets to build upon and avoid shaming people for poor health. Community engagement is asset-based and family-oriented. 
• This is everyone’s responsibility: Diabetes prevention is a shared responsibility of the entire community, including the private sector, governments, schools, families, and individuals at risk for diabetes and includes sustainably improving social determinants of health.  
• Think holistically about health: We will support the prevention and integration of behavioral health in diabetes prevention in promoting holistic wellness; mind, body, and spiritual.
• Foster health equity people and families: We commit to foster health equity for individuals and families with the knowledge and cost-effective care and tools they need to take their health into their own hands. 

Partners:

• MPH Salud
• The Valley Baptist Legacy Foundation
• Texas Department of State Health Services
• Texas A&M Health Science Center School of Public Health
• Methodist Healthcare Ministries of South Texas
• Nuestra Clinica del Valle
• Tropical Texas Behavioral Health
• Rio Grande Valley Health Information Exchange
• Hope
• Knapp Community Care Foundation
• The University of Texas Health Science Center at Houston
• Behavioral Health Solutions

UCD Health Connect

UCD Health Connect is a community data resource sharing data on diabetes, obesity and related issues from UCD partners. It contains information on diabetes prevention, local Rio Grande Valley data from UTHealth School of Public Health, clinic partners and other UCD participants. UCD Health Connect contains national data from multiple sources, updates information on the progress in UCD screening for diabetes, and provides diabetes prevention programs screened participants with prediabetes or diabetes (about 32% of people in the Rio Grande Valley with type 2 diabetes are unaware of their condition).

Brownsville Farmers Market

The Brownsville Farmers’ Market is a collaborative effort to provide affordable, locally grown produce to area residents and increase the awareness of chronic diseases associated with obesity. Health care experts are on hand to educate shoppers on nutrition, obesity, and diabetes. The market has expanded to two other communities.

Delivery System Reform and Inventive Payment (DSRIP) Programs

DSRIP programs are part of the state’s Medicaid 1115 waiver, which allocates funding to offset the cost of uncompensated care. The programs are designed with the “triple aim” of increasing access to care, reducing unnecessary costs and improving the quality of care and health outcomes in the Rio Grande Valley.

Salud y Vida

The Salud y Vida program addresses the social determinants of health that are often major barriers to self-management of chronic diseases such as type 2 diabetes, hypertension and other chronic conditions. The program brings together clinic partners, non-profits, health information exchange and community health workers, to create a seamless approach to lifestyle management for patients. It’s an innovative strategy that’s improved the control of diabetes and hypertension across the population.

The Salud y Vida website provides detailed information on the process and the positive outcomes of patients who have undergone the program.

Rio Grande Health Information Exchange (RGV HIE) 

The Rio Grande Valley Health Information Exchange (RGV HIE) is a 501(c)3 nonprofit organization established in 2011 dedicated to facilitating the efficient exchange of health information in order to improve the quality of patient care in South Texas. The RGV HIE contains data on more than 600,000 people in the Rio Grande Valley, a critical asset for local research on health issues of the Rio Grande Valley.

Promotora outreach

Community Health Workers (CHWs) or “Promotores” are the foundation of our work in the community, and lead our chronic disease management and prevention efforts. They are from the community and understand the culture, language and needs of the participants we serve. UTHealth School of Public Health in Brownsville employs more than 20 CHWs, certified through a 160-hour course provided by the Texas Department of State Health Services (DSHS). They receive ongoing continuing education and training and are involved in research and service delivery. Our campus also has 6 DSHS certified CHW Instructors and has developed multiple training of trainers curriculum for continuing education delivered across the state.

CHW’s are trained in Motivational Interviewing, phlebotomy, case management, diabetes education and teach exercise, nutrition and healthy cooking classes throughout the community. They also provide follow-up home visits to participants with high blood pressure, high BMI and/uncontrolled diabetes and work with community partners including clinics, mental health authorities, community non-profits, schools and churches to address barriers to healthcare access, healthy lifestyle choices and disease management.

Patient-centered medical homes

Under the DSRIP program, two Federally Qualified Health Centers (encompassing five clinics in the lower Rio Grande Valley) have been transformed into Patient-Centered Medical Homes (PCMH)—a health care delivery model that provides comprehensive and coordinated care. The move created multidisciplinary patient care teams, expanded clinic hours, added nurse-only appointments for services such as flu vaccines and blood pressure follow-up, and a nurse call line for after-hours care. Patients also benefit from a complete referral tracking system to close the loop on specialists and external care, upgraded electronic records and pharmacy systems, and patient data sharing with the area’s hospitals. Each FQHC has also increased its collaborations with external organizations and programs with an emphasis on chronic disease prevention and care, and the reduction of hospital admission and emergency room visits. Clinic patients also have access to the Salud Y Vida chronic disease management program.

Our facilities and resources

Clinical Research Unit

The Clinical Research Unit (CRU) was established in 2004 and is supported by the NIH. It is located in a suite of offices provided to us by the Valley Baptist Medical Center in Brownsville, and, with seven examination rooms, office space, a conference room equipped with video equipment for communicating with collaborators and telemedicine, and a small laboratory area that allows for immediate processing and freezing of specimens. The Brownsville CRU has two outposts, one in Laredo, established in 2012, and another one planned for Hidalgo County. These sites provide a wider community sample. The Laredo CRU consists of four exam rooms and a laboratory area. It is supported by a project manager and three recruiters.

Blanca Ortiz Community Outreach Annex

The Blanca Ortiz Community Outreach Annex is a warm place enriched by the volunteers and staff who work to provide healthy resources for our communities. Our annex includes space for promotoras, a conference room for community meetings, and a clinic space used by the Clinical Research Unit for clinical research activities including participant enrollment in the Cameron County Hispanic Cohort. We also provide office space for local health-oriented non-profit organizations working to improve the health of the community, including Healthy Communities of Brownsville and The Brownsville Farmers’ Market.

UTHealth School of Public Health Laboratory

UTHealth School of Public Health Brownsville campus laboratory has a 6,000 square foot wet-laboratory completed in 2008. The laboratory provides technology and 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. A specimen archive is also managed by the laboratory.

Contact us

Address

Hispanic Health Research Center
UTHealth School of Public Health in Brownsville
One West University Blvd.
Brownsville, TX 78520

Phone

Office: (956) 755-0601
Fax: (956) 755-0606

Emails

CCHC Inquiries: CCHC_admin@uth.tmc.edu 
Research Inquires: CCHCResearch@uth.tmc.edu