The Texas Harris Alzheimer’s Research Study

//The Texas Harris Alzheimer’s Research Study
The Texas Harris Alzheimer’s Research Study2020-02-11T13:23:31-05:00

The Texas Harris Alzheimer’s Research Study began in June of 2005 with the goal of establishing a comprehensive research cohort of well characterized subjects to address improved diagnosis, treatment, and, ultimately, prevention of AD. The research study resulted in a large, standardized and well-curated research database containing integrated psychometric, medical and genetic data, biological markers, whole blood, serum, plasma and DNA from TARCC study participants. Over time, the TARCC sites enrolled a cohort of more than 3,600 study participants representing over 14,500 visits (an average of four annual visits for each subject). The research study database includes individuals diagnosed with Alzheimer's disease (AD), mild cognitive impairment (MCI), and cognitively healthy controls subjects (NC). The inclusion of individuals diagnosed with mild cognitive impairment helps in our understanding of the sequence of neurodegenerative and neurobehavioral changes that occur as AD develops.

The wealth of information contained in the Texas Harris Alzheimer's Research Study stimulates novel, basic and clinical research that furthers our understanding of AD as well as facilitating collaborative research projects among Texas AD researchers. The cohort data and samples are being used to pursue investigator initiated and collaborative research studies to answer questions related to the role of biological and clinical markers of inflammation, cardiovascular factors, blood protein markers, hyperinsulinemia, and other risk factors in the development and progression of AD. A number of significant research developments have resulted from analysis of the Texas Harris Alzheimer's Research Study data.

Blood samples from all consenting TARCC subjects have been deposited in the National Institute on Aging Genetics of Alzheimer’s Disease Data Storage Site (NIAGADS), a national data repository that facilitates access of genetic data to qualified investigators for the study of the genetics of Alzheimer’s Disease and Alzheimer’s Disease Related Dementias. NIAGADS was developed to facilitate the deposition and sharing of whole-genome and whole-exome sequencing data to the research community at large. TARCC samples have been included in prominent publications on the genetic risks, variants of immune response, and implications of brain protein and lipid processing. Ongoing analysis includes examining ancestry self-report information against genetics to further understand variations in risk factors based upon race and ethnicity.

A novel and important strength of the TARCC database is its longitudinal nature, wherein participants were studied annually. Analysis of the longitudinal data allows TARCC investigators to model changes in cognitive function, behavior, and biomarkers over time, allowing for the identification of factors that affect not only risk, but also disease progression. Another unique strength of TARCC is the enrollment of one of the largest number of Mexican American participants in an ongoing AD research study. Approximately 35% of the Texas Harris Alzheimer’s Research Study participants are of Hispanic ethnicity. Mexican-Americans are the fastest growing ethnic group in Texas and are projected to represent a majority of the state's population by 2020 and very little is known about AD in this population. Many of the Mexican American participants in the original Texas Harris Alzheimer’s Research Study are still being followed as part of a TARCC Investigator Grant approved in 2018, which is exploring whether risk factors, clinical features, age at onset and progression rate of AD and MCI differ between non-Caribbean Hispanics and non-Hispanic Whites.

TARCC is a valuable resource to state and national AD research efforts because of the longitudinal nature of the data collected, the inclusion of Mexican Americans, and the availability of neurobehavioral, genetic and biomarker samples. Wider utilization of this unique resource by a diverse group of AD researchers, both in Texas and across the nation is encouraged to advance AD research efforts.

If you are a researcher and interested in pursuing a study using TARCC data or samples, please see our Data Information and Requests page for more information on the data and samples that are available from TARCC.


Review publications by TARCC researchers.