UCLA Biobank Study Reveals Disease Risk and Health Care Utilization Among LA’s Diverse Population

A new study from UCLA Health’s large genetic biobank gives researchers new insights into the disease risks faced by the region’s diverse communities and their access to health care. The effort, Posted in natural medicinemay prove useful in developing personalized medicine and treatment approaches for groups often overlooked by the medical system.

UCLA Health researchers identified 376 population groups based on shared genetic ancestry by leveraging information from nearly 36,000 patients enrolled in the UCLA ATLAS Precision Health Biobank. The ATLAS Biobank, one of the most diverse genetic repositories in the world, links the anonymized electronic health records of consenting UCLA Health patients with information about their genetic makeup obtained from donated biological samples. Using a machine learning algorithm, the researchers were able to identify groups linked by common genetic ancestry, including some not commonly studied in medicine like Iranian Jews and Lebanese Christians.

The researchers found substantial differences in the rates of diagnoses, hospital use and genetic diseases between the clusters. The findings underscore the limitations of the healthcare system’s frequent reliance on broad self-reported data on race and ethnicity to assess patients’ risk of developing disease, and the findings also support expanding genetic screening to more groups, the researchers said.

Notably, however, shared genetic ancestry is only one factor to consider when trying to understand a population’s disease risk. While people with a common genetic ancestry may share a genetic risk for disease, they may also share an environment — including structural factors like discrimination — that could influence their disease risk and how they interact with the health care system.

“The combination of your genetic risk and your environmental risk are the two most important things in determining whether you get a disease. It’s best if your doctor has the best accurate understanding of the populations you might be from in order to assess things like disease risk or the need for genetic testing,” said lead author Christa Caggiano, a doctoral student in the lab of Noah Zaitlen, a professor of computational medicine and neurology at UCLA Health, who is also the study’s corresponding author.

Included in the researchers’ findings:

• There was great genetic diversity among the Mexican and Central American patients, which was partly explained by the fact that individual patients had different indigenous groups as ancestors. The researchers identified several subgroups of Mexican patients, correlated with the geographic region of Mexico and Guatemala. Only the Guatemalan subgroup was associated with pregnancy complications, while the central Mexican subgroup was more prone to nutritional deficiencies. The finding provides further evidence that the healthcare system’s usual practice of grouping patients by Hispanic and Latino is too broad.
• The researchers also looked at specific genetic mutations associated with diseases. While sickle cell disease is widely known to be associated with African ancestry, the researchers also found genetic variants implicated in sickle cell disease and thalassemia, another genetic blood disorder, which were at higher frequencies in the Chinese ancestry group. Although previous research has indicated that this group is at higher risk for such blood diseases, the new finding reinforces how this group can benefit from genetic testing that is not widely available.
• Other findings revealed how communities in the region access care. For example, researchers have found higher rates of people of Iranian Jewish descent being diagnosed with adjustment disorder, a psychiatric disorder that is not commonly coded in medical records. Digging deeper, the researchers found that the diagnoses were tied to a single medical center, indicating how strongly social forces affect care.

The researchers also created a website, ibd.la, to allow users to search the data themselves. Caggiano said the website might be of interest to a patient curious about disease risk in their ethnic group or a researcher working with a specific community.

Other authors include Joel Mefford, Ella Petter, Alec Chiu, Defne Ercelen, Rosemary He, Daniel Tward, Kimberly C. Paul, Timothy S. Chang, Bogdan Pasaniuc, Eimear E. Kenny, Brunilda Balliu, Valerie A. Arboleda, and Gillian Belbin, all from UCLA; Arya Boudaie, Ruhollah Shemirani, Jonathan A. Shortt and Christopher R. Gignoux.

CC was supported by NIH F31NS122538. CC, NZ, DE, and EP were supported by NIH grants R01CA227237, R01ES029929, R01MH122688, U01HG009080, R01HL155024, R01HL151152. R01GM142112 and R01HG006399. The CRG is supported by NIH grants R01HL151152 and R01HG010297. JAS and CRG are supported by NIH grant U01HG011715. NZ, EK, CG, VA, GB were supported by NIH grant R01HG011345. AC was supported by NIH grant T32HG002536 and NSF DGE-1829071. VA was supported by NIH grant DP5OD024579.

CRG owns shares in 23andMe, Inc. EEK has received personal fees from Regeneron Pharmaceuticals, 23&Me, Allelica, and Illumina; received research funding from Allelica; and sits on the advisory boards of Encompass Biosciences, Overtone and Galateo Bio. All other authors declare no competing interests.