Epidemiology and Genetics Branch

Dr. Leonardo Mariño-Ramirez staff profile | Lab members

Scientific Expertise

Biobanks, genetic ancestry, gene by environmental interactions, global genomics

Research and Programmatic Interests

Gene by Environmental Interactions

The research program aims to characterize how genetic and environmental risk factors interact to influence health disparities.

It is widely known that health outcomes are caused by genetics, the environment, and their interactions. Nevertheless, health disparities research often considers genetic and socioenvironmental determinants of health separately. The lab aims to consider the joint effects of genomic diversity and place-based socioenvironmental determinants of health, with an emphasis on the role of gene-environment interactions.

The approach is to use genetic ancestry inference, together with population biobank data and causal inference, to decompose the genetic and socioenvironmental contributions to health disparities that disproportionately affect racial and ethnic minority groups in cosmopolitan countries of the global north.

Most of the work to date has been focused on the United Kingdom Biobank, and we have recently expanded our focus to include the NIH All of Us research project, which covers the U.S. population. It is focused on the study of complex, common diseases that have a high overall burden of morbidity and mortality along with disparate impacts among racial and ethnic groups, with a current focus on cardiometabolic disease and cancer.

Genetic Ancestry

Ancestry refers to the geographic origins of a person’s ancestors, and ancestry impacts health (disparities) in different ways. Ancestry can be defined socially, and it can be inferred genetically.

Socially defined ancestry (i.e. race and ethnicity) affects health via individuals’ social environment and their lived experiences, including socioeconomic deprivation, access to health care or lack thereof, and other structural inequities.

Genetically inferred ancestry, as opposed to the social constructs of race and ethnicity, is a characteristic of the genome. Genetic ancestry affords several advantages for health disparities research: it can be inferred objectively and with precision, independently of the social dimensions of race and ethnicity, at different levels of evolutionary relatedness (continental and subcontinental), and at different levels of resolution (genome-wide or haplotype-specific) as a continuous variable.

A major aim of this lab is to use genetic ancestry inference, together with population biobank data, to decompose the genetic and socioenvironmental contributions to health disparities. However, current methods for genetic ancestry inference are slow and do not scale to biobank size datasets. The lab is currently developing fast and efficient genetic ancestry inference methods that scale to biobank size datasets to address this challenge.

Global Genomics

The “genomics research gap” refers to the current bias in genomic studies, whereby the majority of study participants have European ancestry. Genome-based medicine is at the heart of a revolution in medical care, but the lack of diversity in genomics datasets has the potential to exacerbate health disparities. There is broad agreement on the need for genomic studies to be more representative of all populations so that people everywhere can benefit from improved health outcomes.

Three things are needed to close the genomics research gap:

• More data from diverse global populations; admixed populations are understudied.
• Better research methods so that insights from current studies can be applied across populations (ancestries).
• Local capacity must be developed so that genomic approaches to health care can be implemented worldwide.

The lab is collaborating with colleagues from Colombia to develop CÓDIGO, Consorcio para la Diversidad Genómica, Ancestría y Salud en Colombia to address these pressing needs. The global aims of CÓDIGO are to increase the diversity of human genomic datasets in support of global precision medicine, with an emphasis on admixed genomes. The local aims are to support research on genomics, bioinformatics, and precision medicine in Colombia, building bridges between Colombia, Latin America, and the United States.

CÓDIGO is being developed as a comprehensive platform for analysis of Colombian genomes—which will provide data on sequence variants and clinical annotations—nation-wide and population-specific allele frequencies, and patterns of genetic ancestry and admixture.

Under the CÓDIGO model, individual investigators/laboratories share their genomic data with the CÓDIGO development team, with contributing investigators maintaining ownership and control of their data. Only summary statistics derived from the data are released to the public; no individual genomic data or meta data are released. Finally, all contributing investigators collaborate on and receive credit for the platform and any publications that arise from it.

CÓDIGO has genomic variant data for close to 2,000 participants from 16 populations, with various proportions of African, European, and Native American ancestry.

Dr. Allana T. Forde staff profile | Lab members

Scientific Expertise

African Diaspora, discrimination, epidemiology, epigenetics, health disparities, racism, resilience, stress

Research and Programmatic Interests

The program conducts epidemiologic research studies (quantitative, qualitative) that focus on stressors that are more frequently experienced by racial and ethnic minority populations and the impact that these stressors have on health disparities in the United States and abroad.

Specifically, Dr. Forde aims to reduce/eliminate health disparities by exploring heterogeneity in the experiences of race-related stressors (e.g., discrimination, racism) among African, African American, Afro-Caribbean, and Afro-Latino/a populations to better understand the:

• Impact of race-related stressors on cardiovascular risk, morbidity, and mortality.
• Biological mechanisms through which race-related stressors impact cardiovascular health.
• Protective and adaptive factors that could inform interventions.

Research Projects

Race-Related Experiences Associated With COVID-19 and Health in the United States (REACH-US)

The Race-Related Stressors and Health Disparities Research laboratory designed the REACH-US online survey to investigate:

• Personal and observed experiences of racist acts and discrimination.
• Perceived consequences of these experiences on health, quality of life, and behaviors.
• The impact of discrimination and structural racism on access to services and resources at the start of the COVID-19 pandemic.

The survey was administered to a diverse, nationally representative sample of 5,500 adults aged 18 years and older in the United States between January 26, 2021 and March 3, 2021. The sample included 500 American Indian/Alaska Native, 1,000 Asian, 1,000 Black/African American, 1,000 Hispanic/Latino (which includes Latino and Latina participants), 500 multiracial, 500 Native Hawaiian/Pacific Islander, and 1,000 White adults.

Selected Publicly Available Secondary Data Sources From Publications in the Race-Related Stressors and Health Disparities Research Laboratory

Jackson Heart Study

The Jackson Heart Study (JHS) is the largest single-site, prospective, epidemiologic investigation of cardiovascular disease among African American adults. In addition, the JHS is the largest study to examine the environmental, social, and inherited (genetic) factors associated with diabetes, hypertension, chronic kidney disease, cardiovascular disease, and other health outcomes impacting the African American population.

Dr. Forde serves on the leadership team for the Social Determinants of Health Working Group, which is one of the many working groups established to facilitate manuscript development, mentoring, and research collaborations contributing to the aims of JHS.

Multi-Ethnic Study of Atherosclerosis

The Multi-Ethnic Study of Atherosclerosis (MESA) is a medical research study of subclinical cardiovascular disease (i.e., disease detected non-invasively prior to clinical signs and symptoms) and the risk factors that predict progression to clinically overt cardiovascular disease or progression of subclinical disease.

MESA researchers recruited a diverse, population-based sample of asymptomatic White, African American, Hispanic, and Asian adults from six communities in the United States (New York, Baltimore, Chicago, Los Angeles, Minnesota, Winston Salem).

Health and Retirement Study

The Health and Retirement Study (HRS) is a longitudinal panel study of aging that was designed to explore the changes in labor force participation and the health transitions that individuals undergo toward the end of their work lives and in the years after. HRS collects multidisciplinary survey data including, but not limited to, discrimination, coping, disability, cognitive function, and physical health among a representative sample of older adults in the United States.