March 26, 2025 Story by: Editor
A new study co-authored by a Cornell economist reveals that Black Americans are more likely to participate in medical studies when led by Black doctors and researchers, viewing them as more trustworthy.
The findings highlight the potential benefits of increasing diversity among clinical trial leaders to boost participation from underrepresented groups, particularly Black Americans. Despite making up 13% of the U.S. population, Black individuals represent just 5% of clinical trial participants, even as they experience higher rates of disease and premature death.
Greater racial diversity in clinical trials could ensure that both the risks and benefits of new treatments are properly understood across different populations. It could also lead to wider acceptance of preventive and life-saving treatments, researchers noted.
“If clinical trials don’t adequately represent all the populations that are going to use a drug, this may threaten the generalizability you would hope to have,” said Romaine Campbell, a postdoctoral researcher and incoming faculty member at the Cornell Jeb E. Brooks School of Public Policy and the Department of Economics. “You don’t fully understand whether sub-populations will benefit in the same way as those involved in the trials do.”
Campbell co-authored the study, Investigator Racial Diversity, and Clinical Trial Participation, published in the March issue of the Journal of Health Economics. Other contributors include Dr. Marcella Alsan, a physician and professor of public policy at Harvard University’s Kennedy School of Government; Lukas Leister, a doctoral student in economics at Universitat Pompeu Fabra in Barcelona, Spain; and Dr. Ayotomiwa Ojo, a resident at Northwestern Memorial Hospital in Chicago.
Underrepresentation in Clinical Trials
Black Americans’ low participation in clinical trials is well documented. A recent review of cancer trials found that Black patients made up just 5% of participants for novel checkpoint inhibitors. COVID-19 vaccine trials were slightly more inclusive, with Black participants comprising nearly 9% of enrollees. However, in a recent trial for an Alzheimer’s drug—a disease that disproportionately affects Black Americans—only 19 of more than 1,700 participants were Black.
A 2022 report from the National Academies of Sciences, Engineering, and Medicine, co-authored by Alsan, outlined over a dozen recommendations to improve representation in medical research. In addition to addressing issues like compensation and scheduling flexibility, the report emphasized the need to diversify clinical trial leadership. Currently, fewer than 4% of researchers funded by the National Institutes of Health (NIH) are Black.
Testing the Impact of Investigator Diversity
To assess the potential impact of diverse trial leadership, the research team conducted an online survey with more than 320 Black Americans. Participants were shown a randomly selected headshot of a principal investigator—either white or Black, male or female—sourced from the NIH’s Intramural Research Program website. Machine learning tools ensure consistency in photo quality, age, and facial expressions.
Participants were then informed that the person in the photo was leading an NIH medical study aimed at preventing a disease relevant to their community. They were asked how willing they would be to participate in such a trial.
The study found a 12.6% increase in willingness to participate when the investigator was Black. Gender, however, did not influence participation.
Further analysis identified trust as the key factor driving increased participation. Other factors, such as perceived attractiveness and education level, had a smaller influence.
Addressing Distrust in Medical Research
Black Americans’ historical exclusion from medical research and past unethical experiments—such as the U.S. Public Health Service’s Tuskegee syphilis study (1932-1972)—have contributed to a deep-rooted distrust in medical institutions. This distrust remains a significant barrier to clinical trial participation.
The researchers stressed that fostering trust is essential. While increasing the number of Black clinical trial leaders may take time, Campbell noted that diversity efforts could still be leveraged in the short term. For instance, public health campaigns during the COVID-19 pandemic highlighted Black scientists’ contributions to vaccine development to encourage trust and acceptance.
“We should be more deliberate about diversifying the pool of medical professionals, and in the interim, there are benefits to being strategic about diversity within the existing pool of principal investigators,” Campbell said. “Particularly for clinical trials, we want to make sure we have representative samples so we can best extract the benefits of medical innovation.”
The study was funded by the National Science Foundation.
Source: Cornell Chronicle
