NIMHD Takes the Lead in Expanding the Science of Minority Health and Health Disparities

The National Institute on Minority Health and Health Disparities digs deep to expose roots of health disparities seen in minority groups.

While the existence of health disparities in the United States is a robustly researched and documented fact, pinpointing the reasons why such gaps exist has proven more complicated. That pursuit, however, has turned health disparities and minority health research into scientific disciplines in their own right.

“In the early days [of health disparities research], there was a big focus on existence and intervention—there was an understandable push to do something about it,” says Eliseo Pérez-Stable, MD, director of the National Institute on Minority Health and Health Disparities (NIMHD) at the National Institutes of Health (NIH). “But what are the root causes? What’s the mechanism for seeing the differences?”

NIMHD has been leading and coordinating research into such questions since it was first established as an NIH center in 2000. Among its latest research efforts is the William G. Coleman Jr., PhD, Minority Health and Health Disparities Research Innovation Award, which is designed to advance pioneering science into the roots of health disparities and minority health. In August 2017, the first three Coleman awardees received $15,000 each to support their research. According to Pérez-Stable, the award was created to help fund early career scientists in the field and to honor Coleman, the first black scientific director of NIH’s Intramural Research Program. He also hopes the award will help broaden diversity within the biomedical and scientific workforce.

“Understanding what leads to these different outcomes advances science in a way that wouldn’t necessarily be possible if we weren’t studying them with a racial/ethnic lens,” Pérez-Stable says. “The bottom line—what we’ve learned over the last 20 years—is that there’s a real scientific discipline here that we need to support.”

Breaking new ground in disparity research

The three Coleman projects will look at health gaps from two angles—minority health research and health disparities research. Although they are often put under the same umbrella, they have subtle but important differences, according to Philip Alberti, PhD, AAMC senior director for health equity research and policy.

“Social disadvantage—racism, poverty, etc.—doesn’t play a role in explaining why African Americans are more likely than whites to have sickle cell disease. That’s not inequity: the difference is largely due to biological adaptations, and it’s an important area of inquiry for minority health researchers,” Alberti says. “But black patients, sickle cell patents included, are more likely than whites to have their pain undermanaged. Or wealthy sickle cell patients might receive better care than their less well-off peers. That’s inequity, and those are health injustices we can and should address via health disparities research.”

“Our strength has to focus on the clinical population and the behavioral and social sciences, but we need to learn and maintain a strong connection to what’s going on in the lab so we can apply it. It’s not all biological, but it’s not all social. It’s that blend that makes this research so exciting.”

Eliseo Pérez-Stable, MD
National Institute on Minority Health and Health Disparities

As a member of the Genomics and Health Disparities Interest Group at the National Human Genome Research Institute (NHGRI), Candace Middlebrooks, PhD, MS, connects researchers across NIH disciplines and finds ways to further scientific inquiry into disparities. When the Coleman award was announced, Middlebrooks, a postdoctoral fellow at NHGRI, saw it as the perfect opportunity to make her own scientific contribution.

“I want to make sure I use whatever knowledge I have to help alleviate [disparities],” Middlebrooks says. “I understand health disparities, and I have family members who developed illnesses associated with being impoverished or being from a lower socioeconomic background, so I feel very close to it.”

With support from the Coleman award, Middlebrooks is examining genetic risk indicators for leg ulcer development in U.S. patients with sickle cell disease, an inherited red blood cell disorder that most commonly affects people of African descent. While researchers know that sickle cell is caused by a combination of sickle cell genes from both parents, they are unsure why some people with the disease develop symptoms such as leg ulcers and others don’t. The cause may be partially environmental, but as Middlebrooks hopes to find out, there could be a genetic underpinning as well.

While leg ulcers affect a relatively small percentage of sickle cell patients in the United States, Middlebrooks notes that the painful condition can greatly decrease quality of life, “making it hard to walk, go to work, or do anything enjoyable.”

Middlebrooks is partnering with NHGRI colleague Vence Bonham, JD, principal investigator of the INSIGHTS study, which focuses on sickle cell and accompanying leg ulcers in adults. If Middlebrooks’ research can identify a genetic predisposition for leg ulcers or for the bacterial flora associated with such ulcers, it could eventually inform clinical interventions.

“Now that sequencing is so much cheaper, we’re hoping to seed bigger collaborations and help rejuvenate interest in sickle cell,” Middlebrooks explains.

At NIH’s National Cancer Institute (NCI), Coleman awardee Tracy M. Layne, PhD, MPH, is examining the biochemical characteristics of prostate cancer among black men to better understand their disproportionate disease burden. Data from the Centers for Disease Control and Prevention show black men experience significantly higher rates of prostate cancer and are more likely to die from the disease than other races or ethnic groups. Still, says Layne, a postdoctoral fellow at NCI, while disparities in access to cancer screenings and treatment play a role in such outcomes, there may be genetic underpinnings as well.

“We think access to care likely contributes, but there’s a huge gap in the literature that prospectively examines this population,” she explains. “Most of the literature [on prostate cancer disparities] is documenting the differences in risk without understanding what contributes to the differences. Many of the risk factors don’t consistently explain the greater risk in black men.”

With the Coleman award, Layne is examining blood samples from two prospective studies—the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial and Multiethnic Cohort Study of Diet and Cancer. The samples will undergo metabolic profiling analysis to reveal possible genetic factors that contribute to higher rates of prostate cancer in black men. Layne notes that the study is “agnostic.” In other words, she has no specific hypothesis about what she may find using metabolic profiling, which is a relatively new technique used to study the risk of disease development.

The goal, according to Layne, is that her work will become a jumping-off point for more targeted investigations of prostate cancer disparities.

“I certainly think it’s necessary to see disparities as a science in and of itself,” Layne says. “We can’t afford to approach all health disparities in the same manner—one size fits all won’t always work.”

Pérez-Stable agrees. “Our strength has to focus on the clinical population and the behavioral and social sciences, but we need to learn and maintain a strong connection to what’s going on in the lab so we can apply it. It’s not all biological, but it’s not all social. It’s that blend that makes this research so exciting.”