Scientists call for racial diversity in clinical research

Despite a federal law passed more than 20 years ago that requires scientists to include women and minority subjects as they investigate diseases, clinical research has made very little progress when it comes to minorities, according to a review of more than 10,000 cancer studies.

In a paper published Tuesday in the journal PLOS Medicine, researchers from the University of California, San Francisco; Instituto de Salud Carlos III in Madrid, Spain; and Emory University School of Medicine in Atlanta highlight that, among more than 10,000 studies on cancer funding by the National Cancer Institute (NIH), just 2 percent included a primary focus on racial or ethnic differences in the disease.

Minority subjects were underrepresented in all but 5 percent of federally funded clinical studies on respiratory diseases, the researchers said.

Using a Freedom of Information Act request, the researchers found that award rates for funding grants from the NIH’s Office of Extramural Research are “consistently lower” among non-white applicants, who received grants 42 percent of the time in 1985 and 19.3 percent of the time in 2013. White applicants, meanwhile, received funding grants 48.6 percent of the time in 1985 and 23.3 percent of the time in 2013. The study did not address why grant approvals overall had declined for both groups.

“The NIH alone will not be able to correct the disparities or inequities of the healthcare system," the authors wrote, "but it can send a powerful message that may promote changes in our health care and health science systems."

In 1993 the U.S. passed the NIH Revitalization Act (PDF), which requires medical researchers to prioritize the inclusion of women and minorities as research subjects.

The authors of the study say that since 1993, NIH-funded studies have made huge advances in clinical studies that include women and make note of sex-specific differences in symptoms and treatments. But that the same effort hasn’t been made for including minorities.

Part of the reason, they say, may be because of the historically low representation of minorities graduating with doctoral degrees in the biomedical sciences. They also note that less than 2 percent of principal investigators on NIH-funded research project grants are African American, 3.4 percent are Hispanic and 0.4 percent are Native American, far less then their representation in the U.S. population.

While the authors underscore that not every study needs to look at ethnic differences in disease, including diverse groups in clinical research “can provide meaningful opportunities to examine the complex relationship of ancestral influences, environmental exposures and social factors.”

"Increasing diversity is also a worthwhile effort scientifically," Sam Oh, an epidemiologist and researcher in the UCSF Center for Genes, Environment and Health, and one of the study authors, said in a release. "We can't divert our resources knowing that an intervention is only going to work on a small portion of the population. By understanding that population, we can target our resources effectively for everyone. But we'll only learn that by having study populations that represent everyone."

The researchers cited examples of insights on diseases that scientists have gained in the process of researching racial or ethnic differences in certain illnesses. Scientists, for example, discovered a genetic variant of an estrogen receptor in Latinas that protects them from breast cancer, after they found this difference in subjects with Native American ancestry.

In another study, researchers found that exposure to chemicals such as BPA — which are known to disrupt the body’s endocrine system — are more common in low-income and minority communities, and have been linked to increased rates of premature births in those groups.

Additionally, scientists have discovered that up to 70 percent of Asians and Pacific Islanders lack an enzyme to activate the blood thinner clopidogrel, which is prescribed to reduce stroke risk after angioplasty, making the drug ineffective for them.

The authors credit the NIH with its recent efforts to study racial and ethnic diversity, with President Obama’s launch of a research initiative on precision medicine, which tailors treatments to genetic makeup and will recruit at least 1 million Americans as subjects. NIH is also testing a pilot program that would make anonymous applications for funding grants to help eliminate bias.

"Diversity in science is science done well," Oh said. "You need diversity in the research, diversity in who is being studied and diversity in the people doing the science. Otherwise you become an echo chamber — everyone looks and sounds just like us."