Race and Health Inequalities in Medicine
A recent conference brought together medical professionals and other researchers to explore the intersection of race, genomics, and health inequities.
Published April 14, 2006
By Alan Dove
Academy Contributor
Romulus. Cain. Mr. Hyde. Literature abounds with evil twins. Far less famous, but far more dangerous, are the malevolent siblings that haunt nearly every branch of science. Their fortunes wax and wane, but they never really die. Alchemy now tinkers quietly in chemistry’s attic, but astrology is a media darling that often eclipses her nerdy sister, astronomy. Meanwhile, physicists and mathematicians hear the constant pitter-patter of new generations of cranks, each busily perfecting perpetual motion or squaring circles in his own little corner. A whole gaggle of quackeries trails medical science.
For sheer Gothic horror, though, the doppelganger stalking genetics has no equal. Chiropractors may rip an occasional carotid artery, and a rogue mathematical hermit might send the odd mail bomb now and again, but only eugenics—the belief that the human race can be improved by selective breeding—has spawned continent-wide slaughters of millions of innocent people. Even while genome sequencers amass gigabytes of data supporting the unity of mankind, geneticists continue to look over their shoulders, worried that someone could pervert their findings to terrible new uses.
On December 9, 2005, biological and social scientists met at Hunter College for an interdisciplinary discussion of a particularly dangerous area: the intersection of minorities, genomics, and health inequities. The presentations ranged freely across this contentious triple border, exploring everything from drug development technology to racial profiling. The conference, the 19th Annual International Symposium of the Center for the Study of Gene Structure and Function, featured nearly a dozen excellent talks. A few highlights provide a representative sample of the breadth and depth of topics.
From Racial Profiling in Drug Development to the Genetics of Homosexuality
Conference organizers took a wide view of the term “minorities,” and the discussion spanned everything from the racially profiled drug BiDil to the genetics of homosexuality. Some common themes emerged from these diverse research projects, though, including an enduring division between biological and social scientists on the potential of genomics. While many biologists tend to view the progress of genomics as an unmitigated boon, social scientists remain wary of the new field’s potential for misuse.
Troy Duster of New York University brought this discussion to the biologists’ doorstep, arguing that the science of genomics is already on a collision course with entrenched social problems of race. The completion of the human genome sequence was originally hailed as a landmark demonstration that human races are more similar than they are different, but in recent years old racial concepts have started to creep back into the core of genomics.
As one example, Duster cites BiDil, the first drug with a race-specific prescription label. The original clinical trial of BiDil, a heart disease treatment that targets nitric oxide metabolism, was a failure. Nitromed, the drug’s manufacturer, reanalyzed the data and found that a subset of African American patients benefited from BiDil. The U.S. Food and Drug Administration found the reanalysis persuasive, but Duster systematically dismantled Nitromed’s underlying reasoning.
Should We Have Race-specific Drugs?
“The question for me is, is it nitric oxide deficiency? If this is the case it should be available to all those who have this deficiency; it should not be racialized. What I am opposed to…is the notion that we can [get] a molecular understanding of race with this kind of research,” says Duster.
More ominously, police forces have begun testing new genomic technologies that claim to provide racial profiles from DNA found at crime scenes. This DNA dragnet might catch more criminals, or it might merely amplify existing racial disparities in law enforcement.
David Williams of the University of Michigan underscored the depth of the racial divide with some well-known but still shocking statistics. African Americans lead white Americans in 12 of the top 15 causes of death, translating to about 97,000 excess deaths per year. How many of those 265 deaths a day are due to endemic racism?
On the evidence, quite a few. For example, one of the leading causes of death among blacks in the U.S. is heart disease. Some of that disparity could be genetic, but Williams points out that black Africans have lower rates of hypertension than black or white Americans, clearly pinpointing environmental factors as the main cause. Poor health correlates strongly with low socioeconomic status, but even controlling the data for status does not eliminate the black-white skew. Something other than biology or money is causing the problem.
Racism May Literally Make African Americans Sick
Citing data that show a strong link between perceived racism and cardiovascular disease, Williams argues that a daily grind of inferior treatment can literally make African Americans sick. Another, more pervasive factor is the stubbornly entrenched segregation of housing: even four decades after the Civil Rights Act, black Americans are overwhelmingly concentrated in neighborhoods with fewer jobs, less access to social services, and more crime. Black neighborhoods disproportionately feel the brunt of everything from economic downturns to natural disasters. “When a group is highly segregated, it’s easy to discriminate against that group,” says Williams.
Brian Mustanski of the University of Illinois at Chicago exemplified the breadth of the conference by presenting data on one of the most controversial questions in modern biology: what makes some people gay and others straight? The field of sex research got its first quantitative tools in the 1940s, through the pioneering work of Alfred Kinsey, but sophisticated methods for genome mapping now provide new ways of searching for the biological basis of sexual orientation.
Homosexuality appears to have an inherited component, and earlier pedigree studies suggested that the Xq28 region of the X chromosome might be involved. To probe the issue more deeply, Mustanski and his colleagues mapped genomes from 146 families with at least two gay brothers. The researchers used a technique called microsatellite mapping, which provides a broad but low-resolution view showing which parts of a given genome came from each parent.
Male Homosexuality Appears to be Partly Inherited
Specific regions of chromosomes 7, 8, and 10 co-segregated with male homosexuality in the families. Interestingly, the trait seems to have an imprinted component, meaning some of the genes that determine it behave differently depending on whether they are inherited from the mother or the father. The new work confirmed that the Xq28 region might also help determine sexual orientation, but only in some families.
To date, nearly all of the major studies on the genetics of homosexuality have focused on gay men. Sexual orientation may develop quite differently in women, and studies on female homosexuality will likely require more sophisticated techniques.
Charles Rotimi of Howard University, one of the architects of the Human Genome Project and its descendant, the International HaplotypeMap Genome Mapping (HapMap) Project, discussed his recent work on type 2 diabetes in African populations. Type 2 diabetes, which has reached epidemic proportions as obesity rates have risen worldwide, is especially prevalent among African Americans. The disease, a dysfunction in blood sugar regulation, can lead to blindness, limb loss, heart failure, and stroke. Type 2 diabetes apparently arises from a complex interaction of genetic and environmental factors, making it particularly challenging to study.
In sequencing the human genome and developing the HapMap, researchers used DNA from several populations around the world, including the Yoruba tribe of West Africa. The Africans who were sold into slavery in prior centuries came primarily from a few tribes, including the Yoruba, so a large proportion of modern African Americans are descended from this group. Because West Africans and African Americans share genes but live in radically different socioeconomic environments, they provide a natural experiment for studying type 2 diabetes.
West Africans and African Americans Share Genes, But Not Environments
In a coarse mapping analysis of West Africans, technically similar to the method Mustanski employed in gay men, Rotimi and his colleagues identified specific regions of chromosomes 5 and 19 that may contain genes predisposing some people to diabetes. The researchers now hope to map the genes more finely, using the closely spaced genetic markers that have become available through the HapMap Project.
Though the results are interesting, Rotimi stresses that “conditions like diabetes … are truly complex diseases that are multifactorial at the molecular and the genetic level and also at the environmental level.” Environmentally, the stark social disparities between white and black Americans undoubtedly explain much of the skew in U.S. diabetes rates.
Carlos Bustamante of Cornell University eventually touched on a racial difference in metabolism that has important social impacts, but the bulk of his presentation focused on the universal traits of humanity, and what distinguishes us from other animals. Like many human geneticists, Bustamante has a particular fondness for chimpanzees, since these apes and humans are each other’s closest relatives.
“With the completion of the chimp genome and patterns of variation within the human genome, we can begin to answer the philosophical question of what it means to be human, from a real biological perspective,” says Bustamante. Taking an initial stab at that question, Bustamante and his colleagues analyzed the genomes of the two species with new statistical algorithms. The results reveal protein-coding genes that probably underwent either positive or negative natural selection in the five million years since humans and chimpanzees diverged.
Genome Comparisons Reveal What Makes Us Human
Evolutionary biologists have long argued that mutations are more likely to be harmful than beneficial, and the new data agree: of more than a thousand genes the algorithm highlighted, deleterious mutations appear to have occurred about twice as commonly as beneficial ones during the journey from chimpanzee to human. Reassuringly, the search fingered many genes involved in known genetic diseases, suggesting that the scientists are on the right track to find new medically important genes as well.
The positively selected genes affect smell receptors, components of the immune response, and enzymes that metabolize alcohol. The last group is especially interesting; these genes apparently vary between different ethnic groups, possibly explaining some racial differences in alcoholism rates.
Cause for Optimism and Wariness
Also participating in the event via video confence was John Ruffin, director of the National Center on Minority Health and Health Disparities at the National Institues of Health. Ruffin talked about the major efforts that the NIH was undertaking to coordinate existing national centers in restoring the research infrastructure after the Katrina debacle. He also discussed the strategies that the NIH is deploying to focus national research on understanding the causes of health disparities and addressing these inequities. Additionally, he described techniques for developing more culturally sensitive clinical researchers, and procedures to improve their impact. He saw this conference as an important component of the national effort.
As genomics forges ahead, biological and social scientists clearly have cause for both optimism and wariness. Genetics now proves that all people are fundamentally similar, but the history of eugenics belies our fundamental desire to be different, and the horrific results that can produce. We have met the evil twin, and he is us.
Also read: Big Data’s Influence on the Future of Healthcare
About the Author
Alan Dove earned his PhD in microbiology from Columbia University and is now a science writer and reporter for Nature Medicine, Nature Biotechnology, and Journal of Cell Biology
