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Health Researchers Urge New Focus on Ancestry, Social Structures

Medical anthropologist at work
Medical anthropologist Lesley Jo Weaver collects data from a patient in northern India as part of her research to address inequalities shaping health outcomes of women with Type 2 diabetes. | Sneha Sharma

When medical professionals make appearance-based assumptions about patients without respect to genetic variation, it can lead to serious health consequences, said National Institutes of Health genetic epidemiologist Charles Rotimi at a 18 December 2018 discussion held at the American Association for the Advancement of Science headquarters, sponsored by the AAAS Dialogue on Science, Ethics, and Religion.

Rotimi said that 97.3% of people have mixed genetic ancestry. “At the genome level, trying to use genetics to define what we call ‘race’ is like slicing soup,” Rotimi said. “You can cut wherever you want, but the soup stays mixed.”

“The ubiquity of mixed ancestry emphasizes the importance of accounting for ancestry in history, forensics, and health including drug labeling,” he said. 

Rotimi described a “critically important” example from a 1996 study: An eight -year-old European boy was scheduled for unnecessary surgery because doctors failed to diagnose him with sickle cell anemia. His parents were from Grenada and of Indian, northern European, and Mediterranean ancestry. Rotimi noted that Greece has a higher population of sickle cell carriers than South Africa.

“If we trace our ancestry far back enough, we’re going to end up somewhere on the continent of Africa,” said Rotimi, who is director of the Center for Research on Genomics and Global Health at the NIH. “This common history is the reason why we share so much of our genetic inheritance,” he said, noting that “Black” and “African” are imprecise ways to describe populations.

The human genome looks like a history book that captures the experiences of our ancestors, Rotimi said. For instance, there is a high rate of kidney failure among African-Americans. Although they are 13% of the U.S. population, African Americans make up 32% of patients with kidney failure. Genetic variations associated with increased kidney disease risk likely rose to high population frequency in Africa because they confer resistance to trypanosmal parasite infection and protect against the lethal form of African sleeping sickness, which was historically a bigger threat than kidney failure, Rotimi said.

These data have serious clinical implications for both kidney donors and recipients.

“Individuals who don’t look like Africans but have African ancestry carry this variant. So, you cannot use the concept of black or white to describe it,” Rotimi said. “Ancestry is critically important, especially when talking about precision medicine or treating individuals. It’s a whole lot more important than the way we see ourselves.”

For these reasons, improving the lack of diversity in genomic research has long been Rotimi’s passion. Although Rotimi said that the driving force behind health disparities is social structures, not genetics, he concluded, “The fact that we’re not engaging different populations can actually lead us to wrong decisions.”

Medical anthropologist Lesley Jo Weaver expanded on this idea, describing her research on how structural inequalities shape the health outcomes of women with Type 2 Diabetes in northern India.

“Racial legacies of colonialism underpin many of the health inequalities that we see today in India and beyond,” said Weaver, an assistant professor of international studies at the University of Oregon.

Weaver told the story of a New Delhi woman who found it difficult to properly manage her diabetes because her low caste, dark skin, and lack of education severely limited her opportunities, placing demands on her time and energy that she struggled to meet.

India has the second highest Type 2 Diabetes rate in the world, with 60 million people across all castes suffering from the condition, Weaver said. Systematic inequality is layered on top of systematic inequality to reinforce health disparities in the population, she said. “This is something that public health practitioners rarely think about.”

The women in Weaver’s study who used religious practice as a coping mechanism along with biomedical interventions were more successful at managing the stresses associated with their diabetes than were women who used biomedical interventions alone, but the best health outcomes were found among those who implemented both approaches, she said.

“There is something in our cultural and spiritual heritage that is relevant for scientists and other researchers doing precision medicine and analyzing the human genome,” said Gay Byron, professor of New Testament and Early Christianity at the Howard University School of Divinity.

In discussing the origins of Christianity in ancient Ethiopia, Byron suggested, “It is only in telling our stories in the fullness of their particularity that we can begin to appreciate the full tapestry of health.” 

AAAS DoSER program sponsors discussions that highlight science advances and their societal implications in a variety of contexts, including an annual holiday lecture at AAAS headquarters in December. DoSER public events typically include scientists highlighting areas of rapid scientific advances along with reflections from ethical, theological, and philosophical perspectives on the broader significance of the research.

[Associated image credit: David Meek]

 

 

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Christine DiPasquale

Communications Director