Johns Hopkins Launches Study of Genetic Drivers of Asthma in Blacks

An international team of scientists is undertaking a groundbreaking, $9.5 million study of the genetic coding of Black asthmatics, a group that constitutes a fifth of all Blacks in the United States.

Though zeroing in on hereditary links to the potentially lethal respiratory disorder in Blacks, the research also aims to yield a more comprehensive knowledge of the root causes of certain diseases in Blacks and, thereby, more precisely tailored medical treatment.

“The proof will be in the pudding of what we discover. But this study is the biggest of its kind. It’s the first of its kind,” said Dr. Kathleen Barnes, an immunogeneticist and professor at Johns Hopkins University School of Medicine and Hopkins’ Bloomberg School of Public Health.

With a disproportionate share of medical research previously enrolling mainly White study participants, this Black-focused asthma research represents an essential departure.

“The genetic and genomic roots are significant,” said Dr. Fernando Martinez, a pediatrician and University of Arizona at Tucson professor. Research findings will help clinicians “treat the cause, not just treat the symptoms.”

Blacks are three times as likely as other adults to be hospitalized or die from asthma, researchers said, which kills 4,000 people annually. Asthma also is the most common chronic disease among children of all races.

Contrasting and comparing the source and symptoms of asthma in various racial categories has been the work of a team of multi-disciplined, multi-ethnic asthma researchers at nine institutions that, in addition to Johns Hopkins and Arizona, include the University of Chicago, the University of California at San Francisco, the University of Southern California, Wake Forest University, Harvard Medical School, Henry Ford Health System in Detroit and the National Institute for Environmental Health Sciences.

The $9.5 million, awarded by the National Institutes of Health, will be spent on the efforts of that nine-member consortium and a complement of researchers outside the United States. That coterie is stationed at University of the West Indies campuses in Barbados and Jamaica, University of Leiden in the Netherlands, the University of Cartagena in Colombia, Catholic University of Honduras, University of Bahia in Brazil and the Center for Investigations at the Ecuadorian Foundation for Health Investigation.

Layering their investigation of genetics are the living conditions of asthmatics. Particularly acute among the poor, less educated and the medically uninsured, asthma also has been tied to environment. And whether in Africa or elsewhere, what research shows is that urbanites are more likely than rural dwellers to suffer from asthma.

“Fifty percent of asthma is due to environment,” said Barnes of Johns Hopkins. “The most common are allergens [including] cockroaches, household dust mites, pollens and mold. Increasingly, diesel exhaust and pollutants are factors. … There are lots of theories. Then, there’s the whole other issue of what comes first the chicken or the egg with the epidemic of obesity in the U.S. We know obesity can worsen asthma.”

The geneticists, immunologists, epidemiologists, allergists and other investigators—several also are based in West Africa—will be surveying socioeconomic circumstances and the DNA of 500 Blacks with asthma and 500 without it.

The DNA extracted by the asthma researchers will help to amplify data in the growing human genome that is archived at and made available to the public by the National Library of Medicine, which, like the environmental health sciences institute, is part of the National Institutes of Health.

“In the case of asthma,” Arizona’s Martinez said, “probably 90 percent of the therapies that we use today were first put to use during the early 1900s. We have not been able to develop new medicines that truly change the course of the disease and, eventually, can prevent the disease. We need to understand much more of the biological basis of the disease and, from that, attack the specific causes of disease that are heterogeneous and, therefore, different in different [patients].”