A New Hypothesis For Asthma in Blacks: Are Medications Part Of The Problem?
Medical researchers have been trying for years to figure out why asthma is much more prevalent among African Americans than whites. The easy answers include numerous environmental factors, such as allergens associated with pollution, cockroaches, dust mites and mold. These can be found in any household, but are thought to be more common in substandard dwellings in poor neighborhoods where asthma is more widespread.
A new, federal study is looking beyond environmental factors to explain uncontrollable asthma among many African Americans. The researchers want to know whether asthma treatments themselves might be part of the problem. Their study, funded by the National Institute of Health, is described as a definitive look at why some of the treatments are ineffective for blacks, and whether genes influence how some blacks respond to the therapies.
Asthma sufferers experience lung inflammation resulting from any number of triggers. The inflammation causes the airways to become narrow or blocked, making it difficult for the victims to breathe. It’s an experience endured by more than 20 millions of Americans, including 500,000 Missouri residents. The most recent Missouri data showed that the illness touched at least one in every 10 black households, compared to one in every 15 white homes.
First step: study the treatment of asthma
The three-year, federal study covers 14 states and 30 sites, including St. Louis. The goal is to figure out the best approaches to managing the disease in a population that experiences more asthma-triggered wheezing and coughing, more hospitalizations related to the attacks and more asthma-linked deaths than whites.
“While national asthma guidelines provide recommendations for all patients with asthma, it is possible that African Americans respond differently to asthma medications,” said Dr. Michael Wechsler, the principal investigator.
The lead investigator for the St. Louis portion of the NIH study is Dr. Leonard Bacharier, a Washington University pediatrician at St. Louis Children’s Hospital. He said the study is expected to have 500 participants, including 60 recruited from the St. Louis area.
“This is a very big study to try to help us understand what to offer the patient whose asthma isn’t well controlled,” he said. “The reason it’s so large is that it’s the first study that will span the entire age range, starting with children as young as 5 and going all the way through adults.”
Participants will begin with low doses of inhaled steroids, which are used to reduce inflammation. The study will test the impact of different doses of inhaled steroids administered with or without the benefit of a long acting bronchodilator, a substance that relaxes bronchial muscles and helps the steroid travel deeper into the lungs to clear inflammation. Typically, a patient carries a quick-acting bronchodilator for relief for a few hours. The long-acting bronchodilator works for 12 hours or more.
In addition to comparing the impact of a combination of medications and doses, the study will determine whether children and adults show similar responses to the treatments.
Second step: asthma and genetics
Bacharier said the second part of the study is a look at genetic footprints. The second part is equally important in understanding how asthma and the therapies used to treat it work in black patients.
“We are proposing that the responses (to various asthma therapies) are linked to the proportion of African ancestry that the individual has. We don’t know how that’s going to turn out. But you have to set up a question in order to answer it,” Bacharier said.
He stressed that all the findings from the genetic research are "kept completely separate from patient names, addresses and what not. The information is as secure as possible. And we are only looking for genetics that relate to allergy and asthma.”
He called this study “a really great opportunity to help us identify and deliver the best asthma care to a population that experiences more asthma and asthma-related life compromises than there needs to.”
The study is called Best African American Response to Asthma Drugs trial or BARD. Individuals interested in participating can reach the BARD coordinator by calling 314-286-1173 or 1-866-841-2273.
Among those taking a big interest in this research is Dr. William Kincaid, who worked on the problem when he headed the St. Louis Asthma Consortium. He said he isn't surprised that researchers have taken so long to seek definitive answers to how well the drugs work in African Americans.
Belated focus on the ways some drugs work in individual groups reflects the way some medical research is conducted, Kincaid said. As an example, he said it took years for heart disease research to include women, even though they suffer high rates of heart-related illnesses and make up half the nation’s population.
“It doesn’t surprise me that (the researchers) are finally working their way down the list to try to understand how to use these (asthma) medications more effectively," Kincaid said. It’s good that they are finally getting at this, so that the data used is more accurate and more targeted to the population that we are treating.”