DAVID GREENE, HOST:
Asthma - it is the leading chronic disease among children. And it hits some populations more than others. African-American children have asthma at much higher rates than white kids. Some of the causes are environmental. But as Lesley McClurg from station KQED in San Francisco reports, genetics plays a role as well.
LESLEY MCCLURG, BYLINE: Zunika Crenshaw cringes as a tire swing whips her kids around in circles on a sunny afternoon.
ZUNIKA CRENSHAW: You guys, be careful. I think that's a little too fast.
MCCLURG: The family is playing in a park in the city of Pleasanton, an eastern suburb of San Francisco. Four of her kids have asthma. So does Crenshaw herself. Three-year-old Jhase runs over to her mother wheezing.
CRENSHAW: Are you feeling OK?
MCCLURG: Crenshaw grabs an inhaler.
CRENSHAW: Ah, go ahead. Ready?
(SOUNDBITE OF INHALER)
MCCLURG: Crenshaw drops the inhaler in a purse full of medications.
CRENSHAW: Zyrtec. And this is ClariSpray. And there's albuterol and Dulera.
MCCLURG: And there are more drugs at home. When the kids start missing lots of school from asthma attacks, it's time to re-evaluate prescriptions and head to something called the Breathmobile, a long motorhome converted into a free-roaming clinic in the Bay Area.
MARY FRAZIER: Tiny breath in. Now take that big one, as big as you can. Deep breath.
MCCLURG: Inside the nonprofit's mobile clinic, a nurse tests the lungs of a 5-year-old girl fiddling with her tight braids. According to the Centers for Disease Control and Prevention, this African-American girl is twice as likely to have asthma compared to a white child and 10 times more likely than white kids to die of asthma-related complications.
Mary Frazier, a registered nurse with the Breathmobile, says asthma is caused by a number of external environmental factors, including air pollution, access to health care...
FRAZIER: ...Pests, molds, mildews, pets in the house, someone who smokes in the house.
MCCLURG: But asthma also runs in the family. And Frazier says her pediatric patients are more likely to have asthma if their parents suffer from the disease.
Marquitta White is a geneticist at University of California, San Francisco. She specializes in minority groups with asthma.
MARQUITTA WHITE: On average, 60 percent of what's going to determine whether or not you have asthma or not is going to be due to genetic factors.
MCCLURG: The subject hits home for White. She's African-American and has three nephews with the disease. White hopes her research can help fill in missing scientific data.
WHITE: The majority of genetic studies, not just in asthma but in most diseases, are done in Caucasian or European-descent populations.
MCCLURG: This general focus on Caucasians pushed Congress to pass legislation in 1993 requiring that publicly-funded medical studies include more minorities. But a recent review of studies since the law passed found that only 5 percent of publicly-funded research on lung disease included non-white patients.
WHITE: Which means that most patients aren't getting the best care because we don't really know what the disease ideology is in their particular population.
MCCLURG: In fact, White recently published a study finding that the majority of genetic information scientists have about asthma only applies to Caucasians.
White works in an ethnically-diverse lab, led by pulmonologist Esteban Burchard. He believes a lot of health disparities could be explained if more minorities were included in genetic research. Burchard uses the analogy of heart disease to make his point. There was a time when doctors only studied men who suffered from heart failure.
ESTEBAN BURCHARD: But women present differently than men do for heart attacks. And so a whole generation of physicians were misclassifying, misdiagnosing women, simply because women were not involved in the original clinical trials.
MCCLURG: And so Burchard's lab is now studying why inhalers provide relief for some children but not for others. The scientists are studying the genes of black, Mexican-American and Puerto Rican children to better understand drug responses in each population.
BURCHARD: This is the first thing that people throw away, the package insert.
MCCLURG: Burchard unfolds a giant sheet of directions inside a box of a common asthma medication.
BURCHARD: I've highlighted in yellow and circled in big red ink.
MCCLURG: He points to a technical paragraph printed in tiny font, stating that there's a much higher risk of death from the medication for African-Americans than for white patients. He says that's tragic.
He hopes there will be a day when researchers and doctors prioritize race and ethnicity when studying a disease or prescribing drugs. He says that would at least, in part, level the playing field and provide better care to African-Americans.
For NPR News, I'm Lesley McClurg in San Francisco.
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