Racial Disparities in Asthma
Why do they exist, and what can physicians do?
Asthma is one of the most common chronic diseases in America, affecting about 8% of the US population—24.7 million Americans in total.1 Although asthma is often perceived as a disease of childhood, the perception is inaccurate: Adults older than 65 suffer from asthma at the same rate as the general population, and they bear a much higher share of the burden of asthma mortality.2
While the disease is common among Americans generally, not all racial and ethnic groups suffer equally. Only 8% of white and 6% of Hispanic Americans have asthma. By contrast, the prevalence of asthma is more than 10% among American Indians/Alaska Natives and 11% among Black Americans. Though Hispanic Americans have low rates of asthma overall, people of Puerto Rican descent are paradoxically at the highest risk of any group, with a prevalence of 15%.1,2
“We are seeing the concentration of the poor health outcomes with asthma in communities of color,” says Neeta Thakur, MD, an assistant professor of medicine at the University of California, San Francisco.
The good news is that there are solutions—and physicians have an important role to play in implementing them, says Sanaz Eftekhari, vice president of corporate affairs and research at the Asthma and Allergy Foundation of America. “There’s actually so much evidence out there about why it exists. There’s also a lot of evidence out there about how to change it.”
The Scope of the Problem
Take emergency department (ED) visits, for example. In 2017, Black Americans visited the ED five times more frequently than did white Americans.1 This is significant because a higher frequency of ED visits indicates poorer asthma management.
Asthma-related mortality is also dramatically higher among Black Americans than among their white peers: There are only 7.4 asthma deaths per million people among white Americans every year, compared with 22.3 deaths per million people among Blacks. The death rate among people of Puerto Rican descent is also strikingly high—about three times the rate in the white population and the broader Hispanic population in the United States.1
The substantial racial disparities in asthma outcomes persist into old age. A study of older asthma patients published last year found that 32% of Black participants and 23% of Hispanic participants reported having an ED visit related to asthma within the previous 12 months—as compared with only 14% of non-Hispanic white patients.3 Those data on older Hispanic adults may seem surprising, since the largest Hispanic American subgroup (Mexican Americans) generally have low rates of asthma, but other research supports the fact that older Hispanic adults have particularly bad asthma outcomes. A study in Rhode Island found that older Hispanic adults were three times more likely to be hospitalized for asthma than were non-Hispanic whites in the same age group and over 50% more likely to be hospitalized than non-Hispanic blacks.4 Similar disparities in hospitalization rates among older adults have been found in other states.5
What Factors Contribute to the Disparities?
Consider a common scenario for an elderly Puerto Rican or Black American: “That person may be a smoker—either former or a current smoker. Puerto Ricans smoke more than other groups,” says Juan C. Celedón, MD, DrPH, Niels K. Jerne Professor of Pediatrics and division chief of pulmonology at the University of Pittsburgh School of Medicine. “He or she may also be exposed to air pollution because his or her house may be close to a factory or a highway. Obesity is also more common in these two groups, and it is a risk factor. They may also live in housing in the projects in apartments that are old and that may have higher levels of allergens, such as cockroaches, dust mites, etc. They may also live in a neighborhood that has a higher rate of crime or violence. That leads to stress—and there is some evidence that stress can worsen asthma—and they may also not go out as much because of fear, which decreases their physical activity and increases their weight. Add to all of this that health literacy may also be lower in those groups, and some of them may not have health insurance.”
While there are multiple factors involved in disparities, it’s possible to group the various causes into specific categories.
There are a variety of reasons why poverty is linked to asthma. Poverty can affect food access and understanding of nutrition (and thus diet quality). It also affects access to health care and is associated with lower health literacy. But perhaps one of the most significant ways poverty affects asthma risk is that it influences a person’s physical environment.
“Asthma, more than a lot of other diseases, is impacted by your surroundings,” Eftekhari says. “Your physical environment plays a big role in your asthma outcomes, because oftentimes asthma is triggered by some allergen or triggered by something external—tobacco smoke, for example, or perfume, or pollen.”
Unfortunately, people in poverty are more likely to live in substandard housing with greater exposure to triggers such as mold, mice, rats, cockroaches, dust mites, and chemical pollutants. They tend to live in areas with more air pollution and to work in occupations with increased exposure to environmental risk factors for asthma.
The link between socioeconomic status and asthma goes a long way toward explaining racial disparities in asthma. Only 10% of white Americans live at or below the poverty line, compared with 19% of Hispanics and 23% of Black Americans.1 Though Black individuals are at higher risk of asthma and of poor asthma outcomes, multiple studies show that much of the disparity disappears when researchers control for socioeconomic variables.9-11
Consider housing discrimination as an example. In the 20th century, banks routinely denied home loans or home insurance to buyers attempting to purchase homes in predominantly Black neighborhoods (a practice known as redlining), because these buyers were deemed to be a poor financial risk. Similarly, housing communities in suburbs became very popular for white families after World War II, but these communities often contained overtly discriminatory covenants that prevented the sale or rental of homes to Black residents. Policies and practices such as this promoted housing segregation, impacted the quality of housing available to Black Americans, and severely limited Black Americans’ ability to build wealth through home equity.13
Some research suggests that these policies could still be affecting asthma now, even though the policies themselves are no longer in force. An ecological study in which Thakur was involved last year found that the population of neighborhoods that were redlined in the 1930s have a higher number of asthma-related ED visits today than do those of communities that were considered low risk for those same loans.14 While the study was not able to show that the link was causal, the findings nevertheless raise important questions, Thakur says.
“The reason why certain racial or ethnic groups have higher rates of certain respiratory disease—including but not limited to asthma—is because the exposures or risk factors that lead to these diseases are more common in those racial or ethnic groups. [So] you have to ask the next logical question: why? Why are these exposures more common in these groups?” Celedón says. In large part, the answer is “poverty. In this country, race and ethnicity are tied to socioeconomic status. [This is] tied to other things like systemic racism and redlining. All these factors play a role.”
One such factor is genes. Twin studies indicate that genetic variation accounts for about one-half of a person’s risk of developing asthma.17 Genetic factors also influence progression of the disease as well as response to treatment.
Such genetic influences appear to explain at least some of the racial and ethnic disparities in asthma. Individuals with African ancestry have higher rates of asthma not only in the United States but also outside of it, including in African countries, which suggests a role of genes.18 Shared African ancestry may explain why both Black and Puerto Rican individuals have comparatively high rates of asthma while Mexican Americans have low rates.19 Importantly, genetic influences appear to interact with environmental exposures to increase asthma risk.17
But while biological factors affect asthma risk, it’s important not to overestimate their contribution. As Celedón notes, studies of Mexican immigrants to the United States indicate that first-generation immigrants—that is, immigrants who were born in Mexico—have very low rates of asthma, whereas those born in the United States have substantially higher rates.20,21 This fact underscores the role of environmental and behavioral factors in asthma prevalence and outcomes.
“There are genetic risk factors for asthma, but I don’t think they vary so greatly across populations to explain why we see such disparities in asthma in the United States,” Thakur says.
Skepticism of medicine and lack of adherence to therapy are not the only behavioral issues that affect asthma incidence and outcomes. Diet and smoking help explain the substantial disparities in asthma between Puerto Ricans and Mexicans, Celedón says. “Remember that ancestry is also a marker of behavior, culture, and environment,” he says. “First-generation Mexican immigrants—their diet is very different from Puerto Ricans. Puerto Rico is a US territory; it’s very Westernized. Mexican diets tend to have less saturated fats, sweets, and sugary drinks.” This matters because diet affects obesity, which is in turn a large risk factor for asthma, Celedón says. As for smoking habits, 28.5% of Puerto Ricans are smokers, compared with just over 19% of US adults of Mexican descent.27
What Can Physicians Do?
Ask about the patient’s environment.
“If a person comes to me with uncontrolled asthma and I do allergy testing and I see cockroach allergen and dust mites are really high in them, then it’s imperative that I ask them about their environment,” Thakur says. “Just giving them medication doesn’t address the thing that’s giving them constant inflammation in their lungs and making them feel poorly.”
According to Thakur, many clinicians ask about environment relatively late in patients’ courses with asthma—often after they have had repeated visits for uncontrolled disease. “One of my own practices is that the first time someone comes in to see me with uncontrolled asthma, I ask them about their environment on day one, because I know those mitigation strategies can take some time to access and deploy for patients,” Thakur says.
Many areas of the country have asthma home visiting programs, and clinicians should refer to such programs whenever possible. This way, patient can have a community health worker visit their home, evaluate the environment for asthma triggers, and recommend remediation strategies. But in areas where home visiting programs are not available, it’s all the more important for physicians to ask questions about the patient’s environment in clinic.
Make sure patients understand the different types of asthma medications.
According to Eftekhari, many patients do not understand the difference between long-term control medications vs short-term relief medications, do not understand why they need to use their inhalers on days they are not experiencing symptoms, and do not understand inhaler technique.
To help address shortfalls in patients’ understanding, clinicians should encourage all asthma patients to take a basic asthma self-management education course, Eftekhari says. The Asthma and Allergy Foundation of America provides one such course for free at pathlms.com/aafa/courses/8092.
Be sensitive to potential communication barriers, and be sure to speak in plain language that patients can understand.
For some minority patients at high risk of asthma, a language barrier may affect the patient’s understanding of the messages they hear in physicians’ offices about their conditions. In settings where this is an issue, Eftekhari encourages making patient education materials available in patients’ native languages if possible.
Even if the patient and physician both speak the same language, it’s still important to speak in language that patients can easily understand. “These groups that are more affected with asthma tend to have lower health literacy—the capacity to understand prescriptions, why a medication works, why it doesn’t work,” Celedón says. Thus, even if the patient speaks English, providers should still communicate in plain language.
Be conscious of cultural beliefs around medications and the medical establishment.
“Latinos are afraid of side effects from inhaled steroids,” Celedón says. “This is true even when health insurance is available.” The key to addressing a barrier like this, again, is good communication—listening for patients’ concerns and then speaking to those concerns directly, in language that the patient can understand.
Finally, Celedón says, physicians shouldn’t forget the bigger picture of the overarching social and structural conditions that drive asthma. While these aren’t issues clinicians can solve in office visits, they can still raise their voices to advocate for policy changes and systemic improvements to housing conditions, air quality, and other factors that significantly affect asthma disparities. “All physicians should be advocates,” Celedón says.
— Jamie Santa Cruz is a health and medical writer in the greater Denver area.
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