City living can make asthma worse for poor children, study finds

March 15, 2017
A new study by Johns Hopkins researchers found that while living in inner-city areas doesn't increase the chances of developing asthma, it can make existing asthma worse. Credit: Pixabay

Results of a new study by Johns Hopkins researchers using national data add to evidence that living in inner cities can worsen asthma in poor children. They also document persistent racial/ethnic disparities in asthma.

A report of the study's findings, published in The Journal of Allergy and Clinical Immunology on March 8, shows that urban living and black race are strong independent for increased asthma morbidity—defined as higher rates of asthma-related emergency room visits and hospitalizations—but urban living does not increase the risk for having asthma.

"Our findings serve as evidence that there are differences between risk factors linked to developing asthma and those linked to making asthma worse if you already have it," says Corinne Keet, M.D., Ph.D., associate professor of pediatrics at the Johns Hopkins University School of Medicine and the paper's lead author.

To the researchers' knowledge, few previous studies have been conducted on a national level to determine the effects of inner-city living on both asthma prevalence and severity. While Keet's previous work published in 2015 using a national survey showed that living in an urban area was not a risk factor for having asthma, that study didn't allow for analysis of asthma morbidity.

The research team sought to determine those effects by analyzing information gathered by the U.S. Centers for Medicare and Medicaid Services on the health care utilization of 16,860,716 children ages 5 to 19 who were enrolled in Medicaid in 2009 and 2010.

The team first narrowed the pool of data to children who had at least one asthma-related outpatient or Emergency Department visit over the two-year period. Based on the county they lived in, these 1,534,820 children were categorized by urbanization status and based on their ZIP code, categorized as living in a poor or not poor neighborhood.

Urbanization status identification took into account locations including urban, suburban, medium metro, and a category that combined smaller metro and rural regions. Inner-city residence was defined as living in an urban county and ZIP code where at least 20 percent of households were below the federal poverty line, defined as an income of less than $22,050 for a family of four in 2009.

The team excluded states that were missing more than 10 percent of data on race/ethnicity, states in which all major race/ethnicity groups were not represented and states that did not have urban areas.

The results for 18 states that met the study's final guidelines showed that children who lived in nonurban areas were 18 to 21 percent less likely to be at risk for hospitalizations, even after accounting for race/ethnicity. The researchers also found that compared to non-Hispanic white children, black children and children of "other" races had 89 and 61 percent, respectively, higher risks of asthma-related hospitalizations.

Unlike other racial/ethnic groups, Hispanic children who live in a nonurban area did not experience reduced risks of emergency room visits or hospitalizations. And contrary to Keet's previous studies, which reported that poverty was protective against rates for Hispanic children, the team found no similar association for asthma morbidity.

Keet says that among the Medicaid population she studied, 30 percent of asthma-related hospitalizations were likely attributable to socioeconomic, geographic and/or racial/ethnic disparities; 19 percent of hospitalizations were estimated to be attributable to black race/ethnicity; 4 percent were attributable to living in a poor area; and 7 percent were attributable to living in an urban area.

Children who lived in inner-city areas had an overall 40 percent higher risk of asthma-related emergency room visits and 62 percent higher risk of asthma-related hospitalizations. After adjusting for race/ethnicity, risk was lowered to 14 percent and 30 percent higher for emergency room visits and hospitalizations, respectively.

While this study did not look at any specific environmental exposures associated with urbanization, the findings are in keeping with previous work that shows that certain risk factors concentrated in urban areas, such as exposure to mice and cockroach allergens and air pollution, are associated with asthma morbidity.

Keet says the new study affirms her team's earlier finding that asthma rates or prevalence were not affected by residing in inner-city areas, strengthening evidence that risk factors for the cause of asthma are independent of those that worsen it. For example, exposure to pest allergens is associated with increased asthma morbidity but protects high-risk from developing allergies.

"These results show that despite several decades of research on racial/ethnic and geographic disparities in asthma morbidity, there are still very large differences in rates of visits and hospitalizations by race and neighborhood characteristics. These findings emphasize that we need to redouble our efforts to find comprehensive solutions to address asthma disparities," concludes Keet.

The study's two main limitations were that not all states could be included because of differences in Medicaid data collection, and that it is possible that some of the differences in and hospitalizations could be related to how patients seek care for , rather than only reflecting underlying disease severity.

Explore further: AAAAI: asthma more likely to prove fatal in black children

Related Stories

AAAAI: asthma more likely to prove fatal in black children

March 7, 2017
(HealthDay)—Black American children are six times more likely to die from asthma than their white or Hispanic peers, according to research presented at the annual meeting of the American Academy of Allergy, Asthma & Immunology, ...

Racial gap in children's asthma linked to social inequality in Houston neighborhoods

March 1, 2017
African-American and poor children in the United States suffer disproportionately from asthma. But according to a new study from sociologists at Rice University, racial and socio-economic gaps in the proportion of children ...

New study suggests urban living may be overrated as risk factor for asthma

January 20, 2015
Challenging the long-standing belief that city dwellers suffer disproportionately from asthma, the results of a new Johns Hopkins Children's Center study of more than 23,000 U.S. children reveal that income, race and ethnic ...

Odds of having asthma 53 percent higher in food deserts

November 11, 2016
Living in a food desert - an urban area where it is difficult to buy affordable or good-quality fresh food - means you're at increased risk to have asthma. Children who were studied who did not have access to fresh fruits ...

Home remediation in low-income housing shows significant effect on childhood asthma

November 4, 2015
Children with asthma living in low-income, urban public housing had significantly fewer visits to the emergency department (ED), less use of rescue medication, and less disrupted sleep with a program that combines home repairs ...

Mouse infestations cause more asthma symptoms than cockroach exposure

November 7, 2014
Past research has been inconsistent in determining the relative effects of mouse droppings vs. cockroach exposure on asthma in children. According to a study being presented at the American College of Allergy, Asthma and ...

Recommended for you

Exposure to larger air particles linked to increased risk of asthma in children

December 15, 2017
Researchers at The Johns Hopkins University report statistical evidence that children exposed to airborne coarse particulate matter—a mix of dust, sand and non-exhaust tailpipe emissions, such as tire rubber—are more ...

Bioengineers imagine the future of vaccines and immunotherapy

December 14, 2017
In the not-too-distant future, nanoparticles delivered to a cancer patient's immune cells might teach the cells to destroy tumors. A flu vaccine might look and feel like applying a small, round Band-Aid to your skin.

Immune cells turn back time to achieve memory

December 13, 2017
Memory T cells earn their name by embodying the memory of the immune system - they help the body remember what infections or vaccines someone has been exposed to. But to become memory T cells, the cells go backwards in time, ...

Steroid study sheds light on long term side effects of medicines

December 13, 2017
Fresh insights into key hormones found in commonly prescribed medicines have been discovered, providing further understanding of the medicines' side effects.

The immune cells that help tumors instead of destroying them

December 12, 2017
Lung cancer is the leading cause of cancer-associated deaths. One of the most promising ways to treat it is by immunotherapy, a strategy that turns the patient's immune system against the tumor. In the past twenty years, ...

Cancer gene plays key role in cystic fibrosis lung infections

December 12, 2017
PTEN is best known as a tumor suppressor, a type of protein that protects cells from growing uncontrollably and becoming cancerous. But according to a new study from Columbia University Medical Center (CUMC), PTEN has a second, ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.