Using health records and location data to identify asthma triggers

Indoor allergens such as cockroaches, dust, and mold are known to contribute to a range of health complications, including childhood asthma, which is the leading pediatric chronic disease in the United States and one that disproportionately affects Black and Latino children. But these triggers are often difficult for doctors to pinpoint and treat without detailed knowledge of patients' specific living conditions and environmental exposures. 

A new study led by Boston University School of Public Health (BUSPH) researchers suggests that it is possible to predict whether children with asthma are exposed to certain allergens simply based on where they live-and whether this exposure may be exacerbating their respiratory issues.

Published in the journal Annals of Epidemiology, the study used a novel modeling method to link electronic health records containing data on in-home environmental exposures to housing and neighborhood location data for children with asthma living in low-income households. Children living in homes with greater chances of having cockroaches and rodents had worse lung function.

With existing medical record information, doctors could predict if a patient might be exposed to mouse and roach allergens at home. This information can be used to address home risk factors and improve asthma control, in addition to other strategies such as medication. It can also help children without asthma, since these allergens are implicated in the development of asthma as well as exacerbations."

Dr. Patricia Fabian, study co-corresponding and senior author, associate professor of environmental health at BUSPH and associate director at BU Institute for Global Sustainability

As the majority of the children in the study were Black and lived in historically segregated neighborhoods, these findings highlight the consequences of longstanding racial inequities in housing characteristics and quality, borne by structural racism. Discriminatory policies such as redlining resulted in broad disinvestment in housing for Black families and other racial minorities, decreasing their home quality and stability, as well as neighborhood resources-all of which can lead to environments where roaches and other pests can thrive in greater quantities. Black children are twice as likely to develop asthma than White children, and their mortality rate from asthma is nearly eight times higher than White children.

While some studies have suggested that childhood exposure to indoor allergens may help prevent children from developing asthma, other data indicate that this exposure exacerbates this condition in children. Many animal-related allergens, in particular, are known triggers for asthma attacks, Dr. Fabian says.

"In the case of roaches, allergens are in their droppings and body parts, and for mice, allergens are in their urine and saliva," she says. "These allergens are small and can become airborne, easily reaching the respiratory system and triggering asthma attacks."

The findings build upon a 2022 study in Annals of Epidemiology in which the authors first developed these prediction models for the presence of in-home asthma triggers among children with asthma, using machine learning methods, EHR data, and publicly available geospatial data matched to patients' addresses at Boston Medical Center (BMC), the largest safety-net hospital in the Northeast. For the newest study, the researchers applied these models and linked this information to lung function test data from EHRs for 1,070 children with asthma at BMC.

"These studies were a proof of concept that we could analyze child lung function at the level of individual homes without going into homes to measure levels of allergens," says study co-corresponding author Dr. Matthew Bozigar, assistant professor of epidemiology at Oregon State University. "We combined granular data with advanced methods to account for error-such as estimating if a home likely had cockroaches-and linked these exposures with clinical lung function metrics."

Rather than documenting asthma disparities, they focused on parcel-level housing factors linked to poor lung function within an already-affected population, he says. "We followed recent scholarship in identifying structural drivers of disparities, avoiding the use of race as a proxy for systemic racism."

The authors emphasize that this methodology may also be utilized to provide valuable insight about other disparities, populations, and adverse health outcomes. 

"Every hospital and clinic collects electronic health records for their patients, which means this approach is scalable to most populations in the world, as long as records are kept consistently," Dr. Fabian says. "New advances in satellite, housing and environmental data collection are expanding our ability to connect health data to geospatial data worldwide, as well. Any health outcome that is connected to risk factors related to housing can be studied using similar methods."

Coauthors include Catherine Connolly, postdoctoral research scientist at Columbia University Mailman School of Public Health at the time of the study; Kimberly Vermeer, founder and president of Urban Habitat Initiatives; Luis Carvalho, associate professor of mathematics and statistics at BU College of Arts & Sciences; Robyn Cohen, pediatric pulmonologist and director of BMC's Pediatric Pulmonary & Allergy Clinic; Julianne Dugas, an analyst at SPH's Biostatistics and Epidemiology Data Analytics Center at the time of the study; and Jonathan Levy, chair and professor of environmental health at SPH. The study was funded by the National Institutes of Health.