Your environment can increase your risk of hospitalization for breathing

The range of symptoms of COVID-19 varies — some feel a mild flu, some are hospitalized, some die. Many studies have linked the severity of COVID-19 symptoms to a person’s biological factors, but little is known about the impact of non-biological factors, such as the environment in which the person lives.

A new study published June 14, 2023, in the journal PLoS ONE, is the first to show that built-in environments can pose independent risks that define individuals hospitalized with COVID-19 disease.

The authors found that in a cohort of more than 18,000 people with SARS-CoV-2 infection, living in multi-family buildings, living in neighborhoods with higher levels of air pollution (PM2.5) and living in neighborhoods with lower walkability and cycling ability was associated with greater incidence rates of hospitalization, even when controlling for socioeconomic vulnerability and individual-level demographic and medical characteristics. Neighborhoods with higher quality and access to public transport were also associated with higher incidence rates of hospitalization.

The study identified differences between the two largest ethnic groups in the region. Higher PM2.5 levels lead to higher hospitalization rates for Latinx individuals, and density and overcrowding show a stronger association for non-Hispanic white individuals.

These findings could help inform public health and urban planning initiatives to lower the risk of hospitalizations associated with COVID-19 and other respiratory pathogens.

“For urban planners, these findings underscore what we are already trying to do to build healthier communities—creating more walking conveniences, cycling capabilities and infrastructure that will reduce air pollution,” said Alessandro Rigolon, associate professor at the University of Utah and the study’s lead author. “From a public health perspective, these findings could help test and vaccination campaigns target areas with higher air pollution or housing large numbers of families.”

The study also reveals how urban policies from the past continue to impact the daily lives of many communities.

“We found significantly higher rates of COVID-19 hospitalizations along the I-25 and I-70 corridors and in the North Denver industrial area,” said Jeremy Németh, professor at the University of Colorado Denver and co-author of the study. “These are the same areas that have experienced decades of disinvestment and increased air pollution because of the racist land use policies imposed on our cities in the early 20th century.”

Environmental built environment

The study analyzed environmental characteristics in the Denver Metro Area associated with the hospitalization of 18,042 people who tested positive for SARS-CoV-2 between May and December in 2020, before a vaccine became widely available. Researchers from the Denver Metro Area’s two major health care systems, Denver Health and the University of Colorado Hospital, reviewed more than 30,000 eligible individual cases. They limited the cohort to those living in larger metro areas, and matched available health record data for each case. Variables pulled from medical records included age and body mass index (BMI), evidence of tobacco use, hypertension, chronic lung disease, some forms of cardiovascular disease, and chronic kidney disease. Researchers at the University of Colorado Denver then converted the addresses of people in the final cohort into their geospatial coordinates and assigned environmental variables accordingly.

Ethical oversight and approval for this study was provided by the Colorado Multiple Institutional Review Board and all protected health information was anonymized prior to sharing.

“Very few studies are as comprehensive as ours. We can control for several individual-level factors that, for people with COVID-19, will increase the likelihood of being hospitalized,” said Rigolon.

Taking most biological factors into account, the authors identified four environmental characteristics that might contribute to COVID-19 hospitalizations: overcrowding and overcrowding, including living in overcrowded homes or multi-family buildings; environmental hazards, such as air pollution levels (PM 2.5) and proximity to roads; environmental facilities, including access to parks; and mobility options, including access to public transit, walkability, and the ability to cycle.

The authors are not surprised that individuals with compromised pulmonary and immune systems who deal with chronic air pollution will not respond well to respiratory disease and are more likely to require hospitalization after contracting COVID-19. Their finding that higher PM2.5 levels impact Latinx individuals more than non-Hispanic white individuals underscores a worldwide problem—air pollution disproportionately affects People of Color. While the findings support making the existing environment more walkable and cycleable, the authors emphasize that future planning efforts to reduce emissions must be centered around the principle of environmental equity. Because walkability is so protective in Latinx communities, the authors suggest that cities should prioritize investments to make Latinx-dominant neighborhoods pedestrian-friendly.

The density and density results underscore the need for vaccination and testing efforts to focus on areas with multi-family housing to reduce the risk of severe disease. As living in transit-rich neighborhoods is associated with a higher risk of hospitalization from COVID-19, public health measures such as education and outreach campaigns in this area are especially important.

“So many health differences follow geographic lines. We’ve long suspected that more than a pre-existing medical condition was to blame for the discrepancy. It’s been exciting to work with the city planning team to pinpoint which environmental factors are partly to blame for the disproportionate hospitalization rates we continue to see. This will help public health leaders continue to advocate for healthier cities, and it helps inform outreach efforts to tackle COVID-19 and other respiratory diseases,” said Sarah Rowan, professor of medicine at the University of Colorado School of Medicine, Denver Health infectious diseases. physician and senior author of the study.

Environment in other areas, other diseases?

The authors wanted to replicate this study in other regions such as the Salt Lake Valley in Utah, which has similar environmental and population characteristics to the Denver Metro Area. They also want to expand to other respiratory illnesses where people are hospitalized, such as the flu. While it can take several years to process large volumes of patient records, studies that can look at health and built environment outcomes at the individual level are invaluable.

“Urban planning was born out of a public health problem in the US when cities became very crowded, very polluted, and sanitation became a problem. It is natural for urban planners to conduct research that involves public health,” said Rigolon.

Additional contributing authors include Brenn Anderson-Gregson, Ann Rae Miller and Priyanka deSouza of the Department of Urban and Regional Planning, University of Colorado Denver; Brian Montague and Kristine M. Erlandson of the Division of Infectious Diseases, University of Colorado School of Medicine; and Cory Hussain, University of Colorado School of Medicine and Denver Health.