Study: Urban density not linked to higher coronavirus infection rates -- and is linked to lower COVID-19 death rates

June 18, 2020

A new study suggests that denser places, assumed by many to be more conducive to the spread of the coronavirus that causes COVID-19, are not linked to higher infection rates. The study, led by a researcher at the Johns Hopkins Bloomberg School of Public Health, also found that dense areas were associated with lower COVID-19 death rates.

The study was published online June 18 in the Journal of the American Planning Association.

For their analysis, the researchers examined SARS-CoV-2 infection rates and COVID-19 death rates in 913 metropolitan counties in the U.S. When other factors such as race and education were taken into account, the authors found that county density was not significantly associated with county infection rate.

The authors also found that denser counties, as compared to more sprawling ones, tended to have lower death rates--possibly because they enjoyed a higher level of development including better health care systems.

On the other hand, the authors found that higher coronavirus infection and COVID-19 mortality rates in counties are more related to the larger context of metropolitan size in which counties are located. Large metropolitan areas with a higher number of counties tightly linked together through economic, social, and commuting relationships are the most vulnerable to the pandemic outbreaks.

"These findings suggest that urban planners should continue to practice and advocate for compact places rather than sprawling ones, due to the myriad well-established benefits of the former, including health benefits," says study lead author Shima Hamidi, PhD, a Bloomberg Assistant Professor of American Health in Environmental Challenges in the Department of Environmental Health and Engineering at the Bloomberg School.

Recent polls suggest that many Americans now consider an exodus from big cities likely, possibly due to the belief that more density equals more infection risk. Some government officials have posited that urban density is linked to the transmissibility of the virus.

Hamidi, whose research background is in urban planning and architecture, and colleagues found otherwise. She and her colleagues, Sadegh Sabouri, a doctoral student, and Reid Ewing, Distinguished Professor of City and Metropolitan Planning at the University of Utah, examined data from January 20 through May 25 on 913 metropolitan U.S. counties, using an approach known as Structural Equation Modeling and taking into account factors such as population size, education levels, and demographic variables including age and race, and health care infrastructure such as ICU bed capacity.

The researchers determined from this analysis that, when controlling for other factors, a measure of density that they termed the "activity density"--which takes into account both residents and workers in a given area--did not have a significant association with SARS-CoV-2 infection rates. Higher activity density did, however, have a significant association with COVID-19 death rates, but an unexpected one.

"The fact that density is unrelated to confirmed virus infection rates and inversely related to confirmed COVID-19 death rates is important, unexpected, and profound," says Hamidi. "It counters a narrative that, absent data and analysis, would challenge the foundation of modern cities and could lead to a population shift from urban centers to suburban and exurban areas."

The analysis found that after controlling for factors such as metropolitan size, education, race, and age, doubling the activity density was associated with an 11.3 percent lower death rate. The authors say that this is possibly due to a faster and more widespread adoption of social distancing practices and better quality of health care in areas of denser population.

The authors conclude that a higher county population, a higher proportion of people age 60 and up, a lower proportion of college-educated people, and a higher proportion of African Americans were all associated with a greater infection rate and mortality rate.

The researchers have been updating the data as the pandemic progresses, and are finding that the associations they have uncovered are becoming even stronger, Hamidi says. The team is also conducting a longitudinal study that tracks the relationships among density, the county-level SARS-CoV-2 infection rates and mortality rates, and explanatory factors as they change over time, and have found consistent results regarding the inverse relationship between density and the COVID-19 mortality rate.

"Does Density Aggravate the COVID-19 Pandemic? Early Results and Lessons for Planners" was written by Shima Hamidi, Sadegh Sabouri, and Reid Ewing.
-end-
Media contacts:

Nicole Hughes
nhughes4@jhu.edu

Carly Kempler
ckemple2@jhu.edu

Johns Hopkins University Bloomberg School of Public Health

Related Public Health Articles from Brightsurf:

COVID-19 and the decolonization of Indigenous public health
Indigenous self-determination, leadership and knowledge have helped protect Indigenous communities in Canada during the coronavirus disease 2019 (COVID-19) pandemic, and these principles should be incorporated into public health in future, argue the authors of a commentary in CMAJ (Canadian Medical Association Journal) http://www.cmaj.ca/lookup/doi/10.1503/cmaj.200852.

Public health consequences of policing homelessness
In a new study examining homelessness, researchers find that policy such a lifestyle has massive public health implications, making sleeping on the street even MORE unhealthy.

Electronic health information exchange improves public health disease reporting
Disease tracking is an important area of focus for health departments in the midst of the COVID-19 pandemic.

Pandemic likely to cause long-term health problems, Yale School of Public Health finds
The coronavirus pandemic's life-altering effects are likely to result in lasting physical and mental health consequences for many people--particularly those from vulnerable populations--a new study led by the Yale School of Public Health finds.

The Lancet Public Health: US modelling study estimates impact of school closures for COVID-19 on US health-care workforce and associated mortality
US policymakers considering physical distancing measures to slow the spread of COVID-19 face a difficult trade-off between closing schools to reduce transmission and new cases, and potential health-care worker absenteeism due to additional childcare needs that could ultimately increase mortality from COVID-19, according to new modelling research published in The Lancet Public Health journal.

The Lancet Public Health: Access to identification documents reflecting gender identity may improve trans mental health
Results from a survey of over 20,000 American trans adults suggest that having access to identification documents which reflect their identified gender helps to improve their mental health and may reduce suicidal thoughts, according to a study published in The Lancet Public Health journal.

The Lancet Public Health: Study estimates mental health impact of welfare reform, Universal Credit, in Great Britain
The 2013 Universal Credit welfare reform appears to have led to an increase in the prevalence of psychological distress among unemployed recipients, according to a nationally representative study following more than 52,000 working-age individuals from England, Wales, and Scotland over nine years between 2009-2018, published as part of an issue of The Lancet Public Health journal on income and health.

BU researchers: Pornography is not a 'public health crisis'
Researchers from the Boston University School of Public Health (BUSPH) have written an editorial in the American Journal of Public Health special February issue arguing against the claim that pornography is a public health crisis, and explaining why such a claim actually endangers the health of the public.

The Lancet Public Health: Ageism linked to poorer health in older people in England
Ageism may be linked with poorer health in older people in England, according to an observational study of over 7,500 people aged over 50 published in The Lancet Public Health journal.

Study: Public transportation use linked to better public health
Promoting robust public transportation systems may come with a bonus for public health -- lower obesity rates.

Read More: Public Health News and Public Health Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.