Increases in Asthma Hospitalizations in Maryland Linked to Climate Change and Earlier Spring Onset
July 13, 2020

Climate change affects the timing of spring and is leading to an increase in asthma hospitalizations , according to a new study led by Amir Sapkota of the University of Maryland School of Public Health. The study, published in the Journal of the American Medical Association (JAMA), is the first to provide quantitative data on the connection between climate change, changes in plant phenology and asthma hospitalizations.

Plant phenology is the study of periodic plant cycles and how seasonal and yearly variations in climate influence them.

“Prior studies have shown that changes in plant phenology, such as the timing of spring onset, timing of particular flower bloom, growing season length are the most sensitive indicator of the ecological response to climate change,” explained Amir Sapkota, a professor of applied environmental health and the lead author of the study.

To understand how climate change-driven differences in spring timing are associated with rates of asthma hospitalization in Maryland, the researchers investigated the risk of asthma hospitalization for 29,257 patients from 2001 to 2012 and categorized the timing of spring as very early, early, normal, or late. They used asthma hospitalization data from the Maryland Department of Health, pollen data collected by investigators at Aerobiology Research Laboratories Data and phenology data from the National Aeronautics and Space Administration’s Moderate Resolution Imaging Spectroradiometer. 

They found that very early onset of spring was associated with a 17 percent increase in asthma hospitalizations while the late start of spring was associated with a 7 percent increase.

“Our study shows that the earlier than normal onset of spring increases asthma hospitalization risk rates in Maryland. This is likely related to a longer tree pollen season. Similarly, we observed that the later than normal onset of spring increases asthma hospitalization rates in Maryland. This is likely due to a more intense pollen season because different tree spices bloom simultaneously,” said Dr. Sapkota.

These findings are significant since each year, the production and release of tree pollen triggers springtime allergies and asthma for millions of people in the US. 

“Currently, 8 percent of Americans suffer from asthma, which costs the US economy over $80 billion every year in treatment cost and loss of productivity,” said Dr. Sapkota. "Our data show that ongoing climate change will further exacerbate the asthma burden in our backyard.”

To help, the researchers suggest the need for early warning systems that will inform healthcare providers and patients about the timing of spring pollen season and peak pollen concentration times.

They hope that these findings serve as a call to further investigate the indirect health effects of climate change–driven disruptions in ecosystems.

Dr. Amir Sapkota’s research focuses on the impacts of climate change on human health and the cardiopulmonary health effects of combustion-related air pollutants. He has received multiple grant applications to study underlying population vulnerability to climate change. He currently leads a National Science Foundation and National Oceanic and Atmospheric Administration grant-funded multinational consortium of scientists working to develop innovative solutions to reduce the burden of diarrheal disease caused by extreme weather events in Taiwan, India, China, Bangladesh, Nepal, Vietnam and Indonesia. 

The study, “Association Between Changes in Timing of Spring Onset and Asthma Hospitalization in Maryland” was authored by Amir Sapkota, PhD; Yan Dong, MS; Linze Li, MS; Ghassem Asrar, PhD; Yuyu Zhou, PhD; Xuecao Li, PhD; Frances Coates, MS; Adam J. Spanier, MD, PhD; Jonathan Matz, MD; Leonard Bielory, MD; Allison G. Breitenother, MPH; Clifford Mitchell, MD; Chengsheng Jiang, PhD and published in The Journal of the American Medical Association.

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Association Between Changes in Timing of Spring Onset and Asthma Hospitalization in Maryland