[Skip to Content]
Access to paid content on this site is currently suspended due to excessive activity being detected from your IP address Please contact the publisher to request reinstatement.
[Skip to Content Landing]
Limit 200 characters
Limit 25 characters
Conflicts of Interest Disclosure

Identify all potential conflicts of interest that might be relevant to your comment.

Conflicts of interest comprise financial interests, activities, and relationships within the past 3 years including but not limited to employment, affiliation, grants or funding, consultancies, honoraria or payment, speaker's bureaus, stock ownership or options, expert testimony, royalties, donation of medical equipment, or patents planned, pending, or issued.

Err on the side of full disclosure.

If you have no conflicts of interest, check "No potential conflicts of interest" in the box below. The information will be posted with your response.

Not all submitted comments are published. Please see our commenting policy for details.

Limit 140 characters
Limit 3600 characters or approximately 600 words
    Views 1,189
    Citations 0
    Original Investigation
    July 6, 2020

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

    Author Affiliations
    • 1Maryland Institute for Applied Environmental Health, University of Maryland School of Public Health, College Park
    • 2School of Remote Sensing and Information Engineering, Wuhan University, Wuhan, Hubei, China
    • 3Joint Global Change Research Institute, Pacific Northwest National Laboratory, College Park, Maryland
    • 4Department of Geological and Atmospheric Sciences, Iowa State University, Ames
    • 5Aerobiology Research Laboratories, Nepean, Ontario, Canada
    • 6University of Maryland School of Medicine, Baltimore
    • 7Chesapeake Clinical Research, Chesapeake, Maryland
    • 8Department of Medicine, Hackensack Meridian School of Medicine at Seton Hall University, Nutley, New Jersey
    • 9Center for Environmental Prediction, Rutgers University, New Brunswick, New Jersey
    • 10Environmental Health Bureau, Maryland Department of Health, Baltimore
    JAMA Netw Open. 2020;3(7):e207551. doi:10.1001/jamanetworkopen.2020.7551
    Key Points español 中文 (chinese)

    Question  Are changes in timing of spring onset related to ongoing climate variability and change associated with rates of asthma hospitalization during the spring season?

    Findings  In this cross-sectional study of 29 257 patients with asthma, very early onset of spring was associated with a 17% increase in hospital admissions for asthma and late onset of spring was associated with a 7% increase.

    Meaning  In this study, the observed associations between changes in timing of spring onset and asthma hospitalizations were likely associated with pollen dynamics, ie, early onset of spring could increase the length of the tree pollen season while late onset may increase pollen concentrations because of simultaneous blooming.


    Importance  Ongoing climate change is affecting the health of communities across the globe. While direct consequences, including morbidity and mortality tied to increases in the frequency of extreme weather events, have received significant attention, indirect health effects, particularly those associated with climate change–driven disruptions in ecosystems, are less understood.

    Objective  To investigate how ongoing changes in the timing of spring onset related to climate change are associated with rates of asthma hospitalization in Maryland.

    Design, Setting, and Participants  This cross-sectional study of 29 257 patients with asthma used general additive (quasi Poisson) and mixed-effect (negative binomial) models to investigate the association between changes in the timing of spring onset, detected using satellite observations, and the risk of asthma hospitalization in Maryland from 2001 to 2012. Data analysis was conducted from January 2016 to March 2019.

    Exposures  Phenology data, derived from the National Aeronautics and Space Administration’s Moderate Resolution Imaging Spectroradiometer, were used to calculate location-specific median dates for start of season from 2001 to 2012. How the start of season for a given year and location deviated from the long-term average was calculated and categorized as very early, early, normal, or late.

    Main Outcomes and Measures  Daily asthma hospitalization in Maryland during the spring season (ie, March to May).

    Results  There were 108 358 total asthma hospitalizations during the study period, of which 29 257 (27.0%; 14 379 [49.1%] non-Hispanic black patients; 17 877 [61.1%] women) took place during springtime. In the unadjusted model, very early (incident rate ratio [IRR], 1.17; 95% CI, 1.07-1.28) and late (IRR, 1.07; 95% CI, 1.00-1.15) onset of spring were associated with increased risk of asthma hospitalization. When the analysis was adjusted for extreme heat events and concentrations of particulate matter with an aerodynamic diameter less than 2.5 μm, the risk remained significant for very early spring onset (IRR, 1.10; 95% CI, 1.02-1.20) but not for late spring onset (IRR, 1.03; 95% CI, 0.97-1.11).

    Conclusions and Relevance  These results suggest that ongoing changes in the timing of spring onset, which are related to climate variability and change, are associated with asthma hospitalization. Given the high burden of allergic diseases and the number of individuals sensitized to tree pollen, these findings serve as a wake-up call to public health and medical communities regarding the need to anticipate and adapt to the ongoing changes in the timing and severity of the spring allergy season.