Thunderstorm Asthma Spikes ED Visits

J.Adderton, BSN, MSN

For decades, scientists have predicted global warming will increase the number and intensity of inclement weather events. A band of violent thunderstorms moved through southeastern Australia in the fall of 2016 and triggered a wave of asthma attacks. Melbourne was hard hit with more than 8,000 people rushed to local emergency rooms. This was not the first time a strong storm caused an outbreak of "thunderstorm asthma" The first observed occurrence of the storm phenomenon was documented on July 6, 1985, in Birmingham, England.

An Unlikely Link

It may be difficult to believe that thunderstorms can actually trigger severe asthma attacks. But research has shown thunderstorms increase breathing problems in people with asthma and COPD.

The Study

Vulnerable groups, such as older adults and people with respiratory disease, are at risk for health problems as climate change ramps up weather events. A group of researchers led by Anupam Jena (Harvard) conducted a large study to determine if emergency department visits spiked in the days surrounding a thunderstorm for Medicare patients with respiratory problems and ages 65 and older. The study findings were recently published in JAMA Internal Medicine, August 2020.

Data Collection

The researchers used weather data for all 3,127 US counties from the US National Oceanic and Atmospheric Administration. The data was used to find days between January 1999 to December 2012 when counties had a thunderstorm. A Medicare database was then used to identify Medicare patient ED visits for acute respiratory illnesses during the same timeframe.

This was a large study.... just check out the numbers below:

46,581,214 Medicare beneficiaries aged 65 and older
12,334,021 (26.5%) had COPD
4,891,027 (10.5%) had chronic asthma
3,074,360 (6.6%) had both asthma and COPD

A total of 22 million ED visits and 822,000 county days with thunderstorms occurred during the study period.

**Thunderstorms were defined by higher than average winds, lightning, and precipitation levels.

Findings

The researchers found temperature and particulate matter (such as dust, pollen, spores, and smoke,) significantly increased before the thunderstorms and decreased after. Here's what they found:

The day before the thunderstorms

Above average ED visits peaked at 1.8 additional visits per million beneficiaries, with an additional:

6.3 visits per million for asthma patients
6.4 visits per million for COPD patients
9.4 visits per million for patients with COPD and asthma

Overall, approximately 52,000 additional respiratory ED visits were estimated to occur in the 3 or more days surrounding a major storm over the 14-year study.

Interestingly, a similar association between thunderstorms and visits for the study controls, sepsis or pulmonary embolism, wasn't found.

Perfect Storm or Calm Before the Storm?

It makes sense to think rain would wash away pollen and other respiratory irritants. But some thunderstorms, especially in the Spring and Summer can actually stir up large amounts of pollen. How does this happen?

Large amounts of pollen and spores pile up before a thunderstorm event.
A recipe of changes in wind speed, temperatures and humidity causes the pollen to be pulled into the air.
Rain wets the pollen and causes it to burst open, releasing hundreds of allergen particles.
Smaller particles can enter the small airways of the lungs, triggering an asthma attack or other respiratory symptoms.

Calm Before the Storm

The study's authors theorize that "thunderstorm asthma" doesn't really need a "perfect storm" to cause respiratory symptoms. The researchers found ED visits also increase with average thunderstorms and it's actually the "calm before the storm" that sets things in motion.

Air flow significantly slows a week before the storm.
During this time, there is a large build-up of pollution particles.
EDs see a gradual increase in respiratory ailments in the week leading up to the storm.

Why Does it Matter?

Global warming will continue and we will experience an increase in thunderstorm frequency and severity. The study serves as a good reminder that weather is connected to health, especially in vulnerable populations.