For some people, it’s the calm before the storm that causes them distress during rough weather seasons. It’s long been recognized that sudden changes in weather and air composition, such as smog setting in from bush fires, could bring on asthma attacks but new research has identified that for an unusual respiratory condition called thunderstorm asthma, there’s a spike in people presenting to hospital days before the storm itself hits.
The study, published in the journal JAMA Internal Medicine, looked at atmospheric and lightning data from the US National Oceanic and Atmospheric Administration (NOAA) providing information from counties in the continental United States from 1999 to 2012. They combined the information with records of insurance claims and comorbidity data from Medicare patients aged 65 and over, specifically focusing on visits to the Emergency Department (ED) regarding respiratory illness.
Using a statistical model, they looked for correlations between the climatological and health records and found that before the onset of thunderstorms, temperature and concentrations of particulate matter in the air spiked. These levels dropped on the day of the storm and continued to drop as the storm progressed.
Their results also revealed that in the three days leading up to a storm, the average number of visits to the ED per 1 million Medicare patients increased, particularly among those with asthma or Chronic Obstructive Pulmonary Disease (COPD), which are considered comorbid factors for thunderstorm asthma.
Previous research regarding the cause of thunderstorm asthma has listed pollen to be a prime suspect, though this analysis of historic data didn’t see a spike in pollen during the three-day window where the spike occurred. So, is pollen out of the question?
“Our study by no means ruled out pollen as a cause of thunderstorm asthma, and it is highly likely that the pollen theory contributes to asthma outbreaks seen around the world,” Christopher Worsham, MD from Harvard Medical School, told IFLScience. “Our study looked only at Medicare patients who are above 65, and asthma and COPD in older adults can be much different than in younger adults, since in many older adults’ allergies to things like pollen can wane.
“The other important aspect of this study was that because we included every single lightning strike in the US, what we’re seeing is an average effect of storms," he added. "These massive thunderstorm asthma outbreaks, such as the one in Melbourne, seem to be the result of a “perfect storm” where the exact necessary predisposing conditions come together with rain, wind, pollen, and population density.”