Is a thunderstorm in the forecast? Your roof may not be the only thing in danger. A new study suggests that if you’re 65 or older, you are more likely to visit the emergency room for a respiratory problem in the days before a severe storm.

In a study published in JAMA Internal Medicine, a group of researchers analyzed Medicare insurance claims and found a correlation between respiratory ER visits and thunderstorms.

The analysis combined insurance and Medicare data associated with acute respiratory diagnoses during ER visits with weather data from the National Oceanic and Atmospheric Administration for all counties within the continental United States between 1999 and 2012. All told, they looked at more than 822,000 days with major thunderstorms and more than 22 million emergency department visits.

During days before thunderstorms, Medicare patients’ visits to the emergency department for respiratory illnesses increased, especially among patients with both asthma and chronic obstructive pulmonary disease. Overall, there were 5.3 additional visits per million Medicare patients during the three days surrounding major thunderstorms — about 52,000 additional visits to the emergency room in total.

The researchers couldn’t find the same associations for nonrespiratory conditions such as sepsis.

Other researchers have hypothesized that asthma can coincide with thunderstorms because the precipitation could cause pollen particles to burst and become easier to breathe in. But since the bulk of the ER visits happened before storms, the authors of the current study do not think pollen release was at play.


Instead, they write, “rises in particulate matter concentration and temperature may be the dominant mechanism of thunderstorm-associated acute respiratory disease in older Americans.”

Severe storms are expected to increase over the coming years because of warming oceans caused by human-driven climate change. As global warming continues, it’s expected to drive more stormy days, particularly in the eastern United States. Some models have shown that severe thunderstorms might double in places such as Atlanta and New York if greenhouse gases continue to rise.

Since the study looked at Medicare beneficiaries, it only studied people 65 and older. Still, it offers new insight into a potential effect of climate change. Global warming is expected to drive many things, such as heatstroke, diarrheal illnesses, drinking and eating newly flourishing marine bacteria. And now thunderstorm-induced respiratory trouble in older adults can be added to the list.