Severe migraine attacks might be predictable, with 20-year population data linking pollution spikes and weather shifts to surges in migraine-related emergency visits.

Results of 20-year population-based case-crossover analysis showed short-term spikes in nitrogen dioxide (NO₂), a marker of traffic-related pollution, and solar radiation emerged as acute migraine triggers. While cumulative exposure to fine particulate matter (PM_2.5) and NO₂ signaled higher ongoing disease burden.

“Together, these findings support a layered model of migraine activity, in which environmental exposures act both as acute triggers and as modulators of susceptibility over time,” the authors, led by Ido Peles, MD, of Ben-Gurion University of the Negev in Beer-Sheva, Israel, wrote.

The study was published online on April 15 in Neurology.

Combined Impact of Environmental Factors

Migraine is a leading cause of neurologic disability worldwide, and predicting the onset of attacks is challenging. Prior research has pointed to weather and air quality as possible triggers, but results have been inconsistent and often focused on single exposures.

The investigators tested a broader “layered” model, in which underlying biological vulnerability interacts with both intermediate-term environmental conditions and acute triggers to influence migraine activity.

A total of 7032 adults with migraine diagnoses or triptan prescriptions were followed for an average of 10 years in a single geographic region. Daily exposure to air pollution — from traffic, industry, and dust storms — and meteorologic data from monitoring stations were linked to individual patients.

Outcomes included emergency migraine-related healthcare encounters as a marker of triggered events and quarterly triptan use as a marker for disease activity.

On the day with the highest number of emergency migraine visits, pollution levels exceeded study averages: PM₁₀ reached 119.9 µg/m³ vs 57.9 µg/m³ on average, PM_2.5 was 27.3 µg/m³ vs 22.3 µg/m³, and NO₂ was 11.2 vs 8.7 parts per billion.

The day with the fewest emergency migraine encounters also had lower than average pollution levels.

After adjusting for multiple factors that could affect the risk for migraine attacks, short-term exposure to higher levels of NO₂ and solar radiation were both associated with an increased risk for emergency migraine-related encounters — with odds ratios (OR) of 1.41 and 1.23, respectively.

Cumulative exposure to higher NO₂ levels and PM_2.5 were both associated with increased triptan use (incidence rate ratio, 1.10 and 1.09, respectively) — suggesting a role in sustained migraine activity rather than just acute triggering.

How to Counsel Patients

Weekly weather conditions modified short-term effects. High temperatures and low humidity during summer amplified the effect of NO₂ on the risk for migraine (OR, 2.18), whereas cold and humid winter weeks intensified the effect of PM_2.5 (OR, 3.78).

These interactions support the idea that environmental factors do not act in isolation but instead combine to influence migraine susceptibility, the researchers said.

The findings also highlight opportunities for anticipating what care will be needed, Peles said in a news release.

“As climate change intensifies the frequency of heat waves, dust storms, and pollution episodes, we will need to integrate these environmental risk factors into our guidance for people with migraine,” said Peles.

“When high-risk exposure periods are in the forecast, doctors can advise people to limit their outdoor activity and use air filters, take short-term preventative medications and start using their migraine drugs at the first sign of a problem to ward off attacks,” Peles noted.

The authors noted several study limitations.

Because it relied on fixed monitoring stations, the study could not account for individual-level exposure differences, such as time spent indoors or use of air conditioning.

In addition, outcomes were based on emergency visits and prescription data, meaning the results primarily reflect more severe migraine episodes and may not apply to milder cases that are managed at home.

The study had no commercial funding. Disclosure information for study authors is available with the original study publication.