Research Summary

Air Pollution, Climate Associated With Emergency Migraine Care Visits

Edited by:
Anthony Calabro, MA

Key Highlights

  • Short-term NO2 and solar radiation exposure were associated with increased odds of emergency migraine-related encounters.
  • Same-day exposures showed no effect; associations were observed with lagged exposures.
  • Cumulative NO2 and PM2.5 exposure were associated with higher triptan dispensation.
  • Weekly climatic conditions modified short-term risks, supporting a layered environmental model of migraine activity.

In a population-based case-crossover study published in Neurology, environmental exposures across multiple time scales were associated with migraine activity among adults in Be’er Sheva, Israel. Short-term exposure to nitrogen dioxide (NO2) and solar radiation was associated with an increased risk of emergency migraine-related health care encounters, whereas cumulative exposure to NO2 and particulate matter ≤2.5 µm (PM2.5) was associated with higher triptan dispensation.

The investigators reported that these findings support a layered model of migraine activity, in which environmental factors may act as both acute triggers and intermediate-term modulators of susceptibility.

The study included adults aged 18 years or older from the Negev Migraine Cohort (2000–2023) identified through electronic medical records from Clalit Health Services and Soroka University Medical Center. Eligible participants had a migraine diagnosis or triptan prescription and resided in Be’er Sheva. Environmental exposure data, including air pollutants and meteorological variables, were obtained from fixed monitoring stations and assigned based on proximity.

The primary outcome for migraine triggering was emergency migraine-related health care encounters, including emergency department and primary care visits coded for acute migraine. Quarterly triptan dispensation, analyzed among patients who had ever used triptans, served as a proxy for disease activity. Associations were evaluated using conditional logistic regression for short-term exposures and Poisson regression for cumulative exposures, with additional analyses assessing modification by weekly climatic conditions.

Study Findings

The analysis included 7,032 adults with migraine (77.4% women; mean age, 46.9 years), of whom 31.5% experienced at least 1 emergency migraine-related encounter during follow-up, contributing 24,608 events. Triptans were used by 46.7% of patients.

Same-day environmental exposures showed no effect; significant associations were observed for lagged exposures. NO2 exposure 1 day before an event was associated with increased odds of emergency migraine-related encounters (odds ratio [OR], 1.41; 95% CI, 1.13-1.77; P = .003), as was solar radiation (OR, 1.23; 95% CI, 1.07-1.42; P = .004). Solar radiation remained associated at 2 days (OR, 1.24; 95% CI, 1.06-1.44; P = .007) and 7 days (OR, 1.33; 95% CI, 1.03-1.71; P = .029) before an event. PM2.5 was not significantly associated with emergency migraine-related encounters across lag periods.

For cumulative exposure, NO2 during the preceding quarter was associated with higher triptan dispensation (incidence rate ratio [IRR], 1.10; 95% CI, 1.00-1.21; P = .048). PM2.5 exposure during the preceding quarter was also associated with increased triptan dispensation (IRR, 1.09; 95% CI, 1.00-1.19; P = .049).

Weekly climatic conditions modified these associations. Elevated temperatures and reduced humidity during summer amplified the effect of daily NO2 exposure (OR, 2.18; 95% CI, 1.06-3.30; P = .046), whereas reduced temperatures and elevated humidity during winter intensified the effect of PM2.5 (OR, 3.78; 95% CI, 1.74-5.82; P = .003).

Clinical Implications

According to the study authors, the findings support a layered model in which environmental exposures may influence migraine activity as both short-term triggers and intermediate-term modulators of susceptibility. The authors noted that these results highlight potential opportunities for anticipatory prevention during forecasted periods of high-risk environmental exposure.

The authors identified several limitations. Exposure assessment relied on fixed monitoring stations and did not account for individual-level behaviors or microenvironmental variability. In addition, outcomes were based on emergency health care encounters and triptan dispensation rather than diary-based headache data, likely capturing more severe migraine episodes and underestimating overall migraine activity.

Expert Commentary

“Clinically, these results highlight opportunities for anticipatory prevention; aligning behavioral strategies, short-term prophylaxis, and acute treatment with forecasted high-risk exposure periods,” the researchers concluded.

Reference:
Peles I, Novack L, Gordon M, Sarov B, Novack V, Ifergane G. Acute environmental triggers and intermediate-term modulators of emergency migraine-related health care encounters. Neurology. 2026;106(9):e214936. doi:10.1212/WNL.0000000000214936