Long-term ambient air pollutant exposure and risk of migraine and recurrent headache in children: A 12-year cohort study

Abstract Background Although research has suggested environmental factors to be triggers of headache, the contribution of long-term air pollution exposure to migraine and recurrent headaches (migraine/headaches) is poorly understood. Hence, we executed this nationwide cohort study to investigate the association of levels of ambient air pollution with the incidence and the risk of migraine/headaches in Taiwan children from 2000 to 2012. Methods We collected data from the Taiwan National Health Insurance Research Database and linked them to the Taiwan Air Quality Monitoring Database. Overall 218,008 children aged <18 (0-17) years old were identified from January 1, 2000 and then followed until they were diagnosed by a physician >=3 times with migraine/headaches or until December 31, 2012. We categorized the annual average concentration of each air pollutant (fine particulate matter, total hydrocarbon, methane, sulfur dioxide, and nitrogen dioxide) into quartiles (Q1-Q4). We measured the incidence rate, hazard ratios (HRs), and the corresponding 95% confidence intervals for migraine/headaches stratified by the quartiles. Results A total of 28037 children (12.9%) were identified with migraine/headaches. The incidence rate and adjusted HR for migraine/headaches increased with higher-level exposure of air pollutants, except sulfur dioxide. Conclusions We herein demonstrate that long-term ambient air pollutant exposure might be a risk factor for childhood migraine/headaches.