Short-term environmental nitrogen dioxide exposure and neurology clinic visits for headaches, a time-series study in Wuhan, China

Background Previous studies showed the adverse impacts of air pollution on headache attacks in developed countries. However, evidence is limited to the impact of exposure to air pollutants on headache attacks. In this study, we aimed to explore the impact of nitrogen dioxide (NO 2 ) exposure on neurology clinic visits (NCVs) for headache onsets. Methods Records of NCVs for headaches, concentrations of ambient NO 2 , and meteorological variables were collected in Wuhan, China, from January 1st, 2017, to November 30th, 2019. A time-series study was conducted to investigate the short-term effects of NO 2 exposure on daily NCVs for headaches. Stratified analyses were also computed according to season, age, and sex, and the exposure–response (E-R) curve was then plotted. Results A total of 11,436 records of NCVs for headaches were enrolled in our study during the period. A 10-μg/m 3 increase of ambient NO 2 corresponded to a 3.64% elevation of daily NCVs for headaches (95%CI: 1.02%, 6.32%, P = 0.006). Moreover, females aged less than 50 years of age were more susceptible compared to males (4.10% vs. 2.97%, P = 0.007). The short-term effects of NO 2 exposure on daily NCVs for headaches were stronger in cool seasons than in warm seasons (6.31% vs. 0.79%, P = 0.0009). Conclusion Our findings highlight that short-term exposure to ambient NO 2 positively correlated with NCVs for headaches in Wuhan, China, and the adverse effects varied by season, age, and sex.