A case-crossover study on association between short-term atmospheric NO₂ exposure and outpatient visits due to pediatric neurological system conditions in Shijiazhuang

Background Nitrogen dioxide (NO₂), a crucial component of traffic pollutants, has been shown in studies to exert toxic effects on the nervous system. However, there is a limited body of research examining the relationship between NO₂ exposure and neurological disorders in children.

Objective To explore the impact of short-term NO₂ exposure on the outpatient visits due to pediatric neurological diseases in Shijiazhuang.

Methods From 2013 to 2021, we collected outpatient data related to neurological diseases at the Children's Hospital in Shijiazhuang, Hebei Province. We also collected air pollution data and meteorological data of the same city. The air pollution data included daily average concentrations of inhalable particles (PM₁₀), fine particulate matter (PM_2.5), sulfur dioxide (SO₂), NO₂, carbon monoxide (CO), and daily maximum 8-hour average concentration of ozone (O₃). The meteorological data comprised daily average atmospheric pressure, temperature, relative humidity, wind speed, and sunshine duration. Employing a time-stratified case-crossover design, we used conditional logistic regression models to analyze the association between NO₂ and pediatric outpatient visits for neurological diseases. Stratification analyses were conducted based on gender (male, female) and age groups (0-6 years, 7-14 years).

Results The study included a total of 154348 valid pediatric outpatient visits for neurological diseases. The daily average concentration of NO₂ was 49.3 μg·m⁻³ for the study period. The results from the single-pollutant model indicated that NO₂ increased the risk of pediatric neurological outpatient visits, with the highest association observed at lag0. Specifically, for every 10 μg·m⁻³ increase in atmospheric NO₂ exposure, there was a 1.40% increase (95%CI: 1.05%, 1.74%) in pediatric neurological outpatient visits. The stratification analyses revealed that increased atmospheric NO₂ exposure was associated with an elevated risk of neurological outpatient visits for girls (ER=1.54, 95%CI: 1.01, 2.08) and children aged 7-14 years (ER=2.35, 95%CI: 1.68, 3.02). Even after introducing PM_2.5 (ER=1.96, 95%CI: 1.49, 2.43), SO₂ (ER=2.09, 95%CI: 1.62, 2.55), and O₃ (ER=1.40, 95%CI: 1.06, 1.74) to the models, the impact of NO₂ exposure on pediatric neurological outpatient visits remained statistically significant. The results of the multi-pollutant model also indicated a significant association (ER=2.53, 95%CI: 1.97, 3.08).

Conclusion The effect of short-term exposure to atmospheric NO₂ on the outpatient visits of children with neurological diseases in Shijiazhuang is acute and independent, especially for children aged 7-14.