Associations of fine particulate matter and its chemical constituents with outpatient visits for pediatric seizures

Growing epidemiological evidence has reported neurological effects of fine particulate matter (PM2.5), showing stronger effects of certain PM2.5 constituents. Among the neurologic outcomes examined so far, pediatric seizure has been rarely assessed. We conducted a time-stratified case-crossover study using pediatric seizure outpatient data from a children's hospital in Shanghai. Individual-level daily concentration of PM2.5 and its chemical components (black carbon, organic matter, nitrate, sulfate, and ammonium) were estimated with a satellite-based spatiotemporal model. A conditional logistic regression with distributed lag model (DLM) was applied to estimate the associations of PM2.5 and components with pediatric seizure risk over 14 days preceding to the onset date. Quantile-based g-computation (qgcomp) approach was used to assess the joint effect of a mixture of PM2.5 components. Analyses were further stratified by sex, age, onset with/without fever, and onset with/without epilepsy. A positive association between PM2.5 or each of the components, except organic matter, and pediatric seizure onset was observed with lag windows ranging from 0 to 7 days up to 0–14 days. In the multi-pollutant model, per interquartile range (IQR) increase in exposure to the mixture of all five PM2.5 components were associated with a odds ratio (OR) of 1.03 (95 % CI: 0.95, 2.57). Black carbon and nitrate contributed the most to the positive association, accounting for 47 % and 42 %, respectively. Subgroup analyses showed a larger effect size in children under 5 years old, males, children with concomitant seizure and fever, and children without epilepsy, respectively. Short-term (daily average) exposure to PM2.5 may be a risk factor for the onset of pediatric seizure. Black carbon and nitrate were the two most important constituents contributing to the PM2.5 effect. In addition, younger children, males, and children with seizure and fever co-occurring, and children without epilepsy appeared more susceptible.

Duke Scholars

Author Junfeng Zhang Environmental Natural Science

Author Shiyu Zhang