Association of short-term exposure to ambient fine particulate matter and ozone with outpatient visits for anxiety disorders: A hospital-based case-crossover study in South China.

The short-term adverse effects of ambient fine particulate matter (PM 2.5) and ozone (O 3) on anxiety disorders (ADs) remained inconclusive. We applied an individual-level time-stratified case-crossover study, which including 126,112 outpatient visits for ADs during 2019–2021 in Guangdong province, China, to investigate the association of short-term exposure to PM 2.5 and O 3 with outpatient visits for ADs, and estimate excess outpatient visits in South China. Daily residential air pollutant exposure assessments were performed by extracting grid data (spatial resolution: 1 km × 1 km) from validated datasets. We employed the conditional logistic regression model to quantify the associations and excess outpatient visits. The results of the single-pollutant models showed that each 10 μg/m3 increase of PM 2.5 and O 3 exposures was significantly associated with a 3.14 % (95 % confidence interval: 2.47 %, 3.81 %) and 0.88 % (0.49 %, 1.26 %) increase in odds of outpatient visits for ADs, respectively. These associations remained robust in 2-pollutant models. The proportion of outpatient visits attributable to PM 2.5 and O 3 exposures was up to 7.20 % and 8.93 %, respectively. Older adults appeared to be more susceptible to PM 2.5 exposure, especially in cool season, and subjects with recurrent outpatient visits were more susceptible to O 3 exposure. As our study subjects were from one single hospital in China, it should be cautious when generalizing our findings to other regions. Short-term exposure to ambient PM 2.5 and O 3 was significantly associated with a higher odds of outpatient visits for ADs, which can contribute to considerable excess outpatient visits. • Exposure to ambient PM 2.5 and O 3 was associated with an increased odds of outpatient visits for anxiety disorders. • PM 2.5 and O 3 exposures were attributable to considerable excess outpatient visits. • Older adults were more susceptible to PM 2.5 exposure, especially in cool season. • Subjects with recurrent outpatient visits were more susceptible to O 3 exposure. [ABSTRACT FROM AUTHOR]