Sulfur dioxide and exacerbation of allergic respiratory diseases: A time-stratified case-crossover study

Strong epidemiological evidence suggests that air pollution plays a significant role in the exacerbation of allergic respiratory diseases. This study aimed to assess the potential relationship between daily levels of sulfur dioxide (SO₂) and emergency department (ED) visits for allergic diseases.

Data regarding ED visits for allergic respiratory diseases were routinely collected from the EDs in the Zlatibor district, and the General Hospital, Užice. The daily average concentrations of SO₂ were obtained from the regional automatic air quality monitoring stations. All data were collected from June 2012 to July 2014. A time-stratified case-crossover design was used. Crude odds ratios (ORs) and ORs adjusted for weather conditions were calculated using conditional logistic regression.

Statistically significant associations were seen between 0-day lagged exposure to SO₂ and ED visits for all allergic diseases (OR = 1.62; 95% confidence interval [CI]: 1.05-2.48; P = 0.028) and between 2-day lagged exposure to SO₂ and ED visits for asthma with allergic rhinitis (OR = 2.00; 95% CI: 1.03-3.88; P = 0.042). These results were adjusted for temperature, temperature², and humidity.

Our results suggest that short-term exposure to SO₂ conferred an increased risk of ED visits for allergic respiratory diseases, particularly for asthma with concomitant allergic rhinitis.