Relationship between short-term exposure to sulfur dioxide and emergency ambulance dispatches due to cardiovascular disease.

Background: The relationship between sulfur dioxide (SO₂) and cardiovascular disease (CVD) remains inconclusive. We aimed to clarify the association between short-term exposure to SO₂ and emergency ambulance dispatches (EADs) due to CVD.

Methods: We collected daily data on the number of EADs due to CVD, air pollutants, and meteorological factors between October 2013 and June 2018 in Guangzhou, China. We used the quasi-Poisson generalized additive model combined with a distributed lag nonlinear model to estimate the short-term effect of SO₂ on EADs due to CVD in multivariable models. Subgroup and sensitivity analyses were also performed.

Results: A total of 37,889 EADs due to CVD were documented during the study period. The average daily SO₂ concentration was 12.5 μg/m³. A significant relationship between SO₂ and EADs due to CVD was found, with a relative risk of 1.04 (95% confidence interval: 1.02, 1.06) with each 10 μg/m³ increment of SO₂ at lag 0-1_. The relationship was stronger in males, for participants aged ≥65 years, and in the cold season; however, no significant modification by subgroup was found in the association between SO₂ and EADs due to CVD. Similar results from sensitivity analyses to the main findings were observed.

Conclusions: Short-term exposure to SO₂ was significantly associated with increased EADs due to CVD.