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 mu g/m(3). 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 mu g/m(3) 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 SO(2 )was significantly associated with increased EADs due to CVD.