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Cardiovascular and cerebrovascular emergency department visits associated with wildfire smoke exposure in California 2015#
Citation:
Zach, W., S. Hoshiko, J. Fahimi, R. Harrison, W. Cascio, AND A. Rappold. Cardiovascular and cerebrovascular emergency department visits associated with wildfire smoke exposure in California 2015#. International Society of Environmental Epidemiology, Ottawa, Ontario, CANADA, August 26 - 30, 2018.
Impact/Purpose:
A comprehensive study of cardiovascular effects during wildfire smoke exposure. This same presentation was cleared November 2017 for the APHA Meeting in Atlanta, GA.
Description:
Background: Frequency of large wildfires is increasing. Fine particulate matter (PM2.5) found in smoke can exacerbate respiratory conditions; however, evidence for cardiovascular and cerebrovascular events has been inconsistent. Methods: We conducted a time series analysis of adult cardiovascular and cerebrovascular events for the 2015 wildfire season in 8 California Air Basins. We used estimated fire-PM2.5 concentrations and satellite data from the Hazard Mapping System together with California statewide emergency department (ED) data. We examined ZIP code-level associations between daily maximum PM2.5 levels and ED visits using a quasipoisson regression model with logged ZIP code population as a baseline offset. Age- and gender-stratified population subsets were modeled with lags up to 5 days to estimate cumulative relative risk (RR) per 10 µg/m3 increase in fire-PM2.5. Models included smoothing splines; heat index; day of week; and seasonality. Results: All-cause cardiovascular ED visits across all lags were elevated (RR of 1.07, 95%CI[1.05, 1.09]), as were all-cause cerebrovascular (1.13 [1.05-1.21]), and all-cause respiratory visits (1.10 [1.08,1.12]). No significant association was found for the control condition of acute appendicitis (0.93 [0.81,1.06]). Elevated individual diagnoses included ischemic heart disease (1.09 [1.05, 1.13]), heart failure (1.10 [1.06,1.14]), and dysrhythmia (1.14 [1.11,1.17]). Ischemic strokes were elevated up to 5 lag days for adults 65 years and older (1.21 [1.05, 1.37]). Dose-dependent responses were observed for fire-PM2.5 and nearly all diagnosis categories, across all 5 lags. Conclusions: Wildfire PM2.5 elevated the risk of cardiovascular and cerebrovascular ED visits.