Introduction:
Extreme weather events such as dust storms are predicted to become more frequent as the global climate warms through the 21st century. Studies of Asian, Saharan, Arabian, and Australian dust storms have found associations with cardiovascular and total non-accidental mortality and hospitalizations for stroke. However, the only population-level epidemiological work on dust storms in the United States was focused on a single small metropolitan area (Spokane, WA), and it is uncertain whether its null results are representative of the country as a whole.
Hypothesis:
Dust storms in the United States are associated with daily cardiovascular mortality.
Methods:
Dust storm incidence data (N=141), including date and approximate location, as well as meteorological station observations, were taken from the U.S. National Weather Service. County-level mortality data for the years 1993-2005 were acquired from the National Center for Health Statistics. Ambient particulate matter monitor concentrations were obtained from the U.S. Environmental Protection Agency. Inference was performed used conditional logistic regression models under a case-crossover design while accounting for the nonlinear effect of temperature.
Results:
We found a 9.5% increase in cardiovascular mortality at a two-day lag (95% CI: [0.31%,19.5%], p = 0.042). The results were robust to adjusting for heat waves and ambient particulate matter concentrations. Analysis of storms occurring only on days with <0.1 inches of precipitation strengthened these results and in addition yielded a mean daily increase of 4.0% across lags 0-5 (95% CI: [0.07%,20.8%], p = 0.046). In Arizona, the U.S. state with the largest number of storms, we observed a 13.0% increase at a three-day lag (CI: [0.40%,27.1%], p = 0.043).
Conclusions:
Dust storms in the U.S. are associated with increases in lagged cardiovascular mortality. This has implications for the development of public health advisories and suggests that further public health interventions may be needed.
Disclaimer:
This work does not represent official U.S. Environmental Protection Agency policy.
Ozone, Fine Particulate Matter, and Chronic Lower Respiratory Disease Mortality in the United States