Estimating the number of excess deaths attributable to heat in 297 United States counties

There is a well-established relationship between high ambient temperature and risk of death. However, the number of deaths attributable to heat each year in the United States remains incompletely quantified. Methods We replicated the approach from a large, international study to estimate temperature-mortality associations in 297 United States counties and additionally calculated the number of deaths attributable to heat, a quantity of likely interest to policymakers and the public. Results Across 297 counties representing 61.9% of the United States population in 2000, we estimate that an average of 5,608 (95% empirical confidence interval = 4,748, 6,291) deaths were attributable to heat annually, 1997-2006. Conclusions Our results suggest that the number of deaths related to heat in the United States is substantially larger than previously reported.