Background: The hottest year on record for the contiguous United States was 2012. July 2012 ranked as Wisconsin's fourth warmest July, which has profound implications for heat-related mortality.
Methods: We conducted a case series of 27 heat-related fatalities in Wisconsin during summer 2012. Data from death certificates supplemented by coroner reports were analyzed to characterize factors that increase vulnerability to heat-related fatality.
Results: The 2012 heat-related fatalities occurred in both urban and rural counties. All cases had 1 or more known risk factors: 100% lacked functioning residential air conditioning; 70% were over age 65; 75% had a cardiovascular disease; and 52% had a mental health condition. Of the 14 cases with a mental health condition, half were known to be taking psychotropic medication. None of the decedents had been in air conditioning immediately prior to death, and 8 (36%) had been using fans.
Conclusions: Air conditioning is known to be a strong protective factor in preventing heat-related deaths whereas fans have not been shown to be significantly protective across all exposure situations. Prevention efforts should stress reducing social isolation by encouraging checks by friends, neighbors, or police. Prevention messages should also warn patients on psychotropic medications that the medication could increase their risk of heat-related illness or fatality.