Heat-related hospitalizations in Illinois: Rural vs. urban counties

Periods of prolonged heat in US cities have resulted in recognized disease outbreaks.  A well-known example of this is the 1995 Chicago heat wave, in which approximately 700 people died.  Less well studied are health risks of heat related illness (HRI) in rural areas.  We evaluated data provided by hospitals in the 102 counties of Illinois from 1987-2013 and characterized the occurrence and risk of HRI, defined by ICD-9 codes 992 and/or E900.  A total of 8,727 cases of HRI occurred, with the  highest risks observed among those over age 80 years.  Residents of rural counties were at 64% greater risk for HRI than residents of urban counties.  The elevated risk among people in rural counties was largely driven by an excess risk among people under the age of 40 years in rural areas.  The elevated risk in rural areas in younger individuals could be due to the physical demands of agricultural work.  As summer temperatures in the US are expected to continue increasing, a better understanding of the determinants of risk of HRI in rural areas is needed.  Preparedness and response, public education,   and outreach efforts tailored to the needs of rural areas are needed.