Geographic distribution of heat-related deaths among elderly persons. Use of county-level dot maps for injury surveillance and epidemiologic research.

Mapping is a useful tool for initiating data analysis of relatively infrequent injury events and can lead to interesting hypotheses that can then be tested in further epidemiologic studies. From national death certificate data for the years 1979 through 1985, we made dot maps of fatalities due to excessive heat (International Classification of Diseases code E900) among persons 65 years or older. The maps show clusterings of deaths, particularly in the central, south central, and southeastern sections of the United States, to an extent not fully explained by the population density or temperature extremes. The counties principally affected were highly urbanized and, for races other than white, were relatively poor. Our maps identify counties in which heat-related health problems in the elderly are particularly severe. Public health officials in high-risk areas should undertake heat-wave contingency planning and physicians practicing in such areas should familiarize themselves with the treatment of the spectrum of heat-related illnesses.