Heat-Related Deaths - Four States, July-August 2001, and United States, 1979-1999

Morbidity and Mortality Weekly Report. 2002;51(26) 

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Each year in the United States, approximately 400 deaths are attributed to excessive natural heat; these deaths are preventable [1]. This report describes heat-related deaths in Missouri, New Mexico, Oklahoma, and Texas when elevated temperatures were recorded for several consecutive days during July--August 2001; summarizes heat-related deaths in the United States during 1979--1999; and presents risk factors and preventive measures associated with heat-related illness and death, especially in susceptible populations.

In late July 2001, the National Oceanographic and Atmospheric Association (NOAA) reported temperatures averaging 5º F (-15º C)--10º F (-12º C) above normal in the southern plains states [2]. The intense heat and humidity prompted NOAA's National Weather Service to issue heat advisories* in Missouri, New Mexico, Oklahoma, and Texas ([2]; Missouri Department of Health and Senior Services, personal communication 2002). During July--August 2001, a total of 95 deaths was attributed to excessive natural heat in the affected states. Provisional mortality statistics were obtained from the vital statistics section of each state, and information about underlying cause of death, age, sex, date of death, and contributing causes were provided. Peak mortality occurred during the reported 8-day heat advisory period (Figure 1). Six (6%) deaths occurred among children aged ≤4 years and 42 (41%) among persons aged ≥75 years; 69 (73%) deaths occurred among males.

Case 1. In Oklahoma in mid-July 2001, a man aged 29 years was found disoriented and wandering in a commercial parking lot. He apparently had fallen and had abrasions on his knees and a broken tooth. In the emergency department, he was semiconscious but combative. His rectal temperature increased from 105.4º F (40.7º C) to 107.8º F (42.1º C) in <1 hour. Despite medical treatment for hyperthermia, he was pronounced dead 22 hours after being found. Laboratory tests at autopsy were positive for cocaine and alcohol. The medical examiner attributed the cause of death to heat-related illness.

Case 2. In Oklahoma in mid-July 2001, police were called to check on a man aged 62 years with a history of alcoholism, heavy smoking, and poor diet who had not been seen for 7 days. The man was found dead by the police in his home, which was very hot; an ambient temperature was not recorded. A fan and air-conditioning unit in the home were in working order but turned off. Postmortem blood alcohol level was 0.07%. Following an autopsy, the death was attributed to hyperthermia.

Case 3. In Texas in late July 2001, a boy aged 2 years was found in a motor vehicle with the windows rolled up for an undetermined length of time. The boy had locked himself in the car and could not get out. The temperature inside the car was not measured, nor was the outside temperature recorded; however, the high temperatures in central Texas during this time ranged from the mid-to-high 90s. The boy arrived at the hospital with an oral temperature of 102º F (39º C) and died 2 days later. The death was attributed to heatstroke.

Case 4. In a border town in Chihuahua State, Mexico, in August 2001, a man aged 21 years was found collapsed and incoherent on the street. A witness reported that he had complained about abdominal pain and vomiting. He arrived at an emergency department in New Mexico 3 hours after he was found. His rectal temperature was 105.7º F (40.9º C). The patient had laboratory evidence of rhabdomyolysis, severe dehydration, and renal failure. Blood alcohol level and a screen for drugs were negative. He died 3 hours after arrival at the hospital. Cause of death was attributed to hyperthermia due to environmental heat exposure. High temperature at the border that day was 90º F (32º C).

During 1979--1999, a total of 8,015 deaths in the United States was associated with excessive heat exposure†, 3,829 (48%) were "due to weather conditions," 377 (5%) were "of man-made origins" (i.e., heat generated in vehicles, kitchens, boiler rooms, furnace rooms, and factories), and 3,809 (48%) were "of unspecified origin" [3]; 182 deaths per year (range: 54--651) were associated with excessive heat due to weather conditions. Of the 3,764 (98%) deaths specified as due to weather conditions with a reported age [3], 142 (4%) occurred among children aged ≤4 years, and 1,068 (28%) occurred among persons aged ≥75 years (Figure 2).

Reported by: R Moore, Statistical Svcs Div, Bur of Vital Statistics, Texas Dept of Health. Missouri Dept of Health and Senior Svcs. S Mallonee, MPH, T Garwe, MPH, Oklahoma State Dept of Heath. New Mexico Dept of Health. RI Sabogal, MSPH, L Zanardi, MD, Div of Environmental Hazards and Health Effects, National Center for Environmental Health; J Redd, MD, J Malone, MD, EIS officers, CDC.


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