Hypothermia Surveillance

Hypothermia is defined as a drop in body temperature to less than 94.1° F as a result of exposure to cold weather or a cold natural environment.  Without immediate and aggressive efforts to reverse the body’s core temperature loss and restore it to safer levels, hypothermia can quickly lead to a dangerous loss of physical and mental abilities, unconsciousness and death.  In Missouri, 454 people have died from the cold during the winter months since 1979 when hypothermia data collection was first begun by the former Missouri Division of Health. Hypothermia Deaths, 1979-2007 Chart. The winter season is defined as October 1 to March 31 each year. While data has been collected since 1979, more detailed information regarding cases of hypothermia is available from winter seasons 1989-2007.

Senior citizens are more likely to be victims of cold-related illness resulting in death.  During the winter seasons 1989-2007, 145 (48.5%) hypothermia deaths were people age 65 years and older. Hypothermia Deaths by Age Group Handicapped or older individuals often fall outside and are unable to reach shelter or help.  Individuals with dementia can wander and are unable to find shelter or their way home.

Additional risk factors are present in many of the deaths due to hypothermia in Missouri. In 42 of the 234 (17.9%) deaths of people age 45 and older, debilitating medical conditions are contributing causes.  Substance abuse is often a contributing cause in hypothermia deaths of individuals between the ages of 25-64. During the winter seasons 1989-2007, substance abuse was a factor in 72 of the 145 (49.7%) deaths in this age group. Fortunately, deaths from hypothermia in people less than 25 years of age are rare, accounting for only 9 (3.0%) of the total 299 Missouri hypothermia deaths during this timeframe.  None of the deaths were children less than age 5 years. Hypothermia Deaths by Age and Risk Factor

The graph Hypothermia Deaths by Risk Factor shows the ages and risk factors for the 299 people who have died in Missouri from hypothermia during the winter seasons 1989-2007. Of the 299 deaths, 26 are shown as “other.”  These 26 include: 8 (30.8%) drowning victims, 6 (23.1%) drivers whose motor vehicles have become disabled, 4 (15.4%) people involved in homicidal or other criminal activity, 3 (11.5%) individuals participating in outdoor and/or recreational activity, 3 (11.5%) people who committed suicide, and 2 (7.7%) children over 5 years of age who wandered outside.

In Missouri during the winter seasons 1989 through 2007, the largest number of deaths was among white males, comprising 52.5% (157) of the 299 total cold related deaths. Hypothermia Deaths by Race and Sex

Jackson County, St. Louis County and St. Louis City accounted for 46.8% (140) of deaths with 53.2% (159) occurring in other areas of Missouri. Hypothermia Deaths by Geographic Area

Since 2006, Missouri has also been using Electronic Surveillance System for the Early Notification of Community-based Epidemics (ESSENCE) software to collect emergency department (ED) data.  ESSENCE data do not represent all cases of hypothermia among Missouri residents or all cases of hypothermia among patients visiting ESSENCE hospital EDs.  These data represent all ED visits among ESSENCE hospitals with the keywords “therm” or “cold exposure” contained within the chief complaint recorded upon admission to the ED.   Currently 85 hospitals contribute data to ESSENCE; please see the Missouri ESSENCE Map for more information. 

During the winter season 2006-2007, ESSENCE indicates there were 129 Missouri residents who visited emergency departments due to cold weather exposure, and there were 103 during winter season 2007-2008.

Missouri is the only state that conducts on-going statewide surveillance for cold weather-related illnesses and deaths. Health care providers are required to report cases of hypothermia to the Missouri Department of Health and Senior Services.