From 1976 through 1985, 7450 deaths were caused by exposure to
cold*
in the United States (Figure 1). Of health effects associated with
cold
exposure, hypothermia--defined as a core body temperature of less
than
or equal to35 C (less than or equal to95 F)--is the most commonly
fatal
syndrome. Persons greater than or equal to60 years of age are
particularly susceptible to hypothermia and account for more than
half
of all deaths (1). Younger persons subjected to overwhelming cold
stress are also vulnerable (2). Although deaths attributable to
hypothermia occur infrequently in children, infants less than 1
year of
age are at relatively high risk. Rates of death from hypothermia
are
generally higher in males than in females, but these differences
are
less substantial in children and the elderly (3).
Persons with hypothyroidism are at increased risk for hypothermia
(4).
In addition, a variety of drugs, principally sedative-hypnotics,
may
predispose users to hypothermia; ethanol and neuroleptic
medications
particularly increase susceptibility to cold (2).
As the body temperature of a cold-exposed person decreases,
impaired
consciousness, confusion, or disorientation may occur. Because
mental
status is altered, a mildly hypothermic person may fail to take
appropriate corrective measures to lessen exposure. In response to
the
decline in core temperature, vasoconstriction (causing pallor) and
shivering occur. However, shivering decreases markedly in severe
hypo-
thermia because thermoregulation becomes impaired. Severely
hypothermic
persons lose consciousness and develop shallow respirations.
Ventricular fibrillation and death may follow (2).
Reported by: Health Studies Br, Div of Environmental Hazards and
Health
Effects, Center for Environmental Health and Injury Control, CDC.
Editorial Note
Editorial Note: This preliminary study of mortality data suggests
a
trend toward increased incidence of hypothermia. Although
age-adjusted
rates are required to properly evaluate the hypothesis that
mortality
due to effects of cold is increasing, the crude numbers of deaths
(Figure 1) strongly suggest such a trend.
Hypothermia prevention programs should focus on persons
particularly
susceptible to hypothermia and those likely to be subjected to
unusual
cold stress. Persons caring for the elderly should be alerted to
hypothermia's symptoms and signs, and elderly persons living alone
should be visited frequently. Since adequate caloric intake is
important in preventing hypothermia, programs designed to improve
nutrition in the elderly may also be helpful. Programs that ensure
home
heating for the elderly may also help prevent hypothermia.
Younger persons likely to be subjected to cold stress (e.g.,
skiers
and hikers) should be educated concerning the need for adequate
clothing and the importance of abstaining from alcohol use during
prolonged cold exposure. Shelter should be offered to homeless
persons
who would otherwise sleep outdoors on cold winter nights.
Persons using medications (particularly neuroleptic medications)
that
are likely to increase susceptibility to the cold should be advised
by
their physicians regarding their increased vulnerability to cold
stress.
References
Kilbourne EM. Illness due to thermal extremes. In: Last JM, ed.
Maxcy-Rosenau public health and preventive medicine. 12th ed.
Norwalk,
Connecticut: Appleton-Century-Crofts, 1986: 711-4.
2.Collins KJ. Hypothermia: the facts. New York: Oxford University
Press, 1983.
3.CDC. Hypothermia-associated deaths--United States, 1968-1980.
MMWR
1985;34:753-4.
4.Forester CF. Coma in myxedema: report of a case and review of the
world literature. Arch Intern Med 1963;111:734-43.
*Deaths attributed to excessive cold (ICD code E901) were analyzed
using mortality data tapes for 1976-1985 from the National Center
for
Health Statistics.
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