Update: Cold weather injuries, active and reserve components, U.S. Armed Forces, July 2007-June 2012.

From July 2011 through June 2012, the number of active and reserve component service members treated for cold injuries (n=499) was lower than the number in each of the four previous one year periods. Over the last five years, frostbite was the most common type of cold injury in all the Services except for the Marine Corps, in which hypothermia was slightly more frequent. Service members who were female, less than 20 years old, or of black, non-Hispanic race/ethnicity tended to have higher cold injury rates than their respective counterparts. Army personnel accounted for the majority of cold injuries. Service members who train in and deploy to areas with wet and freezing conditions - and their supervisors at all levels - should be able to recognize the signs of cold injury and should know and implement the standard countermeasures against the threat of cold injury.

The influence of ethnicity on thermoregulation after acute cold exposure.

OBJECTIVE: It is well established that a combination of factors, including ethnicity, may influence an individual's response to cold stress. Previous work from our laboratory has demonstrated that when faced with a cold challenge, there is a similar response in heat production between Caucasian (CAU) and African American (AA) individuals that is accompanied by a differential response in core temperature. The objective of this study was to evaluate the influence of ethnicity (CAU vs AA) on the thermoregulatory response after acute cold exposure (ACE-REC, 25 degrees C air). METHODS: Five AA males (20.8 +/- 0.5 years) and 10 CAU males (25.6+/-4.9 years) underwent pre-experimental testing to determine Vo(2max) (AA = 37.2 +/- 0.1 mLxkg(-1)xmin(-1), CAU = 44.3 +/- 8.7 mLxkg(-1)xmin(-1)) and body composition (AA = 14.6 +/- 5.4%, CAU = 19.2 +/- 5.0%). Participants underwent acute cold exposure that consisted of 120 minutes of exposure to 10 degrees C air (ACE) followed by 120 minutes of recovery in 25 degrees C air (ACE-REC). Rectal temperature (T(re)) was measured via a rectal thermistor. Mean skin temperature (T(sk)) was assessed with thermistors. Oxygen consumption (Vo(2)) was assessed via indirect open circuit spirometry. Rectal temperature and T(sk) were measured continuously, and if T(re) < or = 35 degrees C, testing was terminated. RESULTS: Analysis of variance for ACE-REC revealed a significant main effect for T(sk) across time (P < .001), T(re) across time (P < .001), and Vo(2) across time (P < .001). In addition, a significant time x ethnicity interaction was revealed for T(re) (P = .008), T(sk) (P = .042), and Vo(2) (P = .019) during ACE-REC. CONCLUSIONS: Based on these data, there is a differential response between CAU and AA across time for Vo(2), T(re), and T(sk) ACE-REC.

The influence of ethnicity on thermosensitivity during cold water immersion.

PURPOSE: This investigation evaluated the influence of ethnicity, Caucasian (CAU) vs. African American (AA), on thermosensitivity and metabolic heat production (HP) during cold water immersion (20 degrees C) in 15 CAU (22.7 +/- 2.7 yr) vs. 7 AA (21.7 +/- 2.7 yr) males. METHODS: Following a 20-min baseline period (BASE), subjects were immersed in 20 degrees C water until esophageal temperature (Tes) reached 36.5 degrees C or for a maximum pre-occlusion (Pre-OCC) time of 40 min. Arm and thigh cuffs were then inflated to 180 and 220 mm Hg, respectively, for 10 min (OCC). Following release of the inflated cuffs (Post-OCC), the slope of the relationship between the decrease in Tes and the increase in HP was used to define thermosensitivity (beta). RESULTS: ANOVA revealed no significant difference in thermosensitivity between CAU and AA (CAU = 3.56 +/- 1.54 vs. AA = 2.43 +/- 1.58 W.kg(-1). degrees C(-1)). No significant differences (p > 0.05) were found for Tsk (CAU = 24.2 +/- 1.1 vs. AA = 25.1 +/- 1.1 degrees C) or HP (p > 0.05; CAU = 2.5 +/- 0.8 vs. AA = 36.5 +/- 1.8 W.kg(-1)). However, a significant (p < 0.05) main effect for ethnicity for Tes was observed (CAU = 36.7 +/- 1.8 vs. AA = 36.5 +/- 1.8 degrees C). CONCLUSION: These data suggest, despite a differential response in Tes between AA and CAU groups, the beta of HP during cold water immersion is similar between CAU and AA. Therefore, these data demonstrate that when faced with a cold challenge, there is a similar response in HP between CAU and AA that is accompanied by a differential response in Tes.

Pedestrian and hypothermia deaths among Native Americans in New Mexico. Between bar and home.

OBJECTIVE: To determine the nature of excess injury mortality among Native Americans in New Mexico. DESIGN: Retrospective review of death certificates for deaths from unintentional injuries. SETTING: The state of New Mexico. SUBJECTS: New Mexico residents who died of unintentional injuries between January 1, 1980, and December 31, 1989. MAIN OUTCOME MEASURE: Cause-specific mortality rates. RESULTS: Over half of the excess mortality from all unintentional injuries among Native Americans resulted from hypothermia and from pedestrian-motor vehicle crashes. New Mexico Native Americans were nearly eight times more likely to die in pedestrian--motor vehicle crashes and were 30 times more likely to die of hypothermia compared with other New Mexico residents. At death, 90% of those Native Americans tested were highly intoxicated (median blood alcohol concentrations of 0.24 and 0.18 g/dL [corrected] for pedestrian and hypothermia deaths, respectively). Despite the fact that most Native Americans in New Mexico live on reservations, most deaths occurred at off-reservation sites in border towns and on roads leading back to the reservation. CONCLUSIONS: The possession and sale of alcohol is illegal on many Native American reservations. This policy forces Native Americans who want to drink to travel long distances to obtain alcohol. These data suggest that this policy is also the likely explanation for the markedly increased risk of death from hypothermia and pedestrian-motor vehicle crashes in this population.

Risk factors for infantile hypothermia in early neonatal life.

Hypothermia in infancy is not uncommon among the low socioeconomic population in various parts of the world. It is prevalent in Israel and is associated with severe morbidity and mortality. We tried to identify neonates at risk among the population of the Negev district of Israel. Ninety-one infant hospitalized with infantile hypothermia (IH) during the years 1974 to 1981 were identified. The neonates belonged to two distinct ethnic groups, Bedouins and Jews, and were compared with 120 healthy controls of similar background. Our data show that premature infants and babies with low birth weight born during the cold season to young (inexperienced) mothers of lower socioeconomic strata and who sustained perinatal morbidity are at risk for IH. It is suggested that parents of infants at risk should be approached while the baby is till in the nursery, be advised about the possibility of hypothermia, and institute the appropriate preventive measures.