Frostbite of the face and ears: epidemiological study of risk factors in Finnish conscripts.

OBJECTIVE

To determine the incidence of and the risk factors for local cold injuries of the face and ears in peacetime military service.

DESIGN

Prospective, controlled epidemiological study using a questionnaire.

SETTING

Finnish defence forces, 1976-89.

SUBJECTS: 913 young male conscripts with local frostbite of the head that needed medical attention and 2478 uninjured control conscripts.

MAIN OUTCOME MEASURES: Type of activity, clothing, and other risk factors at the time of cold injury. Odds ratios were used to calculate risk. Controls were handled as one group.

RESULTS

The mean annual incidence of frostbite was 1.8 per 1000 conscripts. Frostbite of the ear was most common (533 conscripts (58%)), followed by frostbite of the nose (197 (22%)) and of the cheeks and other regions of the face (183 (20%)). Most conscripts (803 (88%)) had mild or superficial frostbite. Risk factors included not wearing a hat with earflaps (odds ratio 18.5 for frostbite of the ear); not wearing a scarf (odds ratio 2.1 and 3.8 for frostbite of the ear and cheeks respectively); using protective ointments (odds ratio 3.3, 4.5, and 5.6 for frostbite of the cheeks, ear, and nose respectively); being extremely sensitive to cold and having hands and feet that sweat profusely (odds ratio 3.5 for frostbite of the nose); and being transported in the open or in open vehicles under windy conditions (odds ratio 2.2 for frostbite of the cheek).

CONCLUSIONS

Wearing warm clothing, including a scarf and a hat with earflaps, helps to prevent frostbite. Each person's sensitivity to cold may also be important. The routine use of protective ointments should not be recommended.