Case-control study of the effectiveness of different types of helmets for the prevention of head injuries among motorcycle riders in Taipei, Taiwan.

A total of 1,351 victims of motorcycle accidents, brought to one of 15 hospitals responsible for emergency care in Taipei, Taiwan, between August 1 and October 15, 1990, were enrolled in a case-control study to investigate the effectiveness of different types of helmets for the prevention of head injuries. A total of 562 of those with head injuries were assigned to the case group, while the remaining 789 victims without head injuries were considered as emergency room controls. The case group was subdivided into daytime and evening cases, according to the time of accident. For each daytime case, we took four pictures of passing motorcycles at the same time and place during the week after each accident. Of the 254 daytime cases, we successfully took pictures for 224 (88%) and identified 1,094 motorcycle riders in the pictures as street controls. Logistic regression analyses were used to determine the roles of the following variables in predicting risk of head injury: age, sex, riding position, weather, place of accident, helmet type, and motorcycle type, and status of helmet wearing. The relative risk of head injury among motorcycle riders was significantly reduced by wearing a full-face helmet, but not by wearing a full- or a partial-coverage helmet.