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[An assessment of the effect of helmet use among cyclists and the risk of head injury and death in Spain, 1990 to 1999].

BACKGROUND AND OBJECTIVE
This study aimed to assess the protective effect of helmet use by cyclists on risk of suffering head injury or dying as a consequence of a traffic crash.


SUBJECTS AND METHOD
26,832 cyclists involved in traffic crashes with victims registered in the Dirección General de Tráfico database from 1990 to 1999 in Spain were studied. From this database, variables relating to each cyclist (i.e., age, sex, presence of head trauma, severity of lesions) and those related with the crash (i.e., place, date, type of crash), were collected. The odds ratio and the proportion of the population attributable risk for non-use of a helmet by cyclist were estimated.


RESULTS
An adjusted odds ratio of 2.45 (2.19-2.73) for the association between non-use of a helmet and the risk of head injury was obtained. As death of the cyclist as the outcome, the corresponding odds ratio was 1.35 (1.09-1.67). The values of proportion of the population attributable risk were 0.51 (0.47-0.55) and 0.22 (0.07-0.36), for head injury and death, respectively.


CONCLUSIONS
This study confirms that helmet use among cyclists significantly decreased the risk of head injury and, to a lesser extent, death. These results constitute a strong argument for increasing in the frequency of helmet use among cyclists in Spain.