| Motor vehicle-related traumatic brain injury (TBI) is a major public health problem. Far-reaching consequences of TBI include disability, pain, loss of productivity, and tremendous use of medical resources. A clear understanding of the problem of motor vehicle-related TBI is needed to develop and implement effective countermeasures.; The purpose of this retrospective injury surveillance study was to demonstrate how speed, measured by posted speed limit, on Missouri roadways contributed to the problem of TBI.; This study involved the investigation of traffic crash and hospital discharge records of driver injury cases linked in the 1999 Missouri Crash Outcome Data Evaluation System (CODES). ICDMAP 90 software was used to calculate maximum Abbreviated Injury Scale (AIS-90) scores for the body region of the head. TBI proportions were calculated by dividing total TBI cases in CODES by the total number of injury cases linked in CODES (N = 60,918). The proportion and severity of TBI by posted speed limit were analyzed using a chi-square test of homogeneity of proportions, the Mantel-Haenszel chi-square test for trends, logistic regression analysis, Spearman's correlation coefficient, and multiple linear regression analysis. Indicators of TBI were adjusted by reported use of safety belt, airbag deployment, vehicle type, driver age, and gender.; Increasing rate of posted speed limit was positively associated with an increasing proportion of TBI. There was a correlation between TBI severity and posted speed limit, but it was not linear. Only two speed zones, 55 and 70 mph, had a significant effect on TBI severity. The reported use of a safety belt reduced the occurrence and severity of TBI, and airbag deployment was associated with a greater occurrence of TBI.; This investigation demonstrated how ICDMAP 90 can be used to calculate the frequency, proportion, and severity of TBI in CODES investigations. Further research is needed to explore why increased TBI severity did not occur in a linear fashion with posted speed zones, and why airbag deployment was associated with a greater occurrence of TBI. |
