An Evidence-Based Review: Helmet Efficacy to Reduce Head Injury and Mortality in Motorcycle Crashes: EAST Practice Management Guidelines

Abstract

According to the National Highway Traffic Safety Association, in 2008, 5,290 motorcyclists died and 96,000 were injured. Motorcycles make up ∼3% of all registered vehicles in the United States and account for only 0.4% of all vehicle miles traveled. However, motorcycle crashes accounted for ∼10% of all motor vehicle crash fatalities, and per mile traveled, motor cycle crashes are ∼37 times more lethal than automobile crashes. Head injuries are one of the most common injuries after motorcycle crashes and were estimated to be the cause of death in >50% of these fatalities. In close to a third of these victims, the head injury is the sole organ system that is injured. However, in the majority of patients, estimated as high as 90% of some patient cohorts, a head injury is present along with other injuries. Despite these facts, it is estimated that only 50% of motorcyclists routinely wear helmets. It was intuitive even to our earliest ancestors that a hard shell would protect the head from injury. However, establishing the effectiveness of the motorcycle helmet remains a challenging effort especially in light of the powerful opposition to universal helmet laws. Furthermore, quantifying the protective effect of helmets supports the promotion of helmet programs regardless of the controversial nature of legislative efforts. In the United States, an increasing recognition that helmet use is associated with reductions in fatalities without apparent harm increased the implementation of universal helmet laws. In response to the 1966 Federal Highway Act, which withheld federal funds from states that did not enact a helmet law, Georgia became the first state to enact a mandatory universal motorcycle helmet law in 1967. By 1975, 47 of the 50 states had universal helmet laws. However, public and political concerns over individual rights versus public safety opened a new debate. In the following years, political changes reversed and/or limited previous sanctions and grants that encouraged states to enact universal helmet laws, which further eroded support for helmet laws. An increasing number of states either repealed their mandatory laws altogether or significantly reduced the laws to apply only to minors. At present, only 20 states have universal helmet laws, another 26 states require only partial coverage, and 4 states have no helmet laws (Colorado, Illinois, Iowa, and New Hampshire). A large volume of literature has quantified the consequences of not wearing a helmet while riding a motorcycle. Although motorcycle riding and registration are increasing and more states with universal helmet laws are introducing bills to repeal their laws, the debate continues on the personal advantages of helmet usage. Therefore, we have reviewed the literature and summarize the evidence basis for the use of motorcycle helmets. In particular, we have sought to assess the impact of helmet use on overall mortality, head injury-related mortality, nonlethal head injury after a motorcycle crash, and the impact universal helmet laws on helmet use. STATEMENT OF PROBLEM Motorcycles are a significant cause of injury-related fatality and disability. In particular, head injury is a common associated cause of death and long-term disability after a motorcycle crash. Despite these facts, there remains an ongoing controversy as to the survival and disability advantages for riders who wear motorcycle helmets. In the public and legislative sectors, there remains a significant policy controversy resulting in a push to retain partial coverage helmet laws and to repeal universal helmet laws in many others. QUESTIONS TO BE ADDRESSED Do nonhelmeted riders in comparison with helmeted riders have a higher or lower overall death rate after a motorcycle crash? Do nonhelmeted riders in comparison with helmeted riders incur higher or lower rates of lethal head injury after a motorcycle crash? Do nonhelmeted riders in comparison with helmeted riders incur higher or lower rates of nonlethal head injury or is the nonlethal head injury more or less severe after a motorcycle crash? Do geographical areas (i.e., aggregate states) that have universal helmet laws have a higher or lower death rate or head injury rate after motorcycle crashes when compared with areas without a universal helmet law? METHODS AND PROCESS A computerized search of the world's literature was undertaken using PubMed, of the US National Library of Medicine, extending back to 1990 to the present (2009) using the key words: helmet + (motorcycle OR crash). There were 507 citations identified. The abstract for each was reviewed, and 197 candidate articles having possible applicability to the guideline topic were retrieved and reviewed. General reviews, letters to the editor, single case reports, and retrospective reviews of poor quality were excluded. This left 45 articles that were felt to have sufficient merit to form the basis for the guidelines (Table 1). The articles were reviewed in detail by the authors J.M., G.H.T., and J.C.D.TABLE 1: