In 1997, 92,253 people died from unintentional injuries, the leading cause of death from age 1-44.1 In 1997, 42,013 of the unintentional injury deaths resulted from motor vehicle crashes2 and the balance from other unintentional injuries such as falls, drownings, burns, and unintended gun shot wounds.
Alcohol is a major contributor to traffic crashes. Thirty-eight percent of traffic deaths involve alcohol and each year at least 300,000 persons are injured annually in police- reported alcohol-related traffic crashes.3 Even at blood alcohol concentrations (BACs) as low as .02, alcohol affects driver performance by slowing reaction time and the decision making process.4 Epidemiologic research comparing BACs of drivers in single vehicle fatal crashes with those of drivers stopped at random in nationwide surveys indicates that each .02 increase in BAC nearly doubles a driver's fatal crash risk, and more than doubles the risk for male drivers age 16-20.5 The risk increases more rapidly with each drink among drivers under age 21.5,6
Alcohol use is also associated with non-traffic unintended injuries. A case control study assessing the risk of falls when drinking revealed a 10-fold increased risk of death at BACs between .10 and .15 percent and a 60-fold increased risk at BACs above .16.7 Nationwide analyses of 331 Medical Examiner studies of 7,459 unintentional non-traffic injury deaths, over 80 percent of whom were tested for alcohol, revealed that 31 percent of unintentional injury deaths had BACs of .10 or higher.8
To reduce alcohol-related fatal crashes among youth, all states have adopted a minimum legal drinking age (MLDA) of 21. States adopting MLDAs of 21 in the early 1980s experienced a 10 -15 percent decline in alcohol-related traffic deaths among drivers in the targeted ages compared with states that did not adopt such laws.9 The National Highway Traffic Safety Administration (NHTSA) has estimated that the MLDA of 21 prevents 700-1,000 traffic deaths annually among persons under 21, and over 18,000 traffic deaths among persons under 21 have been prevented since 1975.3 Benefits of raising the drinking age may extend beyond reductions in traffic crashes. Jones and colleagues (1992)10 reported lower rates of death caused by suicide and unintentional non traffic injuries among persons under 21 in states with higher MLDAs.
MLDA laws not only decreased drinking among persons under 21, they also lowered drinking among people age 21-25 who grew up in states with MLDAs of 21 relative to those who grew up in other states.11 However, it is not known whether these laws and other efforts to prevent underage drinking reduce drinking and unintentional injury involvement later in life.
A recent analysis of the National Longitudinal Alcohol Epidemiology Survey (NLAES)12 found that age of drinking onset was strongly related to having experienced alcohol dependence during one's life as defined by Diagnostic and Statistical Manual, Fourth Edition (DSM-IV)13, a finding previously reported in smaller studies14 and those using Diagnostic Interview Schedule of the Diagnostic and Statistical Manual, American Psychiatric Association (DIS DSMIII) criteria.15 Among both males and females, and persons with and without a family history of alcoholism, persons who began drinking regularly before age 14 were at least 3 times more likely than those who did not drink until they were over age 21 to experience diagnosable alcohol dependence during their life. Questions in that survey permit us to explore whether early age of drinking onset was related to respondents drinking heavily, placing themselves in situations that increased their risk of injury, and having experienced an unintentional injury after drinking, even after controlling for alcohol dependence and other personal characteristics associated with the age respondents started drinking.