Context Bicycling is one of the leading causes of recreational injuries. Elevated
blood alcohol concentrations (BACs) are found in about one third of fatally
injured bicyclists aged 15 years or older.
Objective To assess the relative risk of fatal and serious bicycling injury according
to BAC.
Design Matched case-control study.
Setting and Subjects Bicyclists aged 15 years or older who were fatally or seriously injured
while riding a bicycle during the day in Maryland in 1985-1997 (cases, n =
124) and bicyclists aged 15 years or older who were interviewed and given
a breath test for estimated BAC during roadside surveys that took place in
June 1996 through May 1998 at the same site, time of day, day of week, and
month of year in which a case bicyclist was injured (controls, n = 342).
Main Outcome Measure Odds ratio of bicycling injury according to estimated BAC.
Results An estimated positive BAC (≥0.02 g/dL) was detected in 12.9% of the
case bicyclists (23.5% of the 34 fatally injured and 8.9% of the 90 seriously
injured) compared with 2.9% of the control bicyclists (P<.001). Relative to an estimated BAC of less than 0.02 g/dL, the
adjusted odds ratio of bicycling injury was 5.6 (95% confidence interval [CI],
2.2-14.0) for a BAC of 0.02 g/dL or higher and was 20.2 (95% CI, 4.2-96.3)
for a BAC of 0.08 g/dL or higher. Rates of helmet use at the time of injury
or interview were 5% and 35%, respectively, for those with and without a positive
BAC (P = .007).
Conclusion Alcohol use while bicycle riding is associated with a substantially
increased risk of fatal or serious injury.