Blood-alcohol levels: show me the evidence

I would like to respond to the concerns of some of our colleagues regarding the validity of the CMA position regarding the lowering of the legal blood-alcohol level content for drivers from 0.08% to 0.05%, as well as the process employed in the formulation of this policy.

On July 23, 1997, the CMA Board of Directors reaffirmed a 10-year-old resolution that supported lowering the legal blood-alcohol content (BAC) for drivers from 0.08% to 0.05%.

This decision was based on a substantial body of scientific evidence demonstrating that significant impairment of driving-related skills (such as vigilance, alertness, and response times) occur in the majority of people at blood-alcohol levels even lower than 0.05%.

MADD Canada (Mothers Against Drunk Driving) recently released a review of international literature on this subject,¹ demonstrating that impairment begins at 0.02%. The review noted the following three factors.

First, on a driving simulator, American researchers found that the percentage of subjects who were impaired in their ability to maintain lane position was 70% at 0.02% BAC.

Second, a 1997 study reported that, in the 6 years following the introduction of the 0.02% BAC limit in Sweden, there was a 9.7% reduction in fatal crashes, an 11% reduction in single- vehicle crashes and a 7.5% reduction in all crashes.

Third, Maryland's 0.02% BAC restriction resulted in a 21% decrease in the number of young crash-involved drivers judged to have been drinking. In addition, a public education campaign resulted in a further 30% decrease.

No one should be driving under the influence of alcohol. While targeted approaches to high-risk groups are necessary for dealing with the public health problem of alcohol-related injury, these are not sufficient. A comprehensive, multi-pronged approach, dealing with public awareness and education initiatives, addiction prevention, treatment and counselling, and enforcement of deterrent legislation are key components of a global health approach to this problem.

When CMA develops policy, our standard process is to consult broadly within the profession, building on current policies, and inviting input into our proposed submission. We also consult outside of the profession.

Grass roots membership views are brought to us by the Board of Directors and General Council's advisory groups (for example, the Council on Health Care and Promotion, the Committee on Ethics, and so on), which have broad, expert representation from specialty and general practice physicians across the country.

The final response is then approved by the CMA Board of Directors or General Council. We understand that the result may not necessarily reflect the views of all of our 53 000 members, but we strive to develop evidence-based policies that reflect a consensus among our elected officials.

Henry Haddad President Canadian Medical Association Ottawa, Ont.