The acceptable risk of driving after myocardial infarction: are bus drivers a special case?
BACKGROUND
Bus drivers frequently encounter difficulty in returning to their former employment after recovery from myocardial infarction. The risk that a recurrence of myocardial infarction may cause a personal-injury accident is analyzed.


METHODS
The Cumulative Medical Index and Current Contents was searched systematically from 1980 to date, accepting papers irrespective of language. Relevant earlier material was drawn from the author's published reviews on bus driving and myocardial infarction and vehicle accidents. One hundred twenty-three articles were included in the database, of which 110 were used in the review.


RESULTS
The risk of a personal injury accident or fatality from a sudden cardiovascular incident is calculated as the product of typical driving time per day (Td = 0.167), vehicle characteristics (V) (a low factor of 0.167 for an urban bus because of slow speed and use of reserved curb lanes), the risk of recurrence of a sudden cardiovascular incident (SCI) (.015, somewhat greater in bus drivers than in the general population), and the risk that such an incident will cause a personal-injury accident (Ac) (at 0.005, probably lower than in the general population because of low vehicle speeds and the bus driver's experience in defensive driving).


CONCLUSIONS
The overall risk is 0.00002, 1 in 50,000 driver-years, is lower than accepted for passenger-car operators, and only slightly greater than for the older symptom-free adult. Bus drivers who meet the current standards of the Canadian Cardiovascular Society should be encouraged to return to their former employment.
Shephard
R J
RJ
Faculty of Physical Education and Health, and Graduate Department of Community Health, University of Toronto, Toronto Rehabilitation Centre, Ontario, Canada.
D000063:Accidents, Traffic; D000328:Adult; D001334:Automobile Driving; D002170:Canada; D006801:Humans; D009203:Myocardial Infarction; D016272:Occupational Health; D012008:Recurrence; D012306:Risk; D012307:Risk Factors