Evid Based Med doi:10.1136/eb-2012-101116
  • Prognosis
  • Cohort study

Medical warnings reduce older drivers’ risk of motor vehicle injury while adversely affecting mental health and physician relationship

  1. Thelma J Mielenz
  1. Departments of Anesthesiology and Epidemiology, Columbia University, New York, New York, USA
  1. Correspondence to : Guohua Li, MD, DrPH
    Center for Injury Epidemiology and Prevention at Columbia University Medical Center, 722 West 168th Street, Rm 524, New York, NY 10032, USA; gl2240{at}

Commentary on: [CrossRef][Medline]Google Scholar


Driving is an important indicator of mobility in industrialised nations. Over 80% of individuals aged 65 years and older in the USA continue to drive. Research indicates that driving confers significant health benefit to older people, including increased social engagement, increased functional independence, decreased risk of depression and decreased use of long-term care.1 Unfortunately, driving is not free of risk. Older drivers tend to have higher per capita mortality from motor vehicle crashes and higher crash involvement per mile driven than drivers aged 35–64.2 The excess mortality from motor vehicle crashes for older adults is due largely to their depleted ability to survive injuries.3 Although their safety records are better than adolescent and young adult drivers, there is a pervasive misperception that older drivers are a major threat to other road users. In the past two decades, a variety of programmes, ranging from cognitive screening to driving rehabilitative therapy and restricted licensing, have been proposed to reduce the perceived risk posed by unfit older drivers. Public policy that optimises the balance between mobility benefit and crash risk for older drivers is elusive and lacks an empirical basis.


Redelmeier and colleagues assessed the effectiveness of physicians’ warnings for medically unfit drivers in reducing crash injury. Physicians in Ontario, Canada are required to issue warnings to patients with medical conditions that may impair their driving safety. To facilitate compliance with the policy, the provincial government introduced a financial incentive in 2006 by compensating the physician at $36.25 per warning issued. They collected data for over 100 000 patients (53% were 60 years of age or older) who received warnings from their physicians in Ontario between April 2006 and December 2009. Using a case-crossover design, they estimated the risk of emergency department visits for traffic injury while driving in these patients after receiving physician warnings.


This risk decreased by more than 40% after the first medical warning from the patient's physician. Sensitivity analysis and stratification analysis showed that the estimated effect of physician warning on driver injury risk was robust and persisted across patient demographic characteristics and medical conditions. Of note, these patients did not experience any discernible increase in their rates of injury as pedestrians and car passengers after receiving physician warnings. The benefit of injury reduction resulting from physician warning, however, is offset to some degree by a 20% increase in emergency department visits for depression and a 23% decrease in patient visits to responsible physicians (an indicator of compromised patient–physician relationship and disrupted continuity of care). In short, restricting the driving of medically unfit older adults reduces their risk of motor vehicle injury, while adversely affecting their mental health and quality of life due to diminished mobility.


The results of this study are generally consistent with previous reports.4 ,5 A noted limitation is the unknown mechanism of decreased risk. Resolution of this mobility versus safety dilemma for older and medically unfit drivers will require more patient-centred and policy-oriented research, as exemplified by the Redelmeier and colleagues study, to better understand the benefit and the risk of different interventions. When driving cessation is discussed with a patient, information about acceptable alternative transportation means should be offered; mobility counsellors are emerging to fill this gap.6 For older adults who cease driving, there is an unmet need to redefine transportation to allow for continued community participation (eg, an innovative New York City senior centre programme offering door-to-door transportation services to older adults with mobility facilitators). Finally, it is important to foster technological advances to motor vehicles including ergonomic changes and auto-pilot car designs for older adults to improve safety and help them maintain their mobility. Ageing and driving are complex issues that warrant multifaceted solutions.


  • Funding Funded by Grant R49CE002096 from the National Center for Injury Prevention and Control, Centers for Disease Control and Prevention to the Center for Injury Epidemiology and Prevention at Columbia University. Its contents are solely the responsibility of the authors and do not necessarily represent the official views of the Centers for Disease Control and Prevention.

  • Competing interests None.


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