Driver health and crash involvement: A case-control study

The study investigates the relative crash involvement risk associated with diagnosed medical conditions, subjective symptoms and the use of some medicines based on self-report questionnaires from 4448 crash-involved drivers. Whereas many previous studies of medical conditions and crash risk have focussed exclusively on elderly drivers, this study included drivers of all ages. Relative risk for each health condition was estimated by comparing drivers with and without the condition, regarding the odds of being at fault for the crash. Statistical significance was tested by a logistic regression analysis for each condition with crash culpability as the dependent variable. Relative risks were expressed as odds ratios (OR) adjusted for age and annual driving distance. The analyses identified the following significant risk factors: non-medicated diabetes (OR = 3.08), a history of myocardial infarction (OR = 1.77), using glasses when driving (OR = 1.26), myopia (OR = 1.22), sleep onset insomnia (OR = 1.87), frequent tiredness (OR = 1.36), anxiety (OR = 3.15), feeling depressed (OR = 2.43) and taking antidepressants (OR = 1.70). In addition, there was a relatively large and nearly significant relative risk for drivers who had suffered a stroke (OR = 1.93). For some additional conditions the crude odds ratios were significant, but failed to reach significance after correction for age and annual driving distance.