Abstract
Purpose: :
to explore the factors which are predictive of stopping or restricting driving in older drivers.
Methods: :
We enrolled 1425 drivers aged 67-87, who were residents of greater Salisbury from the Maryland Department of Motor Vehicles roster at baseline. We selected all those who reported driving beyond their neighborhood. At one year post enrollment, we categorized this group into those who stopped driving, those who no longer drove beyond their local neighborhood and those who continued to drive beyond their local neighborhood. Change in miles driven in 5-day on road assessments were compared between groups. Multivariate analysis determined the demographic, visual and cognitive factors predictive of stopping or reducing driving.
Results: :
Of the 1425 licensed drivers enrolled, mean age was 75±5, 50% male. A total of 1237 or 87% were interviewed and/or had driving assessment at one year. Those already limiting their driving at baseline were excluded (n=35). At follow-up, 1.5% (18/1202) had stopped and 3.4% (41/1202) restricted their driving. Those who limited their driving had an average decrease of 40±96 miles (5-day odometer readings) to on average 5 miles/day while those not limited, reduced 6±106 miles and drove approximately 20 miles/day at follow-up. In the multivariate model, males were less likely to stop or restrict driving (OR 0.19, 95% CI 0.09-0.40). Those with higher cognitive function were also less likely (0.83, 0.70-0.98 per point Mini-Mental State Examination). Depressive symptoms increased (OR 1.09, 1.02-1.17 per point General Depression Score) likelihood of restricting or stopping driving. Baseline visual acuity predicted stopping or reducing driving (OR 1.16, 1.03-1.51, per line lost) and good contrast sensitivity was marginally associated with decreased likelihood of stopping or reducing driving (OR 0.88, 0.77-1.01 per letter seen). Visual field loss and visual attention were not associated with driving changes.
Conclusions: :
In this cohort, visual acuity and cognitive function were independently associated with incident cessation or restriction of driving space. However, other factors such as depressive symptoms are also predictive of future change in driving habits.
Keywords: aging: visual performance • clinical (human) or epidemiologic studies: risk factor assessment