Table 4.

Liner regression assessing variables association with error item during on-road driving.

	Error item
	Confirmation		Turn left		Maintains driving lane position		Maintains appropriate speed
	R2= 0.069		R2= 0.094		R2= 0.174		R2= 0.085
	β	p-value	β	p-value	β	p-value	β	p-value
Predictor variable	[95%CI]		[95% CI]		[95% CI]		[95% CI]
Age (years)	0.115	0.216	0.075	0.411	0.196	0.026	−0.074	0.418
	[−0.09, 0.38]		[−0.12, 0.30]		[0.02, 0.25]		[−0.19 0.08]
Gender (F)	0.086	0.350	0.196	0.032	0.089	0.303	0.213	0.020
	[−0.73, 2.06]		[0.12, 2.64]		[−0.33, 1.05]		[0.15, 1.73]
Education (years)	0.136	0.122	0.110	0.202	0.067	0.420	0.008	0.929
	[−0.13, 1.08]		[−0.19, 0.89]		[−0.18, 0.42]		[−0.32, 0.36]
Estimated driving distance per year (10,000 km)	0.052	0.566	−0.032	0.716	0.111	0.192	0.122	0.173
	[−2.94, 5.37]		[−4.43, 3.05]		[−0.69, 3.41]		[−0.72, 3.98]
MMSE-J	0.064	0.489	0.027	0.765	−0.077	0.381	−0.155	0.093
	[−0.57, 1.18]		[−0.67, 0.91]		[−0.62, 0.23]		[−0.92, 0.07]
dCDT score	−0.231	0.011	−0.246	0.006	−0.322	0.000	0.128	0.155
	[−1.54, −0.20]		[−1.44, −0.24]		[−0.96, −0.30]		[−0.10, 0.65]

F, female; MMSE-J, Mini-Mental State Examination-Japanese; dCDT, digital Clock Drawing Test; R², coefficient of determination; β, beta coefficient; CI, confidence interval.