Table 1.

Characteristics of participants (N = 83) and associations with median response time while performing the task (DSST) in the scanner (Spearman or Pearson). Measures are from day of MRI (2010–2013) unless otherwise specified.

		Mean ± SD or N (%)	Correlation coefficient, p values
Demographic characteristics	Age at MRI (years)	49.04 ± 6.89	−0.37, <0.001
	Education (years)	15 ± 2	−0.09, 0.38
	Female	42 (48%)	0.12, 0.27
Diabetes-related factors and complications	T1D duration at MRI (years)	40.80 ± 6.26	0.28, 0.01
	Age at T1D diagnosis (years)	8.24 ± 4.25	0.18, 0.10
	Serum glucose (mg/dL)	177.52 ± 90.68	−0.06, 0.61
	HbA1c (%)	7.96 ± 2.32	0.15, 0.17
	HbA1c months (AU)	971.15 ± 374.24	0.32, <0.001
	Confirmed distal symmetric polyneuropathy∗	38 (48%)	0.38, <0.001
	Overt nephropathy∗	23 (32%)	0.33, <0.001
	Proliferative retinopathy∗	39 (45%)	0.36, <0.001
MRI measures	Correct median response time (ms)	1353.39 ± 322.12	—
	White matter hyperintensity volume (% total brain volume)	0.002 ± 0.003	0.24, 0.02
	White matter hyperintensity severity, Fazekas rating = 3	10 (11%)	0.25, 0.02
Cognitive measures	NAART (verbal IQ estimate)	108 ± 7	−0.17, 0.14
	Digit symbol substitution test, number complete in 90 seconds (pencil and paper test)	56 ± 13	−0.56, <0.001
	Information processing domain, z-score	0.54 ± 0.82	−0.57, <0.001
	Clinically relevant cognitive impairment	28 (35%)	0.37, <0.001

^∗Documented in 2004–2006.