Table 1—

Characteristics of studies that have assessed cognitive functioning in patients with type 1 diabetes and nondiabetic control subjects

First author (ref.)n (grp 1)/(grp 2)% Males (grp 1)/(grp 2)Age (grp 1)/(grp 2) (years)Subjects matched forHbA1c or HbA1 (%)Duration (years)Calculated age at onset (years)Included complications and characteristicsExclusion criteria or absent characteristics
Meuter et al. 1980 (17)112/11250/5038 ± 14.3/NDEND10.5 ± 9.317H,Hy,N,R,NeND
Franceschi et al. 1984 (18)37/2643/4225.8 ± 5/26.4 ± 5E,O,SES12.7 ± 2.57.7 ± 5.518Hy,N,RH,Ne,CI,DL,P
Skenazy et al. 1984 (19)
    Visually impaired20/2470/6728 ± 6.1/22.6 ± 5.6NDND18.7 ± 5.99H,Hy,N,R,NeND
    Nonvisually impaired19/2453/6732.1 ± 6.2/22.6 ± 5.6NDND15.3 ± 7.817H,Hy,N,R,NeND
Lawson et al. 1984 (5)48/4054/4838.3 ± 14.6/38.8 ± 12.8ND9.113 ± 10.815Hy,NP
Grill et al. 1990 (20)6/5ND37.1 ± 6.9/30.3 ± 4.5ND6.9 ± 0.719.4 ± 5.118Hy,RCV,Ne,H,CI,N
Widom et al. 1990 (21)
    Poor metabolic control9/1044/6022 ± 3/27 ± 3.2ND11.8 ± 1.212 ± 610RN,Ne,
    Good metabolic control8/1050/6027 ± 5.7/27 ± 3.2ND8 ± 0.67 ± 2.820NDN,Ne,R
Dejgaard et al. 1991 (22)20/120ND/ND44 ± 9/NDND9.1 ± 1.426 ± 918Hy,N,R,NeP
Pozzessere et al. 1991 (23)16/1670/7033.2 ± 12.6/33.4 ± 12.5E7 ± 1.69 ± 7.724HHy,NA,P,DL
Blackman et al. 1992 (24)14/1043/5029.5 ± 6/26.7 ± 6ND11 ± 1.9NDNDNDHy,N
Ryan et al. 1992 (2)75/7545/2535.5 ± 5.6/36.2 ± 6.8E,SES10.326.6 ± 6.79Hy,N,R,ND
Sachon et al. 1992 (3)
    Severe hypoglycemia30/2577/4841 ± 13/38 ± 15O,SES7.4 ± 1.218 ± 1323Hy,N,Ne,RND
    No hypoglycemia25/2560/4834 ± 10/38 ± 15O,SES8.6 ± 1.915 ± 1118N,Ne,RHy,ND
Wirsen et al. 1992 (25)10/12100/100R 20–43/R 18–32E,7.9 ± 0.6NDNDHyN
Cox et al. 1993 (26)10/1040/ND34/NDE,O9.81816NDND
Deary et al. 1993 (1)100/100ND/ND40.9 ± 8.8/40.2 ± 6.7END>5>19Hy,R,N,NeP
Ryan et al. 1993 (6)
    Females41/410/033.4 ± 5.5/35.2 ± 8.4E,SES10.9 ± 1.825.3 ± 6.68Hy,N,Ne,RND
    Males41/41100/10033.4 ± 5.2/34.7 ± 7.5E,SES10.6 ± 227.1 ± 5.56Hy,N,Ne,RND
Ryan et al. 1993 (27)142/10051/4733.5 ± 5.6/34.1 ± 6.7E,SES10.6 ± 1.824.8 ± 6.18Hy,N,Ne,RND
Maran et al. 1995 (28)
    Good metabolic control8/875/6336 ± 3/31 ± 2ND7.7 ± 0.316 ± 220HyND
    Poor metabolic control10/860/6332 ± 4/31 ± 2ND10.1 ± 0.217 ± 315NDND
Hershey et al. 1997 (29)
    Severe hypoglycemia26/21ND/ND26.2 ± 6.6/27.8 ± 8.1END>5<14HyR,N
    No hypoglycemia12/21ND/ND22.8 ± 7.7/27.8 ± 8.1END>5<14Hy,R,N
Kramer et al. 1998 (30)108/10845/ND36 ± 13/36 ± 13NDND>1>16H,Hy,N,R,P,Ne
Snoek et al. 1998 (31)
    Severe hypoglycemia9/9100/10036.9 ± 6.7/NDND7.413.424HyP,
    No hypoglycemia9/9100/10036.9 ± 6.7/NDND7.413.424Hy,P,
Lobmann et al. 2000 (32)12/1233/5831 ± 7/27 ± 3ND7.4 ± 1.87.8 ± 8.623HyN,R,H,CI,Ne,
  • Data are means ± SD, unless otherwise indicated. CI, cardiac insufficiency; DL, dyslipidemia; E, education; H, hypertension or hypertensive treatment; Hy, severe hypoglycemic episodes; N, neuropathy; ND, not specifically defined; Ne, nephropathy and/or microalbuminuria; O, occupation; P, psychiatric problems and/or use of psychoactive drugs and/or addiction to alcohol or other substances; R, retinopathy; SES, socioeconomic status.