Table 2

Characteristics of the study participants

VariableDCCT/EDIC: T1D (N = 1,082)WESDR: T1D
(N = 281)LonGenityLifeLines
OPEL, ND
(N = 192)OPUS, ND
(N = 261)T2D (N = 58)ND (N = 8,721)T2D (N = 318)
MMean ± SD
or N (%)MMean ± SD
or N (%)MMean ± SD
or N (%)MMean ± SD
or N (%)MMean ± SD
or N (%)MMean ± SD
or N (%)MMean ± SD
or N (%)
Sex (Male)0579 (53.51)0143 (50.89)079 (41.15)0131 (50.19)036 (62.07)03,590 (41.17)0168 (52.83)
Age (years)051.51 ± 6.98055.92 ± 8.68074.1 ± 5.91075.79 ± 6.67075.36 ± 7.23049.1 ± 11.18058.94 ± 10.81
Smoking status00.87 ± 1.73*00.15 ± 0.270105 (54.69)2129 (49.43)228 (48.28)01,922 (22.04)055 (17.3)
00.73 ± 1.58§
00.75 ± 1.76||
Skin tone0261.73 ± 41.260258.5 ± 45.970241.58 ± 36.830240.87 ± 37.150246.62 ± 45.24
Latitude (north)0800 (73.94)
eGFR (mL/min/1.73 m2)0108.67 ± 10.11395.44 ± 19.14068.89 ± 16.16267.1 ± 17.32164.15 ± 1719113.07 ± 30.890118.34 ± 45.45
BMI (kg/m2)326.41 ± 4.17030.5 ± 5.39
Diabetes duration (years)029.81 ± 4.88042.02 ± 6.6624.93 ± 1.08205.63 ± 7.96
HbA1c (%)#08.17 ± 0.9408.68 ± 0.92325.55 ± 0.3106.84 ± 1.15
HbA1c (mmol/mol)066 ± 7.59071 ± 7.533237 ± 2.07051 ± 8.57
  • M, number of subjects with missing data.

  • *Smoking status during EDIC years 1–5 as a continuous variable (minimum = 0, maximum = 5) calculated by summing smoking status (smoker = 1, nonsmoker = 0) in EDIC years 1–5.

  • †Mean of smoking status (smoker = 1, nonsmoker = 0), asked every 5 years through the study.

  • ‡Current smoker.

  • §Smoking status during EDIC years 6–10 as a continuous variable (minimum = 0, maximum = 5) calculated by summing smoking status (smoker = 1, nonsmoker = 0) in EDIC years 6–10.

  • ||Smoking status during EDIC years 11–16 as a continuous variable (minimum = 0, maximum = 6), calculated by summing smoking status (smoker = 1, nonsmoker = 0) in EDIC years 11–16.

  • ¶DCCT/EDIC, WESDR, LonGenity used Chronic Kidney Disease Epidemiology Collaboration equation (35) to estimate glomerular filtration rate from serum creatinines, measured annually, every 5 years, and once, respectively; Cockcroft-Gault equation was used in LifeLines to estimate glomerular filtration rate from serum creatinine.

  • #Time weighted in DCCT/EDIC, calculated by summing (DCCT eligibility HbA1c × duration of diabetes at DCCT baseline), (DCCT mean HbA1c × years of follow-up in DCCT), and (EDIC mean HbA1c × years of follow-up in EDIC) and dividing by total duration of diabetes, and WESDR, calculated by summing (eligibility HbA1c × duration of diabetes at baseline) and (mean HbA1c during the study × years of follow-up) and dividing by total duration of diabetes; single measurement in LifeLine.