Table 1 Characteristics of the study population based on hemoglobin A _1C (HbA1c) level quintiles

Hemoglobin A_1c (HbA_1c) median values, %

5.04

5.35

5.45

5.76

6.17

  No. at risk

190

205

258

246

251

  Age, year

70.3 ± 6.3

70.5 ± 7.6

70.3 ± 6.7

70.7 ± 7.0

70.3 ± 7.0

  Systolic blood pressure, mmHg

144 ± 20

147 ± 22

143 ± 19

143 ± 19

146 ± 22

0.107

  Antihypertensive medication use, %

35.8

30.2

38.8

35.8

40.6

0.165

  Body mass index, kg/m²

22.8 ± 2.8

23.5 ± 3.1

23.1 ± 2.8

23.9 ± 2.9

24.2 ± 3.4

<0.001

  Current drinker, %

53.2

52.2

51.6

42.3

44.2

0.058

  Current smoker, %

20.5

17.6

24.0

17.5

19.5

0.381

  Serum triglycerides, mg/dL

98 ± 50

119 ± 80

105 ± 58

129 ± 82

134 ± 98

<0.001

  Serum HDL-cholesterol, mg/dL

56 ± 15

54 ± 14

56 ± 15

53 ± 14

53 ± 15

0.059

  Serum aspartate aminotransferase (AST), IU/L

25 ± 12

25 ± 9

24 ± 7

25 ± 8

27 ± 13

0.033

  Glucose-lowering medication use, %

2.1

2.0

1.2

2.8

27.9

<0.001

  Lipid-lowering medication use, %

3.2

5.9

5.4

7.7

10.8

0.020

  History of cardiovascular disease, %

9.5

8.3

12.4

15.9

16.3

0.033

  Taking medication for cardiovascular disease, %

7.4

7.3

11.2

14.6

14.3

0.025

  Serum creatinine, mg/dL

0.98 ± 0.32

0.92 ± 0.28

0.92 ± 0.29

0.88 ± 0.22

0.88 ± 0.22

<0.001

  Glomerular filtration rate (GFR), mL/min/1.73 m²

63.7 ± 17.9

67.2 ± 17.6

67.6 ± 17.2

69.5 ± 16.4

70.5 ± 16.8

<0.001

  No. at risk

103

102

127

98

90

  Age, year

71.5 ± 6.7

71.5 ± 8.1

70.2 ± 7.2

71.6 ± 7.3

70.7 ± 7.2

  Systolic blood pressure, mmHg

140 ± 21

142 ± 20

140 ± 18

138 ± 17

140 ± 22

0.543

  Antihypertensive medication use, %

28.2

25.5

29.1

23.5

25.6

0.778

  Body mass index, kg/m²

20.8 ± 1.5

20.9 ± 1.5

20.8 ± 1.7

21.1 ± 1.5

20.7 ± 1.6

0.429

  Current drinker, %

60.2

50.0

50.2

48.2

49.0

0.004

  Current smoker, %

23.3

20.6

29.9

21.4

21.1

0.524

  Serum triglycerides, mg/dL

90 ± 52

101 ± 55

93 ± 50

107 ± 66

103 ± 66

0.175

  Serum HDL-cholesterol, mg/dL

60 ± 15

56 ± 14

58 ± 15

56 ± 15

57 ± 16

0.370

  Serum aspartate aminotransferase (AST), IU/L

26 ± 14

25 ± 9

23 ± 5

25 ± 9

25 ± 10

0.328

  Glucose-lowering medication use, %

3.9

2.9

0.8

10.2

30.0

<0.001

  Lipid-lowering medication use, %

2.9

5.9

4.7

8.2

5.6

0.573

  History of cardiovascular disease, %

7.8

4.9

8.7

14.3

16.7

0.032

  Taking medication for cardiovascular disease, %

5.8

3.9

7.8

13.3

12.2

0.068

  Serum creatinine, mg/dL

1.00 ± 0.37

0.94 ± 0.35

0.91 ± 0.34

0.85 ± 0.16

0.88 ± 0.25

0.006

  GFR, mL/min/1.73 m²

62.4 ± 17.0

68.0 ± 20.6

69.6 ± 18.5

71.1 ± 14.7

70.1 ± 17.3

0.004

  No. at risk

87

103

131

148

161

  Age, year

68.9 ± 5.6

69.5 ± 6.9

70.4 ± 6.1

70.2 ± 6.8

70.1 ± 7.2

  Systolic blood pressure, mmHg

149 ± 17

152 ± 23

147 ± 19

146 ± 20

150 ± 21

0.154

  Antihypertensive medication use, %

44.8

35.0

48.1

43.9

49.1

0.258

  Body mass index, kg/m²

25.1 ± 1.9

26.0 ± 2.1

25.4 ± 1.7

25.7 ± 1.8

26.1 ± 2.5

0.001

  Current drinker, %

44.8

54.4

55.0

46.6

47.2

0.296

  Current smoker, %

17.2

14.6

18.3

14.9

18.6

0.822

  Serum triglycerides, mg/dL

106 ± 45

137 ± 96

116 ± 62

143 ± 88

152 ± 108

<0.001

  Serum HDL-cholesterol, mg/dL

51 ± 14

52 ± 15

54 ± 14

51 ± 12

51 ± 13

0.300

  Serum aspartate aminotransferase (AST), IU/L

24 ± 10

26 ± 10

24 ± 8

25 ± 8

28 ± 15

0.021

  Glucose-lowering medication use, %

0.0

1.0

1.5

4.1

26.7

<0.001

  Lipid-lowering medication use, %

3.4

5.8

6.1

7.4

13.7

0.028

  History of cardiovascular disease, %

11.5

11.7

16.0

16.9

16.1

0.770

  Taking medication for cardiovascular disease, %

9.2

10.7

14.5

15.5

15.5

0.645

  Serum creatinine, mg/dL

0.96 ± 0.26

0.91 ± 0.18

0.93 ± 0.23

0.91 ± 0.25

0.87 ± 0.20

0.021

  GFR, mL/min/1.73 m²

65.3 ± 18.8

66.5 ± 14.0

65.6 ± 15.5

68.4 ± 17.4

70.5 ± 16.2

0.021