Table 1 Clinical characteristics of Younger group and Older group

Total Participants

421,229

2,368

0.6

418,861

99.4

237,474

32,893

13.9

204,581

86.1

Age

< 0.001

< 0.001

 Mean ± Standard deviation

53.0 ± 5.2

50.3 ± 6.8

74.2 ± 6.6

68.3 ± 5.4

Sex

0.002

< 0.001

 Male

206,289

1,236

52.2

205,053

49.0

105,868

10,725

32.6

95,143

46.5

 Female

214,940

1,132

47.8

213,808

51.0

131,606

22,168

67.4

109,438

53.5

Risk factors of interest

 Hypertension

115,954

1,057

44.6

114,897

27.4

< 0.001

154,574

23,901

72.7

130,673

63.9

< 0.001

 Diabetes mellitus

89,105

910

38.4

88,195

21.1

< 0.001

117,142

17,143

52.1

99,999

48.9

< 0.001

 Atrial fibrillation

5,269

54

2.3

5,215

1.2

< 0.001

9,940

1,564

4.8

8,376

4.1

< 0.001

 Hyperlipidemia

123,711

989

41.8

122,722

29.3

< 0.001

138,984

16,756

50.9

122,228

59.7

< 0.001

 Osteoporosis

49,302

417

17.6

48,885

11.7

< 0.001

90,494

15,689

47.7

74,805

36.6

< 0.001

Other risk factors in the Charlson comorbidity index

 Myocardial infarct

18,267

198

8.4

18,069

4.3

< 0.001

33,889

5,319

16.2

28,570

14.0

< 0.001

 Congestive heart failure

7,121

93

3.9

7,028

1.7

< 0.001

19,661

3,683

11.2

15,978

7.8

< 0.001

 Peripheral vascular disease

55,432

557

23.5

54,875

13.1

< 0.001

91,160

13,832

42.1

77,328

37.8

< 0.001

 Cerebrovascular disease

24,434

499

21.1

23,935

5.7

< 0.001

52,585

9,685

29.4

42,900

21.0

< 0.001

 Chronic pulmonary disease

146,184

933

39.4

145,251

34.7

< 0.001

138,475

19,467

59.2

119,008

58.2

< 0.001

 Rheumatic or connective tissue disease

6,623

40

1.7

6,583

1.6

0.647

7,123

925

2.8

6,198

3.0

0.032

 Gastric or peptic ulcer

157,368

1,000

42.2

156,368

37.3

< 0.001

135,912

17,723

53.9

118,189

57.8

< 0.001

 Mild liver disease

180,848

1,354

57.2

179,494

42.9

< 0.001

145,014

18,247

55.5

126,767

62.0

< 0.001

 Hemiplegia or paraplegia

3,221

152

6.4

3,069

0.7

< 0.001

6,223

1,333

4.1

4,890

2.4

< 0.001

 Moderate or severe renal disease

5,535

72

3.0

5,463

1.3

< 0.001

9,301

1,236

3.8

8,065

3.9

0.109

Socioeconomic status

< 0.001

< 0.001

 Upper 20%

121,591

400

16.9

121,191

28.9

72,803

10,797

32.8

62,006

30.3

 Lower 80%

299,638

1,968

83.1

297,670

71.1

164,671

22,096

67.2

142,575

69.7

Residential area

< 0.001

< 0.001

 Urban

199,689

1,011

42.7

198,678

47.4

102,405

12,191

37.1

90,214

44.1

 Rural

221,540

1,357

57.3

220,183

52.6

135,069

20,702

62.9

114,367

55.9