Table 1 Baseline characteristics of participants with/without hysterectomy from the Korea National Health Insurance Database, 2007-2020^a

Number of participants

89,768

66,204

155,972

Adnexal surgery during hysterectomy

 Hysterectomy

77.7

77.7

 Hysterectomy + adnexal surgery

22.3

22.3

Median age (years)

48 [43–53]

46 [44–49]

47 [44–52]

 < 0.001

Age at inclusion (years)

 < 0.001

 40 ~ 44

30.9

32.7

31.6

 45 ~ 49

24.2

43.7

32.5

 50 ~ 54

25.1

20.1

23.0

 55 ~ 59

19.8

3.6

12.9

Year at inclusion

 < 0.001

 2011

21.3

29.1

24.6

 2012

22.6

25.8

24.0

 2013

27.3

23.2

25.5

 2014

28.9

21.9

25.9

SES

 < 0.001

 Mid ~ high SES

96.8

97.7

97.2

 Low SES

3.2

2.3

2.8

Region

 < 0.001

 Urban area

53.4

64.0

57.9

 Rural area

46.6

36.0

42.1

CCI

 < 0.001

 0

74.3

76.9

75.4

 1

14.6

13.2

14

  ≥ 2

11.1

9.9

10.6

Parity in cohort

 < 0.001

 0

96

98.7

97.1

 1

2.5

0.9

1.9

  ≥ 2

1.5

0.4

1.0

Menopause before inclusion

 < 0.001

 Absent

79.4

91.8

84.6

 Present

20.6

8.2

15.4

MHT before inclusion

 < 0.001

 Absent

96.1

98.6

97.1

 Present

3.9

1.4

2.9

Adnexal surgery before inclusion

 < 0.001

 Absent

98.1

98.9

98.5

 Present

1.9

1.1

1.5

Diseases of the gallbladder and biliary tract before inclusion

 < 0.001

 Absent

98.3

98.7

98.5

 Present

1.7

1.3

1.5

Uterine leiomyoma

 < 0.001

 Absent

90.9

21.0

61.2

 Present

9.1

79.0

38.8

Endometriosis

 < 0.001

 Absent

97.9

73.3

87.5

 Present

2.1

26.7

12.5

MHT after inclusion

 < 0.001

 Absent

93.0

85.7

89.9

 Present

7.0

14.3

10.1