Table 2 Hazard ratios and 95% confidence intervals for development of retinal vein occlusion in postmenopausal women according to female reproductive factors.

From: Early menopause is associated with increased risk of retinal vascular occlusions: a nationwide cohort study

Retinal vein occlusion

Subject no.

Case no.

Duration (person-years)

IR per 100,000 person-years

Model 1 HR (95% CI)

Model 2 HR (95% CI)

Model 3 HR (95% CI)

Overall

2,289,347

7461

11,192,885

66.66

   

Age at menarche

 < 14 years

142,577

344

690,223

49.84

1.00 (ref)

1.00 (ref)

1.00 (ref)

 14–15 years

734,166

2151

3,569,702

60.26

1.09 (0.97–1.23)

1.10 (0.98–1.23)

1.10 (0.98–1.23)

 16–17 years

875,342

2891

4,289,549

67.40

1.08 (0.96–1.21)

1.08 (0.96–1.21)

1.07 (0.95–1.20)

 ≥ 18 years

537,262

2075

2,643,411

78.50

1.13 (1.00–1.27)

1.14 (1.01–1.28)

1.12 (0.99–1.26)

Age at menopause

 < 45 years

120,874

534

595,118

89.73

1.00 (ref)

1.00 (ref)

1.00 (ref)

 45–49 years

529,786

1782

2,597,852

68.60

0.88 (0.80–0.97)

0.89 (0.81–0.98)

0.90 (0.82–0.99)

 50–54 years

1,333,631

4098

6,509,463

62.95

0.85 (0.78–0.93)

0.86 (0.79–0.94)

0.88 (0.80–0.96)

 ≥ 55 years

305,056

1047

1,490,454

70.25

0.85 (0.76–0.94)

0.84 (0.76–0.94)

0.85 (0.76–0.95)

Parity

 Nulliparous

40,211

130

194,953

66.68

1.00 (ref)

1.00 (ref)

1.00 (ref)

 1 child

186,256

518

904,174

57.29

0.94 (0.78–1.14)

0.95 (0.79–1.16)

0.96 (0.78–1.18)

 ≥ 2 children

2,062,880

6813

10,093,759

67.50

0.90 (0.75–1.07)

0.91 (0.76–1.08)

0.89 (0.74–1.09)

Duration of breastfeeding

 Never

191,413

528

925,916

57.02

1.00 (ref)

1.00 (ref)

1.00 (ref)

 < 0.5 year

208,816

488

1,006,405

48.49

0.88 (0.78–0.99)

0.90 (0.80–1.02)

0.93 (0.81–1.06)

 0.5 to < 1 year

426,428

1123

2,079,940

53.99

0.89 (0.80–0.99)

0.90 (0.81–1.00)

0.94 (0.84–1.05)

 ≥ 1 year

1,462,690

5322

7,180,625

74.12

1.01 (0.92–1.11)

1.01 (0.92–1.11)

1.04 (0.94–1.15)

Hormone replacement therapy

 Never used

1,834,474

5995

8,966,668

66.86

1.00 (ref)

1.00 (ref)

1.00 (ref)

 < 2 years

202,796

620

995,995

62.25

1.07 (0.98–1.16)

1.08 (0.99–1.17)

1.07 (0.99–1.17)

 2–5 years

86,281

286

424,267

67.41

1.09 (0.96–1.23)

1.11 (0.98–1.25)

1.11 (0.98–1.25)

 ≥ 5 years

70,579

266

347,636

76.52

1.13 (0.99–1.28)

1.14 (1.00–1.29)

1.13 (0.99–1.28)

 Unknown

95,217

294

458,319

64.15

0.91 (0.81–1.03)

0.9 (0.8–1.01)

0.93 (0.82–1.06)

Oral contraceptive pill use

 Never used

1,838,861

5919

8,989,145

65.85

1.00 (ref)

1.00 (ref)

1.00 (ref)

 < 1 year

201,721

682

989,036

68.96

1.07 (0.98–1.15)

1.05 (0.97–1.14)

1.05 (0.97–1.13)

 ≥ 1 year

134,661

501

662,606

75.61

1.09 (1.00–1.20)

1.05 (0.96–1.16)

1.04 (0.95–1.14)

 Unknown

114,104

359

552,098

65.02

0.93 (0.83–1.03)

0.91 (0.82–1.02)

0.95 (0.85–1.06)

  1. Model 1: adjusted for age. Model 2: adjusted for age, income level, systemic comorbidities (hypertension, diabetes mellitus, dyslipidemia, stroke, heart disease, and chronic kidney disease), and behavioral factors (smoking history, drinking habit, physical activity, body mass index). Model 3: adjusted for age, income level, systemic comorbidities, behavioral factors, and female reproductive factors (age at menarche, age at menopause, parity, breastfeeding, hormone replacement therapy, oral contraceptive pill).
  2. IR, incidence rate; HR, hazard ratio; CI, confidence interval.
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