Table 1 Characteristics of individuals with a gastrointestinal (GI) biopsy result of normal mucosa and their matched references, a nationwide matched cohort study in Sweden, 1965–2016

Age at cohort entry, years ^a

 Mean ± SD

42.6 ± 19.9

41.4 ± 19.6

 Median (IQR)

41.6 (26.5, 57.6)

40.2 (25.8, 55.9)

  < 18 y

37,162 (9.0)

185,918 (9.6)

 18–39.9 y

159,128 (38.3)

776,081 (40.0)

 40–59.9 y

128,543 (31.0)

597,589 (30.8)

  ≥ 60 y

90,259 (21.7)

379,627 (19.6)

Sex

 Male

161,935 (39.0)

774,466 (39.9)

 Female

253,157 (61.0)

1,164,749 (60.1)

Country of birth

 Nordic country

372,414 (89.7)

1,695,737 (87.4)

 Other country

42,678 (10.3)

243,478 (12.6)

Biopsy location ^b

 Upper GI

252,130 (60.7)

1,178,909 (60.8)

 Lower GI

162,962 (39.3)

760,306 (39.2)

Calendar period of cohort entry

 1969–1989

37,065 (8.9)

175,750 (9.1)

 1990–1999

105,966 (25.5)

497,625 (25.7)

 2000–2009

159,364 (38.4)

741,892 (38.3)

 2010–2016

112,697 (27.2)

523,948 (27.0)

Educational attainment

 0–9 y

87,205 (21.0)

401,459 (20.7)

 10–12 y

155,033 (37.4)

705,301 (36.4)

  ≥ 13 y

103,714 (25.0)

486,016 (25.1)

 Missing

69,140 (16.7)

346,439 (17.9)

Number of healthcare visit

 0

262,249 (63.2)

1,474,064 (76.0)

 1

63,749 (15.4)

231,583 (11.9)

 2–3

48,551 (11.7)

144,925 (7.5)

  ≥ 4

40,543 (9.8)

88,643 (4.6)

Charlson comorbidity index

 0

336,937 (81.2)

1,732,278 (89.3)

 1

58,881 (14.2)

165,699 (8.5)

  ≥ 2

19,274 (4.6)

41,238 (2.1)

History before start of follow-up

 GI disease

192,744 (46.4)

269,048 (13.9)

 Endoscopy

129,815 (31.3)

40,494 (2.1)

 Colectomy or proctocolectomy

283 (0.1)

275 (0.0)

Follow-up years since biopsy

 Median (IQR)

10.9 (5.7, 17.8)

11.1 (5.8, 18.2)

 0.5–1 y

5460 (1.3)

22,315 (1.2)

 1–4.9 y

82,598 (19.9)

378,898 (19.5)

 5–9.9 y

102,809 (24.8)

471,651 (24.3)

 10–19.9 y

147,159 (35.5)

687,486 (35.5)

 20–29.9 y

64,044 (15.4)

313,228 (16.2)

  ≥ 30 y

13,022 (3.1)

65,637 (3.4)