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. 2022 Jul 27;9(1):e000947. doi: 10.1136/bmjgast-2022-000947

Table 4.

Unadjusted incidence of gastric and colon cancers stratified by iron deficiency and symptoms in 9783 anaemic women aged 20–49 years

Sample size (n) Cancer* (n) NND one cancer
(95% CI)
Incidence/1000 patients
(95% CI)
P value
Gastric cancer, age 20–49 years
Random 9783 6 1631 (748 to 3558) 0.61 (0.28 to 1.34)
Iron deficiency
 (+) 6627 4 1657 (645 to 4260) 0.60 (0.23 to 1.55) >0.99
 (−) 3156 2 1578 (434 to 5754) 0.63 (0.17 to 2.31)
Any symptoms
 Yes 5078 6 847 (389 to 1847) 1.18 (0.54 to 2.58) 0.03
 No 4705 0
UGI symptoms
 Yes 3705 5 741 (317 to 1735) 1.35 (0.58 to 3.16) 0.03
 No 6078 1 6078 (1074 to 34,431) 0.16 (0.03 to 0.93)
Dysphagia
 Yes 286 2 143 (40 to 521) 6.99 (1.92 to 25.10) 0.01
 No 9497 4 2375 (924 to 6105) 0.42 (0.16 to 1.08)
Weight loss
 Yes 220 3 74 (26 to 216) 13.6 (4.65 to 39.3) <0.001
 No 9563 3 3188 (1085 to 9373) 0.31 (0.11 to 0.92)
Any gastric symptoms: UGI and/or dysphagia
 All women
 Yes 3793 5 759 (325 to 1776) 1.32 (0.56 to 3.08) 0.04
 No 5990 1 5990 (1059 to 33,933) 0.17 (0.03 to 0.95)
 Iron deficient (+) women (n=6627)
 Yes 2563 4 641 (250 to 1648) 1.56 (0.61 to 4.01) 0.02
 No 4064 0
 Iron deficient (−) women (n=3156)
 Yes 1230 1 1230 (218 to 6968) 0.81 (0.14 to 4.59) >0.99
 No 1926 1 1926 (341 to 10,910) 0.52 (0.09 to 2.94)
Colon cancer, age 20–49 years
Random 9783 26 377 (257 to 552) 2.66 (1.81 to 3.89)
Iron deficiency
 (+) 6627 18 369 (234 to 582) 2.72 (1.72 to 4.29) >0.99
 (−) 3156 8 395 (201 to 779) 2.53 (1.29 to 4.99)
Any symptoms
 Yes 5078 21 242 (159 to 370) 4.14 (2.71 to 6.31) 0.003
 No 4705 5 941 (403 to 2203) 1.28 (0.45 to 2.49)
LGI symptoms
 Yes 2471 16 155 (96 to 251) 6.48 (3.99 to 10.50) <0.001
 No 7312 10 732 (398 to 1346) 1.37 (0.74 to 2.52)
Rectal bleed
 Yes 577 10 58 (32 to 106) 17.30 (9.44 to 31.60) <0.001
 No 9206 16 576 (355 to 935) 1.74 (1.07 to 2.82)
Weight loss
 Yes 220 1 220 (40 to 1246) 4.55 (0.80 to 25.30) 0.48
 No 9563 25 383 (260 to 565) 2.61 (1.77 to 3.86)
Any colon symptoms: LGI and/or rectal bleed
 All women
 Yes 2793 19 147 (95 to 230) 6.80 (4.36 to 10.60) <0.001
 No 6990 7 999 (485 to 2062) 1.00 (0.49 to 2.07)
 Iron deficient (+) women (n=6627)
 Yes 1849 14 133 (79 to 222) 7.57 (4.52 to 12.70) <0.001
 No 4778 4 1195 (465 to 3072) 0.84 (0.33 to 2.15)
 Iron deficient (−) women (n=3156)
 Yes 944 5 189 (82 to 442) 5.30 (2.26 to 12.30) 0.02
 No 2212 3 738 (252 to 2168) 1.36 (0.46 to 3.98)

Comparisons were made using Fisher’s exact tests.

*Within 5 years of the iron deficiency test date.

(−), negative; (+), positive; –, not applicable; LGI, lower gastrointestinal; NND, number needed to detect; UGI, upper gastrointestinal.