Table 1

Baseline characteristics of colorectal cancer screening population by outcome of polyps or high-risk adenomas (n=2548)

nPolypsHigh-risk adenomas
No
n=1450 (57%)
Yes
n=1098 (43%)
No
n=2359 (93%)
Yes
n=189 (7%)
Demographics
 Age (years)
  <403427 (2%)7 (1%)33 (1%)1 (1%)
  40–4910270 (5%)32 (3%)96 (4%)6 (3%)
  50–591169713 (49%)456 (42%)1104 (47%)65 (34%)
  60+12431450 (44%)603 (55%)1126 (48%)117 (62%)
p*<0.01p<0.01
 Sex
  Female1163775 (63%)388 (35%)1113 (47%)50 (26%)
  Male1385675 (47%)710 (65%)1246 (53%)139 (74%)
p<0.01p<0.01
 Ethnicity
  Non-white358213 (15%)145 (13%)328 (14%)30 (16%)
  White21901237 (85%)953 (87%)2031 (86%)159 (84%)
p=0.29p=0.45
 BMI (kg/m2)
  <25853540 (37%)313 (29%)810 (34%)43 (23%)
  25–301129638 (44%)491 (45%)1035 (44%)94 (50%)
  30+566272 (19%)294 (27%)514 (22%)52 (28%)
p<0.01p<0.01
Family and personal health
 Smoking
  Never1339834 (58%)505 (46%)1261 (53%)78 (41%)
  Former1011535 (37%)476 (43%)930 (39%)81 (43%)
  Current19881 (6%)117 (11%)168 (7%)30 (16%)
p<0.01p<0.01
 Reason for colonoscopy
  Average risk20671223 (84%)844 (77%)1945 (82%)122 (65%)
  FIT+/FOBT+20966 (5%)143 (13%)161 (7%)48 (25%)
  Family history272161 (11%)111 (10%)253 (11%)19 (10%)
p<0.01p<0.01
Lifetime NSAIDs
  NSAID use
   Never946513 (35%)433 (39%)850 (36%)96 (51%)
   Ever1135937 (65%)665 (61%)1509 (64%)93 (49%)
p=0.04p<0.01
 NSAID use frequency
  No regular use946513 (43%)433 (47%)850 (43%)96 (60%)
  Monthly406245 (20%)161 (18%)383 (20%)23 (14%)
  Weekly292162 (14%)130 (14%)273 (14%)19 (12%)
  Daily465272 (23%)193 (21%)442 (23%)23 (14%)
p=0.15p<0.01
 Daily dose-years of NSAID use†
   None9460 (0)0 (0)0 (0)0 (0)
   T13330.06 (0.06)0.05 (0.05)0.06 (0.06)0.06 (0.05)
   T26690.45 (0.21)0.44 (0.19)0.45 (0.20)0.47 (0.22)
   T3 (high)6004.53 (6.70)4.77 (5.84)4.60 (6.23)5.27 (8.43)
p=0.05p<0.01
Dietary fibre intake
 Total fibre‡§
  Q1 (low)54811.01 (2.58)10.51 (2.65)10.87 (2.60)10.00 (2.78)
  Q254516.75 (1.41)16.98 (1.34)16.84 (1.39)16.85 (1.34)
  Q354922.14 (1.91)22.04 (1.75)22.10 (1.85)22.11 (1.90)
  Q4 (high)55233.88 (8.23)33.59 (8.89)33.83 (8.54)32.58 (6.67)
p=0.51p=0.09
 Soluble fibre‡¶
  Q1 (low)5473.69 (0.86)3.61 (0.87)3.68 (0.85)3.38 (0.99)
  Q25515.61 (0.46)5.66 (0.46)5.63 (0.46)5.56 (0.49)
  Q35457.32 (0.59)7.33 (0.56)7.32 (0.58)7.35 (0.53)
  Q4 (high)55111.17 (2.79)11.32 (3.20)11.22 (2.96)11.16 (2.45)
p=0.08p=0.06
 Insoluble fibre‡**
  Q1 (low)5477.16 (1.68)6.79 (1.77)7.04 (1.71)6.61 (1.83)
  Q254511.02 (0.99)11.14 (0.89)11.06 (0.95)11.10 (0.90)
  Q354814.72 (1.23)14.70 (1.22)14.72 (1.22)14.63 (1.28)
  Q4 (high)55422.67 (5.54)22.58 (5.79)22.69 (5.69)21.55 (4.08)
p=0.39p=0.09
  • *p-Values from Pearson’s χ2 test of independence.

  • †Tertile cut-offs for NSAID use were: 4.5×10−5–00.164, 0.165–0.894 and ≥0.904 daily dose-years.

  • ‡Missing questionnaire data on fibre intake lead to reduced sample size (n=2194).

  • §Quartile cut-offs for total dietary fibre intake were: ≤14.3, 14.31–19.14, 19.15–25.51 and ≥25.52 g/day.

  • ¶Quartile cut-offs for dietary insoluble fibre intake were: ≤9.36, 9.37–12.72, 12.73–16.96 and ≥16.98 g/day.

  • **Quartile cut-offs for dietary soluble fibre intake were: ≤4.83, 4.84–6.42, 6.43–8.44 and ≥8.45 g/day.

  • BMI, body mass index; FIT, faecal immunochemical test; FOBT, faecal occult blood test; NSAIDs, non-steroidal anti-inflammatory drugs.