Table 2.

Logistic regression estimates of colon outcomes according to quartiles of total dietary, soluble and insoluble fibres and measures of non-steroidal anti-inflammatory drug use (n_fibre=2194; n_NSAID=2548)

	Polyps				High-risk adenomatous polyps
	Controls	Cases	Crude OR (95% CI)	Adjusted* OR (95% CI)	Controls	Cases	Crude OR (95% CI)	Adjusted* OR (95% CI)
Total dietary fibre†
Q1 (low)	320	228	1.0 (ref.)	1.0 (ref.)	506	42	1.0 (ref.)	1.0 (ref.)
Q2	330	215	0.91 (0.72 to 1.16)	0.88 (0.68 to 1.14)	509	36	0.85 (0.54 to 1.35)	0.82 (0.50 to 1.34)
Q3	334	215	0.90 (0.71 to 1.15)	0.86 (0.65 to 1.13)	510	39	0.92 (0.59 to 1.45)	0.93 (0.53 to 1.51)
Q4 (high)	347	205	0.83 (0.65 to 1.06)	0.77 (0.56 to 1.07)	529	23	0.52 (0.31 to 0.88)	0.46 (0.23 to 0.93)
			Ptrend=0.14	Ptrend=0.14			Ptrend=0.03	Ptrend=0.08
Soluble fibre‡
Q1 (low)	314	233	1.0 (ref.)	1.0 (ref.)	506	41	1.0 (ref.)	1.0 (ref.)
Q2	341	210	0.83 (0.65 to 1.06)	0.76 (0.59 to 0.99)	517	34	0.81 (0.51 to 1.30)	0.75 (0.45 to 1.25)
Q3	321	224	0.94 (0.74 to 1.20)	0.83 (0.63 to 1.09)	503	42	1.03 (0.66 to 1.61)	0.96 (0.57 to 1.63)
Q4 (high)	355	196	0.74 (0.58 to 0.95)	0.62 (0.44 to 0.88)	528	23	0.54 (0.32 to 0.91)	0.48 (0.23 to 0.98)
			Ptrend=0.05	Ptrend=0.02			Ptrend=0.07	Ptrend=0.16
Insoluble fibre§
Q1 (low)	320	227	1.0 (ref.)	1.0 (ref.)	503	44	1.0 (ref.)	1.0 (ref.)
Q2	333	212	0.90 (0.70 to 1.14)	0.89 (0.68 to 1.15)	510	35	0.78 (0.49 to 1.24)	0.80 (0.49 to 1.31)
Q3	327	221	0.95 (0.75 to 1.21)	0.94 (0.71 to 1.23)	511	37	0.83 (0.53 to 1.30)	0.84 (0.50 to 1.41)
Q4 (high)	351	203	0.82 (0.64 to 1.04)	0.77 (0.56 to 1.07)	530	24	0.52 (0.31 to 0.86)	0.48 (0.25 to 0.93)
			Ptrend=0.16	Ptrend=0.19			Ptrend=0.02	Ptrend=0.06
Ever used NSAIDs
No	513	433	1.0 (ref.)	1.0 (ref.)	850	96	1.0 (ref.)	1.0 (ref.)
Yes	937	665	0.84 (0.72 to 0.99)	0.98 (0.83 to 1.16)	1509	93	0.55 (0.41 to 0.73)	0.65 (0.47 to 0.89)
NSAID daily dose-years¶
None	513	433	1.0 (ref.)	1.0 (ref.)	850	96	1.0 (ref.)	1.0 (ref.)
T1	246	221	0.76 (0.61 to 0.94)	0.87 (0.69 to 1.09)	536	31	0.51 (0.34 to 0.78)	0.60 (0.39 to 0.92)
T2	279	224	0.95 (0.77 to 1.18)	1.12 (0.89 to 1.41)	469	34	0.64 (0.43 to 0.96)	0.76 (0.50 to 1.17)
T3 (high)	312	220	0.84 (0.67 to 1.04)	0.99 (0.79 to 1.25)	504	28	0.49 (0.32 to 0.76)	0.63 (0.40 to 1.00)
			Ptrend=0.21	Ptrend=0.58			Ptrend<0.01	Ptrend=0.03
NSAID use frequency
No regular use	513	433	1.0 (ref.)	1.0 (ref.)	850	96	1.0 (ref.)	1.0 (ref.)
Monthly	245	161	0.79 (0.64 to 0.99)	1.00 (0.79 to 1.26)	383	23	0.47 (0.30 to 0.74)	0.60 (0.37 to 0.95)
Weekly	162	130	0.89 (0.70 to 1.15)	1.06 (0.81 to 1.38)	273	19	0.56 (0.35 to 0.92)	0.72 (0.43 to 1.20)
Daily	272	193	0.84 (0.67 to 1.05)	0.91 (0.71 to 1.15)	442	23	0.46 (0.29 to 0.74)	0.53 (0.32 to 0.86)
			Ptrend=0.18	Ptrend=0.70			Ptrend<0.01	Ptrend=0.01

*Multivariate models adjusted for age, sex, BMI, smoking status (never, former and current), reason for colonoscopy (average risk, FOBT/FIT+ and family history) and family history of polyps (yes, no). Dietary fibre intake analyses additionally adjusted for total daily caloric intake.

†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 soluble fibre intake were: ≤4.83, 4.84–6.42, 6.43–8.44 and ≥8.45 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.

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

NSAID, non-steroidal anti-inflammatory drug; Ref., reference group.