Table 3.

BMI-stratified logistic regression estimates of polyps according to total, soluble and insoluble dietary fibre quartiles (n=2194)

Polyps	BMI									pinteraction
	Normal weight (n=732)			Overweight (n=974)			Obese (n=488)
	Controls	Cases	Adjusted* OR (95% CI)	Controls	Cases	Adjusted* OR (95% CI)	Controls	Cases	Adjusted* OR (95% CI)
Total fibre†
Q1	113	66	1.0 (ref.)	139	88	1.0 (ref.)	68	74	1.0 (ref.)	0.02
Q2	124	49	0.62 (0.39 to1.01)	149	109	1.15 (0.78 to1.70)	57	57	0.84 (0.49 to1.45)
Q3	118	62	0.80 (0.49 to1.31)	158	96	0.96 (0.63 to1.46)	58	57	0.76 (0.42 to1.36)
Q4	132	68	0.71 (0.40 to1.27)	142	93	1.06 (0.64 to1.75)	73	44	0.41 (0.20 to0.83)
			Ptrend=0.39			Ptrend=0.91			Ptrend=0.02
Soluble fibre‡
Q1	117	62	1.0 (ref.)	132	93	1.0 (ref.)	65	78	1.0 (ref.)	0.01
Q2	128	56	0.75 (0.47 to1.22)	153	103	0.89 (0.60 to1.32)	60	51	0.57 (0.33 to0.99)
Q3	117	65	0.89 (0.54 to1.45)	151	97	0.81 (0.53 to1.24)	53	62	0.75 (0.41 to1.35)
Q4	125	62	0.74 (0.41 to1.35)	152	93	0.79 (0.47 to1.33)	78	41	0.26 (0.12 to0.56)
			Ptrend=0.48			Ptrend=0.32			Ptrend<0.01
Insoluble fibre§
Q1	112	63	1.0 (ref.)	142	89	1.0 (ref.)	66	75	1.0 (ref.)	0.02
Q2	129	48	0.61 (0.38 to0.99)	145	105	1.19 (0.80 to1.77)	59	59	0.85 (0.49 to1.46)
Q3	112	69	1.01 (0.62 to1.65)	158	98	1.04 (0.69 to1.58)	57	54	0.67 (0.37 to1.21)
Q4	134	65	0.67 (0.38 to1.21)	143	94	1.14 (0.70 to1.86)	74	44	0.39 (0.19 to0.77)
			Ptrend=0.51			Ptrend=0.79			Ptrend<0.01

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

†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.

BMI, body mass index; Ref., reference group.