Table 3

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

PolypsBMIpinteraction
Normal weight (n=732)Overweight (n=974)Obese (n=488)
ControlsCasesAdjusted*
OR (95% CI)
ControlsCasesAdjusted*
OR (95% CI)
ControlsCasesAdjusted*
OR (95% CI)
 Total fibre†
 Q1113661.0 (ref.)139881.0 (ref.)68741.0 (ref.)0.02
 Q2124490.62 (0.39 to1.01)1491091.15 (0.78 to1.70)57570.84 (0.49 to1.45)
 Q3118620.80 (0.49 to1.31)158960.96 (0.63 to1.46)58570.76 (0.42 to1.36)
 Q4132680.71 (0.40 to1.27)142931.06 (0.64 to1.75)73440.41 (0.20 to0.83)
Ptrend=0.39Ptrend=0.91Ptrend=0.02
 Soluble fibre‡
 Q1117621.0 (ref.)132931.0 (ref.)65781.0 (ref.)0.01
 Q2128560.75 (0.47 to1.22)1531030.89 (0.60 to1.32)60510.57 (0.33 to0.99)
 Q3117650.89 (0.54 to1.45)151970.81 (0.53 to1.24)53620.75 (0.41 to1.35)
 Q4125620.74 (0.41 to1.35)152930.79 (0.47 to1.33)78410.26 (0.12 to0.56)
Ptrend=0.48Ptrend=0.32Ptrend<0.01
 Insoluble fibre§
 Q1112631.0 (ref.)142891.0 (ref.)66751.0 (ref.)0.02
 Q2129480.61 (0.38 to0.99)1451051.19 (0.80 to1.77)59590.85 (0.49 to1.46)
 Q3112691.01 (0.62 to1.65)158981.04 (0.69 to1.58)57540.67 (0.37 to1.21)
 Q4134650.67 (0.38 to1.21)143941.14 (0.70 to1.86)74440.39 (0.19 to0.77)
Ptrend=0.51Ptrend=0.79Ptrend<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.