Table 3.

RRs with 95% CIs for colorectal cancer by quartile of energy-adjusted intake of soluble and insoluble dietary fiber in the JACC Study, 1988 to 1997 (n = 43,115)

Quartiles of energy-adjusted intake of soluble or insoluble dietary fiber
Ptrend
1234
Soluble dietary fiber (g/day)1.2 ± 0.41.7 ± 0.42.1 ± 0.42.6 ± 0.5
Person-years79,32580,94482,89184,113
Colorectal cancer
    Number of cancer cases98106113126
    Age- and sex-adjusted RR (95% CI)1.000.97 (0.74-1.28)0.94 (0.71-1.23)0.90 (0.68-1.17)0.40
    Multivariate RR (95% CI)*1.000.85 (0.64-1.14)0.76 (0.55-1.04)0.67 (0.47-0.95)0.022
Colon cancer
    Number of cancer cases70776480
    Age- and sex-adjusted RR (95% CI)1.000.98 (0.71-1.36)0.73 (0.52-1.03)0.77 (0.56-1.07)0.049
    Multivariate RR (95% CI)*1.000.85 (0.61-1.20)0.58 (0.39-0.85)0.55 (0.36-0.84)0.002
Rectal cancer
    Number of cancer cases27224944
    Age- and sex-adjusted RR (95% CI)1.000.73 (0.42-1.29)1.50 (0.94-2.41)1.19 (0.73-1.93)0.13
    Multivariate RR (95% CI)*1.000.66 (0.37-1.19)1.26 (0.73-2.19)0.94 (0.49-1.78)0.64
Insoluble dietary fiber (g/day)5.3 ± 1.57.0 ± 1.58.2 ± 1.89.6 ± 2.1
Person-years78,63281,09383,28384,266
Colorectal cancer
    Number of cancer cases93120102128
    Age- and sex-adjusted RR (95% CI)1.001.12 (0.85-1.47)0.86 (0.65-1.14)0.91 (0.70-1.20)0.21
    Multivariate RR (95% CI)*1.001.06 (0.80-1.40)0.77 (0.56-1.05)0.77 (0.55-1.08)0.041
Colon cancer
    Number of cancer cases67865880
    Age- and sex-adjusted RR (95% CI)1.001.11 (0.80-1.52)0.67 (0.47-0.95)0.77 (0.55-1.07)0.016
    Multivariate RR (95% CI)*1.001.05 (0.75-1.46)0.59 (0.40-0.88)0.63 (0.42-0.96)0.004
Rectal cancer
    Number of cancer cases25294246
    Age- and sex-adjusted RR (95% CI)1.001.02 (0.59-1.74)1.35 (0.82-2.22)1.29 (0.78-2.12)0.20
    Multivariate RR (95% CI)*1.000.95 (0.55-1.66)1.20 (0.68-2.09)1.08 (0.58-2.02)0.66
  • NOTE: Plus-minus values are means ± SD.

  • * The RRs were adjusted for age (as a continuous variable), sex, area (Hokkaido and Tohoku, Kanto, Chubu, Kinki, Chugoku, or Kyushu), educational level (attended school until the age of ≤15, 16-18, or ≥19 y), family history of colorectal cancer in parents and/or siblings (yes or no), alcohol consumption [never drink, ex-drinkers, or current drinkers who consume <2 or ≥2 Japanese drinks (<46 or ≥46 g of ethanol) per day for men, and never drink, ex-drinkers, or current drinkers for women], smoking (never smoke, ex-smokers, or current smokers), BMI (<20.0, 20.0-24.9, or ≥25.0 kg/m2), daily walking habits (≤30 or >30 min/day), exercise (seldom or never, or 1-2, 3-4, or ≥5 h a week), sedentary work (yes or no), consumption of beef (almost never, 1-2 times a month, 1-2 times a week, ≥3 times a week) and pork (almost never, 1-2 times a month, 1-2 times a week, ≥3 times a week), energy intake (as a continuous variable), and energy-adjusted intakes of folate, calcium, and vitamin D (sex-specific quartile for each).