Table 1.

Adjusted RRs of CRC in relation to quintiles of GI and GL, Iowa Women's Health Study (1986-2000)

FactorQuintile
P for trend
12345
CRC (n events = 954)
GI<81.081.0-84.184.2-86.586.6-89.3>89.3
    n events186165195195213
    RR, adjusted for age and energy1.00.871.021.001.080.18
    95% CI0.70-1.070.83-1.250.82-1.230.89-1.32
    RR, multiply-adjusted*1.00.861.031.041.080.15
    95% CI0.69-1.060.84-1.260.84-1.270.88-1.32
GL<146147-163164-176177-192>193
    n events175197190203189
    RR, adjusted for age and energy1.01.050.981.040.980.86
    95% CI0.85-1.290.80-1.210.85-1.280.80-1.21
    RR, multiply-adjusted*1.01.051.041.121.090.33
    95% CI0.85-1.300.84-1.290.91-1.380.88-1.35
GL by BMI
    BMI (<25 kg/m2)
        n events7052587172
        RR, multiply-adjusted1.00.720.831.030.940.57
        95% CI0.50-1.050.58-1.190.73-1.450.66-1.33
    BMI (25-30 kg/m2)
        n events7364857268
        RR, multiply-adjusted1.00.791.090.900.850.59
        95% CI0.56-1.110.79-1.500.65-1.250.60-1.18
    BMI (≥30 kg/m2)
        n events4349525273
        RR, multiply-adjusted1.01.191.201.241.660.02
        95% CI0.78-1.790.80-1.810.83-1.861.13-2.43
    BMI (≥30 kg/m2), nondiabetics
        n events3540444564
        RR, multiply-adjusted1.01.171.221.301.82<0.01
        95% CI0.74-1.850.78-1.920.83-2.021.20-2.76
GL by BMI
    BMI (<25 kg/m2)
        n events6069607559
        RR, multiply-adjusted1.01.120.941.090.790.25
        95% CI0.78-1.610.65-1.370.76-1.560.54-1.16
    BMI (25-30 kg/m2)
        n events7579716374
        RR, multiply-adjusted1.00.920.830.780.990.63
        95% CI0.66-1.280.60-1.170.55-1.110.71-1.37
    BMI (≥30 kg/m2)
        n events4049596556
        RR, multiply-adjusted1.01.171.561.781.79<0.01
        95% CI0.77-1.791.03-2.351.19-2.661.19-2.70
    BMI (≥30 kg/m2), nondiabetics
        n events2742496050
        RR, multiply-adjusted1.01.471.852.372.24<0.01
        95% CI0.91-2.401.15-3.001.49-3.771.39-3.60
  • * Adjusted for age (continuous), energy (quintiles), activity level (high, medium, low), multivitamin use (yes, no), diabetes (yes, no), smoking (pack-years), BMI (quintiles), and waist/hip ratio (quintiles).

  • Adjusted for all characteristics listed above, except adjusted for BMI (continuous) within BMI quintiles.