Table 2.

Dietary insulin load, dietary insulin index, and risk of colorectal cancer

Dietary insulin load (quintiles) P trend
12345
NHS
  Quintile median547608646683745
  Person-years419,379425,767425,292428,077426,756
Colorectal
  No. of cases297291298269265
  Age-adjusted1.01.00 (0.85–1.17)1.03 (0.88–1.21)0.92 (0.78–1.09)0.87 (0.73–1.02)0.03
  Multivariatea1.01.02 (0.86–1.21)1.07 (0.90–1.27)0.97 (0.81–1.16)0.92 (0.77–1.11)0.17
Colon
  No. of cases224219230201193
  Age-adjusted1.01.00 (0.83–1.20)1.05 (0.88–1.27)0.92 (0.76–1.11)0.83 (0.69–1.01)0.03
  Multivariatea1.01.00 (0.83–1.22)1.06 (0.87–1.29)0.94 (0.76–1.15)0.86 (0.70–1.07)0.09
Rectum
  No. of cases6466636466
  Age-adjusted1.01.05 (0.74–1.48)1.01 (0.71–1.43)1.01 (0.72–1.44)1.01 (0.72–1.43)0.66
  Multivariatea1.01.16 (0.81–1.66)1.16 (0.80–1.69)1.19 (0.81–1.73)1.21 (0.82–1.77)0.63
HPFS
  Quintile median673757807855930
  Person-years159,437165,231163,027165,223166,122
Colorectal
  No. of cases254217213200177
  Age-adjusted1.00.88 (0.73–1.05)0.89 (0.74–1.07)0.81 (0.67–0.97)0.72 (0.59–0.87)<0.001
  Multivariatea1.00.96 (0.79–1.16)1.02 (0.84–1.25)0.97 (0.78–1.19)0.90 (0.72–1.12)0.29
Colon
  No. of cases164136139143112
  Age-adjusted1.00.86 (0.69–1.09)0.90 (0.71–1.13)0.90 (0.71–1.12)0.70 (0.55–0.89)0.01
  Multivariatea1.00.93 (0.73–1.18)1.00 (0.78–1.29)1.04 (0.81–1.35)0.85 (0.65–1.12)0.34
Rectum
  No. of cases5151453144
  Age-adjusted1.01.02 (0.69–1.50)0.98 (0.66–1.47)0.63 (0.40–0.98)0.92 (0.61–1.38)0.20
  Multivariatea1.01.10 (0.73–1.66)1.13 (0.73–1.76)0.74 (0.45–1.21)1.11 (0.69–1.77)0.81
NHS and HPFS, multivariatea,b
sp;  Colorectal1.00.99 (0.87–1.12)1.05 (0.92–1.19)0.97 (0.84–1.11)0.91 (0.79–1.05)0.09
  Colon1.00.97 (0.83–1.13)1.04 (0.89–1.21)0.98 (0.83–1.15)0.86 (0.72–1.01)0.06
  Rectum1.01.12 (0.86–1.47)1.14 (0.86–1.52)0.95 (0.58–1.54)1.15 (0.86–1.55)0.89
Dietary insulin index (quintiles) P trend
1 2 3 4 5
NHS
  Quintile median3438404246
  Person-years418,534425,664425,518427,728427,828
Colorectal
  No. of cases  304284282269281
  Age-adjusted1.00.95 (0.80–1.11)0.95 (0.81–1.12)0.90 (0.75–1.05)0.90 (0.76–1.06)0.05
  Multivariatea1.00.96 (0.81–1.14)0.98 (0.82–1.16)0.92 (0.77–1.10)0.95 (0.79–1.13)0.22
Colon
  No. of cases222215224201205
  Age-adjusted1.00.98 (0.81–1.19)1.05 (0.87–1.26)0.91 (0.75–1.11)0.90 (0.74–1.09)0.06
  Multivariatea1.00.99 (0.81–1.20)1.05 (0.86–1.28)0.93 (0.75–1.15)0.93 (0.75–1.15)0.13

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