Table 2.

Dietary insulin load, dietary insulin index, and risk of colorectal cancer (Cont'd)

Dietary insulin load (quintiles)Ptrend
12345
Rectum
  No. of cases7166545973
  Age-adjusted1.00.93 (0.67–1.31)0.77 (0.54–1.09)0.82 (0.58–1.16)0.99 (0.72–1.38)0.78
  Multivariatea1.01.01 (0.71–1.43)0.85 (0.58–1.24)0.92 (0.63–1.35)1.14 (0.79–1.66)0.50
HPFS
  Quintile median3438414347
  Person-years159,133163,853164,305166,404165,344
Colorectal
  No. of cases252223213196177
  Age-adjusted1.00.90 (0.75–1.08)0.89 (0.74–1.07)0.80 (0.67–0.97)0.74 (0.61–0.90)0.001
  Multivariatea1.00.99 (0.82–1.20)1.03 (0.84–1.26)0.97 (0.78–1.19)0.92 (0.74–1.15)0.41
Colon
  No. of cases165140138136115
  Age-adjusted1.00.87 (0.69–1.09)0.88 (0.70–1.11)0.85 (0.68–1.07)0.73 (0.57–0.93)0.01
  Multivariatea1.00.94 (0.74–1.19)0.98 (0.77–1.26)0.99 (0.77–1.28)0.88 (0.67–1.16)0.44
Rectum
  No. of cases5151433641
  Age-adjusted1.01.04 (0.70–1.53)0.91 (0.60–1.37)0.74 (0.48–1.14)0.87 (0.58–1.32)0.26
  Multivariatea1.01.12 (0.74–1.69)1.05 (0.67–1.64)0.87 (0.54–1.41)1.05 (0.65–1.69)0.95
NHS and HPFS, multivariate a,b
  Colorectal1.00.97 (0.86–1.10)1.00 (0.88–1.14)0.94 (0.82–1.07)0.93 (0.81–1.08)0.14
  Colon1.00.96 (0.83–1.12)1.03 (0.88–1.20)0.95 (0.81–1.12)0.91 (0.77–1.07)0.09
  Rectum1.01.05 (0.80–1.37)0.92 (0.69–1.23)0.89 (0.66–1.20)1.09 (0.81–1.47)0.66

NOTE: Dietary insulin load and dietary insulin index were measured at baseline, 1980 for NHS and 1986 for HPFS.

  • aAdjusted for age, body mass index (kg/m2 in quintiles), physical activity (quintiles), family history of colorectal cancer (yes/no), lower endoscopy (yes/no), ulcerative colitis (yes/no), history of polyps (yes/no), aspirin use (never, 1–3, 4–7, ≥ 8 tablets/wk), multivitamin use (yes/no), pack-years of smoking (never smoker, 1–9, 10–24, 25–44, and ≥ 45 pack-years), alcohol intake (NHS: never, 0.1–4.9, 5–14.9, ≥ 15 g/d; HPFS: never, 0.1–9.9, 10–19.9, ≥ 20 g/d), and energy intake (quintiles).

  • bNHS and HPFS were pooled using random-effects models.