Table 3.

Multivariate-adjusted HRs (95% CI) for subtypes of incident colorectal cancer in relation to history of allergy, IWHS 1997-2004

Allergy characteristicsNo. casesColon cancer,* HR (95% CI)No. casesProximal colon cancer,* HR (95% CI)No. casesDistal colon cancer,* HR (95% CI)No. casesRectal cancer,* HR (95% CI)
No allergy2591 (reference)1861 (reference)651 (reference)531 (reference)
Allergy860.77 (0.60-0.99)640.78 (0.58-1.05)200.76 (0.45-1.26)160.63 (0.36-1.12)
Except asthma570.71 (0.53-0.95)370.63 (0.43-0.90)180.94 (0.55-1.60)140.78 (0.43-1.41)
Asthma240.90 (0.59-1.39)221.13 (0.72-1.75)20.33 (0.08-1.37)20.32 (0.08-1.31)
Hay fever260.88 (0.58-1.34)200.92 (0.57-1.50)40.58 (0.21-1.61)30.46 (0.14-1.47)
Skin allergies310.70 (0.48-1.03)230.71 (0.45-1.10)80.79 (0.38-1.65)60.60 (0.26-1.41)
Other allergies430.71 (0.51-0.98)310.71 (0.48-1.04)110.75 (0.39-1.42)80.54 (0.26-1.15)
No. allergies in a person
    02591 (reference)1861 (reference)651 (reference)531 (reference)
    1440.74 (0.54-1.03)290.67 (0.45-1.00)140.98 (0.55-1.75)110.82 (0.43-1.58)
    ≥2190.61 (0.38-0.99)130.57 (0.32-1.03)50.68 (0.27-1.71)30.41 (0.13-1.33)
P trend0.040.060.420.14
  • * Total number of women with colon and rectal cancers (n = 414) is larger than the number of women with colorectal cancer (n = 410) because 4 women had both colon and rectal cancers. Colon cancer (n = 345) includes proximal (n = 250), distal (n = 85), not otherwise specified (n = 7), and overlapping lesion of colon (n = 3).

  • Adjusted for age, pack-years, total energy intake, calcium, red meat, and multivitamin use in 1986, BMI in 1997, and diabetes and HRT use before 1997.

  • For this analysis, only women who answered all four specific allergy questions were included.