Table 3.

Colorectal cancer subsites by OC duration among 88,691 NHSI and 93,080 NHSII participants

Duration of OC use (years)Never≤1>1 to <2≥2 to <5≥5 to <1010+
N cases
HR (95% CI)aPtrend
NHSI
Colorectal1,1191956715515474
ref.1.07 (0.91–1.25)1.09 (0.85–1.41)0.96 (0.80–1.15)0.99 (0.83–1.18)0.98 (0.77–1.25)0.69
 Colon8771595011912357
ref.1.14 (0.96–1.36)1.07 (0.80–1.44)0.98 (0.80–1.20)1.02 (0.84–1.25)0.98 (0.74–1.28)0.79
  Proximal colon51110530597939
ref.1.34 (1.08–1.67)1.20 (0.82–1.74)0.89 (0.67–1.17)1.19 (0.93–1.52)1.17 (0.84–1.63)0.36
  Distal colon3405317544215
ref.0.93 (0.69–1.25)0.85 (0.52–1.40)1.05 (0.78–1.42)0.84 (0.60–1.17)0.64 (0.38–1.09)0.09
 Rectum2423617363117
ref.0.84 (0.59–1.21)1.13 (0.68–1.89)0.89 (0.61–1.29)0.86 (0.59–1.27)1.01 (0.61–1.66)0.72
NHSII
Duration of OC use (years)Never≤1>1 to <55+
Colorectal59286851
ref.1.13 (0.71–1.81)1.31 (0.90–1.91)0.86 (0.58–1.28)0.23
 Colon47204329
ref.1.02 (0.59–1.75)1.04 (0.67–1.62)0.61 (0.38–0.99)0.02
  Proximal colon2682113
ref.0.75 (0.33–1.69)0.96 (0.53–1.74)0.51 (0.26–1.00)0.05
  Distal colon21122115
ref.1.34 (0.64–2.78)1.11 (0.59–2.08)0.71 (0.36–1.40)0.15
 Rectum1282522
ref.1.58 (0.64–3.94)2.37 (1.16–4.81)1.86 (0.91–3.82)0.24
  • aAdjusted for age, BMI, height, physical activity, smoking, processed and red meat, folate, calcium, total energy intake, aspirin use, alcohol, age at first birth, parity, HT use, family history, and previous endoscopy screening.